* Makefile.am, regcomp.c, regex.c, regex_internal.c, regex_internal.h,

regexec.c: Add new regex files from glibc 2.3.1.

7 files changed, 8658 insertions, 0 deletions

diff --git a/util/ChangeLog b/util/ChangeLog
index e9caf465a..6dfab1fb1 100644
--- a/util/ChangeLog
+++ b/util/ChangeLog
@@ -1,3 +1,8 @@
+2002-10-19  David Shaw  <[email protected]>
+
+	* Makefile.am, regcomp.c, regex.c, regex_internal.c,
+	regex_internal.h, regexec.c: Add new regex files from glibc 2.3.1.
+
 2002-10-17  David Shaw  <[email protected]>
 
 	* http.c (connect_server): Try all A records for names with
diff --git a/util/Makefile.am b/util/Makefile.am
index a8d40da2d..b3c1e26e0 100644
--- a/util/Makefile.am
+++ b/util/Makefile.am
@@ -22,12 +22,15 @@ INCLUDES = -I.. -I$(top_srcdir)/include -I$(top_srcdir)/intl
 
 noinst_LIBRARIES = libutil.a
 
+EXTRA_libutil_a_SOURCES = regcomp.c regex.c regexec.c regex_internal.c regex_internal.h
 
 #libutil_a_LDFLAGS =
 libutil_a_SOURCES = g10u.c logger.c fileutil.c miscutil.c strgutil.c  \
 		     ttyio.c  argparse.c memory.c secmem.c errors.c iobuf.c \
 		     dotlock.c http.c simple-gettext.c w32reg.c
 
+libutil_a_DEPENDENCIES = @REGEX_O@
+libutil_a_LIBADD = @REGEX_O@
 
 http-test:  http.c
 	gcc -DHAVE_CONFIG_H -I. -I. -I.. $(INCLUDES) -g -Wall -DTEST \
diff --git a/util/regcomp.c b/util/regcomp.c
new file mode 100644
index 000000000..13cce2573
--- /dev/null
+++ b/util/regcomp.c
@@ -0,0 +1,3491 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email protected]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <assert.h>
+#include <ctype.h>
+#include <limits.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined HAVE_WCHAR_H || defined _LIBC
+# include <wchar.h>
+#endif /* HAVE_WCHAR_H || _LIBC */
+#if defined HAVE_WCTYPE_H || defined _LIBC
+# include <wctype.h>
+#endif /* HAVE_WCTYPE_H || _LIBC */
+
+/* In case that the system doesn't have isblank().  */
+#if !defined _LIBC && !defined HAVE_ISBLANK && !defined isblank
+# define isblank(ch) ((ch) == ' ' || (ch) == '\t')
+#endif
+
+#ifdef _LIBC
+# ifndef _RE_DEFINE_LOCALE_FUNCTIONS
+#  define _RE_DEFINE_LOCALE_FUNCTIONS 1
+#   include <locale/localeinfo.h>
+#   include <locale/elem-hash.h>
+#   include <locale/coll-lookup.h>
+# endif
+#endif
+
+/* This is for other GNU distributions with internationalized messages.  */
+#if HAVE_LIBINTL_H || defined _LIBC
+# include <libintl.h>
+# ifdef _LIBC
+#  undef gettext
+#  define gettext(msgid) \
+  INTUSE(__dcgettext) (INTUSE(_libc_intl_domainname), msgid, LC_MESSAGES)
+# endif
+#else
+# define gettext(msgid) (msgid)
+#endif
+
+#ifndef gettext_noop
+/* This define is so xgettext can find the internationalizable
+   strings.  */
+# define gettext_noop(String) String
+#endif
+
+#include "_regex.h" /* gnupg */
+#include "regex_internal.h"
+
+static reg_errcode_t re_compile_internal (regex_t *preg, const char * pattern,
+                                          int length, reg_syntax_t syntax);
+static void re_compile_fastmap_iter (regex_t *bufp,
+                                     const re_dfastate_t *init_state,
+                                     char *fastmap);
+static reg_errcode_t init_dfa (re_dfa_t *dfa, int pat_len);
+static reg_errcode_t init_word_char (re_dfa_t *dfa);
+#ifdef RE_ENABLE_I18N
+static void free_charset (re_charset_t *cset);
+#endif /* RE_ENABLE_I18N */
+static void free_workarea_compile (regex_t *preg);
+static reg_errcode_t create_initial_state (re_dfa_t *dfa);
+static reg_errcode_t analyze (re_dfa_t *dfa);
+static reg_errcode_t analyze_tree (re_dfa_t *dfa, bin_tree_t *node);
+static void calc_first (re_dfa_t *dfa, bin_tree_t *node);
+static void calc_next (re_dfa_t *dfa, bin_tree_t *node);
+static void calc_epsdest (re_dfa_t *dfa, bin_tree_t *node);
+static reg_errcode_t duplicate_node (int *new_idx, re_dfa_t *dfa, int org_idx,
+                                     unsigned int constraint);
+static reg_errcode_t calc_eclosure (re_dfa_t *dfa);
+static reg_errcode_t calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa,
+                                         int node, int root);
+static void calc_inveclosure (re_dfa_t *dfa);
+static int fetch_number (re_string_t *input, re_token_t *token,
+                         reg_syntax_t syntax);
+static re_token_t fetch_token (re_string_t *input, reg_syntax_t syntax);
+static int peek_token (re_token_t *token, re_string_t *input,
+                        reg_syntax_t syntax);
+static int peek_token_bracket (re_token_t *token, re_string_t *input,
+                               reg_syntax_t syntax);
+static bin_tree_t *parse (re_string_t *regexp, regex_t *preg,
+                          reg_syntax_t syntax, reg_errcode_t *err);
+static bin_tree_t *parse_reg_exp (re_string_t *regexp, regex_t *preg,
+                                  re_token_t *token, reg_syntax_t syntax,
+                                  int nest, reg_errcode_t *err);
+static bin_tree_t *parse_branch (re_string_t *regexp, regex_t *preg,
+                                 re_token_t *token, reg_syntax_t syntax,
+                                 int nest, reg_errcode_t *err);
+static bin_tree_t *parse_expression (re_string_t *regexp, regex_t *preg,
+                                     re_token_t *token, reg_syntax_t syntax,
+                                     int nest, reg_errcode_t *err);
+static bin_tree_t *parse_sub_exp (re_string_t *regexp, regex_t *preg,
+                                  re_token_t *token, reg_syntax_t syntax,
+                                  int nest, reg_errcode_t *err);
+static bin_tree_t *parse_dup_op (bin_tree_t *dup_elem, re_string_t *regexp,
+                                 re_dfa_t *dfa, re_token_t *token,
+                                 reg_syntax_t syntax, reg_errcode_t *err);
+static bin_tree_t *parse_bracket_exp (re_string_t *regexp, re_dfa_t *dfa,
+                                      re_token_t *token, reg_syntax_t syntax,
+                                      reg_errcode_t *err);
+static reg_errcode_t parse_bracket_element (bracket_elem_t *elem,
+                                            re_string_t *regexp,
+                                            re_token_t *token, int token_len,
+                                            re_dfa_t *dfa,
+                                            reg_syntax_t syntax);
+static reg_errcode_t parse_bracket_symbol (bracket_elem_t *elem,
+                                          re_string_t *regexp,
+                                          re_token_t *token);
+#ifndef _LIBC
+# ifdef RE_ENABLE_I18N
+static reg_errcode_t build_range_exp (re_bitset_ptr_t sbcset,
+                                      re_charset_t *mbcset, int *range_alloc,
+                                      bracket_elem_t *start_elem,
+                                      bracket_elem_t *end_elem);
+static reg_errcode_t build_collating_symbol (re_bitset_ptr_t sbcset,
+                                             re_charset_t *mbcset,
+                                             int *coll_sym_alloc,
+                                             const unsigned char *name);
+# else /* not RE_ENABLE_I18N */
+static reg_errcode_t build_range_exp (re_bitset_ptr_t sbcset,
+                                      bracket_elem_t *start_elem,
+                                      bracket_elem_t *end_elem);
+static reg_errcode_t build_collating_symbol (re_bitset_ptr_t sbcset,
+                                             const unsigned char *name);
+# endif /* not RE_ENABLE_I18N */
+#endif /* not _LIBC */
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t build_equiv_class (re_bitset_ptr_t sbcset,
+                                        re_charset_t *mbcset,
+                                        int *equiv_class_alloc,
+                                        const unsigned char *name);
+static reg_errcode_t build_charclass (re_bitset_ptr_t sbcset,
+                                      re_charset_t *mbcset,
+                                      int *char_class_alloc,
+                                      const unsigned char *class_name,
+                                      reg_syntax_t syntax);
+#else  /* not RE_ENABLE_I18N */
+static reg_errcode_t build_equiv_class (re_bitset_ptr_t sbcset,
+                                        const unsigned char *name);
+static reg_errcode_t build_charclass (re_bitset_ptr_t sbcset,
+                                      const unsigned char *class_name,
+                                      reg_syntax_t syntax);
+#endif /* not RE_ENABLE_I18N */
+static bin_tree_t *build_word_op (re_dfa_t *dfa, int not, reg_errcode_t *err);
+static void free_bin_tree (bin_tree_t *tree);
+static bin_tree_t *create_tree (bin_tree_t *left, bin_tree_t *right,
+                                re_token_type_t type, int index);
+static bin_tree_t *duplicate_tree (const bin_tree_t *src, re_dfa_t *dfa);
+
+/* This table gives an error message for each of the error codes listed
+   in regex.h.  Obviously the order here has to be same as there.
+   POSIX doesn't require that we do anything for REG_NOERROR,
+   but why not be nice?  */
+
+const char __re_error_msgid[] attribute_hidden =
+  {
+#define REG_NOERROR_IDX	0
+    gettext_noop ("Success")	/* REG_NOERROR */
+    "\0"
+#define REG_NOMATCH_IDX (REG_NOERROR_IDX + sizeof "Success")
+    gettext_noop ("No match")	/* REG_NOMATCH */
+    "\0"
+#define REG_BADPAT_IDX	(REG_NOMATCH_IDX + sizeof "No match")
+    gettext_noop ("Invalid regular expression") /* REG_BADPAT */
+    "\0"
+#define REG_ECOLLATE_IDX (REG_BADPAT_IDX + sizeof "Invalid regular expression")
+    gettext_noop ("Invalid collation character") /* REG_ECOLLATE */
+    "\0"
+#define REG_ECTYPE_IDX	(REG_ECOLLATE_IDX + sizeof "Invalid collation character")
+    gettext_noop ("Invalid character class name") /* REG_ECTYPE */
+    "\0"
+#define REG_EESCAPE_IDX	(REG_ECTYPE_IDX + sizeof "Invalid character class name")
+    gettext_noop ("Trailing backslash") /* REG_EESCAPE */
+    "\0"
+#define REG_ESUBREG_IDX	(REG_EESCAPE_IDX + sizeof "Trailing backslash")
+    gettext_noop ("Invalid back reference") /* REG_ESUBREG */
+    "\0"
+#define REG_EBRACK_IDX	(REG_ESUBREG_IDX + sizeof "Invalid back reference")
+    gettext_noop ("Unmatched [ or [^")	/* REG_EBRACK */
+    "\0"
+#define REG_EPAREN_IDX	(REG_EBRACK_IDX + sizeof "Unmatched [ or [^")
+    gettext_noop ("Unmatched ( or \\(") /* REG_EPAREN */
+    "\0"
+#define REG_EBRACE_IDX	(REG_EPAREN_IDX + sizeof "Unmatched ( or \\(")
+    gettext_noop ("Unmatched \\{") /* REG_EBRACE */
+    "\0"
+#define REG_BADBR_IDX	(REG_EBRACE_IDX + sizeof "Unmatched \\{")
+    gettext_noop ("Invalid content of \\{\\}") /* REG_BADBR */
+    "\0"
+#define REG_ERANGE_IDX	(REG_BADBR_IDX + sizeof "Invalid content of \\{\\}")
+    gettext_noop ("Invalid range end")	/* REG_ERANGE */
+    "\0"
+#define REG_ESPACE_IDX	(REG_ERANGE_IDX + sizeof "Invalid range end")
+    gettext_noop ("Memory exhausted") /* REG_ESPACE */
+    "\0"
+#define REG_BADRPT_IDX	(REG_ESPACE_IDX + sizeof "Memory exhausted")
+    gettext_noop ("Invalid preceding regular expression") /* REG_BADRPT */
+    "\0"
+#define REG_EEND_IDX	(REG_BADRPT_IDX + sizeof "Invalid preceding regular expression")
+    gettext_noop ("Premature end of regular expression") /* REG_EEND */
+    "\0"
+#define REG_ESIZE_IDX	(REG_EEND_IDX + sizeof "Premature end of regular expression")
+    gettext_noop ("Regular expression too big") /* REG_ESIZE */
+    "\0"
+#define REG_ERPAREN_IDX	(REG_ESIZE_IDX + sizeof "Regular expression too big")
+    gettext_noop ("Unmatched ) or \\)") /* REG_ERPAREN */
+  };
+
+const size_t __re_error_msgid_idx[] attribute_hidden =
+  {
+    REG_NOERROR_IDX,
+    REG_NOMATCH_IDX,
+    REG_BADPAT_IDX,
+    REG_ECOLLATE_IDX,
+    REG_ECTYPE_IDX,
+    REG_EESCAPE_IDX,
+    REG_ESUBREG_IDX,
+    REG_EBRACK_IDX,
+    REG_EPAREN_IDX,
+    REG_EBRACE_IDX,
+    REG_BADBR_IDX,
+    REG_ERANGE_IDX,
+    REG_ESPACE_IDX,
+    REG_BADRPT_IDX,
+    REG_EEND_IDX,
+    REG_ESIZE_IDX,
+    REG_ERPAREN_IDX
+  };
+
+/* Entry points for GNU code.  */
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length LENGTH) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in BUFP on entry.  */
+
+const char *
+re_compile_pattern (pattern, length, bufp)
+    const char *pattern;
+    size_t length;
+    struct re_pattern_buffer *bufp;
+{
+  reg_errcode_t ret;
+
+  /* GNU code is written to assume at least RE_NREGS registers will be set
+     (and at least one extra will be -1).  */
+  bufp->regs_allocated = REGS_UNALLOCATED;
+
+  /* And GNU code determines whether or not to get register information
+     by passing null for the REGS argument to re_match, etc., not by
+     setting no_sub.  */
+  bufp->no_sub = 0;
+
+  /* Match anchors at newline.  */
+  bufp->newline_anchor = 1;
+
+  ret = re_compile_internal (bufp, pattern, length, re_syntax_options);
+
+  if (!ret)
+    return NULL;
+  return gettext (__re_error_msgid + __re_error_msgid_idx[(int) ret]);
+}
+#ifdef _LIBC
+weak_alias (__re_compile_pattern, re_compile_pattern)
+#endif
+
+/* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
+   also be assigned to arbitrarily: each pattern buffer stores its own
+   syntax, so it can be changed between regex compilations.  */
+/* This has no initializer because initialized variables in Emacs
+   become read-only after dumping.  */
+reg_syntax_t re_syntax_options;
+
+
+/* Specify the precise syntax of regexps for compilation.  This provides
+   for compatibility for various utilities which historically have
+   different, incompatible syntaxes.
+
+   The argument SYNTAX is a bit mask comprised of the various bits
+   defined in regex.h.  We return the old syntax.  */
+
+reg_syntax_t
+re_set_syntax (syntax)
+    reg_syntax_t syntax;
+{
+  reg_syntax_t ret = re_syntax_options;
+
+  re_syntax_options = syntax;
+  return ret;
+}
+#ifdef _LIBC
+weak_alias (__re_set_syntax, re_set_syntax)
+#endif
+
+int
+re_compile_fastmap (bufp)
+    struct re_pattern_buffer *bufp;
+{
+  re_dfa_t *dfa = (re_dfa_t *) bufp->buffer;
+  char *fastmap = bufp->fastmap;
+
+  memset (fastmap, '\0', sizeof (char) * SBC_MAX);
+  re_compile_fastmap_iter (bufp, dfa->init_state, fastmap);
+  if (dfa->init_state != dfa->init_state_word)
+    re_compile_fastmap_iter (bufp, dfa->init_state_word, fastmap);
+  if (dfa->init_state != dfa->init_state_nl)
+    re_compile_fastmap_iter (bufp, dfa->init_state_nl, fastmap);
+  if (dfa->init_state != dfa->init_state_begbuf)
+    re_compile_fastmap_iter (bufp, dfa->init_state_begbuf, fastmap);
+  bufp->fastmap_accurate = 1;
+  return 0;
+}
+#ifdef _LIBC
+weak_alias (__re_compile_fastmap, re_compile_fastmap)
+#endif
+
+/* Helper function for re_compile_fastmap.
+   Compile fastmap for the initial_state INIT_STATE.  */
+
+static void
+re_compile_fastmap_iter (bufp, init_state, fastmap)
+     regex_t *bufp;
+     const re_dfastate_t *init_state;
+     char *fastmap;
+{
+  re_dfa_t *dfa = (re_dfa_t *) bufp->buffer;
+  int node_cnt;
+  for (node_cnt = 0; node_cnt < init_state->nodes.nelem; ++node_cnt)
+    {
+      int node = init_state->nodes.elems[node_cnt];
+      re_token_type_t type = dfa->nodes[node].type;
+      if (type == OP_CONTEXT_NODE)
+        {
+          node = dfa->nodes[node].opr.ctx_info->entity;
+          type = dfa->nodes[node].type;
+        }
+
+      if (type == CHARACTER)
+        fastmap[dfa->nodes[node].opr.c] = 1;
+      else if (type == SIMPLE_BRACKET)
+        {
+          int i, j, ch;
+          for (i = 0, ch = 0; i < BITSET_UINTS; ++i)
+            for (j = 0; j < UINT_BITS; ++j, ++ch)
+              if (dfa->nodes[node].opr.sbcset[i] & (1 << j))
+                fastmap[ch] = 1;
+        }
+#ifdef RE_ENABLE_I18N
+      else if (type == COMPLEX_BRACKET)
+        {
+          int i;
+          re_charset_t *cset = dfa->nodes[node].opr.mbcset;
+          if (cset->non_match || cset->ncoll_syms || cset->nequiv_classes
+              || cset->nranges || cset->nchar_classes)
+            {
+# ifdef _LIBC
+              if (_NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES) != 0)
+                {
+                  /* In this case we want to catch the bytes which are
+                     the first byte of any collation elements.
+                     e.g. In da_DK, we want to catch 'a' since "aa"
+                          is a valid collation element, and don't catch
+                          'b' since 'b' is the only collation element
+                          which starts from 'b'.  */
+                  int j, ch;
+                  const int32_t *table = (const int32_t *)
+                    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+                  for (i = 0, ch = 0; i < BITSET_UINTS; ++i)
+                    for (j = 0; j < UINT_BITS; ++j, ++ch)
+                      if (table[ch] < 0)
+                        fastmap[ch] = 1;
+                }
+# else
+              if (MB_CUR_MAX > 1)
+                for (i = 0; i < SBC_MAX; ++i)
+                  if (__btowc (i) == WEOF)
+                    fastmap[i] = 1;
+# endif /* not _LIBC */
+            }
+          for (i = 0; i < cset->nmbchars; ++i)
+            {
+              char buf[256];
+              wctomb (buf, cset->mbchars[i]);
+              fastmap[*(unsigned char *) buf] = 1;
+            }
+        }
+#endif /* RE_ENABLE_I18N */
+      else if (type == END_OF_RE || type == OP_PERIOD
+#ifdef RE_ENABLE_I18N
+               || type == COMPLEX_BRACKET
+#endif /* RE_ENABLE_I18N */
+              )
+        {
+          memset (fastmap, '\1', sizeof (char) * SBC_MAX);
+          if (type == END_OF_RE)
+            bufp->can_be_null = 1;
+          return;
+        }
+    }
+}
+
+/* Entry point for POSIX code.  */
+/* regcomp takes a regular expression as a string and compiles it.
+
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
+
+     `buffer' to the compiled pattern;
+     `used' to the length of the compiled pattern;
+     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     `fastmap' to an allocated space for the fastmap;
+     `fastmap_accurate' to zero;
+     `re_nsub' to the number of subexpressions in PATTERN.
+
+   PATTERN is the address of the pattern string.
+
+   CFLAGS is a series of bits which affect compilation.
+
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
+
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
+
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
+
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
+
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
+
+int
+regcomp (preg, pattern, cflags)
+    regex_t *__restrict preg;
+    const char *__restrict pattern;
+    int cflags;
+{
+  reg_errcode_t ret;
+  reg_syntax_t syntax = ((cflags & REG_EXTENDED) ? RE_SYNTAX_POSIX_EXTENDED
+                         : RE_SYNTAX_POSIX_BASIC);
+
+  preg->buffer = NULL;
+  preg->allocated = 0;
+  preg->used = 0;
+
+  /* Try to allocate space for the fastmap.  */
+  preg->fastmap = re_malloc (char, SBC_MAX);
+  if (BE (preg->fastmap == NULL, 0))
+    return REG_ESPACE;
+
+  syntax |= (cflags & REG_ICASE) ? RE_ICASE : 0;
+
+  /* If REG_NEWLINE is set, newlines are treated differently.  */
+  if (cflags & REG_NEWLINE)
+    { /* REG_NEWLINE implies neither . nor [^...] match newline.  */
+      syntax &= ~RE_DOT_NEWLINE;
+      syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+      /* It also changes the matching behavior.  */
+      preg->newline_anchor = 1;
+    }
+  else
+    preg->newline_anchor = 0;
+  preg->no_sub = !!(cflags & REG_NOSUB);
+  preg->translate = NULL;
+
+  ret = re_compile_internal (preg, pattern, strlen (pattern), syntax);
+
+  /* POSIX doesn't distinguish between an unmatched open-group and an
+     unmatched close-group: both are REG_EPAREN.  */
+  if (ret == REG_ERPAREN)
+    ret = REG_EPAREN;
+
+  /* We have already checked preg->fastmap != NULL.  */
+  if (BE (ret == REG_NOERROR, 1))
+    {
+      /* Compute the fastmap now, since regexec cannot modify the pattern
+	 buffer.  */
+      if (BE (re_compile_fastmap (preg) == -2, 0))
+	{
+	  /* Some error occurred while computing the fastmap, just forget
+	     about it.  */
+	  re_free (preg->fastmap);
+	  preg->fastmap = NULL;
+	}
+    }
+
+  return (int) ret;
+}
+#ifdef _LIBC
+weak_alias (__regcomp, regcomp)
+#endif
+
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   We don't use PREG here.  */
+
+size_t
+regerror (errcode, preg, errbuf, errbuf_size)
+    int errcode;
+    const regex_t *preg;
+    char *errbuf;
+    size_t errbuf_size;
+{
+  const char *msg;
+  size_t msg_size;
+
+  if (BE (errcode < 0
+          || errcode >= (int) (sizeof (__re_error_msgid_idx)
+                               / sizeof (__re_error_msgid_idx[0])), 0))
+    /* Only error codes returned by the rest of the code should be passed
+       to this routine.  If we are given anything else, or if other regex
+       code generates an invalid error code, then the program has a bug.
+       Dump core so we can fix it.  */
+    abort ();
+
+  msg = gettext (__re_error_msgid + __re_error_msgid_idx[errcode]);
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+
+  if (BE (errbuf_size != 0, 1))
+    {
+      if (BE (msg_size > errbuf_size, 0))
+        {
+#if defined HAVE_MEMPCPY || defined _LIBC
+	  *((char *) __mempcpy (errbuf, msg, errbuf_size - 1)) = '\0';
+#else
+          memcpy (errbuf, msg, errbuf_size - 1);
+          errbuf[errbuf_size - 1] = 0;
+#endif
+        }
+      else
+        memcpy (errbuf, msg, msg_size);
+    }
+
+  return msg_size;
+}
+#ifdef _LIBC
+weak_alias (__regerror, regerror)
+#endif
+
+/* Free dynamically allocated space used by PREG.  */
+
+void
+regfree (preg)
+    regex_t *preg;
+{
+  int i, j;
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  if (BE (dfa != NULL, 1))
+    {
+      re_free (dfa->subexps);
+
+      for (i = 0; i < dfa->nodes_len; ++i)
+        {
+          re_token_t *node = dfa->nodes + i;
+#ifdef RE_ENABLE_I18N
+          if (node->type == COMPLEX_BRACKET && node->duplicated == 0)
+            free_charset (node->opr.mbcset);
+          else
+#endif /* RE_ENABLE_I18N */
+          if (node->type == SIMPLE_BRACKET && node->duplicated == 0)
+            re_free (node->opr.sbcset);
+          else if (node->type == OP_CONTEXT_NODE)
+            {
+              if (dfa->nodes[node->opr.ctx_info->entity].type == OP_BACK_REF)
+                {
+                  if (node->opr.ctx_info->bkref_eclosure != NULL)
+                    re_node_set_free (node->opr.ctx_info->bkref_eclosure);
+                  re_free (node->opr.ctx_info->bkref_eclosure);
+                }
+              re_free (node->opr.ctx_info);
+            }
+        }
+      re_free (dfa->firsts);
+      re_free (dfa->nexts);
+      for (i = 0; i < dfa->nodes_len; ++i)
+        {
+          if (dfa->eclosures != NULL)
+            re_node_set_free (dfa->eclosures + i);
+          if (dfa->inveclosures != NULL)
+            re_node_set_free (dfa->inveclosures + i);
+          if (dfa->edests != NULL)
+            re_node_set_free (dfa->edests + i);
+        }
+      re_free (dfa->edests);
+      re_free (dfa->eclosures);
+      re_free (dfa->inveclosures);
+      re_free (dfa->nodes);
+
+      for (i = 0; i <= dfa->state_hash_mask; ++i)
+        {
+          struct re_state_table_entry *entry = dfa->state_table + i;
+          for (j = 0; j < entry->num; ++j)
+            {
+              re_dfastate_t *state = entry->array[j];
+              if (state->entrance_nodes != &state->nodes)
+                {
+                  re_node_set_free (state->entrance_nodes);
+                  re_free (state->entrance_nodes);
+                }
+              re_node_set_free (&state->nodes);
+              re_free (state->trtable);
+              re_free (state->trtable_search);
+              re_free (state);
+            }
+          re_free (entry->array);
+        }
+      re_free (dfa->state_table);
+
+      if (dfa->word_char != NULL)
+        re_free (dfa->word_char);
+#ifdef DEBUG
+      re_free (dfa->re_str);
+#endif
+      re_free (dfa);
+    }
+  re_free (preg->fastmap);
+}
+#ifdef _LIBC
+weak_alias (__regfree, regfree)
+#endif
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+
+#if defined _REGEX_RE_COMP || defined _LIBC
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
+
+char *
+# ifdef _LIBC
+/* Make these definitions weak in libc, so POSIX programs can redefine
+   these names if they don't use our functions, and still use
+   regcomp/regexec above without link errors.  */
+weak_function
+# endif
+re_comp (s)
+     const char *s;
+{
+  reg_errcode_t ret;
+
+  if (!s)
+    {
+      if (!re_comp_buf.buffer)
+	return gettext ("No previous regular expression");
+      return 0;
+    }
+
+  if (!re_comp_buf.buffer)
+    {
+      re_comp_buf.fastmap = (char *) malloc (SBC_MAX);
+      if (re_comp_buf.fastmap == NULL)
+	return (char *) gettext (__re_error_msgid
+				 + __re_error_msgid_idx[(int) REG_ESPACE]);
+    }
+
+  /* Since `re_exec' always passes NULL for the `regs' argument, we
+     don't need to initialize the pattern buffer fields which affect it.  */
+
+  /* Match anchors at newlines.  */
+  re_comp_buf.newline_anchor = 1;
+
+  ret = re_compile_internal (&re_comp_buf, s, strlen (s), re_syntax_options);
+
+  if (!ret)
+    return NULL;
+
+  /* Yes, we're discarding `const' here if !HAVE_LIBINTL.  */
+  return (char *) gettext (__re_error_msgid + __re_error_msgid_idx[(int) ret]);
+}
+#endif /* _REGEX_RE_COMP */
+
+/* Internal entry point.
+   Compile the regular expression PATTERN, whose length is LENGTH.
+   SYNTAX indicate regular expression's syntax.  */
+
+static reg_errcode_t
+re_compile_internal (preg, pattern, length, syntax)
+     regex_t *preg;
+     const char * pattern;
+     int length;
+     reg_syntax_t syntax;
+{
+  reg_errcode_t err = REG_NOERROR;
+  re_dfa_t *dfa;
+  re_string_t regexp;
+
+  /* Initialize the pattern buffer.  */
+  preg->fastmap_accurate = 0;
+  preg->syntax = syntax;
+  preg->not_bol = preg->not_eol = 0;
+  preg->used = 0;
+  preg->re_nsub = 0;
+
+  /* Initialize the dfa.  */
+  dfa = (re_dfa_t *) preg->buffer;
+  if (preg->allocated < sizeof (re_dfa_t))
+    {
+      /* If zero allocated, but buffer is non-null, try to realloc
+	 enough space.  This loses if buffer's address is bogus, but
+	 that is the user's responsibility.  If ->buffer is NULL this
+	 is a simple allocation.  */
+      dfa = re_realloc (preg->buffer, re_dfa_t, 1);
+      if (dfa == NULL)
+	return REG_ESPACE;
+      preg->allocated = sizeof (re_dfa_t);
+    }
+  preg->buffer = (unsigned char *) dfa;
+  preg->used = sizeof (re_dfa_t);
+
+  err = init_dfa (dfa, length);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (dfa);
+      preg->buffer = NULL;
+      return err;
+    }
+#ifdef DEBUG
+  dfa->re_str = re_malloc (char, length + 1);
+  strncpy (dfa->re_str, pattern, length + 1);
+#endif
+
+  err = re_string_construct (&regexp, pattern, length, preg->translate,
+                             syntax & RE_ICASE);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (dfa);
+      preg->buffer = NULL;
+      return err;
+    }
+
+  /* Parse the regular expression, and build a structure tree.  */
+  preg->re_nsub = 0;
+  dfa->str_tree = parse (&regexp, preg, syntax, &err);
+  if (BE (dfa->str_tree == NULL, 0))
+    goto re_compile_internal_free_return;
+
+  /* Analyze the tree and collect information which is necessary to
+     create the dfa.  */
+  err = analyze (dfa);
+  if (BE (err != REG_NOERROR, 0))
+    goto re_compile_internal_free_return;
+
+  /* Then create the initial state of the dfa.  */
+  err = create_initial_state (dfa);
+  if (BE (err != REG_NOERROR, 0))
+    goto re_compile_internal_free_return;
+
+ re_compile_internal_free_return:
+  /* Release work areas.  */
+  free_workarea_compile (preg);
+  re_string_destruct (&regexp);
+
+  return err;
+}
+
+/* Initialize DFA.  We use the length of the regular expression PAT_LEN
+   as the initial length of some arrays.  */
+
+static reg_errcode_t
+init_dfa (dfa, pat_len)
+     re_dfa_t *dfa;
+     int pat_len;
+{
+  int table_size;
+
+  memset (dfa, '\0', sizeof (re_dfa_t));
+
+  dfa->nodes_alloc = pat_len + 1;
+  dfa->nodes = re_malloc (re_token_t, dfa->nodes_alloc);
+
+  dfa->states_alloc = pat_len + 1;
+
+  /*  table_size = 2 ^ ceil(log pat_len) */
+  for (table_size = 1; table_size > 0; table_size <<= 1)
+    if (table_size > pat_len)
+      break;
+
+  dfa->state_table = calloc (sizeof (struct re_state_table_entry), table_size);
+  dfa->state_hash_mask = table_size - 1;
+
+  dfa->subexps_alloc = 1;
+  dfa->subexps = re_malloc (re_subexp_t, dfa->subexps_alloc);
+  dfa->word_char = NULL;
+
+  if (BE (dfa->nodes == NULL || dfa->state_table == NULL
+          || dfa->subexps == NULL, 0))
+    {
+      /* We don't bother to free anything which was allocated.  Very
+	 soon the process will go down anyway.  */
+      dfa->subexps = NULL;
+      dfa->state_table = NULL;
+      dfa->nodes = NULL;
+      return REG_ESPACE;
+    }
+  return REG_NOERROR;
+}
+
+/* Initialize WORD_CHAR table, which indicate which character is
+   "word".  In this case "word" means that it is the word construction
+   character used by some operators like "\<", "\>", etc.  */
+
+static reg_errcode_t
+init_word_char (dfa)
+     re_dfa_t *dfa;
+{
+  int i, j, ch;
+  dfa->word_char = (re_bitset_ptr_t) calloc (sizeof (bitset), 1);
+  if (BE (dfa->word_char == NULL, 0))
+    return REG_ESPACE;
+  for (i = 0, ch = 0; i < BITSET_UINTS; ++i)
+    for (j = 0; j < UINT_BITS; ++j, ++ch)
+      if (isalnum (ch) || ch == '_')
+        dfa->word_char[i] |= 1 << j;
+  return REG_NOERROR;
+}
+
+/* Free the work area which are only used while compiling.  */
+
+static void
+free_workarea_compile (preg)
+     regex_t *preg;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  free_bin_tree (dfa->str_tree);
+  dfa->str_tree = NULL;
+}
+
+/* Create initial states for all contexts.  */
+
+static reg_errcode_t
+create_initial_state (dfa)
+     re_dfa_t *dfa;
+{
+  int first, i;
+  reg_errcode_t err;
+  re_node_set init_nodes;
+
+  /* Initial states have the epsilon closure of the node which is
+     the first node of the regular expression.  */
+  first = dfa->str_tree->first;
+  dfa->init_node = first;
+  err = re_node_set_init_copy (&init_nodes, dfa->eclosures + first);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* The back-references which are in initial states can epsilon transit,
+     since in this case all of the subexpressions can be null.
+     Then we add epsilon closures of the nodes which are the next nodes of
+     the back-references.  */
+  if (dfa->nbackref > 0)
+    for (i = 0; i < init_nodes.nelem; ++i)
+      {
+        int node_idx = init_nodes.elems[i];
+        re_token_type_t type = dfa->nodes[node_idx].type;
+
+        int clexp_idx;
+        int entity = (type != OP_CONTEXT_NODE ? node_idx
+                      : dfa->nodes[node_idx].opr.ctx_info->entity);
+        if ((type != OP_CONTEXT_NODE
+             || (dfa->nodes[entity].type != OP_BACK_REF))
+            && (type != OP_BACK_REF))
+          continue;
+        for (clexp_idx = 0; clexp_idx < init_nodes.nelem; ++clexp_idx)
+          {
+            re_token_t *clexp_node;
+            clexp_node = dfa->nodes + init_nodes.elems[clexp_idx];
+            if (clexp_node->type == OP_CLOSE_SUBEXP
+                && clexp_node->opr.idx + 1 == dfa->nodes[entity].opr.idx)
+              break;
+          }
+        if (clexp_idx == init_nodes.nelem)
+          continue;
+
+        if (type == OP_CONTEXT_NODE
+            && (dfa->nodes[dfa->nodes[node_idx].opr.ctx_info->entity].type
+                == OP_BACK_REF))
+          {
+            int prev_nelem = init_nodes.nelem;
+            re_node_set_merge (&init_nodes,
+                           dfa->nodes[node_idx].opr.ctx_info->bkref_eclosure);
+            if (prev_nelem < init_nodes.nelem)
+              i = 0;
+          }
+        else if (type == OP_BACK_REF)
+          {
+            int next_idx = dfa->nexts[node_idx];
+            if (!re_node_set_contains (&init_nodes, next_idx))
+              {
+                re_node_set_merge (&init_nodes, dfa->eclosures + next_idx);
+                i = 0;
+              }
+          }
+      }
+
+  /* It must be the first time to invoke acquire_state.  */
+  dfa->init_state = re_acquire_state_context (&err, dfa, &init_nodes, 0);
+  /* We don't check ERR here, since the initial state must not be NULL.  */
+  if (BE (dfa->init_state == NULL, 0))
+    return err;
+  if (dfa->init_state->has_constraint)
+    {
+      dfa->init_state_word = re_acquire_state_context (&err, dfa, &init_nodes,
+                                                       CONTEXT_WORD);
+      dfa->init_state_nl = re_acquire_state_context (&err, dfa, &init_nodes,
+                                                     CONTEXT_NEWLINE);
+      dfa->init_state_begbuf = re_acquire_state_context (&err, dfa,
+                                                         &init_nodes,
+                                                         CONTEXT_NEWLINE
+                                                         | CONTEXT_BEGBUF);
+      if (BE (dfa->init_state_word == NULL || dfa->init_state_nl == NULL
+              || dfa->init_state_begbuf == NULL, 0))
+        return err;
+    }
+  else
+    dfa->init_state_word = dfa->init_state_nl
+      = dfa->init_state_begbuf = dfa->init_state;
+
+  re_node_set_free (&init_nodes);
+  return REG_NOERROR;
+}
+
+/* Analyze the structure tree, and calculate "first", "next", "edest",
+   "eclosure", and "inveclosure".  */
+
+static reg_errcode_t
+analyze (dfa)
+     re_dfa_t *dfa;
+{
+  int i;
+  reg_errcode_t ret;
+
+  /* Allocate arrays.  */
+  dfa->firsts = re_malloc (int, dfa->nodes_alloc);
+  dfa->nexts = re_malloc (int, dfa->nodes_alloc);
+  dfa->edests = re_malloc (re_node_set, dfa->nodes_alloc);
+  dfa->eclosures = re_malloc (re_node_set, dfa->nodes_alloc);
+  dfa->inveclosures = re_malloc (re_node_set, dfa->nodes_alloc);
+  if (BE (dfa->firsts == NULL || dfa->nexts == NULL || dfa->edests == NULL
+          || dfa->eclosures == NULL || dfa->inveclosures == NULL, 0))
+    return REG_ESPACE;
+  /* Initialize them.  */
+  for (i = 0; i < dfa->nodes_len; ++i)
+    {
+      dfa->firsts[i] = -1;
+      dfa->nexts[i] = -1;
+      re_node_set_init_empty (dfa->edests + i);
+      re_node_set_init_empty (dfa->eclosures + i);
+      re_node_set_init_empty (dfa->inveclosures + i);
+    }
+
+  ret = analyze_tree (dfa, dfa->str_tree);
+  if (BE (ret == REG_NOERROR, 1))
+    {
+      ret = calc_eclosure (dfa);
+      if (ret == REG_NOERROR)
+	calc_inveclosure (dfa);
+    }
+  return ret;
+}
+
+/* Helper functions for analyze.
+   This function calculate "first", "next", and "edest" for the subtree
+   whose root is NODE.  */
+
+static reg_errcode_t
+analyze_tree (dfa, node)
+     re_dfa_t *dfa;
+     bin_tree_t *node;
+{
+  reg_errcode_t ret;
+  if (node->first == -1)
+    calc_first (dfa, node);
+  if (node->next == -1)
+    calc_next (dfa, node);
+  if (node->eclosure.nelem == 0)
+    calc_epsdest (dfa, node);
+  /* Calculate "first" etc. for the left child.  */
+  if (node->left != NULL)
+    {
+      ret = analyze_tree (dfa, node->left);
+      if (BE (ret != REG_NOERROR, 0))
+        return ret;
+    }
+  /* Calculate "first" etc. for the right child.  */
+  if (node->right != NULL)
+    {
+      ret = analyze_tree (dfa, node->right);
+      if (BE (ret != REG_NOERROR, 0))
+        return ret;
+    }
+  return REG_NOERROR;
+}
+
+/* Calculate "first" for the node NODE.  */
+static void
+calc_first (dfa, node)
+     re_dfa_t *dfa;
+     bin_tree_t *node;
+{
+  int idx, type;
+  idx = node->node_idx;
+  type = (node->type == 0) ? dfa->nodes[idx].type : node->type;
+
+  switch (type)
+    {
+#ifdef DEBUG
+    case OP_OPEN_BRACKET:
+    case OP_CLOSE_BRACKET:
+    case OP_OPEN_DUP_NUM:
+    case OP_CLOSE_DUP_NUM:
+    case OP_NON_MATCH_LIST:
+    case OP_OPEN_COLL_ELEM:
+    case OP_CLOSE_COLL_ELEM:
+    case OP_OPEN_EQUIV_CLASS:
+    case OP_CLOSE_EQUIV_CLASS:
+    case OP_OPEN_CHAR_CLASS:
+    case OP_CLOSE_CHAR_CLASS:
+      /* These must not be appeared here.  */
+      assert (0);
+#endif
+    case END_OF_RE:
+    case CHARACTER:
+    case OP_PERIOD:
+    case OP_DUP_ASTERISK:
+    case OP_DUP_QUESTION:
+#ifdef RE_ENABLE_I18N
+    case COMPLEX_BRACKET:
+#endif /* RE_ENABLE_I18N */
+    case SIMPLE_BRACKET:
+    case OP_BACK_REF:
+    case ANCHOR:
+    case OP_OPEN_SUBEXP:
+    case OP_CLOSE_SUBEXP:
+      node->first = idx;
+      break;
+    case OP_DUP_PLUS:
+#ifdef DEBUG
+      assert (node->left != NULL);
+#endif
+      if (node->left->first == -1)
+        calc_first (dfa, node->left);
+      node->first = node->left->first;
+      break;
+    case OP_ALT:
+      node->first = idx;
+      break;
+      /* else fall through */
+    default:
+#ifdef DEBUG
+      assert (node->left != NULL);
+#endif
+      if (node->left->first == -1)
+        calc_first (dfa, node->left);
+      node->first = node->left->first;
+      break;
+    }
+  if (node->type == 0)
+    dfa->firsts[idx] = node->first;
+}
+
+/* Calculate "next" for the node NODE.  */
+
+static void
+calc_next (dfa, node)
+     re_dfa_t *dfa;
+     bin_tree_t *node;
+{
+  int idx, type;
+  bin_tree_t *parent = node->parent;
+  if (parent == NULL)
+    {
+      node->next = -1;
+      idx = node->node_idx;
+      if (node->type == 0)
+        dfa->nexts[idx] = node->next;
+      return;
+    }
+
+  idx = parent->node_idx;
+  type = (parent->type == 0) ? dfa->nodes[idx].type : parent->type;
+
+  switch (type)
+    {
+    case OP_DUP_ASTERISK:
+    case OP_DUP_PLUS:
+      node->next = idx;
+      break;
+    case CONCAT:
+      if (parent->left == node)
+        {
+          if (parent->right->first == -1)
+            calc_first (dfa, parent->right);
+          node->next = parent->right->first;
+          break;
+        }
+      /* else fall through */
+    default:
+      if (parent->next == -1)
+        calc_next (dfa, parent);
+      node->next = parent->next;
+      break;
+    }
+  idx = node->node_idx;
+  if (node->type == 0)
+    dfa->nexts[idx] = node->next;
+}
+
+/* Calculate "edest" for the node NODE.  */
+
+static void
+calc_epsdest (dfa, node)
+     re_dfa_t *dfa;
+     bin_tree_t *node;
+{
+  int idx;
+  idx = node->node_idx;
+  if (node->type == 0)
+    {
+      if (dfa->nodes[idx].type == OP_DUP_ASTERISK
+          || dfa->nodes[idx].type == OP_DUP_PLUS
+          || dfa->nodes[idx].type == OP_DUP_QUESTION)
+        {
+          if (node->left->first == -1)
+            calc_first (dfa, node->left);
+          if (node->next == -1)
+            calc_next (dfa, node);
+          re_node_set_init_2 (dfa->edests + idx, node->left->first,
+                              node->next);
+        }
+      else if (dfa->nodes[idx].type == OP_ALT)
+        {
+          int left, right;
+          if (node->left != NULL)
+            {
+              if (node->left->first == -1)
+                calc_first (dfa, node->left);
+              left = node->left->first;
+            }
+          else
+            {
+              if (node->next == -1)
+                calc_next (dfa, node);
+              left = node->next;
+            }
+          if (node->right != NULL)
+            {
+              if (node->right->first == -1)
+                calc_first (dfa, node->right);
+              right = node->right->first;
+            }
+          else
+            {
+              if (node->next == -1)
+                calc_next (dfa, node);
+              right = node->next;
+            }
+          re_node_set_init_2 (dfa->edests + idx, left, right);
+        }
+      else if (dfa->nodes[idx].type == ANCHOR
+               || dfa->nodes[idx].type == OP_OPEN_SUBEXP
+               || dfa->nodes[idx].type == OP_CLOSE_SUBEXP)
+        re_node_set_init_1 (dfa->edests + idx, node->next);
+    }
+}
+
+/* Duplicate the node whose index is ORG_IDX and set the constraint CONSTRAINT.
+   The new index will be stored in NEW_IDX and return REG_NOERROR if succeeded,
+   otherwise return the error code.  */
+
+static reg_errcode_t
+duplicate_node (new_idx, dfa, org_idx, constraint)
+     re_dfa_t *dfa;
+     int *new_idx, org_idx;
+     unsigned int constraint;
+{
+  re_token_t dup;
+  int dup_idx;
+  reg_errcode_t err;
+
+  dup.type = OP_CONTEXT_NODE;
+  if (dfa->nodes[org_idx].type == OP_CONTEXT_NODE)
+    {
+      /* If the node whose index is ORG_IDX is the same as the intended
+         node, use it.  */
+      if (dfa->nodes[org_idx].constraint == constraint)
+        {
+          *new_idx = org_idx;
+          return REG_NOERROR;
+        }
+      dup.constraint = constraint |
+        dfa->nodes[org_idx].constraint;
+    }
+  else
+    dup.constraint = constraint;
+
+  /* In case that `entity' points OP_CONTEXT_NODE,
+     we correct `entity' to real entity in calc_inveclosures(). */
+  dup.opr.ctx_info = malloc (sizeof (*dup.opr.ctx_info));
+  dup_idx = re_dfa_add_node (dfa, dup, 1);
+  if (BE (dup.opr.ctx_info == NULL || dup_idx == -1, 0))
+    return REG_ESPACE;
+  dup.opr.ctx_info->entity = org_idx;
+  dup.opr.ctx_info->bkref_eclosure = NULL;
+
+  dfa->nodes[dup_idx].duplicated = 1;
+  dfa->firsts[dup_idx] = dfa->firsts[org_idx];
+  dfa->nexts[dup_idx] = dfa->nexts[org_idx];
+  err = re_node_set_init_copy (dfa->edests + dup_idx, dfa->edests + org_idx);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  /* Since we don't duplicate epsilon nodes, epsilon closure have
+     only itself.  */
+  err = re_node_set_init_1 (dfa->eclosures + dup_idx, dup_idx);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  err = re_node_set_init_1 (dfa->inveclosures + dup_idx, dup_idx);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  /* Then we must update inveclosure for this node.
+     We process them at last part of calc_eclosure(),
+     since we don't complete to calculate them here.  */
+
+  *new_idx = dup_idx;
+  return REG_NOERROR;
+}
+
+static void
+calc_inveclosure (dfa)
+     re_dfa_t *dfa;
+{
+  int src, idx, dest, entity;
+  for (src = 0; src < dfa->nodes_len; ++src)
+    {
+      for (idx = 0; idx < dfa->eclosures[src].nelem; ++idx)
+        {
+          dest = dfa->eclosures[src].elems[idx];
+          re_node_set_insert (dfa->inveclosures + dest, src);
+        }
+
+      entity = src;
+      while (dfa->nodes[entity].type == OP_CONTEXT_NODE)
+        {
+          entity = dfa->nodes[entity].opr.ctx_info->entity;
+          re_node_set_merge (dfa->inveclosures + src,
+                             dfa->inveclosures + entity);
+          dfa->nodes[src].opr.ctx_info->entity = entity;
+        }
+    }
+}
+
+/* Calculate "eclosure" for all the node in DFA.  */
+
+static reg_errcode_t
+calc_eclosure (dfa)
+     re_dfa_t *dfa;
+{
+  int idx, node_idx, max, incomplete = 0;
+#ifdef DEBUG
+  assert (dfa->nodes_len > 0);
+#endif
+  /* For each nodes, calculate epsilon closure.  */
+  for (node_idx = 0, max = dfa->nodes_len; ; ++node_idx)
+    {
+      reg_errcode_t err;
+      re_node_set eclosure_elem;
+      if (node_idx == max)
+        {
+          if (!incomplete)
+            break;
+          incomplete = 0;
+          node_idx = 0;
+        }
+
+#ifdef DEBUG
+      assert (dfa->nodes[node_idx].type != OP_CONTEXT_NODE);
+      assert (dfa->eclosures[node_idx].nelem != -1);
+#endif
+      /* If we have already calculated, skip it.  */
+      if (dfa->eclosures[node_idx].nelem != 0)
+        continue;
+      /* Calculate epsilon closure of `node_idx'.  */
+      err = calc_eclosure_iter (&eclosure_elem, dfa, node_idx, 1);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+
+      if (dfa->eclosures[node_idx].nelem == 0)
+        {
+          incomplete = 1;
+          re_node_set_free (&eclosure_elem);
+        }
+    }
+
+  /* for duplicated nodes.  */
+  for (idx = max; idx < dfa->nodes_len; ++idx)
+    {
+      int entity, i, constraint;
+      re_node_set *bkref_eclosure;
+      entity = dfa->nodes[idx].opr.ctx_info->entity;
+      re_node_set_merge (dfa->inveclosures + idx, dfa->inveclosures + entity);
+      if (dfa->nodes[entity].type != OP_BACK_REF)
+        continue;
+
+      /* If the node is backreference, duplicate the epsilon closure of
+         the next node. Since it may epsilon transit.  */
+      /* Note: duplicate_node() may realloc dfa->eclosures, etc.  */
+      bkref_eclosure = re_malloc (re_node_set, 1);
+      if (BE (bkref_eclosure == NULL, 0))
+	return REG_ESPACE;
+      re_node_set_init_empty (bkref_eclosure);
+      constraint = dfa->nodes[idx].constraint;
+      for (i = 0; i < dfa->eclosures[dfa->nexts[idx]].nelem; ++i)
+        {
+          int dest_node_idx = dfa->eclosures[dfa->nexts[idx]].elems[i];
+          if (!IS_EPSILON_NODE (dfa->nodes[dest_node_idx].type))
+            {
+              reg_errcode_t err;
+              err = duplicate_node (&dest_node_idx, dfa, dest_node_idx,
+                                    constraint);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+            }
+          re_node_set_insert (bkref_eclosure, dest_node_idx);
+        }
+      dfa->nodes[idx].opr.ctx_info->bkref_eclosure = bkref_eclosure;
+    }
+
+  return REG_NOERROR;
+}
+
+/* Calculate epsilon closure of NODE.  */
+
+static reg_errcode_t
+calc_eclosure_iter (new_set, dfa, node, root)
+     re_node_set *new_set;
+     re_dfa_t *dfa;
+     int node, root;
+{
+  reg_errcode_t err;
+  unsigned int constraint;
+  int i, max, incomplete = 0;
+  re_node_set eclosure;
+  err = re_node_set_alloc (&eclosure, dfa->edests[node].nelem + 1);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* This indicates that we are calculating this node now.
+     We reference this value to avoid infinite loop.  */
+  dfa->eclosures[node].nelem = -1;
+
+  constraint = ((dfa->nodes[node].type == ANCHOR)
+                ? dfa->nodes[node].opr.ctx_type : 0);
+
+  /* Expand each epsilon destination nodes.  */
+  if (dfa->edests[node].nelem != 0)
+    for (i = 0; i < dfa->edests[node].nelem; ++i)
+      {
+        re_node_set eclosure_elem;
+        int edest = dfa->edests[node].elems[i];
+        /* If calculating the epsilon closure of `edest' is in progress,
+           return intermediate result.  */
+        if (dfa->eclosures[edest].nelem == -1)
+          {
+            incomplete = 1;
+            continue;
+          }
+        /* If we haven't calculated the epsilon closure of `edest' yet,
+           calculate now. Otherwise use calculated epsilon closure.  */
+        if (dfa->eclosures[edest].nelem == 0)
+          {
+            err = calc_eclosure_iter (&eclosure_elem, dfa, edest, 0);
+            if (BE (err != REG_NOERROR, 0))
+              return err;
+          }
+        else
+          eclosure_elem = dfa->eclosures[edest];
+        /* Merge the epsilon closure of `edest'.  */
+        re_node_set_merge (&eclosure, &eclosure_elem);
+        /* If the epsilon closure of `edest' is incomplete,
+           the epsilon closure of this node is also incomplete.  */
+        if (dfa->eclosures[edest].nelem == 0)
+          {
+            incomplete = 1;
+            re_node_set_free (&eclosure_elem);
+          }
+      }
+
+  /* If the current node has constraints, duplicate all non-epsilon nodes.
+     Since they must inherit the constraints.  */
+  if (constraint)
+    for (i = 0, max = eclosure.nelem; i < max; ++i)
+      {
+        int dest = eclosure.elems[i];
+        if (!IS_EPSILON_NODE (dfa->nodes[dest].type))
+          {
+            int dup_dest;
+            reg_errcode_t err;
+            err = duplicate_node (&dup_dest, dfa, dest, constraint);
+            if (BE (err != REG_NOERROR, 0))
+              return err;
+            if (dest != dup_dest)
+              {
+                re_node_set_remove_at (&eclosure, i--);
+                re_node_set_insert (&eclosure, dup_dest);
+                --max;
+              }
+          }
+      }
+
+  /* Epsilon closures include itself.  */
+  re_node_set_insert (&eclosure, node);
+  if (incomplete && !root)
+    dfa->eclosures[node].nelem = 0;
+  else
+    dfa->eclosures[node] = eclosure;
+  *new_set = eclosure;
+  return REG_NOERROR;
+}
+
+/* Functions for token which are used in the parser.  */
+
+/* Fetch a token from INPUT.
+   We must not use this function inside bracket expressions.  */
+
+static re_token_t
+fetch_token (input, syntax)
+     re_string_t *input;
+     reg_syntax_t syntax;
+{
+  re_token_t token;
+  int consumed_byte;
+  consumed_byte = peek_token (&token, input, syntax);
+  re_string_skip_bytes (input, consumed_byte);
+  return token;
+}
+
+/* Peek a token from INPUT, and return the length of the token.
+   We must not use this function inside bracket expressions.  */
+
+static int
+peek_token (token, input, syntax)
+     re_token_t *token;
+     re_string_t *input;
+     reg_syntax_t syntax;
+{
+  unsigned char c;
+
+  if (re_string_eoi (input))
+    {
+      token->type = END_OF_RE;
+      return 0;
+    }
+
+  c = re_string_peek_byte (input, 0);
+  token->opr.c = c;
+
+#ifdef RE_ENABLE_I18N
+  token->mb_partial = 0;
+  if (MB_CUR_MAX > 1 &&
+      !re_string_first_byte (input, re_string_cur_idx (input)))
+    {
+      token->type = CHARACTER;
+      token->mb_partial = 1;
+      return 1;
+    }
+#endif
+  if (c == '\\')
+    {
+      unsigned char c2;
+      if (re_string_cur_idx (input) + 1 >= re_string_length (input))
+        {
+          token->type = BACK_SLASH;
+          return 1;
+        }
+
+      c2 = re_string_peek_byte_case (input, 1);
+      token->opr.c = c2;
+      token->type = CHARACTER;
+      switch (c2)
+        {
+        case '|':
+          if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_NO_BK_VBAR))
+            token->type = OP_ALT;
+          break;
+        case '1': case '2': case '3': case '4': case '5':
+        case '6': case '7': case '8': case '9':
+          if (!(syntax & RE_NO_BK_REFS))
+            {
+              token->type = OP_BACK_REF;
+              token->opr.idx = c2 - '0';
+            }
+          break;
+        case '<':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = WORD_FIRST;
+            }
+          break;
+        case '>':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = WORD_LAST;
+            }
+          break;
+        case 'b':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = WORD_DELIM;
+            }
+          break;
+        case 'B':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = INSIDE_WORD;
+            }
+          break;
+        case 'w':
+          if (!(syntax & RE_NO_GNU_OPS))
+            token->type = OP_WORD;
+          break;
+        case 'W':
+          if (!(syntax & RE_NO_GNU_OPS))
+            token->type = OP_NOTWORD;
+          break;
+        case '`':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = BUF_FIRST;
+            }
+          break;
+        case '\'':
+          if (!(syntax & RE_NO_GNU_OPS))
+            {
+              token->type = ANCHOR;
+              token->opr.idx = BUF_LAST;
+            }
+          break;
+        case '(':
+          if (!(syntax & RE_NO_BK_PARENS))
+            token->type = OP_OPEN_SUBEXP;
+          break;
+        case ')':
+          if (!(syntax & RE_NO_BK_PARENS))
+            token->type = OP_CLOSE_SUBEXP;
+          break;
+        case '+':
+          if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_BK_PLUS_QM))
+            token->type = OP_DUP_PLUS;
+          break;
+        case '?':
+          if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_BK_PLUS_QM))
+            token->type = OP_DUP_QUESTION;
+          break;
+        case '{':
+          if ((syntax & RE_INTERVALS) && (!(syntax & RE_NO_BK_BRACES)))
+            token->type = OP_OPEN_DUP_NUM;
+          break;
+        case '}':
+          if ((syntax & RE_INTERVALS) && (!(syntax & RE_NO_BK_BRACES)))
+            token->type = OP_CLOSE_DUP_NUM;
+          break;
+        default:
+          break;
+        }
+      return 2;
+    }
+
+  token->type = CHARACTER;
+  switch (c)
+    {
+    case '\n':
+      if (syntax & RE_NEWLINE_ALT)
+        token->type = OP_ALT;
+      break;
+    case '|':
+      if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_NO_BK_VBAR))
+        token->type = OP_ALT;
+      break;
+    case '*':
+      token->type = OP_DUP_ASTERISK;
+      break;
+    case '+':
+      if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_BK_PLUS_QM))
+        token->type = OP_DUP_PLUS;
+      break;
+    case '?':
+      if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_BK_PLUS_QM))
+        token->type = OP_DUP_QUESTION;
+      break;
+    case '{':
+      if ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+        token->type = OP_OPEN_DUP_NUM;
+      break;
+    case '}':
+      if ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+        token->type = OP_CLOSE_DUP_NUM;
+      break;
+    case '(':
+      if (syntax & RE_NO_BK_PARENS)
+        token->type = OP_OPEN_SUBEXP;
+      break;
+    case ')':
+      if (syntax & RE_NO_BK_PARENS)
+        token->type = OP_CLOSE_SUBEXP;
+      break;
+    case '[':
+      token->type = OP_OPEN_BRACKET;
+      break;
+    case '.':
+      token->type = OP_PERIOD;
+      break;
+    case '^':
+      if (!(syntax & RE_CONTEXT_INDEP_ANCHORS) &&
+          re_string_cur_idx (input) != 0)
+        {
+          char prev = re_string_peek_byte (input, -1);
+          if (prev != '|' && prev != '(' &&
+              (!(syntax & RE_NEWLINE_ALT) || prev != '\n'))
+            break;
+        }
+      token->type = ANCHOR;
+      token->opr.idx = LINE_FIRST;
+      break;
+    case '$':
+      if (!(syntax & RE_CONTEXT_INDEP_ANCHORS) &&
+          re_string_cur_idx (input) + 1 != re_string_length (input))
+        {
+          re_token_t next;
+          re_string_skip_bytes (input, 1);
+          peek_token (&next, input, syntax);
+          re_string_skip_bytes (input, -1);
+          if (next.type != OP_ALT && next.type != OP_CLOSE_SUBEXP)
+            break;
+        }
+      token->type = ANCHOR;
+      token->opr.idx = LINE_LAST;
+      break;
+    default:
+      break;
+    }
+  return 1;
+}
+
+/* Peek a token from INPUT, and return the length of the token.
+   We must not use this function out of bracket expressions.  */
+
+static int
+peek_token_bracket (token, input, syntax)
+     re_token_t *token;
+     re_string_t *input;
+     reg_syntax_t syntax;
+{
+  unsigned char c;
+  if (re_string_eoi (input))
+    {
+      token->type = END_OF_RE;
+      return 0;
+    }
+  c = re_string_peek_byte (input, 0);
+  token->opr.c = c;
+
+#ifdef RE_ENABLE_I18N
+  if (MB_CUR_MAX > 1 &&
+      !re_string_first_byte (input, re_string_cur_idx (input)))
+    {
+      token->type = CHARACTER;
+      return 1;
+    }
+#endif /* RE_ENABLE_I18N */
+
+  if (c == '\\' && (syntax & RE_BACKSLASH_ESCAPE_IN_LISTS))
+    {
+      /* In this case, '\' escape a character.  */
+      unsigned char c2;
+      c2 = re_string_peek_byte (input, 1);
+      token->opr.c = c2;
+      token->type = CHARACTER;
+      return 1;
+    }
+  if (c == '[') /* '[' is a special char in a bracket exps.  */
+    {
+      unsigned char c2;
+      int token_len;
+      c2 = re_string_peek_byte (input, 1);
+      token->opr.c = c2;
+      token_len = 2;
+      switch (c2)
+        {
+        case '.':
+          token->type = OP_OPEN_COLL_ELEM;
+          break;
+        case '=':
+          token->type = OP_OPEN_EQUIV_CLASS;
+          break;
+        case ':':
+          if (syntax & RE_CHAR_CLASSES)
+            {
+              token->type = OP_OPEN_CHAR_CLASS;
+              break;
+            }
+          /* else fall through.  */
+        default:
+          token->type = CHARACTER;
+          token->opr.c = c;
+          token_len = 1;
+          break;
+        }
+      return token_len;
+    }
+  switch (c)
+    {
+    case '-':
+      token->type = OP_CHARSET_RANGE;
+      break;
+    case ']':
+      token->type = OP_CLOSE_BRACKET;
+      break;
+    case '^':
+      token->type = OP_NON_MATCH_LIST;
+      break;
+    default:
+      token->type = CHARACTER;
+    }
+  return 1;
+}
+
+/* Functions for parser.  */
+
+/* Entry point of the parser.
+   Parse the regular expression REGEXP and return the structure tree.
+   If an error is occured, ERR is set by error code, and return NULL.
+   This function build the following tree, from regular expression <reg_exp>:
+           CAT
+           / \
+          /   \
+   <reg_exp>  EOR
+
+   CAT means concatenation.
+   EOR means end of regular expression.  */
+
+static bin_tree_t *
+parse (regexp, preg, syntax, err)
+     re_string_t *regexp;
+     regex_t *preg;
+     reg_syntax_t syntax;
+     reg_errcode_t *err;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  bin_tree_t *tree, *eor, *root;
+  re_token_t current_token;
+  int new_idx;
+  current_token = fetch_token (regexp, syntax);
+  tree = parse_reg_exp (regexp, preg, &current_token, syntax, 0, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+  new_idx = re_dfa_add_node (dfa, current_token, 0);
+  eor = create_tree (NULL, NULL, 0, new_idx);
+  if (tree != NULL)
+    root = create_tree (tree, eor, CONCAT, 0);
+  else
+    root = eor;
+  if (BE (new_idx == -1 || eor == NULL || root == NULL, 0))
+    return *err = REG_ESPACE, NULL;
+  return root;
+}
+
+/* This function build the following tree, from regular expression
+   <branch1>|<branch2>:
+           ALT
+           / \
+          /   \
+   <branch1> <branch2>
+
+   ALT means alternative, which represents the operator `|'.  */
+
+static bin_tree_t *
+parse_reg_exp (regexp, preg, token, syntax, nest, err)
+     re_string_t *regexp;
+     regex_t *preg;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     int nest;
+     reg_errcode_t *err;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  bin_tree_t *tree, *branch = NULL;
+  int new_idx;
+  tree = parse_branch (regexp, preg, token, syntax, nest, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+
+  while (token->type == OP_ALT)
+    {
+      re_token_t alt_token = *token;
+      new_idx = re_dfa_add_node (dfa, alt_token, 0);
+      *token = fetch_token (regexp, syntax);
+      if (token->type != OP_ALT && token->type != END_OF_RE
+          && (nest == 0 || token->type != OP_CLOSE_SUBEXP))
+        {
+          branch = parse_branch (regexp, preg, token, syntax, nest, err);
+          if (BE (*err != REG_NOERROR && branch == NULL, 0))
+            {
+              free_bin_tree (tree);
+              return NULL;
+            }
+        }
+      else
+	branch = NULL;
+      tree = create_tree (tree, branch, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+      dfa->has_plural_match = 1;
+    }
+  return tree;
+}
+
+/* This function build the following tree, from regular expression
+   <exp1><exp2>:
+        CAT
+        / \
+       /   \
+   <exp1> <exp2>
+
+   CAT means concatenation.  */
+
+static bin_tree_t *
+parse_branch (regexp, preg, token, syntax, nest, err)
+     re_string_t *regexp;
+     regex_t *preg;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     int nest;
+     reg_errcode_t *err;
+{
+  bin_tree_t *tree, *exp;
+  tree = parse_expression (regexp, preg, token, syntax, nest, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+
+  while (token->type != OP_ALT && token->type != END_OF_RE
+         && (nest == 0 || token->type != OP_CLOSE_SUBEXP))
+    {
+      exp = parse_expression (regexp, preg, token, syntax, nest, err);
+      if (BE (*err != REG_NOERROR && exp == NULL, 0))
+        {
+          free_bin_tree (tree);
+          return NULL;
+        }
+      if (tree != NULL && exp != NULL)
+        {
+          tree = create_tree (tree, exp, CONCAT, 0);
+          if (tree == NULL)
+            return *err = REG_ESPACE, NULL;
+        }
+      else if (tree == NULL)
+        tree = exp;
+      /* Otherwise exp == NULL, we don't need to create new tree.  */
+    }
+  return tree;
+}
+
+/* This function build the following tree, from regular expression a*:
+         *
+         |
+         a
+*/
+
+static bin_tree_t *
+parse_expression (regexp, preg, token, syntax, nest, err)
+     re_string_t *regexp;
+     regex_t *preg;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     int nest;
+     reg_errcode_t *err;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  bin_tree_t *tree;
+  int new_idx;
+  switch (token->type)
+    {
+    case CHARACTER:
+      new_idx = re_dfa_add_node (dfa, *token, 0);
+      tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+	{
+	  while (!re_string_eoi (regexp)
+		 && !re_string_first_byte (regexp, re_string_cur_idx (regexp)))
+	    {
+              bin_tree_t *mbc_remain;
+              *token = fetch_token (regexp, syntax);
+              new_idx = re_dfa_add_node (dfa, *token, 0);
+              mbc_remain = create_tree (NULL, NULL, 0, new_idx);
+              tree = create_tree (tree, mbc_remain, CONCAT, 0);
+              if (BE (new_idx == -1 || mbc_remain == NULL || tree == NULL, 0))
+                return *err = REG_ESPACE, NULL;
+            }
+	}
+#endif
+      break;
+    case OP_OPEN_SUBEXP:
+      tree = parse_sub_exp (regexp, preg, token, syntax, nest + 1, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+      break;
+    case OP_OPEN_BRACKET:
+      tree = parse_bracket_exp (regexp, dfa, token, syntax, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+      break;
+    case OP_BACK_REF:
+      if (BE (preg->re_nsub < token->opr.idx
+              || dfa->subexps[token->opr.idx - 1].end == -1, 0))
+        {
+          *err = REG_ESUBREG;
+          return NULL;
+        }
+      new_idx = re_dfa_add_node (dfa, *token, 0);
+      tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+      ++dfa->nbackref;
+      dfa->has_mb_node = 1;
+      break;
+    case OP_DUP_ASTERISK:
+    case OP_DUP_PLUS:
+    case OP_DUP_QUESTION:
+    case OP_OPEN_DUP_NUM:
+      if (syntax & RE_CONTEXT_INVALID_OPS)
+        return *err = REG_BADRPT, NULL;
+      else if (syntax & RE_CONTEXT_INDEP_OPS)
+        {
+          *token = fetch_token (regexp, syntax);
+          return parse_expression (regexp, preg, token, syntax, nest, err);
+        }
+      /* else fall through  */
+    case OP_CLOSE_SUBEXP:
+      if ((token->type == OP_CLOSE_SUBEXP) &&
+          !(syntax & RE_UNMATCHED_RIGHT_PAREN_ORD))
+        return *err = REG_ERPAREN, NULL;
+      /* else fall through  */
+    case OP_CLOSE_DUP_NUM:
+      /* We treat it as a normal character.  */
+
+      /* Then we can these characters as normal characters.  */
+      token->type = CHARACTER;
+      new_idx = re_dfa_add_node (dfa, *token, 0);
+      tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+      break;
+    case ANCHOR:
+      if (dfa->word_char == NULL)
+        {
+          *err = init_word_char (dfa);
+          if (BE (*err != REG_NOERROR, 0))
+            return NULL;
+        }
+      if (token->opr.ctx_type == WORD_DELIM)
+        {
+          bin_tree_t *tree_first, *tree_last;
+          int idx_first, idx_last;
+          token->opr.ctx_type = WORD_FIRST;
+          idx_first = re_dfa_add_node (dfa, *token, 0);
+          tree_first = create_tree (NULL, NULL, 0, idx_first);
+          token->opr.ctx_type = WORD_LAST;
+          idx_last = re_dfa_add_node (dfa, *token, 0);
+          tree_last = create_tree (NULL, NULL, 0, idx_last);
+          token->type = OP_ALT;
+          new_idx = re_dfa_add_node (dfa, *token, 0);
+          tree = create_tree (tree_first, tree_last, 0, new_idx);
+          if (BE (idx_first == -1 || idx_last == -1 || new_idx == -1
+                  || tree_first == NULL || tree_last == NULL
+                  || tree == NULL, 0))
+            return *err = REG_ESPACE, NULL;
+        }
+      else
+        {
+          new_idx = re_dfa_add_node (dfa, *token, 0);
+          tree = create_tree (NULL, NULL, 0, new_idx);
+          if (BE (new_idx == -1 || tree == NULL, 0))
+            return *err = REG_ESPACE, NULL;
+        }
+      /* We must return here, since ANCHORs can't be followed
+         by repetition operators.
+         eg. RE"^*" is invalid or "<ANCHOR(^)><CHAR(*)>",
+             it must not be "<ANCHOR(^)><REPEAT(*)>".  */
+      *token = fetch_token (regexp, syntax);
+      return tree;
+    case OP_PERIOD:
+      new_idx = re_dfa_add_node (dfa, *token, 0);
+      tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+      if (MB_CUR_MAX > 1)
+        dfa->has_mb_node = 1;
+      break;
+    case OP_WORD:
+      tree = build_word_op (dfa, 0, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+      break;
+    case OP_NOTWORD:
+      tree = build_word_op (dfa, 1, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+      break;
+    case OP_ALT:
+    case END_OF_RE:
+      return NULL;
+    case BACK_SLASH:
+      *err = REG_EESCAPE;
+      return NULL;
+    default:
+      /* Must not happen?  */
+#ifdef DEBUG
+      assert (0);
+#endif
+      return NULL;
+    }
+  *token = fetch_token (regexp, syntax);
+
+  while (token->type == OP_DUP_ASTERISK || token->type == OP_DUP_PLUS
+         || token->type == OP_DUP_QUESTION || token->type == OP_OPEN_DUP_NUM)
+    {
+      tree = parse_dup_op (tree, regexp, dfa, token, syntax, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+      dfa->has_plural_match = 1;
+    }
+
+  return tree;
+}
+
+/* This function build the following tree, from regular expression
+   (<reg_exp>):
+         SUBEXP
+            |
+        <reg_exp>
+*/
+
+static bin_tree_t *
+parse_sub_exp (regexp, preg, token, syntax, nest, err)
+     re_string_t *regexp;
+     regex_t *preg;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     int nest;
+     reg_errcode_t *err;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  bin_tree_t *tree, *left_par, *right_par;
+  size_t cur_nsub;
+  int new_idx;
+  cur_nsub = preg->re_nsub++;
+  if (dfa->subexps_alloc < preg->re_nsub)
+    {
+      re_subexp_t *new_array;
+      dfa->subexps_alloc *= 2;
+      new_array = re_realloc (dfa->subexps, re_subexp_t, dfa->subexps_alloc);
+      if (BE (new_array == NULL, 0))
+	{
+	  dfa->subexps_alloc /= 2;
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+      dfa->subexps = new_array;
+    }
+  dfa->subexps[cur_nsub].start = dfa->nodes_len;
+  dfa->subexps[cur_nsub].end = -1;
+
+  new_idx = re_dfa_add_node (dfa, *token, 0);
+  left_par = create_tree (NULL, NULL, 0, new_idx);
+  if (BE (new_idx == -1 || left_par == NULL, 0))
+    return *err = REG_ESPACE, NULL;
+  dfa->nodes[new_idx].opr.idx = cur_nsub;
+  *token = fetch_token (regexp, syntax);
+
+  /* The subexpression may be a null string.  */
+  if (token->type == OP_CLOSE_SUBEXP)
+    tree = NULL;
+  else
+    {
+      tree = parse_reg_exp (regexp, preg, token, syntax, nest, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+        return NULL;
+    }
+  if (BE (token->type != OP_CLOSE_SUBEXP, 0))
+    {
+      free_bin_tree (tree);
+      *err = REG_BADPAT;
+      return NULL;
+    }
+  new_idx = re_dfa_add_node (dfa, *token, 0);
+  dfa->subexps[cur_nsub].end = dfa->nodes_len;
+  right_par = create_tree (NULL, NULL, 0, new_idx);
+  tree = ((tree == NULL) ? right_par
+          : create_tree (tree, right_par, CONCAT, 0));
+  tree = create_tree (left_par, tree, CONCAT, 0);
+  if (BE (new_idx == -1 || right_par == NULL || tree == NULL, 0))
+    return *err = REG_ESPACE, NULL;
+  dfa->nodes[new_idx].opr.idx = cur_nsub;
+
+  return tree;
+}
+
+/* This function parse repetition operators like "*", "+", "{1,3}" etc.  */
+
+static bin_tree_t *
+parse_dup_op (dup_elem, regexp, dfa, token, syntax, err)
+     bin_tree_t *dup_elem;
+     re_string_t *regexp;
+     re_dfa_t *dfa;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     reg_errcode_t *err;
+{
+  re_token_t dup_token;
+  bin_tree_t *tree = dup_elem, *work_tree;
+  int new_idx, start_idx = re_string_cur_idx (regexp);
+  re_token_t start_token = *token;
+  if (token->type == OP_OPEN_DUP_NUM)
+    {
+      int i;
+      int end = 0;
+      int start = fetch_number (regexp, token, syntax);
+      bin_tree_t *elem;
+      if (start == -1)
+        {
+          if (token->type == CHARACTER && token->opr.c == ',')
+            start = 0; /* We treat "{,m}" as "{0,m}".  */
+          else
+            {
+              *err = REG_BADBR; /* <re>{} is invalid.  */
+              return NULL;
+            }
+        }
+      if (BE (start != -2, 1))
+        {
+          /* We treat "{n}" as "{n,n}".  */
+          end = ((token->type == OP_CLOSE_DUP_NUM) ? start
+                 : ((token->type == CHARACTER && token->opr.c == ',')
+                    ? fetch_number (regexp, token, syntax) : -2));
+        }
+      if (BE (start == -2 || end == -2, 0))
+        {
+          /* Invalid sequence.  */
+          if (token->type == OP_CLOSE_DUP_NUM)
+            goto parse_dup_op_invalid_interval;
+          else
+            goto parse_dup_op_ebrace;
+        }
+      if (BE (start == 0 && end == 0, 0))
+        {
+          /* We treat "<re>{0}" and "<re>{0,0}" as null string.  */
+          *token = fetch_token (regexp, syntax);
+          free_bin_tree (dup_elem);
+          return NULL;
+        }
+
+      /* Extract "<re>{n,m}" to "<re><re>...<re><re>{0,<m-n>}".  */
+      elem = tree;
+      for (i = 0; i < start; ++i)
+        if (i != 0)
+          {
+            work_tree = duplicate_tree (elem, dfa);
+            tree = create_tree (tree, work_tree, CONCAT, 0);
+            if (BE (work_tree == NULL || tree == NULL, 0))
+              goto parse_dup_op_espace;
+          }
+
+      if (end == -1)
+        {
+          /* We treat "<re>{0,}" as "<re>*".  */
+          dup_token.type = OP_DUP_ASTERISK;
+          if (start > 0)
+            {
+              elem = duplicate_tree (elem, dfa);
+              new_idx = re_dfa_add_node (dfa, dup_token, 0);
+              work_tree = create_tree (elem, NULL, 0, new_idx);
+              tree = create_tree (tree, work_tree, CONCAT, 0);
+              if (BE (elem == NULL || new_idx == -1 || work_tree == NULL
+                      || tree == NULL, 0))
+                goto parse_dup_op_espace;
+            }
+          else
+            {
+              new_idx = re_dfa_add_node (dfa, dup_token, 0);
+              tree = create_tree (elem, NULL, 0, new_idx);
+              if (BE (new_idx == -1 || tree == NULL, 0))
+                goto parse_dup_op_espace;
+            }
+        }
+      else if (end - start > 0)
+        {
+          /* Then extract "<re>{0,m}" to "<re>?<re>?...<re>?".  */
+          dup_token.type = OP_DUP_QUESTION;
+          if (start > 0)
+            {
+              elem = duplicate_tree (elem, dfa);
+              new_idx = re_dfa_add_node (dfa, dup_token, 0);
+              elem = create_tree (elem, NULL, 0, new_idx);
+              tree = create_tree (tree, elem, CONCAT, 0);
+              if (BE (elem == NULL || new_idx == -1 || tree == NULL, 0))
+                goto parse_dup_op_espace;
+            }
+          else
+            {
+              new_idx = re_dfa_add_node (dfa, dup_token, 0);
+              tree = elem = create_tree (elem, NULL, 0, new_idx);
+              if (BE (new_idx == -1 || tree == NULL, 0))
+                goto parse_dup_op_espace;
+            }
+          for (i = 1; i < end - start; ++i)
+            {
+              work_tree = duplicate_tree (elem, dfa);
+              tree = create_tree (tree, work_tree, CONCAT, 0);
+              if (BE (work_tree == NULL || tree == NULL, 0))
+                return *err = REG_ESPACE, NULL;
+            }
+        }
+    }
+  else
+    {
+      new_idx = re_dfa_add_node (dfa, *token, 0);
+      tree = create_tree (tree, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || tree == NULL, 0))
+        return *err = REG_ESPACE, NULL;
+    }
+  *token = fetch_token (regexp, syntax);
+  return tree;
+
+ parse_dup_op_espace:
+  free_bin_tree (tree);
+  *err = REG_ESPACE;
+  return NULL;
+
+ parse_dup_op_ebrace:
+  if (BE (!(syntax & RE_INVALID_INTERVAL_ORD), 0))
+    {
+      *err = REG_EBRACE;
+      return NULL;
+    }
+  goto parse_dup_op_rollback;
+ parse_dup_op_invalid_interval:
+  if (BE (!(syntax & RE_INVALID_INTERVAL_ORD), 0))
+    {
+      *err = REG_BADBR;
+      return NULL;
+    }
+ parse_dup_op_rollback:
+  re_string_set_index (regexp, start_idx);
+  *token = start_token;
+  token->type = CHARACTER;
+  return dup_elem;
+}
+
+/* Size of the names for collating symbol/equivalence_class/character_class.
+   I'm not sure, but maybe enough.  */
+#define BRACKET_NAME_BUF_SIZE 32
+
+#ifndef _LIBC
+  /* Local function for parse_bracket_exp only used in case of NOT _LIBC.
+     Build the range expression which starts from START_ELEM, and ends
+     at END_ELEM.  The result are written to MBCSET and SBCSET.
+     RANGE_ALLOC is the allocated size of mbcset->range_starts, and
+     mbcset->range_ends, is a pointer argument sinse we may
+     update it.  */
+
+static reg_errcode_t
+# ifdef RE_ENABLE_I18N
+build_range_exp (sbcset, mbcset, range_alloc, start_elem, end_elem)
+     re_charset_t *mbcset;
+     int *range_alloc;
+# else /* not RE_ENABLE_I18N */
+build_range_exp (sbcset, start_elem, end_elem)
+# endif /* not RE_ENABLE_I18N */
+     re_bitset_ptr_t sbcset;
+     bracket_elem_t *start_elem, *end_elem;
+{
+  unsigned int start_ch, end_ch;
+  /* Equivalence Classes and Character Classes can't be a range start/end.  */
+  if (BE (start_elem->type == EQUIV_CLASS || start_elem->type == CHAR_CLASS
+          || end_elem->type == EQUIV_CLASS || end_elem->type == CHAR_CLASS,
+          0))
+    return REG_ERANGE;
+
+  /* We can handle no multi character collating elements without libc
+     support.  */
+  if (BE ((start_elem->type == COLL_SYM
+           && strlen ((char *) start_elem->opr.name) > 1)
+          || (end_elem->type == COLL_SYM
+              && strlen ((char *) end_elem->opr.name) > 1), 0))
+    return REG_ECOLLATE;
+
+# ifdef RE_ENABLE_I18N
+  {
+    wchar_t wc, start_wc, end_wc;
+    wchar_t cmp_buf[6] = {L'\0', L'\0', L'\0', L'\0', L'\0', L'\0'};
+
+    start_ch = ((start_elem->type == SB_CHAR) ? start_elem->opr.ch
+                : ((start_elem->type == COLL_SYM) ? start_elem->opr.name[0]
+                   : 0));
+    end_ch = ((end_elem->type == SB_CHAR) ? end_elem->opr.ch
+              : ((end_elem->type == COLL_SYM) ? end_elem->opr.name[0]
+                 : 0));
+    start_wc = ((start_elem->type == SB_CHAR || start_elem->type == COLL_SYM)
+                ? __btowc (start_ch) : start_elem->opr.wch);
+    end_wc = ((end_elem->type == SB_CHAR || end_elem->type == COLL_SYM)
+              ? __btowc (end_ch) : end_elem->opr.wch);
+    cmp_buf[0] = start_wc;
+    cmp_buf[4] = end_wc;
+    if (wcscoll (cmp_buf, cmp_buf + 4) > 0)
+      return REG_ERANGE;
+
+    /* Check the space of the arrays.  */
+    if (*range_alloc == mbcset->nranges)
+      {
+        /* There are not enough space, need realloc.  */
+        wchar_t *new_array_start, *new_array_end;
+        int new_nranges;
+
+        /* +1 in case of mbcset->nranges is 0.  */
+        new_nranges = 2 * mbcset->nranges + 1;
+        /* Use realloc since mbcset->range_starts and mbcset->range_ends
+           are NULL if *range_alloc == 0.  */
+        new_array_start = re_realloc (mbcset->range_starts, wchar_t,
+                                      new_nranges);
+        new_array_end = re_realloc (mbcset->range_ends, wchar_t,
+                                    new_nranges);
+
+        if (BE (new_array_start == NULL || new_array_end == NULL, 0))
+          return REG_ESPACE;
+
+        mbcset->range_starts = new_array_start;
+        mbcset->range_ends = new_array_end;
+        *range_alloc = new_nranges;
+      }
+
+    mbcset->range_starts[mbcset->nranges] = start_wc;
+    mbcset->range_ends[mbcset->nranges++] = end_wc;
+
+    /* Build the table for single byte characters.  */
+    for (wc = 0; wc <= SBC_MAX; ++wc)
+      {
+        cmp_buf[2] = wc;
+        if (wcscoll (cmp_buf, cmp_buf + 2) <= 0
+            && wcscoll (cmp_buf + 2, cmp_buf + 4) <= 0)
+          bitset_set (sbcset, wc);
+      }
+  }
+# else /* not RE_ENABLE_I18N */
+  {
+    unsigned int ch;
+    start_ch = ((start_elem->type == SB_CHAR ) ? start_elem->opr.ch
+                : ((start_elem->type == COLL_SYM) ? start_elem->opr.name[0]
+                   : 0));
+    end_ch = ((end_elem->type == SB_CHAR ) ? end_elem->opr.ch
+              : ((end_elem->type == COLL_SYM) ? end_elem->opr.name[0]
+                 : 0));
+    if (start_ch > end_ch)
+      return REG_ERANGE;
+    /* Build the table for single byte characters.  */
+    for (ch = 0; ch <= SBC_MAX; ++ch)
+      if (start_ch <= ch  && ch <= end_ch)
+        bitset_set (sbcset, ch);
+  }
+# endif /* not RE_ENABLE_I18N */
+  return REG_NOERROR;
+}
+#endif /* not _LIBC */
+
+#ifndef _LIBC
+/* Helper function for parse_bracket_exp only used in case of NOT _LIBC..
+   Build the collating element which is represented by NAME.
+   The result are written to MBCSET and SBCSET.
+   COLL_SYM_ALLOC is the allocated size of mbcset->coll_sym, is a
+   pointer argument since we may update it.  */
+
+static reg_errcode_t
+# ifdef RE_ENABLE_I18N
+build_collating_symbol (sbcset, mbcset, coll_sym_alloc, name)
+     re_charset_t *mbcset;
+     int *coll_sym_alloc;
+# else /* not RE_ENABLE_I18N */
+build_collating_symbol (sbcset, name)
+# endif /* not RE_ENABLE_I18N */
+     re_bitset_ptr_t sbcset;
+     const unsigned char *name;
+{
+  size_t name_len = strlen ((const char *) name);
+  if (BE (name_len != 1, 0))
+    return REG_ECOLLATE;
+  else
+    {
+      bitset_set (sbcset, name[0]);
+      return REG_NOERROR;
+    }
+}
+#endif /* not _LIBC */
+
+/* This function parse bracket expression like "[abc]", "[a-c]",
+   "[[.a-a.]]" etc.  */
+
+static bin_tree_t *
+parse_bracket_exp (regexp, dfa, token, syntax, err)
+     re_string_t *regexp;
+     re_dfa_t *dfa;
+     re_token_t *token;
+     reg_syntax_t syntax;
+     reg_errcode_t *err;
+{
+#ifdef _LIBC
+  const unsigned char *collseqmb;
+  const char *collseqwc;
+  uint32_t nrules;
+  int32_t table_size;
+  const int32_t *symb_table;
+  const unsigned char *extra;
+
+  /* Local function for parse_bracket_exp used in _LIBC environement.
+     Seek the collating symbol entry correspondings to NAME.
+     Return the index of the symbol in the SYMB_TABLE.  */
+
+  static inline int32_t
+  seek_collating_symbol_entry (name, name_len)
+         const unsigned char *name;
+         size_t name_len;
+    {
+      int32_t hash = elem_hash ((const char *) name, name_len);
+      int32_t elem = hash % table_size;
+      int32_t second = hash % (table_size - 2);
+      while (symb_table[2 * elem] != 0)
+        {
+          /* First compare the hashing value.  */
+          if (symb_table[2 * elem] == hash
+              /* Compare the length of the name.  */
+              && name_len == extra[symb_table[2 * elem + 1]]
+              /* Compare the name.  */
+              && memcmp (name, &extra[symb_table[2 * elem + 1] + 1],
+                         name_len) == 0)
+            {
+              /* Yep, this is the entry.  */
+              break;
+            }
+
+          /* Next entry.  */
+          elem += second;
+        }
+      return elem;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environement.
+     Look up the collation sequence value of BR_ELEM.
+     Return the value if succeeded, UINT_MAX otherwise.  */
+
+  static inline unsigned int
+  lookup_collation_sequence_value (br_elem)
+         bracket_elem_t *br_elem;
+    {
+      if (br_elem->type == SB_CHAR)
+        {
+          /*
+          if (MB_CUR_MAX == 1)
+          */
+          if (nrules == 0)
+            return collseqmb[br_elem->opr.ch];
+          else
+            {
+              wint_t wc = __btowc (br_elem->opr.ch);
+              return collseq_table_lookup (collseqwc, wc);
+            }
+        }
+      else if (br_elem->type == MB_CHAR)
+        {
+          return collseq_table_lookup (collseqwc, br_elem->opr.wch);
+        }
+      else if (br_elem->type == COLL_SYM)
+        {
+          size_t sym_name_len = strlen ((char *) br_elem->opr.name);
+          if (nrules != 0)
+            {
+              int32_t elem, idx;
+              elem = seek_collating_symbol_entry (br_elem->opr.name,
+                                                  sym_name_len);
+              if (symb_table[2 * elem] != 0)
+                {
+                  /* We found the entry.  */
+                  idx = symb_table[2 * elem + 1];
+                  /* Skip the name of collating element name.  */
+                  idx += 1 + extra[idx];
+                  /* Skip the byte sequence of the collating element.  */
+                  idx += 1 + extra[idx];
+                  /* Adjust for the alignment.  */
+                  idx = (idx + 3) & ~3;
+                  /* Skip the multibyte collation sequence value.  */
+                  idx += sizeof (unsigned int);
+                  /* Skip the wide char sequence of the collating element.  */
+                  idx += sizeof (unsigned int) *
+                    (1 + *(unsigned int *) (extra + idx));
+                  /* Return the collation sequence value.  */
+                  return *(unsigned int *) (extra + idx);
+                }
+              else if (symb_table[2 * elem] == 0 && sym_name_len == 1)
+                {
+                  /* No valid character.  Match it as a single byte
+                     character.  */
+                  return collseqmb[br_elem->opr.name[0]];
+                }
+            }
+          else if (sym_name_len == 1)
+            return collseqmb[br_elem->opr.name[0]];
+        }
+      return UINT_MAX;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environement.
+     Build the range expression which starts from START_ELEM, and ends
+     at END_ELEM.  The result are written to MBCSET and SBCSET.
+     RANGE_ALLOC is the allocated size of mbcset->range_starts, and
+     mbcset->range_ends, is a pointer argument sinse we may
+     update it.  */
+
+  static inline reg_errcode_t
+# ifdef RE_ENABLE_I18N
+  build_range_exp (sbcset, mbcset, range_alloc, start_elem, end_elem)
+         re_charset_t *mbcset;
+         int *range_alloc;
+# else /* not RE_ENABLE_I18N */
+  build_range_exp (sbcset, start_elem, end_elem)
+# endif /* not RE_ENABLE_I18N */
+         re_bitset_ptr_t sbcset;
+         bracket_elem_t *start_elem, *end_elem;
+    {
+      unsigned int ch;
+      uint32_t start_collseq;
+      uint32_t end_collseq;
+
+# ifdef RE_ENABLE_I18N
+      /* Check the space of the arrays.  */
+      if (*range_alloc == mbcset->nranges)
+        {
+          /* There are not enough space, need realloc.  */
+          uint32_t *new_array_start;
+          uint32_t *new_array_end;
+	  int new_nranges;
+
+          /* +1 in case of mbcset->nranges is 0.  */
+          new_nranges = 2 * mbcset->nranges + 1;
+	  /* Use realloc since mbcset->range_starts and mbcset->range_ends
+             are NULL if *range_alloc == 0.  */
+          new_array_start = re_realloc (mbcset->range_starts, uint32_t,
+                                        new_nranges);
+          new_array_end = re_realloc (mbcset->range_ends, uint32_t,
+                                      new_nranges);
+
+          if (BE (new_array_start == NULL || new_array_end == NULL, 0))
+            return REG_ESPACE;
+
+          mbcset->range_starts = new_array_start;
+          mbcset->range_ends = new_array_end;
+	  *range_alloc = new_nranges;
+        }
+# endif /* RE_ENABLE_I18N */
+
+      /* Equivalence Classes and Character Classes can't be a range
+         start/end.  */
+      if (BE (start_elem->type == EQUIV_CLASS || start_elem->type == CHAR_CLASS
+              || end_elem->type == EQUIV_CLASS || end_elem->type == CHAR_CLASS,
+              0))
+        return REG_ERANGE;
+
+      start_collseq = lookup_collation_sequence_value (start_elem);
+      end_collseq = lookup_collation_sequence_value (end_elem);
+      /* Check start/end collation sequence values.  */
+      if (BE (start_collseq == UINT_MAX || end_collseq == UINT_MAX, 0))
+        return REG_ECOLLATE;
+      if (BE ((syntax & RE_NO_EMPTY_RANGES) && start_collseq > end_collseq, 0))
+        return REG_ERANGE;
+
+# ifdef RE_ENABLE_I18N
+      /* Got valid collation sequence values, add them as a new entry.  */
+      mbcset->range_starts[mbcset->nranges] = start_collseq;
+      mbcset->range_ends[mbcset->nranges++] = end_collseq;
+# endif /* RE_ENABLE_I18N */
+
+      /* Build the table for single byte characters.  */
+      for (ch = 0; ch <= SBC_MAX; ch++)
+        {
+          uint32_t ch_collseq;
+          /*
+          if (MB_CUR_MAX == 1)
+          */
+          if (nrules == 0)
+            ch_collseq = collseqmb[ch];
+          else
+            ch_collseq = collseq_table_lookup (collseqwc, __btowc (ch));
+          if (start_collseq <= ch_collseq && ch_collseq <= end_collseq)
+            bitset_set (sbcset, ch);
+        }
+      return REG_NOERROR;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environement.
+     Build the collating element which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     COLL_SYM_ALLOC is the allocated size of mbcset->coll_sym, is a
+     pointer argument sinse we may update it.  */
+
+  static inline reg_errcode_t
+# ifdef RE_ENABLE_I18N
+  build_collating_symbol (sbcset, mbcset, coll_sym_alloc, name)
+         re_charset_t *mbcset;
+         int *coll_sym_alloc;
+# else /* not RE_ENABLE_I18N */
+  build_collating_symbol (sbcset, name)
+# endif /* not RE_ENABLE_I18N */
+         re_bitset_ptr_t sbcset;
+         const unsigned char *name;
+    {
+      int32_t elem, idx;
+      size_t name_len = strlen ((const char *) name);
+      if (nrules != 0)
+        {
+          elem = seek_collating_symbol_entry (name, name_len);
+          if (symb_table[2 * elem] != 0)
+            {
+              /* We found the entry.  */
+              idx = symb_table[2 * elem + 1];
+              /* Skip the name of collating element name.  */
+              idx += 1 + extra[idx];
+            }
+          else if (symb_table[2 * elem] == 0 && name_len == 1)
+            {
+              /* No valid character, treat it as a normal
+                 character.  */
+              bitset_set (sbcset, name[0]);
+              return REG_NOERROR;
+            }
+          else
+            return REG_ECOLLATE;
+
+# ifdef RE_ENABLE_I18N
+          /* Got valid collation sequence, add it as a new entry.  */
+          /* Check the space of the arrays.  */
+          if (*coll_sym_alloc == mbcset->ncoll_syms)
+            {
+              /* Not enough, realloc it.  */
+              /* +1 in case of mbcset->ncoll_syms is 0.  */
+              *coll_sym_alloc = 2 * mbcset->ncoll_syms + 1;
+              /* Use realloc since mbcset->coll_syms is NULL
+                 if *alloc == 0.  */
+              mbcset->coll_syms = re_realloc (mbcset->coll_syms, int32_t,
+                                              *coll_sym_alloc);
+              if (BE (mbcset->coll_syms == NULL, 0))
+                return REG_ESPACE;
+            }
+          mbcset->coll_syms[mbcset->ncoll_syms++] = idx;
+# endif /* RE_ENABLE_I18N */
+          return REG_NOERROR;
+        }
+      else
+        {
+          if (BE (name_len != 1, 0))
+            return REG_ECOLLATE;
+          else
+            {
+              bitset_set (sbcset, name[0]);
+              return REG_NOERROR;
+            }
+        }
+    }
+#endif
+
+  re_token_t br_token;
+  re_bitset_ptr_t sbcset;
+#ifdef RE_ENABLE_I18N
+  re_charset_t *mbcset;
+  int coll_sym_alloc = 0, range_alloc = 0, mbchar_alloc = 0;
+  int equiv_class_alloc = 0, char_class_alloc = 0;
+#else /* not RE_ENABLE_I18N */
+  int non_match = 0;
+#endif /* not RE_ENABLE_I18N */
+  bin_tree_t *work_tree;
+  int token_len, new_idx;
+#ifdef _LIBC
+  collseqmb = (const unsigned char *)
+    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQMB);
+  nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules)
+    {
+      /*
+      if (MB_CUR_MAX > 1)
+      */
+        collseqwc = _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQWC);
+      table_size = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_SYMB_HASH_SIZEMB);
+      symb_table = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+                                                  _NL_COLLATE_SYMB_TABLEMB);
+      extra = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+                                                   _NL_COLLATE_SYMB_EXTRAMB);
+    }
+#endif
+  sbcset = (re_bitset_ptr_t) calloc (sizeof (unsigned int), BITSET_UINTS);
+#ifdef RE_ENABLE_I18N
+  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+#endif /* RE_ENABLE_I18N */
+#ifdef RE_ENABLE_I18N
+  if (BE (sbcset == NULL || mbcset == NULL, 0))
+#else
+  if (BE (sbcset == NULL, 0))
+#endif /* RE_ENABLE_I18N */
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+
+  token_len = peek_token_bracket (token, regexp, syntax);
+  if (BE (token->type == END_OF_RE, 0))
+    {
+      *err = REG_BADPAT;
+      goto parse_bracket_exp_free_return;
+    }
+  if (token->type == OP_NON_MATCH_LIST)
+    {
+#ifdef RE_ENABLE_I18N
+      int i;
+      mbcset->non_match = 1;
+#else /* not RE_ENABLE_I18N */
+      non_match = 1;
+#endif /* not RE_ENABLE_I18N */
+      if (syntax & RE_HAT_LISTS_NOT_NEWLINE)
+        bitset_set (sbcset, '\0');
+      re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+      token_len = peek_token_bracket (token, regexp, syntax);
+      if (BE (token->type == END_OF_RE, 0))
+        {
+          *err = REG_BADPAT;
+          goto parse_bracket_exp_free_return;
+        }
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        for (i = 0; i < SBC_MAX; ++i)
+          if (__btowc (i) == WEOF)
+            bitset_set (sbcset, i);
+#endif /* RE_ENABLE_I18N */
+    }
+
+  /* We treat the first ']' as a normal character.  */
+  if (token->type == OP_CLOSE_BRACKET)
+    token->type = CHARACTER;
+
+  while (1)
+    {
+      bracket_elem_t start_elem, end_elem;
+      unsigned char start_name_buf[BRACKET_NAME_BUF_SIZE];
+      unsigned char end_name_buf[BRACKET_NAME_BUF_SIZE];
+      reg_errcode_t ret;
+      int token_len2 = 0, is_range_exp = 0;
+      re_token_t token2;
+
+      start_elem.opr.name = start_name_buf;
+      ret = parse_bracket_element (&start_elem, regexp, token, token_len, dfa,
+                                   syntax);
+      if (BE (ret != REG_NOERROR, 0))
+        {
+          *err = ret;
+          goto parse_bracket_exp_free_return;
+        }
+
+      token_len = peek_token_bracket (token, regexp, syntax);
+      if (BE (token->type == END_OF_RE, 0))
+        {
+          *err = REG_BADPAT;
+          goto parse_bracket_exp_free_return;
+        }
+      if (token->type == OP_CHARSET_RANGE)
+        {
+          re_string_skip_bytes (regexp, token_len); /* Skip '-'.  */
+          token_len2 = peek_token_bracket (&token2, regexp, syntax);
+          if (BE (token->type == END_OF_RE, 0))
+            {
+              *err = REG_BADPAT;
+              goto parse_bracket_exp_free_return;
+            }
+          if (token2.type == OP_CLOSE_BRACKET)
+            {
+              /* We treat the last '-' as a normal character.  */
+              re_string_skip_bytes (regexp, -token_len);
+              token->type = CHARACTER;
+            }
+          else
+            is_range_exp = 1;
+        }
+
+      if (is_range_exp == 1)
+        {
+          end_elem.opr.name = end_name_buf;
+          ret = parse_bracket_element (&end_elem, regexp, &token2, token_len2,
+                                       dfa, syntax);
+          if (BE (ret != REG_NOERROR, 0))
+            {
+              *err = ret;
+              goto parse_bracket_exp_free_return;
+            }
+
+          token_len = peek_token_bracket (token, regexp, syntax);
+          if (BE (token->type == END_OF_RE, 0))
+            {
+              *err = REG_BADPAT;
+              goto parse_bracket_exp_free_return;
+            }
+          *err = build_range_exp (sbcset,
+#ifdef RE_ENABLE_I18N
+                                  mbcset, &range_alloc,
+#endif /* RE_ENABLE_I18N */
+                                  &start_elem, &end_elem);
+          if (BE (*err != REG_NOERROR, 0))
+            goto parse_bracket_exp_free_return;
+        }
+      else
+        {
+          switch (start_elem.type)
+            {
+            case SB_CHAR:
+              bitset_set (sbcset, start_elem.opr.ch);
+              break;
+#ifdef RE_ENABLE_I18N
+            case MB_CHAR:
+              /* Check whether the array has enough space.  */
+              if (mbchar_alloc == mbcset->nmbchars)
+                {
+                  /* Not enough, realloc it.  */
+                  /* +1 in case of mbcset->nmbchars is 0.  */
+                  mbchar_alloc = 2 * mbcset->nmbchars + 1;
+                  /* Use realloc since array is NULL if *alloc == 0.  */
+                  mbcset->mbchars = re_realloc (mbcset->mbchars, wchar_t,
+                                                mbchar_alloc);
+                  if (BE (mbcset->mbchars == NULL, 0))
+                    goto parse_bracket_exp_espace;
+                }
+              mbcset->mbchars[mbcset->nmbchars++] = start_elem.opr.wch;
+              break;
+#endif /* RE_ENABLE_I18N */
+            case EQUIV_CLASS:
+              *err = build_equiv_class (sbcset,
+#ifdef RE_ENABLE_I18N
+                                        mbcset, &equiv_class_alloc,
+#endif /* RE_ENABLE_I18N */
+					start_elem.opr.name);
+              if (BE (*err != REG_NOERROR, 0))
+                goto parse_bracket_exp_free_return;
+              break;
+            case COLL_SYM:
+              *err = build_collating_symbol (sbcset,
+#ifdef RE_ENABLE_I18N
+                                             mbcset, &coll_sym_alloc,
+#endif /* RE_ENABLE_I18N */
+					     start_elem.opr.name);
+              if (BE (*err != REG_NOERROR, 0))
+                goto parse_bracket_exp_free_return;
+              break;
+            case CHAR_CLASS:
+              ret = build_charclass (sbcset,
+#ifdef RE_ENABLE_I18N
+                                     mbcset, &char_class_alloc,
+#endif /* RE_ENABLE_I18N */
+                                     start_elem.opr.name, syntax);
+              if (BE (ret != REG_NOERROR, 0))
+               goto parse_bracket_exp_espace;
+              break;
+            default:
+              assert (0);
+              break;
+            }
+        }
+      if (token->type == OP_CLOSE_BRACKET)
+        break;
+    }
+
+  re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+
+  /* If it is non-matching list.  */
+#ifdef RE_ENABLE_I18N
+  if (mbcset->non_match)
+#else /* not RE_ENABLE_I18N */
+  if (non_match)
+#endif /* not RE_ENABLE_I18N */
+    bitset_not (sbcset);
+
+  /* Build a tree for simple bracket.  */
+  br_token.type = SIMPLE_BRACKET;
+  br_token.opr.sbcset = sbcset;
+  new_idx = re_dfa_add_node (dfa, br_token, 0);
+  work_tree = create_tree (NULL, NULL, 0, new_idx);
+  if (BE (new_idx == -1 || work_tree == NULL, 0))
+    goto parse_bracket_exp_espace;
+
+#ifdef RE_ENABLE_I18N
+  if (mbcset->nmbchars || mbcset->ncoll_syms || mbcset->nequiv_classes
+      || mbcset->nranges || (MB_CUR_MAX > 1 && (mbcset->nchar_classes
+                                                || mbcset->non_match)))
+    {
+      re_token_t alt_token;
+      bin_tree_t *mbc_tree;
+      /* Build a tree for complex bracket.  */
+      br_token.type = COMPLEX_BRACKET;
+      br_token.opr.mbcset = mbcset;
+      dfa->has_mb_node = 1;
+      new_idx = re_dfa_add_node (dfa, br_token, 0);
+      mbc_tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || mbc_tree == NULL, 0))
+        goto parse_bracket_exp_espace;
+      /* Then join them by ALT node.  */
+      dfa->has_plural_match = 1;
+      alt_token.type = OP_ALT;
+      new_idx = re_dfa_add_node (dfa, alt_token, 0);
+      work_tree = create_tree (work_tree, mbc_tree, 0, new_idx);
+      if (BE (new_idx != -1 && mbc_tree != NULL, 1))
+        return work_tree;
+    }
+  else
+    {
+      free_charset (mbcset);
+      return work_tree;
+    }
+#else /* not RE_ENABLE_I18N */
+  return work_tree;
+#endif /* not RE_ENABLE_I18N */
+
+ parse_bracket_exp_espace:
+  *err = REG_ESPACE;
+ parse_bracket_exp_free_return:
+  re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+  free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+  return NULL;
+}
+
+/* Parse an element in the bracket expression.  */
+
+static reg_errcode_t
+parse_bracket_element (elem, regexp, token, token_len, dfa, syntax)
+     bracket_elem_t *elem;
+     re_string_t *regexp;
+     re_token_t *token;
+     int token_len;
+     re_dfa_t *dfa;
+     reg_syntax_t syntax;
+{
+#ifdef RE_ENABLE_I18N
+  int cur_char_size;
+  cur_char_size = re_string_char_size_at (regexp, re_string_cur_idx (regexp));
+  if (cur_char_size > 1)
+    {
+      elem->type = MB_CHAR;
+      elem->opr.wch = re_string_wchar_at (regexp, re_string_cur_idx (regexp));
+      re_string_skip_bytes (regexp, cur_char_size);
+      return REG_NOERROR;
+    }
+#endif /* RE_ENABLE_I18N */
+  re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+  if (token->type == OP_OPEN_COLL_ELEM || token->type == OP_OPEN_CHAR_CLASS
+      || token->type == OP_OPEN_EQUIV_CLASS)
+    return parse_bracket_symbol (elem, regexp, token);
+  elem->type = SB_CHAR;
+  elem->opr.ch = token->opr.c;
+  return REG_NOERROR;
+}
+
+/* Parse a bracket symbol in the bracket expression.  Bracket symbols are
+   such as [:<character_class>:], [.<collating_element>.], and
+   [=<equivalent_class>=].  */
+
+static reg_errcode_t
+parse_bracket_symbol (elem, regexp, token)
+     bracket_elem_t *elem;
+     re_string_t *regexp;
+     re_token_t *token;
+{
+  unsigned char ch, delim = token->opr.c;
+  int i = 0;
+  for (;; ++i)
+    {
+      if (re_string_eoi(regexp) || i >= BRACKET_NAME_BUF_SIZE)
+        return REG_EBRACK;
+      if (token->type == OP_OPEN_CHAR_CLASS)
+        ch = re_string_fetch_byte_case (regexp);
+      else
+        ch = re_string_fetch_byte (regexp);
+      if (ch == delim && re_string_peek_byte (regexp, 0) == ']')
+        break;
+      elem->opr.name[i] = ch;
+    }
+  re_string_skip_bytes (regexp, 1);
+  elem->opr.name[i] = '\0';
+  switch (token->type)
+    {
+    case OP_OPEN_COLL_ELEM:
+      elem->type = COLL_SYM;
+      break;
+    case OP_OPEN_EQUIV_CLASS:
+      elem->type = EQUIV_CLASS;
+      break;
+    case OP_OPEN_CHAR_CLASS:
+      elem->type = CHAR_CLASS;
+      break;
+    default:
+      break;
+    }
+  return REG_NOERROR;
+}
+
+  /* Helper function for parse_bracket_exp.
+     Build the equivalence class which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     EQUIV_CLASS_ALLOC is the allocated size of mbcset->equiv_classes,
+     is a pointer argument sinse we may update it.  */
+
+static reg_errcode_t
+#ifdef RE_ENABLE_I18N
+build_equiv_class (sbcset, mbcset, equiv_class_alloc, name)
+     re_charset_t *mbcset;
+     int *equiv_class_alloc;
+#else /* not RE_ENABLE_I18N */
+build_equiv_class (sbcset, name)
+#endif /* not RE_ENABLE_I18N */
+     re_bitset_ptr_t sbcset;
+     const unsigned char *name;
+{
+#if defined _LIBC && defined RE_ENABLE_I18N
+  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules != 0)
+    {
+      const int32_t *table, *indirect;
+      const unsigned char *weights, *extra, *cp;
+      unsigned char char_buf[2];
+      int32_t idx1, idx2;
+      unsigned int ch;
+      size_t len;
+      /* This #include defines a local function!  */
+# include <locale/weight.h>
+      /* Calculate the index for equivalence class.  */
+      cp = name;
+      table = (const int32_t *) _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+      weights = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+					       _NL_COLLATE_WEIGHTMB);
+      extra = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+                                                   _NL_COLLATE_EXTRAMB);
+      indirect = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+                                                _NL_COLLATE_INDIRECTMB);
+      idx1 = findidx (&cp);
+      if (BE (idx1 == 0 || cp < name + strlen ((const char *) name), 0))
+        /* This isn't a valid character.  */
+        return REG_ECOLLATE;
+
+      /* Build single byte matcing table for this equivalence class.  */
+      char_buf[1] = (unsigned char) '\0';
+      len = weights[idx1];
+      for (ch = 0; ch < SBC_MAX; ++ch)
+        {
+          char_buf[0] = ch;
+          cp = char_buf;
+          idx2 = findidx (&cp);
+/*
+          idx2 = table[ch];
+*/
+          if (idx2 == 0)
+            /* This isn't a valid character.  */
+            continue;
+          if (len == weights[idx2])
+            {
+              int cnt = 0;
+              while (cnt <= len &&
+                     weights[idx1 + 1 + cnt] == weights[idx2 + 1 + cnt])
+                ++cnt;
+
+              if (cnt > len)
+                bitset_set (sbcset, ch);
+            }
+        }
+      /* Check whether the array has enough space.  */
+      if (*equiv_class_alloc == mbcset->nequiv_classes)
+        {
+          /* Not enough, realloc it.  */
+          /* +1 in case of mbcset->nequiv_classes is 0.  */
+          *equiv_class_alloc = 2 * mbcset->nequiv_classes + 1;
+          /* Use realloc since the array is NULL if *alloc == 0.  */
+          mbcset->equiv_classes = re_realloc (mbcset->equiv_classes, int32_t,
+                                              *equiv_class_alloc);
+          if (BE (mbcset->equiv_classes == NULL, 0))
+            return REG_ESPACE;
+        }
+      mbcset->equiv_classes[mbcset->nequiv_classes++] = idx1;
+    }
+  else
+#endif /* _LIBC && RE_ENABLE_I18N */
+    {
+      if (BE (strlen ((const char *) name) != 1, 0))
+        return REG_ECOLLATE;
+      bitset_set (sbcset, *name);
+    }
+  return REG_NOERROR;
+}
+
+  /* Helper function for parse_bracket_exp.
+     Build the character class which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     CHAR_CLASS_ALLOC is the allocated size of mbcset->char_classes,
+     is a pointer argument sinse we may update it.  */
+
+static reg_errcode_t
+#ifdef RE_ENABLE_I18N
+build_charclass (sbcset, mbcset, char_class_alloc, class_name, syntax)
+     re_charset_t *mbcset;
+     int *char_class_alloc;
+#else /* not RE_ENABLE_I18N */
+build_charclass (sbcset, class_name, syntax)
+#endif /* not RE_ENABLE_I18N */
+     re_bitset_ptr_t sbcset;
+     const unsigned char *class_name;
+     reg_syntax_t syntax;
+{
+  int i;
+  const char *name = (const char *) class_name;
+
+  /* In case of REG_ICASE "upper" and "lower" match the both of
+     upper and lower cases.  */
+  if ((syntax & RE_ICASE)
+      && (strcmp (name, "upper") == 0 || strcmp (name, "lower") == 0))
+    name = "alpha";
+
+#ifdef RE_ENABLE_I18N
+  /* Check the space of the arrays.  */
+  if (*char_class_alloc == mbcset->nchar_classes)
+    {
+      /* Not enough, realloc it.  */
+      /* +1 in case of mbcset->nchar_classes is 0.  */
+      *char_class_alloc = 2 * mbcset->nchar_classes + 1;
+      /* Use realloc since array is NULL if *alloc == 0.  */
+      mbcset->char_classes = re_realloc (mbcset->char_classes, wctype_t,
+                                         *char_class_alloc);
+      if (BE (mbcset->char_classes == NULL, 0))
+        return REG_ESPACE;
+    }
+  mbcset->char_classes[mbcset->nchar_classes++] = __wctype (name);
+#endif /* RE_ENABLE_I18N */
+
+#define BUILD_CHARCLASS_LOOP(ctype_func)\
+    for (i = 0; i < SBC_MAX; ++i)	\
+      {					\
+        if (ctype_func (i))		\
+          bitset_set (sbcset, i);	\
+      }
+
+  if (strcmp (name, "alnum") == 0)
+    BUILD_CHARCLASS_LOOP (isalnum)
+  else if (strcmp (name, "cntrl") == 0)
+    BUILD_CHARCLASS_LOOP (iscntrl)
+  else if (strcmp (name, "lower") == 0)
+    BUILD_CHARCLASS_LOOP (islower)
+  else if (strcmp (name, "space") == 0)
+    BUILD_CHARCLASS_LOOP (isspace)
+  else if (strcmp (name, "alpha") == 0)
+    BUILD_CHARCLASS_LOOP (isalpha)
+  else if (strcmp (name, "digit") == 0)
+    BUILD_CHARCLASS_LOOP (isdigit)
+  else if (strcmp (name, "print") == 0)
+    BUILD_CHARCLASS_LOOP (isprint)
+  else if (strcmp (name, "upper") == 0)
+    BUILD_CHARCLASS_LOOP (isupper)
+  else if (strcmp (name, "blank") == 0)
+    BUILD_CHARCLASS_LOOP (isblank)
+  else if (strcmp (name, "graph") == 0)
+    BUILD_CHARCLASS_LOOP (isgraph)
+  else if (strcmp (name, "punct") == 0)
+    BUILD_CHARCLASS_LOOP (ispunct)
+  else if (strcmp (name, "xdigit") == 0)
+    BUILD_CHARCLASS_LOOP (isxdigit)
+  else
+    return REG_ECTYPE;
+
+  return REG_NOERROR;
+}
+
+static bin_tree_t *
+build_word_op (dfa, not, err)
+     re_dfa_t *dfa;
+     int not;
+     reg_errcode_t *err;
+{
+  re_bitset_ptr_t sbcset;
+#ifdef RE_ENABLE_I18N
+  re_charset_t *mbcset;
+  int alloc = 0;
+#else /* not RE_ENABLE_I18N */
+  int non_match = 0;
+#endif /* not RE_ENABLE_I18N */
+  reg_errcode_t ret;
+  re_token_t br_token;
+  bin_tree_t *tree;
+  int new_idx;
+
+  sbcset = (re_bitset_ptr_t) calloc (sizeof (unsigned int), BITSET_UINTS);
+#ifdef RE_ENABLE_I18N
+  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+#endif /* RE_ENABLE_I18N */
+
+#ifdef RE_ENABLE_I18N
+  if (BE (sbcset == NULL || mbcset == NULL, 0))
+#else /* not RE_ENABLE_I18N */
+  if (BE (sbcset == NULL, 0))
+#endif /* not RE_ENABLE_I18N */
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+
+  if (not)
+    {
+#ifdef RE_ENABLE_I18N
+      int i;
+      /*
+      if (syntax & RE_HAT_LISTS_NOT_NEWLINE)
+        bitset_set(cset->sbcset, '\0');
+      */
+      mbcset->non_match = 1;
+      if (MB_CUR_MAX > 1)
+        for (i = 0; i < SBC_MAX; ++i)
+          if (__btowc (i) == WEOF)
+            bitset_set (sbcset, i);
+#else /* not RE_ENABLE_I18N */
+      non_match = 1;
+#endif /* not RE_ENABLE_I18N */
+    }
+
+  /* We don't care the syntax in this case.  */
+  ret = build_charclass (sbcset,
+#ifdef RE_ENABLE_I18N
+                         mbcset, &alloc,
+#endif /* RE_ENABLE_I18N */
+                         (const unsigned char *) "alpha", 0);
+
+  if (BE (ret != REG_NOERROR, 0))
+    {
+      re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+      free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+      *err = REG_ESPACE;
+      return NULL;
+    }
+  /* \w match '_' also.  */
+  bitset_set (sbcset, '_');
+
+  /* If it is non-matching list.  */
+#ifdef RE_ENABLE_I18N
+  if (mbcset->non_match)
+#else /* not RE_ENABLE_I18N */
+  if (non_match)
+#endif /* not RE_ENABLE_I18N */
+    bitset_not (sbcset);
+
+  /* Build a tree for simple bracket.  */
+  br_token.type = SIMPLE_BRACKET;
+  br_token.opr.sbcset = sbcset;
+  new_idx = re_dfa_add_node (dfa, br_token, 0);
+  tree = create_tree (NULL, NULL, 0, new_idx);
+  if (BE (new_idx == -1 || tree == NULL, 0))
+    goto build_word_op_espace;
+
+#ifdef RE_ENABLE_I18N
+  if (MB_CUR_MAX > 1)
+    {
+      re_token_t alt_token;
+      bin_tree_t *mbc_tree;
+      /* Build a tree for complex bracket.  */
+      br_token.type = COMPLEX_BRACKET;
+      br_token.opr.mbcset = mbcset;
+      dfa->has_mb_node = 1;
+      new_idx = re_dfa_add_node (dfa, br_token, 0);
+      mbc_tree = create_tree (NULL, NULL, 0, new_idx);
+      if (BE (new_idx == -1 || mbc_tree == NULL, 0))
+        goto build_word_op_espace;
+      /* Then join them by ALT node.  */
+      alt_token.type = OP_ALT;
+      new_idx = re_dfa_add_node (dfa, alt_token, 0);
+      tree = create_tree (tree, mbc_tree, 0, new_idx);
+      if (BE (new_idx != -1 && mbc_tree != NULL, 1))
+        return tree;
+    }
+  else
+    {
+      free_charset (mbcset);
+      return tree;
+    }
+#else /* not RE_ENABLE_I18N */
+  return tree;
+#endif /* not RE_ENABLE_I18N */
+
+ build_word_op_espace:
+  re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+  free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+  *err = REG_ESPACE;
+  return NULL;
+}
+
+/* This is intended for the expressions like "a{1,3}".
+   Fetch a number from `input', and return the number.
+   Return -1, if the number field is empty like "{,1}".
+   Return -2, If an error is occured.  */
+
+static int
+fetch_number (input, token, syntax)
+     re_string_t *input;
+     re_token_t *token;
+     reg_syntax_t syntax;
+{
+  int num = -1;
+  unsigned char c;
+  while (1)
+    {
+      *token = fetch_token (input, syntax);
+      c = token->opr.c;
+      if (BE (token->type == END_OF_RE, 0))
+        return -2;
+      if (token->type == OP_CLOSE_DUP_NUM || c == ',')
+        break;
+      num = ((token->type != CHARACTER || c < '0' || '9' < c || num == -2)
+             ? -2 : ((num == -1) ? c - '0' : num * 10 + c - '0'));
+      num = (num > RE_DUP_MAX) ? -2 : num;
+    }
+  return num;
+}
+
+#ifdef RE_ENABLE_I18N
+static void
+free_charset (re_charset_t *cset)
+{
+  re_free (cset->mbchars);
+# ifdef _LIBC
+  re_free (cset->coll_syms);
+  re_free (cset->equiv_classes);
+  re_free (cset->range_starts);
+  re_free (cset->range_ends);
+# endif
+  re_free (cset->char_classes);
+  re_free (cset);
+}
+#endif /* RE_ENABLE_I18N */
+
+/* Functions for binary tree operation.  */
+
+/* Create a node of tree.
+   Note: This function automatically free left and right if malloc fails.  */
+
+static bin_tree_t *
+create_tree (left, right, type, index)
+     bin_tree_t *left;
+     bin_tree_t *right;
+     re_token_type_t type;
+     int index;
+{
+  bin_tree_t *tree;
+  tree = re_malloc (bin_tree_t, 1);
+  if (BE (tree == NULL, 0))
+    {
+      free_bin_tree (left);
+      free_bin_tree (right);
+      return NULL;
+    }
+  tree->parent = NULL;
+  tree->left = left;
+  tree->right = right;
+  tree->type = type;
+  tree->node_idx = index;
+  tree->first = -1;
+  tree->next = -1;
+  re_node_set_init_empty (&tree->eclosure);
+
+  if (left != NULL)
+    left->parent = tree;
+  if (right != NULL)
+    right->parent = tree;
+  return tree;
+}
+
+/* Free the sub tree pointed by TREE.  */
+
+static void
+free_bin_tree (tree)
+     bin_tree_t *tree;
+{
+  if (tree == NULL)
+    return;
+  /*re_node_set_free (&tree->eclosure);*/
+  free_bin_tree (tree->left);
+  free_bin_tree (tree->right);
+  re_free (tree);
+}
+
+/* Duplicate the node SRC, and return new node.  */
+
+static bin_tree_t *
+duplicate_tree (src, dfa)
+     const bin_tree_t *src;
+     re_dfa_t *dfa;
+{
+  bin_tree_t *left = NULL, *right = NULL, *new_tree;
+  int new_node_idx;
+  /* Since node indies must be according to Post-order of the tree,
+     we must duplicate the left at first.  */
+  if (src->left != NULL)
+    {
+      left = duplicate_tree (src->left, dfa);
+      if (left == NULL)
+        return NULL;
+    }
+
+  /* Secondaly, duplicate the right.  */
+  if (src->right != NULL)
+    {
+      right = duplicate_tree (src->right, dfa);
+      if (right == NULL)
+        {
+          free_bin_tree (left);
+          return NULL;
+        }
+    }
+
+  /* At last, duplicate itself.  */
+  if (src->type == NON_TYPE)
+    {
+      new_node_idx = re_dfa_add_node (dfa, dfa->nodes[src->node_idx], 0);
+      dfa->nodes[new_node_idx].duplicated = 1;
+      if (BE (new_node_idx == -1, 0))
+        {
+          free_bin_tree (left);
+          free_bin_tree (right);
+          return NULL;
+        }
+    }
+  else
+    new_node_idx = src->type;
+
+  new_tree = create_tree (left, right, src->type, new_node_idx);
+  if (BE (new_tree == NULL, 0))
+    {
+      free_bin_tree (left);
+      free_bin_tree (right);
+    }
+  return new_tree;
+}
diff --git a/util/regex.c b/util/regex.c
new file mode 100644
index 000000000..1d5dd0f53
--- /dev/null
+++ b/util/regex.c
@@ -0,0 +1,62 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email protected]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifdef _LIBC
+/* We have to keep the namespace clean.  */
+#  define regfree(preg) __regfree (preg)
+#  define regexec(pr, st, nm, pm, ef) __regexec (pr, st, nm, pm, ef)
+#  define regcomp(preg, pattern, cflags) __regcomp (preg, pattern, cflags)
+#  define regerror(errcode, preg, errbuf, errbuf_size) \
+	__regerror(errcode, preg, errbuf, errbuf_size)
+#  define re_set_registers(bu, re, nu, st, en) \
+	__re_set_registers (bu, re, nu, st, en)
+#  define re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop) \
+	__re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+#  define re_match(bufp, string, size, pos, regs) \
+	__re_match (bufp, string, size, pos, regs)
+#  define re_search(bufp, string, size, startpos, range, regs) \
+	__re_search (bufp, string, size, startpos, range, regs)
+#  define re_compile_pattern(pattern, length, bufp) \
+	__re_compile_pattern (pattern, length, bufp)
+#  define re_set_syntax(syntax) __re_set_syntax (syntax)
+#  define re_search_2(bufp, st1, s1, st2, s2, startpos, range, regs, stop) \
+	__re_search_2 (bufp, st1, s1, st2, s2, startpos, range, regs, stop)
+#  define re_compile_fastmap(bufp) __re_compile_fastmap (bufp)
+#endif
+
+#if _LIBC || __GNUC__ >= 3
+# define BE(expr, val) __builtin_expect (expr, val)
+#else
+# define BE(expr, val) (expr)
+# define inline
+#endif
+
+#include "regcomp.c"
+#include "regexec.c"
+#include "regex_internal.c"
+
+/* Binary backward compatibility.  */
+#if _LIBC
+# include <shlib-compat.h>
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3)
+link_warning (re_max_failures, "the 're_max_failures' variable is obsolete and will go away.")
+int re_max_failures = 2000;
+# endif
+#endif
diff --git a/util/regex_internal.c b/util/regex_internal.c
new file mode 100644
index 000000000..94185bf89
--- /dev/null
+++ b/util/regex_internal.c
@@ -0,0 +1,1229 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email protected]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <assert.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined HAVE_WCHAR_H || defined _LIBC
+# include <wchar.h>
+#endif /* HAVE_WCHAR_H || _LIBC */
+#if defined HAVE_WCTYPE_H || defined _LIBC
+# include <wctype.h>
+#endif /* HAVE_WCTYPE_H || _LIBC */
+
+#ifdef _LIBC
+# ifndef _RE_DEFINE_LOCALE_FUNCTIONS
+#  define _RE_DEFINE_LOCALE_FUNCTIONS 1
+#  include <locale/localeinfo.h>
+#  include <locale/elem-hash.h>
+#  include <locale/coll-lookup.h>
+# endif
+#endif
+
+/* This is for other GNU distributions with internationalized messages.  */
+#if HAVE_LIBINTL_H || defined _LIBC
+# include <libintl.h>
+# ifdef _LIBC
+#  undef gettext
+#  define gettext(msgid) \
+  INTUSE(__dcgettext) (_libc_intl_domainname_internal, msgid, LC_MESSAGES)
+# endif
+#else
+# define gettext(msgid) (msgid)
+#endif
+
+#ifndef gettext_noop
+/* This define is so xgettext can find the internationalizable
+   strings.  */
+# define gettext_noop(String) String
+#endif
+
+#include "_regex.h" /* gnupg */
+#include "regex_internal.h"
+
+static void re_string_construct_common (const char *str, int len,
+                                        re_string_t *pstr,
+                                        RE_TRANSLATE_TYPE trans, int icase);
+#ifdef RE_ENABLE_I18N
+static int re_string_skip_chars (re_string_t *pstr, int new_raw_idx);
+#endif /* RE_ENABLE_I18N */
+static re_dfastate_t *create_newstate_common (re_dfa_t *dfa,
+                                              const re_node_set *nodes,
+                                              unsigned int hash);
+static reg_errcode_t register_state (re_dfa_t *dfa, re_dfastate_t *newstate,
+                                     unsigned int hash);
+static re_dfastate_t *create_ci_newstate (re_dfa_t *dfa,
+                                          const re_node_set *nodes,
+                                          unsigned int hash);
+static re_dfastate_t *create_cd_newstate (re_dfa_t *dfa,
+                                          const re_node_set *nodes,
+                                          unsigned int context,
+                                          unsigned int hash);
+static unsigned int inline calc_state_hash (const re_node_set *nodes,
+                                            unsigned int context);
+
+/* Functions for string operation.  */
+
+/* This function allocate the buffers.  It is necessary to call
+   re_string_reconstruct before using the object.  */
+
+static reg_errcode_t
+re_string_allocate (pstr, str, len, init_len, trans, icase)
+     re_string_t *pstr;
+     const char *str;
+     int len, init_len, icase;
+     RE_TRANSLATE_TYPE trans;
+{
+  reg_errcode_t ret;
+  int init_buf_len = (len + 1 < init_len) ? len + 1: init_len;
+  re_string_construct_common (str, len, pstr, trans, icase);
+  pstr->stop = pstr->len;
+
+  ret = re_string_realloc_buffers (pstr, init_buf_len);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  pstr->mbs_case = (MBS_CASE_ALLOCATED (pstr) ? pstr->mbs_case
+                    : (unsigned char *) str);
+  pstr->mbs = MBS_ALLOCATED (pstr) ? pstr->mbs : pstr->mbs_case;
+  pstr->valid_len = (MBS_CASE_ALLOCATED (pstr) || MBS_ALLOCATED (pstr)
+                     || MB_CUR_MAX > 1) ? pstr->valid_len : len;
+  return REG_NOERROR;
+}
+
+/* This function allocate the buffers, and initialize them.  */
+
+static reg_errcode_t
+re_string_construct (pstr, str, len, trans, icase)
+     re_string_t *pstr;
+     const char *str;
+     int len, icase;
+     RE_TRANSLATE_TYPE trans;
+{
+  reg_errcode_t ret;
+  re_string_construct_common (str, len, pstr, trans, icase);
+  pstr->stop = pstr->len;
+  /* Set 0 so that this function can initialize whole buffers.  */
+  pstr->valid_len = 0;
+
+  if (len > 0)
+    {
+      ret = re_string_realloc_buffers (pstr, len + 1);
+      if (BE (ret != REG_NOERROR, 0))
+        return ret;
+    }
+  pstr->mbs_case = (MBS_CASE_ALLOCATED (pstr) ? pstr->mbs_case
+                    : (unsigned char *) str);
+  pstr->mbs = MBS_ALLOCATED (pstr) ? pstr->mbs : pstr->mbs_case;
+
+  if (icase)
+    {
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        build_wcs_upper_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+        build_upper_buffer (pstr);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        build_wcs_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+        {
+          if (trans != NULL)
+            re_string_translate_buffer (pstr);
+          else
+            pstr->valid_len = len;
+        }
+    }
+
+  /* Initialized whole buffers, then valid_len == bufs_len.  */
+  pstr->valid_len = pstr->bufs_len;
+  return REG_NOERROR;
+}
+
+/* Helper functions for re_string_allocate, and re_string_construct.  */
+
+static reg_errcode_t
+re_string_realloc_buffers (pstr, new_buf_len)
+     re_string_t *pstr;
+     int new_buf_len;
+{
+#ifdef RE_ENABLE_I18N
+  if (MB_CUR_MAX > 1)
+    {
+      pstr->wcs = re_realloc (pstr->wcs, wint_t, new_buf_len);
+      if (BE (pstr->wcs == NULL, 0))
+        return REG_ESPACE;
+    }
+#endif /* RE_ENABLE_I18N  */
+  if (MBS_ALLOCATED (pstr))
+    {
+      pstr->mbs = re_realloc (pstr->mbs, unsigned char, new_buf_len);
+      if (BE (pstr->mbs == NULL, 0))
+        return REG_ESPACE;
+    }
+  if (MBS_CASE_ALLOCATED (pstr))
+    {
+      pstr->mbs_case = re_realloc (pstr->mbs_case, unsigned char, new_buf_len);
+      if (BE (pstr->mbs_case == NULL, 0))
+        return REG_ESPACE;
+      if (!MBS_ALLOCATED (pstr))
+        pstr->mbs = pstr->mbs_case;
+    }
+  pstr->bufs_len = new_buf_len;
+  return REG_NOERROR;
+}
+
+
+static void
+re_string_construct_common (str, len, pstr, trans, icase)
+     const char *str;
+     int len;
+     re_string_t *pstr;
+     RE_TRANSLATE_TYPE trans;
+     int icase;
+{
+  memset (pstr, '\0', sizeof (re_string_t));
+  pstr->raw_mbs = (const unsigned char *) str;
+  pstr->len = len;
+  pstr->trans = trans;
+  pstr->icase = icase ? 1 : 0;
+}
+
+#ifdef RE_ENABLE_I18N
+
+/* Build wide character buffer PSTR->WCS.
+   If the byte sequence of the string are:
+     <mb1>(0), <mb1>(1), <mb2>(0), <mb2>(1), <sb3>
+   Then wide character buffer will be:
+     <wc1>   , WEOF    , <wc2>   , WEOF    , <wc3>
+   We use WEOF for padding, they indicate that the position isn't
+   a first byte of a multibyte character.
+
+   Note that this function assumes PSTR->VALID_LEN elements are already
+   built and starts from PSTR->VALID_LEN.  */
+
+static void
+build_wcs_buffer (pstr)
+     re_string_t *pstr;
+{
+  mbstate_t prev_st;
+  int byte_idx, end_idx, mbclen, remain_len;
+  /* Build the buffers from pstr->valid_len to either pstr->len or
+     pstr->bufs_len.  */
+  end_idx = (pstr->bufs_len > pstr->len)? pstr->len : pstr->bufs_len;
+  for (byte_idx = pstr->valid_len; byte_idx < end_idx;)
+    {
+      wchar_t wc;
+      remain_len = end_idx - byte_idx;
+      prev_st = pstr->cur_state;
+      mbclen = mbrtowc (&wc, ((const char *) pstr->raw_mbs + pstr->raw_mbs_idx
+                              + byte_idx), remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2, 0))
+        {
+          /* The buffer doesn't have enough space, finish to build.  */
+          pstr->cur_state = prev_st;
+          break;
+        }
+      else if (BE (mbclen == (size_t) -1 || mbclen == 0, 0))
+        {
+          /* We treat these cases as a singlebyte character.  */
+          mbclen = 1;
+          wc = (wchar_t) pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+          pstr->cur_state = prev_st;
+        }
+
+      /* Apply the translateion if we need.  */
+      if (pstr->trans != NULL && mbclen == 1)
+        {
+          int ch = pstr->trans[pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx]];
+          pstr->mbs_case[byte_idx] = ch;
+        }
+      /* Write wide character and padding.  */
+      pstr->wcs[byte_idx++] = wc;
+      /* Write paddings.  */
+      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+        pstr->wcs[byte_idx++] = WEOF;
+    }
+  pstr->valid_len = byte_idx;
+}
+
+/* Build wide character buffer PSTR->WCS like build_wcs_buffer,
+   but for REG_ICASE.  */
+
+static void
+build_wcs_upper_buffer (pstr)
+     re_string_t *pstr;
+{
+  mbstate_t prev_st;
+  int byte_idx, end_idx, mbclen, remain_len;
+  /* Build the buffers from pstr->valid_len to either pstr->len or
+     pstr->bufs_len.  */
+  end_idx = (pstr->bufs_len > pstr->len)? pstr->len : pstr->bufs_len;
+  for (byte_idx = pstr->valid_len; byte_idx < end_idx;)
+    {
+      wchar_t wc;
+      remain_len = end_idx - byte_idx;
+      prev_st = pstr->cur_state;
+      mbclen = mbrtowc (&wc, ((const char *) pstr->raw_mbs + pstr->raw_mbs_idx
+                              + byte_idx), remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2, 0))
+        {
+          /* The buffer doesn't have enough space, finish to build.  */
+          pstr->cur_state = prev_st;
+          break;
+        }
+      else if (mbclen == 1 || mbclen == (size_t) -1 || mbclen == 0)
+        {
+          /* In case of a singlebyte character.  */
+          int ch = pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+          /* Apply the translateion if we need.  */
+          if (pstr->trans != NULL && mbclen == 1)
+            {
+              ch = pstr->trans[ch];
+              pstr->mbs_case[byte_idx] = ch;
+            }
+          pstr->wcs[byte_idx] = iswlower (wc) ? toupper (wc) : wc;
+          pstr->mbs[byte_idx++] = islower (ch) ? toupper (ch) : ch;
+          if (BE (mbclen == (size_t) -1, 0))
+            pstr->cur_state = prev_st;
+        }
+      else /* mbclen > 1 */
+        {
+          if (iswlower (wc))
+            wcrtomb ((char *) pstr->mbs + byte_idx, towupper (wc), &prev_st);
+          else
+            memcpy (pstr->mbs + byte_idx,
+                    pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx, mbclen);
+          pstr->wcs[byte_idx++] = iswlower (wc) ? toupper (wc) : wc;
+          /* Write paddings.  */
+          for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+            pstr->wcs[byte_idx++] = WEOF;
+        }
+    }
+  pstr->valid_len = byte_idx;
+}
+
+/* Skip characters until the index becomes greater than NEW_RAW_IDX.
+   Return the index.  */
+
+static int
+re_string_skip_chars (pstr, new_raw_idx)
+     re_string_t *pstr;
+     int new_raw_idx;
+{
+  mbstate_t prev_st;
+  int rawbuf_idx, mbclen;
+
+  /* Skip the characters which are not necessary to check.  */
+  for (rawbuf_idx = pstr->raw_mbs_idx + pstr->valid_len;
+       rawbuf_idx < new_raw_idx;)
+    {
+      int remain_len = pstr->len - rawbuf_idx;
+      prev_st = pstr->cur_state;
+      mbclen = mbrlen ((const char *) pstr->raw_mbs + rawbuf_idx, remain_len,
+                       &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2 || mbclen == (size_t) -1 || mbclen == 0, 0))
+        {
+          /* We treat these cases as a singlebyte character.  */
+          mbclen = 1;
+          pstr->cur_state = prev_st;
+        }
+      /* Then proceed the next character.  */
+      rawbuf_idx += mbclen;
+    }
+  return rawbuf_idx;
+}
+#endif /* RE_ENABLE_I18N  */
+
+/* Build the buffer PSTR->MBS, and apply the translation if we need.  
+   This function is used in case of REG_ICASE.  */
+
+static void
+build_upper_buffer (pstr)
+     re_string_t *pstr;
+{
+  int char_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (char_idx = pstr->valid_len; char_idx < end_idx; ++char_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + char_idx];
+      if (pstr->trans != NULL)
+        {
+          ch =  pstr->trans[ch];
+          pstr->mbs_case[char_idx] = ch;
+        }
+      if (islower (ch))
+        pstr->mbs[char_idx] = toupper (ch);
+      else
+        pstr->mbs[char_idx] = ch;
+    }
+  pstr->valid_len = char_idx;
+}
+
+/* Apply TRANS to the buffer in PSTR.  */
+
+static void
+re_string_translate_buffer (pstr)
+     re_string_t *pstr;
+{
+  int buf_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (buf_idx = pstr->valid_len; buf_idx < end_idx; ++buf_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + buf_idx];
+      pstr->mbs_case[buf_idx] = pstr->trans[ch];
+    }
+
+  pstr->valid_len = buf_idx;
+}
+
+/* This function re-construct the buffers.
+   Concretely, convert to wide character in case of MB_CUR_MAX > 1,
+   convert to upper case in case of REG_ICASE, apply translation.  */
+
+static reg_errcode_t
+re_string_reconstruct (pstr, idx, eflags, newline)
+     re_string_t *pstr;
+     int idx, eflags, newline;
+{
+  int offset = idx - pstr->raw_mbs_idx;
+  if (offset < 0)
+    {
+      /* Reset buffer.  */
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
+#endif /* RE_ENABLE_I18N */
+      pstr->len += pstr->raw_mbs_idx;
+      pstr->stop += pstr->raw_mbs_idx;
+      pstr->valid_len = pstr->raw_mbs_idx = 0;
+      pstr->tip_context = ((eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
+                           : CONTEXT_NEWLINE | CONTEXT_BEGBUF);
+      if (!MBS_CASE_ALLOCATED (pstr))
+        pstr->mbs_case = (unsigned char *) pstr->raw_mbs;
+      if (!MBS_ALLOCATED (pstr) && !MBS_CASE_ALLOCATED (pstr))
+        pstr->mbs = (unsigned char *) pstr->raw_mbs;
+      offset = idx;
+    }
+
+  if (offset != 0)
+    {
+      pstr->tip_context = re_string_context_at (pstr, offset - 1, eflags,
+                                                newline);
+      /* Are the characters which are already checked remain?  */
+      if (offset < pstr->valid_len)
+        {
+          /* Yes, move them to the front of the buffer.  */
+#ifdef RE_ENABLE_I18N
+          if (MB_CUR_MAX > 1)
+            memmove (pstr->wcs, pstr->wcs + offset,
+                     (pstr->valid_len - offset) * sizeof (wint_t));
+#endif /* RE_ENABLE_I18N */
+          if (MBS_ALLOCATED (pstr))
+            memmove (pstr->mbs, pstr->mbs + offset,
+                     pstr->valid_len - offset);
+          if (MBS_CASE_ALLOCATED (pstr))
+            memmove (pstr->mbs_case, pstr->mbs_case + offset,
+                     pstr->valid_len - offset);
+          pstr->valid_len -= offset;
+#if DEBUG
+          assert (pstr->valid_len > 0);
+#endif
+        }
+      else
+        {
+          /* No, skip all characters until IDX.  */
+          pstr->valid_len = 0;
+#ifdef RE_ENABLE_I18N
+          if (MB_CUR_MAX > 1)
+            {
+              int wcs_idx;
+              pstr->valid_len = re_string_skip_chars (pstr, idx) - idx;
+              for (wcs_idx = 0; wcs_idx < pstr->valid_len; ++wcs_idx)
+                pstr->wcs[wcs_idx] = WEOF;
+            }
+#endif /* RE_ENABLE_I18N */
+        }
+      if (!MBS_CASE_ALLOCATED (pstr))
+        {
+          pstr->mbs_case += offset; 
+          /* In case of !MBS_ALLOCATED && !MBS_CASE_ALLOCATED.  */
+          if (!MBS_ALLOCATED (pstr))
+            pstr->mbs += offset; 
+        }
+    }
+  pstr->raw_mbs_idx = idx;
+  pstr->len -= offset;
+  pstr->stop -= offset;
+
+  /* Then build the buffers.  */
+#ifdef RE_ENABLE_I18N
+  if (MB_CUR_MAX > 1)
+    {
+      if (pstr->icase)
+        build_wcs_upper_buffer (pstr);
+      else
+        build_wcs_buffer (pstr);
+    }
+  else
+#endif /* RE_ENABLE_I18N */
+    {
+      if (pstr->icase)
+        build_upper_buffer (pstr);
+      else if (pstr->trans != NULL)
+        re_string_translate_buffer (pstr);
+    }
+  pstr->cur_idx = 0;
+
+  return REG_NOERROR;
+}
+
+static void
+re_string_destruct (pstr)
+     re_string_t *pstr;
+{
+#ifdef RE_ENABLE_I18N
+  re_free (pstr->wcs);
+#endif /* RE_ENABLE_I18N  */
+  if (MBS_ALLOCATED (pstr))
+    re_free (pstr->mbs);
+  if (MBS_CASE_ALLOCATED (pstr))
+    re_free (pstr->mbs_case);
+}
+
+/* Return the context at IDX in INPUT.  */
+
+static unsigned int
+re_string_context_at (input, idx, eflags, newline_anchor)
+     const re_string_t *input;
+     int idx, eflags, newline_anchor;
+{
+  int c;
+  if (idx < 0 || idx == input->len)
+    {
+      if (idx < 0)
+        /* In this case, we use the value stored in input->tip_context,
+           since we can't know the character in input->mbs[-1] here.  */
+        return input->tip_context;
+      else /* (idx == input->len) */
+        return ((eflags & REG_NOTEOL) ? CONTEXT_ENDBUF
+                : CONTEXT_NEWLINE | CONTEXT_ENDBUF);
+    }
+  c = re_string_byte_at (input, idx);
+  if (IS_WORD_CHAR (c))
+    return CONTEXT_WORD;
+  return (newline_anchor && IS_NEWLINE (c)) ? CONTEXT_NEWLINE : 0;
+}
+
+/* Functions for set operation.  */
+
+static reg_errcode_t
+re_node_set_alloc (set, size)
+     re_node_set *set;
+     int size;
+{
+  set->alloc = size;
+  set->nelem = 0;
+  set->elems = re_malloc (int, size);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+re_node_set_init_1 (set, elem)
+     re_node_set *set;
+     int elem;
+{
+  set->alloc = 1;
+  set->nelem = 1;
+  set->elems = re_malloc (int, 1);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  set->elems[0] = elem;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+re_node_set_init_2 (set, elem1, elem2)
+     re_node_set *set;
+     int elem1, elem2;
+{
+  set->alloc = 2;
+  set->elems = re_malloc (int, 2);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  if (elem1 == elem2)
+    {
+      set->nelem = 1;
+      set->elems[0] = elem1;
+    }
+  else
+    {
+      set->nelem = 2;
+      if (elem1 < elem2)
+        {
+          set->elems[0] = elem1;
+          set->elems[1] = elem2;
+        }
+      else
+        {
+          set->elems[0] = elem2;
+          set->elems[1] = elem1;
+        }
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+re_node_set_init_copy (dest, src)
+     re_node_set *dest;
+     const re_node_set *src;
+{
+  dest->nelem = src->nelem;
+  if (src->nelem > 0)
+    {
+      dest->alloc = dest->nelem;
+      dest->elems = re_malloc (int, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+        return REG_ESPACE;
+      memcpy (dest->elems, src->elems, src->nelem * sizeof (int));
+    }
+  else
+    re_node_set_init_empty (dest);
+  return REG_NOERROR;
+}
+
+/* Calculate the intersection of the sets SRC1 and SRC2. And merge it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.
+   Note: We assume dest->elems is NULL, when dest->alloc is 0.  */
+
+static reg_errcode_t
+re_node_set_add_intersect (dest, src1, src2)
+     re_node_set *dest;
+     const re_node_set *src1, *src2;
+{
+  int i1, i2, id;
+  if (src1->nelem > 0 && src2->nelem > 0)
+    {
+      if (src1->nelem + src2->nelem + dest->nelem > dest->alloc)
+        {
+          dest->alloc = src1->nelem + src2->nelem + dest->nelem;
+          dest->elems = re_realloc (dest->elems, int, dest->alloc);
+          if (BE (dest->elems == NULL, 0))
+            return REG_ESPACE;
+        }
+    }
+  else
+    return REG_NOERROR;
+
+  for (i1 = i2 = id = 0 ; i1 < src1->nelem && i2 < src2->nelem ;)
+    {
+      if (src1->elems[i1] > src2->elems[i2])
+        {
+          ++i2;
+          continue;
+        }
+      if (src1->elems[i1] == src2->elems[i2])
+        {
+          while (id < dest->nelem && dest->elems[id] < src2->elems[i2])
+            ++id;
+          if (id < dest->nelem && dest->elems[id] == src2->elems[i2])
+            ++id;
+          else
+            {
+              memmove (dest->elems + id + 1, dest->elems + id,
+                       sizeof (int) * (dest->nelem - id));
+              dest->elems[id++] = src2->elems[i2++];
+              ++dest->nelem;
+            }
+        }
+      ++i1;
+    }
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets SRC1 and SRC2. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+re_node_set_init_union (dest, src1, src2)
+     re_node_set *dest;
+     const re_node_set *src1, *src2;
+{
+  int i1, i2, id;
+  if (src1 != NULL && src1->nelem > 0 && src2 != NULL && src2->nelem > 0)
+    {
+      dest->alloc = src1->nelem + src2->nelem;
+      dest->elems = re_malloc (int, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+        return REG_ESPACE;
+    }
+  else
+    {
+      if (src1 != NULL && src1->nelem > 0)
+        return re_node_set_init_copy (dest, src1);
+      else if (src2 != NULL && src2->nelem > 0)
+        return re_node_set_init_copy (dest, src2);
+      else
+        re_node_set_init_empty (dest);
+      return REG_NOERROR;
+    }
+  for (i1 = i2 = id = 0 ; i1 < src1->nelem && i2 < src2->nelem ;)
+    {
+      if (src1->elems[i1] > src2->elems[i2])
+        {
+          dest->elems[id++] = src2->elems[i2++];
+          continue;
+        }
+      if (src1->elems[i1] == src2->elems[i2])
+        ++i2;
+      dest->elems[id++] = src1->elems[i1++];
+    }
+  if (i1 < src1->nelem)
+    {
+      memcpy (dest->elems + id, src1->elems + i1,
+             (src1->nelem - i1) * sizeof (int));
+      id += src1->nelem - i1;
+    }
+  else if (i2 < src2->nelem)
+    {
+      memcpy (dest->elems + id, src2->elems + i2,
+             (src2->nelem - i2) * sizeof (int));
+      id += src2->nelem - i2;
+    }
+  dest->nelem = id;
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets DEST and SRC. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+re_node_set_merge (dest, src)
+     re_node_set *dest;
+     const re_node_set *src;
+{
+  int si, di;
+  if (src == NULL || src->nelem == 0)
+    return REG_NOERROR;
+  if (dest->alloc < src->nelem + dest->nelem)
+    {
+      dest->alloc = 2 * (src->nelem + dest->alloc);
+      dest->elems = re_realloc (dest->elems, int, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+        return REG_ESPACE;
+    }
+
+  for (si = 0, di = 0 ; si < src->nelem && di < dest->nelem ;)
+    {
+      int cp_from, ncp, mid, right, src_elem = src->elems[si];
+      /* Binary search the spot we will add the new element.  */
+      right = dest->nelem;
+      while (di < right)
+        {
+          mid = (di + right) / 2;
+          if (dest->elems[mid] < src_elem)
+            di = mid + 1;
+          else
+            right = mid;
+        }
+      if (di >= dest->nelem)
+        break;
+
+      if (dest->elems[di] == src_elem)
+        {
+          /* Skip since, DEST already has the element.  */
+          ++di;
+          ++si;
+          continue;
+        }
+
+      /* Skip the src elements which are less than dest->elems[di].  */
+      cp_from = si;
+      while (si < src->nelem && src->elems[si] < dest->elems[di])
+        ++si;
+      /* Copy these src elements.  */
+      ncp = si - cp_from;
+      memmove (dest->elems + di + ncp, dest->elems + di,
+               sizeof (int) * (dest->nelem - di));
+      memcpy (dest->elems + di, src->elems + cp_from,
+              sizeof (int) * ncp);
+      /* Update counters.  */
+      di += ncp;
+      dest->nelem += ncp;
+    }
+
+  /* Copy remaining src elements.  */
+  if (si < src->nelem)
+    {
+      memcpy (dest->elems + di, src->elems + si,
+              sizeof (int) * (src->nelem - si));
+      dest->nelem += src->nelem - si;
+    }
+  return REG_NOERROR;
+}
+
+/* Insert the new element ELEM to the re_node_set* SET.
+   return 0 if SET already has ELEM,
+   return -1 if an error is occured, return 1 otherwise.  */
+
+static int
+re_node_set_insert (set, elem)
+     re_node_set *set;
+     int elem;
+{
+  int idx, right, mid;
+  /* In case of the set is empty.  */
+  if (set->elems == NULL || set->alloc == 0)
+    {
+      if (BE (re_node_set_init_1 (set, elem) == REG_NOERROR, 1))
+        return 1;
+      else
+        return -1;
+    }
+
+  /* Binary search the spot we will add the new element.  */
+  idx = 0;
+  right = set->nelem;
+  while (idx < right)
+    {
+      mid = (idx + right) / 2;
+      if (set->elems[mid] < elem)
+        idx = mid + 1;
+      else
+        right = mid;
+    }
+
+  /* Realloc if we need.  */
+  if (set->alloc < set->nelem + 1)
+    {
+      int *new_array;
+      set->alloc = set->alloc * 2;
+      new_array = re_malloc (int, set->alloc);
+      if (BE (new_array == NULL, 0))
+        return -1;
+      /* Copy the elements they are followed by the new element.  */
+      if (idx > 0)
+        memcpy (new_array, set->elems, sizeof (int) * (idx));
+      /* Copy the elements which follows the new element.  */
+      if (set->nelem - idx > 0)
+        memcpy (new_array + idx + 1, set->elems + idx,
+		sizeof (int) * (set->nelem - idx));
+      re_free (set->elems);
+      set->elems = new_array;
+    }
+  else
+    {
+      /* Move the elements which follows the new element.  */
+      if (set->nelem - idx > 0)
+        memmove (set->elems + idx + 1, set->elems + idx,
+                 sizeof (int) * (set->nelem - idx));
+    }
+  /* Insert the new element.  */
+  set->elems[idx] = elem;
+  ++set->nelem;
+  return 1;
+}
+
+/* Compare two node sets SET1 and SET2.
+   return 1 if SET1 and SET2 are equivalent, retrun 0 otherwise.  */
+
+static int
+re_node_set_compare (set1, set2)
+     const re_node_set *set1, *set2;
+{
+  int i;
+  if (set1 == NULL || set2 == NULL || set1->nelem != set2->nelem)
+    return 0;
+  for (i = 0 ; i < set1->nelem ; i++)
+    if (set1->elems[i] != set2->elems[i])
+      return 0;
+  return 1;
+}
+
+/* Return (idx + 1) if SET contains the element ELEM, return 0 otherwise.  */
+
+static int
+re_node_set_contains (set, elem)
+     const re_node_set *set;
+     int elem;
+{
+  int idx, right, mid;
+  if (set->nelem <= 0)
+    return 0;
+
+  /* Binary search the element.  */
+  idx = 0;
+  right = set->nelem - 1;
+  while (idx < right)
+    {
+      mid = (idx + right) / 2;
+      if (set->elems[mid] < elem)
+        idx = mid + 1;
+      else
+        right = mid;
+    }
+  return set->elems[idx] == elem ? idx + 1 : 0;
+}
+
+static void
+re_node_set_remove_at (set, idx)
+     re_node_set *set;
+     int idx;
+{
+  if (idx < 0 || idx >= set->nelem)
+    return;
+  if (idx < set->nelem - 1)
+    memmove (set->elems + idx, set->elems + idx + 1,
+             sizeof (int) * (set->nelem - idx - 1));
+  --set->nelem;
+}
+
+
+/* Add the token TOKEN to dfa->nodes, and return the index of the token.
+   Or return -1, if an error will be occured.  */
+
+static int
+re_dfa_add_node (dfa, token, mode)
+     re_dfa_t *dfa;
+     re_token_t token;
+     int mode;
+{
+  if (dfa->nodes_len >= dfa->nodes_alloc)
+    {
+      re_token_t *new_array;
+      dfa->nodes_alloc *= 2;
+      new_array = re_realloc (dfa->nodes, re_token_t, dfa->nodes_alloc);
+      if (BE (new_array == NULL, 0))
+        return -1;
+      else
+        dfa->nodes = new_array;
+      if (mode)
+        {
+          int *new_firsts, *new_nexts;
+          re_node_set *new_edests, *new_eclosures, *new_inveclosures;
+
+          new_firsts = re_realloc (dfa->firsts, int, dfa->nodes_alloc);
+          new_nexts = re_realloc (dfa->nexts, int, dfa->nodes_alloc);
+          new_edests = re_realloc (dfa->edests, re_node_set, dfa->nodes_alloc);
+          new_eclosures = re_realloc (dfa->eclosures, re_node_set,
+                                      dfa->nodes_alloc);
+          new_inveclosures = re_realloc (dfa->inveclosures, re_node_set,
+                                         dfa->nodes_alloc);
+          if (BE (new_firsts == NULL || new_nexts == NULL || new_edests == NULL
+                  || new_eclosures == NULL || new_inveclosures == NULL, 0))
+            return -1;
+          dfa->firsts = new_firsts;
+          dfa->nexts = new_nexts;
+          dfa->edests = new_edests;
+          dfa->eclosures = new_eclosures;
+          dfa->inveclosures = new_inveclosures;
+        }
+    }
+  dfa->nodes[dfa->nodes_len] = token;
+  dfa->nodes[dfa->nodes_len].duplicated = 0;
+  return dfa->nodes_len++;
+}
+
+static unsigned int inline
+calc_state_hash (nodes, context)
+     const re_node_set *nodes;
+     unsigned int context;
+{
+  unsigned int hash = nodes->nelem + context;
+  int i;
+  for (i = 0 ; i < nodes->nelem ; i++)
+    hash += nodes->elems[i];
+  return hash;
+}
+
+/* Search for the state whose node_set is equivalent to NODES.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+           return value is NULL and ERR is REG_NOERROR.
+         - We never return non-NULL value in case of any errors, it is for
+           optimization.  */
+
+static re_dfastate_t*
+re_acquire_state (err, dfa, nodes)
+     reg_errcode_t *err;
+     re_dfa_t *dfa;
+     const re_node_set *nodes;
+{
+  unsigned int hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  int i;
+  if (BE (nodes->nelem == 0, 0))
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, 0);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (hash != state->hash)
+        continue;
+      if (re_node_set_compare (&state->nodes, nodes))
+        return state;
+    }
+
+  /* There are no appropriate state in the dfa, create the new one.  */
+  new_state = create_ci_newstate (dfa, nodes, hash);
+  if (BE (new_state != NULL, 1))
+    return new_state;
+  else
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+}
+
+/* Search for the state whose node_set is equivalent to NODES and
+   whose context is equivalent to CONTEXT.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+           return value is NULL and ERR is REG_NOERROR.
+         - We never return non-NULL value in case of any errors, it is for
+           optimization.  */
+
+static re_dfastate_t*
+re_acquire_state_context (err, dfa, nodes, context)
+     reg_errcode_t *err;
+     re_dfa_t *dfa;
+     const re_node_set *nodes;
+     unsigned int context;
+{
+  unsigned int hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  int i;
+  if (nodes->nelem == 0)
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, context);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (hash != state->hash)
+        continue;
+      if (re_node_set_compare (state->entrance_nodes, nodes)
+          && state->context == context)
+        return state;
+    }
+  /* There are no appropriate state in `dfa', create the new one.  */
+  new_state = create_cd_newstate (dfa, nodes, context, hash);
+  if (BE (new_state != NULL, 1))
+    return new_state;
+  else
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+}
+
+/* Allocate memory for DFA state and initialize common properties.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+create_newstate_common (dfa, nodes, hash)
+     re_dfa_t *dfa;
+     const re_node_set *nodes;
+     unsigned int hash;
+{
+  re_dfastate_t *newstate;
+  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  re_node_set_init_copy (&newstate->nodes, nodes);
+  newstate->trtable = NULL;
+  newstate->trtable_search = NULL;
+  newstate->hash = hash;
+  return newstate;
+}
+
+/* Store the new state NEWSTATE whose hash value is HASH in appropriate
+   position.  Return value indicate the error code if failed.  */
+
+static reg_errcode_t
+register_state (dfa, newstate, hash)
+     re_dfa_t *dfa;
+     re_dfastate_t *newstate;
+     unsigned int hash;
+{
+  struct re_state_table_entry *spot;
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  if (spot->alloc <= spot->num)
+    {
+      spot->alloc = 2 * spot->num + 2;
+      spot->array = re_realloc (spot->array, re_dfastate_t *, spot->alloc);
+      if (BE (spot->array == NULL, 0))
+        return REG_ESPACE;
+    }
+  spot->array[spot->num++] = newstate;
+  return REG_NOERROR;
+}
+
+/* Create the new state which is independ of contexts.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+create_ci_newstate (dfa, nodes, hash)
+     re_dfa_t *dfa;
+     const re_node_set *nodes;
+     unsigned int hash;
+{
+  int i;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+  newstate = create_newstate_common (dfa, nodes, hash);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  newstate->entrance_nodes = &newstate->nodes;
+
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      if (type == CHARACTER)
+        continue;
+
+      /* If the state has the halt node, the state is a halt state.  */
+      else if (type == END_OF_RE)
+        newstate->halt = 1;
+#ifdef RE_ENABLE_I18N
+      else if (type == COMPLEX_BRACKET
+               || (type == OP_PERIOD && MB_CUR_MAX > 1))
+        newstate->accept_mb = 1;
+#endif /* RE_ENABLE_I18N */
+      else if (type == OP_BACK_REF)
+        newstate->has_backref = 1;
+      else if (type == ANCHOR || OP_CONTEXT_NODE)
+        {
+          newstate->has_constraint = 1;
+          if (type == OP_CONTEXT_NODE
+              && dfa->nodes[node->opr.ctx_info->entity].type == END_OF_RE)
+            newstate->halt = 1;
+        }
+    }
+  err = register_state (dfa, newstate, hash);
+  return (err != REG_NOERROR) ? NULL : newstate;
+}
+
+/* Create the new state which is depend on the context CONTEXT.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+create_cd_newstate (dfa, nodes, context, hash)
+     re_dfa_t *dfa;
+     const re_node_set *nodes;
+     unsigned int context, hash;
+{
+  int i, nctx_nodes = 0;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+
+  newstate = create_newstate_common (dfa, nodes, hash);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  newstate->context = context;
+  newstate->entrance_nodes = &newstate->nodes;
+
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      unsigned int constraint = 0;
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      if (type == CHARACTER)
+        continue;
+
+      /* If the state has the halt node, the state is a halt state.  */
+      else if (type == END_OF_RE)
+        newstate->halt = 1;
+#ifdef RE_ENABLE_I18N
+      else if (type == COMPLEX_BRACKET
+               || (type == OP_PERIOD && MB_CUR_MAX > 1))
+        newstate->accept_mb = 1;
+#endif /* RE_ENABLE_I18N */
+      else if (type == OP_BACK_REF)
+        newstate->has_backref = 1;
+      else if (type == ANCHOR)
+        constraint = node->opr.ctx_type;
+      else if (type == OP_CONTEXT_NODE)
+        {
+          re_token_type_t ctype = dfa->nodes[node->opr.ctx_info->entity].type;
+          constraint = node->constraint;
+          if (ctype == END_OF_RE)
+            newstate->halt = 1;
+          else if (ctype == OP_BACK_REF)
+            newstate->has_backref = 1;
+#ifdef RE_ENABLE_I18N
+          else if (ctype == COMPLEX_BRACKET
+                   || (type == OP_PERIOD && MB_CUR_MAX > 1))
+            newstate->accept_mb = 1;
+#endif /* RE_ENABLE_I18N */
+        }
+
+      if (constraint)
+        {
+          if (newstate->entrance_nodes == &newstate->nodes)
+            {
+              newstate->entrance_nodes = re_malloc (re_node_set, 1);
+	      if (BE (newstate->entrance_nodes == NULL, 0))
+		return NULL;
+              re_node_set_init_copy (newstate->entrance_nodes, nodes);
+              nctx_nodes = 0;
+              newstate->has_constraint = 1;
+            }
+
+          if (NOT_SATISFY_PREV_CONSTRAINT (constraint,context))
+            {
+              re_node_set_remove_at (&newstate->nodes, i - nctx_nodes);
+              ++nctx_nodes;
+            }
+        }
+    }
+  err = register_state (dfa, newstate, hash);
+  return (err != REG_NOERROR) ? NULL : newstate;
+}
diff --git a/util/regex_internal.h b/util/regex_internal.h
new file mode 100644
index 000000000..0bbf1081e
--- /dev/null
+++ b/util/regex_internal.h
@@ -0,0 +1,643 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email protected]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _REGEX_INTERNAL_H
+#define _REGEX_INTERNAL_H 1
+
+/* Number of bits in a byte.  */
+#define BYTE_BITS 8
+/* Number of single byte character.  */
+#define SBC_MAX 256
+
+#define COLL_ELEM_LEN_MAX 8
+
+/* The character which represents newline.  */
+#define NEWLINE_CHAR '\n'
+
+/* Rename to standard API for using out of glibc.  */
+#ifndef _LIBC
+# define __wctype wctype
+# define __iswctype iswctype
+# define __btowc btowc
+# define __mempcpy memcpy
+# define attribute_hidden
+#endif /* not _LIBC */
+
+extern const char __re_error_msgid[] attribute_hidden;
+extern const size_t __re_error_msgid_idx[] attribute_hidden;
+
+/* Number of bits in an unsinged int.  */
+#define UINT_BITS (sizeof (unsigned int) * BYTE_BITS)
+/* Number of unsigned int in an bit_set.  */
+#define BITSET_UINTS ((SBC_MAX + UINT_BITS - 1) / UINT_BITS)
+typedef unsigned int bitset[BITSET_UINTS];
+typedef unsigned int *re_bitset_ptr_t;
+
+#define bitset_set(set,i) (set[i / UINT_BITS] |= 1 << i % UINT_BITS)
+#define bitset_clear(set,i) (set[i / UINT_BITS] &= ~(1 << i % UINT_BITS))
+#define bitset_contain(set,i) (set[i / UINT_BITS] & (1 << i % UINT_BITS))
+#define bitset_empty(set) memset (set, 0, sizeof (unsigned int) * BITSET_UINTS)
+#define bitset_set_all(set) \
+  memset (set, 255, sizeof (unsigned int) * BITSET_UINTS)
+#define bitset_copy(dest,src) \
+  memcpy (dest, src, sizeof (unsigned int) * BITSET_UINTS)
+static inline void bitset_not (bitset set);
+static inline void bitset_merge (bitset dest, const bitset src);
+#if 0 /* gnupg */
+static inline void bitset_not_merge (bitset dest, const bitset src);
+#endif
+
+#define PREV_WORD_CONSTRAINT 0x0001
+#define PREV_NOTWORD_CONSTRAINT 0x0002
+#define NEXT_WORD_CONSTRAINT 0x0004
+#define NEXT_NOTWORD_CONSTRAINT 0x0008
+#define PREV_NEWLINE_CONSTRAINT 0x0010
+#define NEXT_NEWLINE_CONSTRAINT 0x0020
+#define PREV_BEGBUF_CONSTRAINT 0x0040
+#define NEXT_ENDBUF_CONSTRAINT 0x0080
+#define DUMMY_CONSTRAINT 0x0100
+
+typedef enum
+{
+  INSIDE_WORD = PREV_WORD_CONSTRAINT | NEXT_WORD_CONSTRAINT,
+  WORD_FIRST = PREV_NOTWORD_CONSTRAINT | NEXT_WORD_CONSTRAINT,
+  WORD_LAST = PREV_WORD_CONSTRAINT | NEXT_NOTWORD_CONSTRAINT,
+  LINE_FIRST = PREV_NEWLINE_CONSTRAINT,
+  LINE_LAST = NEXT_NEWLINE_CONSTRAINT,
+  BUF_FIRST = PREV_BEGBUF_CONSTRAINT,
+  BUF_LAST = NEXT_ENDBUF_CONSTRAINT,
+  WORD_DELIM = DUMMY_CONSTRAINT
+} re_context_type;
+
+typedef struct
+{
+  int alloc;
+  int nelem;
+  int *elems;
+} re_node_set;
+
+typedef enum
+{
+  NON_TYPE = 0,
+
+  /* Token type, these are used only by token.  */
+  OP_OPEN_BRACKET,
+  OP_CLOSE_BRACKET,
+  OP_CHARSET_RANGE,
+  OP_OPEN_DUP_NUM,
+  OP_CLOSE_DUP_NUM,
+  OP_NON_MATCH_LIST,
+  OP_OPEN_COLL_ELEM,
+  OP_CLOSE_COLL_ELEM,
+  OP_OPEN_EQUIV_CLASS,
+  OP_CLOSE_EQUIV_CLASS,
+  OP_OPEN_CHAR_CLASS,
+  OP_CLOSE_CHAR_CLASS,
+  OP_WORD,
+  OP_NOTWORD,
+  BACK_SLASH,
+
+  /* Tree type, these are used only by tree. */
+  CONCAT,
+  ALT,
+  SUBEXP,
+  SIMPLE_BRACKET,
+#ifdef RE_ENABLE_I18N
+  COMPLEX_BRACKET,
+#endif /* RE_ENABLE_I18N */
+
+  /* Node type, These are used by token, node, tree.  */
+  OP_OPEN_SUBEXP,
+  OP_CLOSE_SUBEXP,
+  OP_PERIOD,
+  CHARACTER,
+  END_OF_RE,
+  OP_ALT,
+  OP_DUP_ASTERISK,
+  OP_DUP_PLUS,
+  OP_DUP_QUESTION,
+  OP_BACK_REF,
+  ANCHOR,
+  OP_CONTEXT_NODE,
+
+  /* Dummy marker.  */
+  END_OF_RE_TOKEN_T
+} re_token_type_t;
+
+#ifdef RE_ENABLE_I18N
+typedef struct
+{
+  /* Multibyte characters.  */
+  wchar_t *mbchars;
+
+  /* Collating symbols.  */
+# ifdef _LIBC
+  int32_t *coll_syms;
+# endif
+
+  /* Equivalence classes. */
+# ifdef _LIBC
+  int32_t *equiv_classes;
+# endif
+
+  /* Range expressions. */
+# ifdef _LIBC
+  uint32_t *range_starts;
+  uint32_t *range_ends;
+# else /* not _LIBC */
+  wchar_t *range_starts;
+  wchar_t *range_ends;
+# endif /* not _LIBC */
+
+  /* Character classes. */
+  wctype_t *char_classes;
+
+  /* If this character set is the non-matching list.  */
+  unsigned int non_match : 1;
+
+  /* # of multibyte characters.  */
+  int nmbchars;
+
+  /* # of collating symbols.  */
+  int ncoll_syms;
+
+  /* # of equivalence classes. */
+  int nequiv_classes;
+
+  /* # of range expressions. */
+  int nranges;
+
+  /* # of character classes. */
+  int nchar_classes;
+} re_charset_t;
+#endif /* RE_ENABLE_I18N */
+
+typedef struct
+{
+  union
+  {
+    unsigned char c;		/* for CHARACTER */
+    re_bitset_ptr_t sbcset;	/* for SIMPLE_BRACKET */
+#ifdef RE_ENABLE_I18N
+    re_charset_t *mbcset;	/* for COMPLEX_BRACKET */
+#endif /* RE_ENABLE_I18N */
+    int idx;			/* for BACK_REF */
+    re_context_type ctx_type;	/* for ANCHOR */
+    struct
+    {
+      int entity;		/* for OP_CONTEXT_NODE, index of the entity */
+      re_node_set *bkref_eclosure;
+    } *ctx_info;
+  } opr;
+#if __GNUC__ >= 2
+  re_token_type_t type : 8;
+#else
+  re_token_type_t type;
+#endif
+  unsigned int constraint : 10;	/* context constraint */
+  unsigned int duplicated : 1;
+#ifdef RE_ENABLE_I18N
+  unsigned int mb_partial : 1;
+#endif
+} re_token_t;
+
+#define IS_EPSILON_NODE(type) \
+  ((type) == OP_ALT || (type) == OP_DUP_ASTERISK || (type) == OP_DUP_PLUS \
+   || (type) == OP_DUP_QUESTION || (type) == ANCHOR \
+   || (type) == OP_OPEN_SUBEXP || (type) == OP_CLOSE_SUBEXP)
+
+#define ACCEPT_MB_NODE(type) \
+  ((type) == COMPLEX_BRACKET || (type) == OP_PERIOD)
+
+struct re_string_t
+{
+  /* Indicate the raw buffer which is the original string passed as an
+     argument of regexec(), re_search(), etc..  */
+  const unsigned char *raw_mbs;
+  /* Store the multibyte string.  In case of "case insensitive mode" like
+     REG_ICASE, upper cases of the string are stored, otherwise MBS points
+     the same address that RAW_MBS points.  */
+  unsigned char *mbs;
+  /* Store the case sensitive multibyte string.  In case of
+     "case insensitive mode", the original string are stored,
+     otherwise MBS_CASE points the same address that MBS points.  */
+  unsigned char *mbs_case;
+#ifdef RE_ENABLE_I18N
+  /* Store the wide character string which is corresponding to MBS.  */
+  wint_t *wcs;
+  mbstate_t cur_state;
+#endif
+  /* Index in RAW_MBS.  Each character mbs[i] corresponds to
+     raw_mbs[raw_mbs_idx + i].  */
+  int raw_mbs_idx;
+  /* The length of the valid characters in the buffers.  */
+  int valid_len;
+  /* The length of the buffers MBS, MBS_CASE, and WCS.  */
+  int bufs_len;
+  /* The index in MBS, which is updated by re_string_fetch_byte.  */
+  int cur_idx;
+  /* This is length_of_RAW_MBS - RAW_MBS_IDX.  */
+  int len;
+  /* End of the buffer may be shorter than its length in the cases such
+     as re_match_2, re_search_2.  Then, we use STOP for end of the buffer
+     instead of LEN.  */
+  int stop;
+
+  /* The context of mbs[0].  We store the context independently, since
+     the context of mbs[0] may be different from raw_mbs[0], which is
+     the beginning of the input string.  */
+  unsigned int tip_context;
+  /* The translation passed as a part of an argument of re_compile_pattern.  */
+  RE_TRANSLATE_TYPE trans;
+  /* 1 if REG_ICASE.  */
+  unsigned int icase : 1;
+};
+typedef struct re_string_t re_string_t;
+/* In case of REG_ICASE, we allocate the buffer dynamically for mbs.  */
+#define MBS_ALLOCATED(pstr) (pstr->icase)
+/* In case that we need translation, we allocate the buffer dynamically
+   for mbs_case.  Note that mbs == mbs_case if not REG_ICASE.  */
+#define MBS_CASE_ALLOCATED(pstr) (pstr->trans != NULL)
+
+
+static reg_errcode_t re_string_allocate (re_string_t *pstr, const char *str,
+                                         int len, int init_len,
+                                         RE_TRANSLATE_TYPE trans, int icase);
+static reg_errcode_t re_string_construct (re_string_t *pstr, const char *str,
+                                          int len, RE_TRANSLATE_TYPE trans,
+                                          int icase);
+static reg_errcode_t re_string_reconstruct (re_string_t *pstr, int idx,
+                                            int eflags, int newline);
+static reg_errcode_t re_string_realloc_buffers (re_string_t *pstr,
+                                                int new_buf_len);
+#ifdef RE_ENABLE_I18N
+static void build_wcs_buffer (re_string_t *pstr);
+static void build_wcs_upper_buffer (re_string_t *pstr);
+#endif /* RE_ENABLE_I18N */
+static void build_upper_buffer (re_string_t *pstr);
+static void re_string_translate_buffer (re_string_t *pstr);
+static void re_string_destruct (re_string_t *pstr);
+#ifdef RE_ENABLE_I18N
+static int re_string_elem_size_at (const re_string_t *pstr, int idx);
+static inline int re_string_char_size_at (const re_string_t *pstr, int idx);
+static inline wint_t re_string_wchar_at (const re_string_t *pstr, int idx);
+#endif /* RE_ENABLE_I18N */
+static unsigned int re_string_context_at (const re_string_t *input, int idx,
+					  int eflags, int newline_anchor);
+#define re_string_peek_byte(pstr, offset) \
+  ((pstr)->mbs[(pstr)->cur_idx + offset])
+#define re_string_peek_byte_case(pstr, offset) \
+  ((pstr)->mbs_case[(pstr)->cur_idx + offset])
+#define re_string_fetch_byte(pstr) \
+  ((pstr)->mbs[(pstr)->cur_idx++])
+#define re_string_fetch_byte_case(pstr) \
+  ((pstr)->mbs_case[(pstr)->cur_idx++])
+#define re_string_first_byte(pstr, idx) \
+  ((idx) == (pstr)->len || (pstr)->wcs[idx] != WEOF)
+#define re_string_is_single_byte_char(pstr, idx) \
+  ((pstr)->wcs[idx] != WEOF && ((pstr)->len == (idx) \
+                                || (pstr)->wcs[(idx) + 1] != WEOF))
+#define re_string_eoi(pstr) ((pstr)->stop <= (pstr)->cur_idx)
+#define re_string_cur_idx(pstr) ((pstr)->cur_idx)
+#define re_string_get_buffer(pstr) ((pstr)->mbs)
+#define re_string_length(pstr) ((pstr)->len)
+#define re_string_byte_at(pstr,idx) ((pstr)->mbs[idx])
+#define re_string_skip_bytes(pstr,idx) ((pstr)->cur_idx += (idx))
+#define re_string_set_index(pstr,idx) ((pstr)->cur_idx = (idx))
+
+#define re_malloc(t,n) ((t *) malloc ((n) * sizeof (t)))
+#define re_realloc(p,t,n) ((t *) realloc (p, (n) * sizeof (t)))
+#define re_free(p) free (p)
+
+struct bin_tree_t
+{
+  struct bin_tree_t *parent;
+  struct bin_tree_t *left;
+  struct bin_tree_t *right;
+
+  /* `node_idx' is the index in dfa->nodes, if `type' == 0.
+     Otherwise `type' indicate the type of this node.  */
+  re_token_type_t type;
+  int node_idx;
+
+  int first;
+  int next;
+  re_node_set eclosure;
+};
+typedef struct bin_tree_t bin_tree_t;
+
+
+#define CONTEXT_WORD 1
+#define CONTEXT_NEWLINE (CONTEXT_WORD << 1)
+#define CONTEXT_BEGBUF (CONTEXT_NEWLINE << 1)
+#define CONTEXT_ENDBUF (CONTEXT_BEGBUF << 1)
+
+#define IS_WORD_CONTEXT(c) ((c) & CONTEXT_WORD)
+#define IS_NEWLINE_CONTEXT(c) ((c) & CONTEXT_NEWLINE)
+#define IS_BEGBUF_CONTEXT(c) ((c) & CONTEXT_BEGBUF)
+#define IS_ENDBUF_CONTEXT(c) ((c) & CONTEXT_ENDBUF)
+#define IS_ORDINARY_CONTEXT(c) ((c) == 0)
+
+#define IS_WORD_CHAR(ch) (isalnum (ch) || (ch) == '_')
+#define IS_NEWLINE(ch) ((ch) == NEWLINE_CHAR)
+
+#define NOT_SATISFY_PREV_CONSTRAINT(constraint,context) \
+ ((((constraint) & PREV_WORD_CONSTRAINT) && !IS_WORD_CONTEXT (context)) \
+  || ((constraint & PREV_NOTWORD_CONSTRAINT) && IS_WORD_CONTEXT (context)) \
+  || ((constraint & PREV_NEWLINE_CONSTRAINT) && !IS_NEWLINE_CONTEXT (context))\
+  || ((constraint & PREV_BEGBUF_CONSTRAINT) && !IS_BEGBUF_CONTEXT (context)))
+
+#define NOT_SATISFY_NEXT_CONSTRAINT(constraint,context) \
+ ((((constraint) & NEXT_WORD_CONSTRAINT) && !IS_WORD_CONTEXT (context)) \
+  || (((constraint) & NEXT_NOTWORD_CONSTRAINT) && IS_WORD_CONTEXT (context)) \
+  || (((constraint) & NEXT_NEWLINE_CONSTRAINT) && !IS_NEWLINE_CONTEXT (context)) \
+  || (((constraint) & NEXT_ENDBUF_CONSTRAINT) && !IS_ENDBUF_CONTEXT (context)))
+
+struct re_dfastate_t
+{
+  unsigned int hash;
+  re_node_set nodes;
+  re_node_set *entrance_nodes;
+  struct re_dfastate_t **trtable;
+  struct re_dfastate_t **trtable_search;
+  /* If this state is a special state.
+     A state is a special state if the state is the halt state, or
+     a anchor.  */
+  unsigned int context : 2;
+  unsigned int halt : 1;
+  /* If this state can accept `multi byte'.
+     Note that we refer to multibyte characters, and multi character
+     collating elements as `multi byte'.  */
+  unsigned int accept_mb : 1;
+  /* If this state has backreference node(s).  */
+  unsigned int has_backref : 1;
+  unsigned int has_constraint : 1;
+};
+typedef struct re_dfastate_t re_dfastate_t;
+
+typedef struct
+{
+  /* start <= node < end  */
+  int start;
+  int end;
+} re_subexp_t;
+
+struct re_state_table_entry
+{
+  int num;
+  int alloc;
+  re_dfastate_t **array;
+};
+
+struct re_backref_cache_entry
+{
+  int node;
+  int str_idx;
+  int subexp_from;
+  int subexp_to;
+  int flag;
+};
+
+typedef struct
+{
+  /* EFLAGS of the argument of regexec.  */
+  int eflags;
+  /* Where the matching ends.  */
+  int match_last;
+  int last_node;
+  /* The string object corresponding to the input string.  */
+  re_string_t *input;
+  /* The state log used by the matcher.  */
+  re_dfastate_t **state_log;
+  int state_log_top;
+  /* Back reference cache.  */
+  int nbkref_ents;
+  int abkref_ents;
+  struct re_backref_cache_entry *bkref_ents;
+  int max_mb_elem_len;
+} re_match_context_t;
+
+typedef struct
+{
+  int cur_bkref;
+  int cls_subexp_idx;
+
+  re_dfastate_t **sifted_states;
+  re_dfastate_t **limited_states;
+
+  re_node_set limits;
+
+  int last_node;
+  int last_str_idx;
+  int check_subexp;
+} re_sift_context_t;
+
+struct re_fail_stack_ent_t
+{
+  int idx;
+  int node;
+  regmatch_t *regs;
+  re_node_set eps_via_nodes;
+};
+
+struct re_fail_stack_t
+{
+  int num;
+  int alloc;
+  struct re_fail_stack_ent_t *stack;
+};
+
+struct re_dfa_t
+{
+  re_bitset_ptr_t word_char;
+
+  /* number of subexpressions `re_nsub' is in regex_t.  */
+  int subexps_alloc;
+  re_subexp_t *subexps;
+
+  re_token_t *nodes;
+  int nodes_alloc;
+  int nodes_len;
+  bin_tree_t *str_tree;
+  int *firsts;
+  int *nexts;
+  re_node_set *edests;
+  re_node_set *eclosures;
+  re_node_set *inveclosures;
+  struct re_state_table_entry *state_table;
+  unsigned int state_hash_mask;
+  re_dfastate_t *init_state;
+  re_dfastate_t *init_state_word;
+  re_dfastate_t *init_state_nl;
+  re_dfastate_t *init_state_begbuf;
+  int states_alloc;
+  int init_node;
+  int nbackref; /* The number of backreference in this dfa.  */
+  /* If this dfa has "multibyte node", which is a backreference or
+     a node which can accept multibyte character or multi character
+     collating element.  */
+#ifdef DEBUG
+  char* re_str;
+#endif
+  unsigned int has_plural_match : 1;
+  unsigned int has_mb_node : 1;
+};
+typedef struct re_dfa_t re_dfa_t;
+
+static reg_errcode_t re_node_set_alloc (re_node_set *set, int size);
+static reg_errcode_t re_node_set_init_1 (re_node_set *set, int elem);
+static reg_errcode_t re_node_set_init_2 (re_node_set *set, int elem1,
+                                         int elem2);
+#define re_node_set_init_empty(set) memset (set, '\0', sizeof (re_node_set))
+static reg_errcode_t re_node_set_init_copy (re_node_set *dest,
+                                            const re_node_set *src);
+static reg_errcode_t re_node_set_add_intersect (re_node_set *dest,
+                                                const re_node_set *src1,
+                                                const re_node_set *src2);
+static reg_errcode_t re_node_set_init_union (re_node_set *dest,
+                                             const re_node_set *src1,
+                                             const re_node_set *src2);
+static reg_errcode_t re_node_set_merge (re_node_set *dest,
+                                        const re_node_set *src);
+static int re_node_set_insert (re_node_set *set, int elem);
+static int re_node_set_compare (const re_node_set *set1,
+                                const re_node_set *set2);
+static int re_node_set_contains (const re_node_set *set, int elem);
+static void re_node_set_remove_at (re_node_set *set, int idx);
+#define re_node_set_empty(p) ((p)->nelem = 0)
+#define re_node_set_free(set) re_free ((set)->elems)
+static int re_dfa_add_node (re_dfa_t *dfa, re_token_t token, int mode);
+static re_dfastate_t *re_acquire_state (reg_errcode_t *err, re_dfa_t *dfa,
+                                        const re_node_set *nodes);
+static re_dfastate_t *re_acquire_state_context (reg_errcode_t *err,
+                                                re_dfa_t *dfa,
+                                                const re_node_set *nodes,
+                                                unsigned int context);
+
+
+typedef enum
+{
+  SB_CHAR,
+  MB_CHAR,
+  EQUIV_CLASS,
+  COLL_SYM,
+  CHAR_CLASS
+} bracket_elem_type;
+
+typedef struct
+{
+  bracket_elem_type type;
+  union
+  {
+    unsigned char ch;
+    unsigned char *name;
+    wchar_t wch;
+  } opr;
+} bracket_elem_t;
+
+
+/* Inline functions for bitset operation.  */
+static inline void
+bitset_not (set)
+     bitset set;
+{
+  int bitset_i;
+  for (bitset_i = 0; bitset_i < BITSET_UINTS; ++bitset_i)
+    set[bitset_i] = ~set[bitset_i];
+}
+
+static inline void
+bitset_merge (dest, src)
+     bitset dest;
+     const bitset src;
+{
+  int bitset_i;
+  for (bitset_i = 0; bitset_i < BITSET_UINTS; ++bitset_i)
+    dest[bitset_i] |= src[bitset_i];
+}
+
+#if 0 /* gnupg */
+static inline void
+bitset_not_merge (dest, src)
+     bitset dest;
+     const bitset src;
+{
+  int i;
+  for (i = 0; i < BITSET_UINTS; ++i)
+    dest[i] |= ~src[i];
+}
+#endif
+
+#ifdef RE_ENABLE_I18N
+/* Inline functions for re_string.  */
+static inline int
+re_string_char_size_at (pstr, idx)
+     const re_string_t *pstr;
+     int idx;
+{
+  int byte_idx;
+  if (MB_CUR_MAX == 1)
+    return 1;
+  for (byte_idx = 1; idx + byte_idx < pstr->len; ++byte_idx)
+    if (pstr->wcs[idx + byte_idx] != WEOF)
+      break;
+  return byte_idx;
+}
+
+static inline wint_t
+re_string_wchar_at (pstr, idx)
+     const re_string_t *pstr;
+     int idx;
+{
+  if (MB_CUR_MAX == 1)
+    return (wint_t) pstr->mbs[idx];
+  return (wint_t) pstr->wcs[idx];
+}
+
+static int
+re_string_elem_size_at (pstr, idx)
+     const re_string_t *pstr;
+     int idx;
+{
+#ifdef _LIBC
+  const unsigned char *p, *extra;
+  const int32_t *table, *indirect;
+  int32_t tmp;
+# include <locale/weight.h>
+  uint_fast32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+
+  if (nrules != 0)
+    {
+      table = (const int32_t *) _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+      extra = (const unsigned char *)
+        _NL_CURRENT (LC_COLLATE, _NL_COLLATE_EXTRAMB);
+      indirect = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+						_NL_COLLATE_INDIRECTMB);
+      p = pstr->mbs + idx;
+      tmp = findidx (&p);
+      return p - pstr->mbs - idx;
+    }
+  else
+#endif /* _LIBC */
+    return 1;
+}
+#endif /* RE_ENABLE_I18N */
+
+#endif /*  _REGEX_INTERNAL_H */
diff --git a/util/regexec.c b/util/regexec.c
new file mode 100644
index 000000000..d791edb36
--- /dev/null
+++ b/util/regexec.c
@@ -0,0 +1,3225 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email protected]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined HAVE_WCHAR_H || defined _LIBC
+# include <wchar.h>
+#endif /* HAVE_WCHAR_H || _LIBC */
+#if defined HAVE_WCTYPE_H || defined _LIBC
+# include <wctype.h>
+#endif /* HAVE_WCTYPE_H || _LIBC */
+
+#ifdef _LIBC
+# ifndef _RE_DEFINE_LOCALE_FUNCTIONS
+#  define _RE_DEFINE_LOCALE_FUNCTIONS 1
+#  include <locale/localeinfo.h>
+#  include <locale/elem-hash.h>
+#  include <locale/coll-lookup.h>
+# endif
+#endif
+
+#include "_regex.h" /* gnupg */
+#include "regex_internal.h"
+
+static reg_errcode_t match_ctx_init (re_match_context_t *cache, int eflags,
+				     re_string_t *input, int n);
+static void match_ctx_free (re_match_context_t *cache);
+static reg_errcode_t match_ctx_add_entry (re_match_context_t *cache, int node,
+                                          int str_idx, int from, int to);
+static void match_ctx_clear_flag (re_match_context_t *mctx);
+static void sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
+                           re_dfastate_t **limited_sts, int last_node,
+                           int last_str_idx, int check_subexp);
+static reg_errcode_t re_search_internal (const regex_t *preg,
+                                         const char *string, int length,
+                                         int start, int range, int stop,
+                                         size_t nmatch, regmatch_t pmatch[],
+                                         int eflags);
+static int re_search_2_stub (struct re_pattern_buffer *bufp,
+                             const char *string1, int length1,
+                             const char *string2, int length2,
+                             int start, int range, struct re_registers *regs,
+                             int stop, int ret_len);
+static int re_search_stub (struct re_pattern_buffer *bufp,
+                           const char *string, int length, int start,
+                           int range, int stop, struct re_registers *regs,
+                           int ret_len);
+static unsigned re_copy_regs (struct re_registers *regs, regmatch_t *pmatch,
+                              int nregs, int regs_allocated);
+static inline re_dfastate_t *acquire_init_state_context (reg_errcode_t *err,
+                                                         const regex_t *preg,
+                                                         const re_match_context_t *mctx,
+                                                         int idx);
+static int check_matching (const regex_t *preg, re_match_context_t *mctx,
+                           int fl_search, int fl_longest_match);
+static int check_halt_node_context (const re_dfa_t *dfa, int node,
+                                    unsigned int context);
+static int check_halt_state_context (const regex_t *preg,
+                                     const re_dfastate_t *state,
+                                     const re_match_context_t *mctx, int idx);
+static void update_regs (re_dfa_t *dfa, regmatch_t *pmatch, int cur_node,
+                         int cur_idx, int nmatch);
+static int proceed_next_node (const regex_t *preg, int nregs, regmatch_t *regs,
+                              const re_match_context_t *mctx,
+                              int *pidx, int node, re_node_set *eps_via_nodes,
+                              struct re_fail_stack_t *fs);
+static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs, 
+                                      int str_idx, int *dests, int nregs,
+                                      regmatch_t *regs,
+                                      re_node_set *eps_via_nodes);
+static int pop_fail_stack (struct re_fail_stack_t *fs, int *pidx, int nregs,
+                           regmatch_t *regs, re_node_set *eps_via_nodes);
+static reg_errcode_t set_regs (const regex_t *preg,
+                               const re_match_context_t *mctx,
+                               size_t nmatch, regmatch_t *pmatch,
+                               int fl_backtrack);
+#ifdef RE_ENABLE_I18N
+static int sift_states_iter_mb (const regex_t *preg,
+                                const re_match_context_t *mctx,
+                                re_sift_context_t *sctx,
+                                int node_idx, int str_idx, int max_str_idx);
+#endif /* RE_ENABLE_I18N */
+static reg_errcode_t sift_states_backward (const regex_t *preg,
+                                           re_match_context_t *mctx,
+                                           re_sift_context_t *sctx);
+static reg_errcode_t update_cur_sifted_state (const regex_t *preg,
+                                              re_match_context_t *mctx,
+                                              re_sift_context_t *sctx,
+                                              int str_idx,
+                                              re_node_set *dest_nodes);
+static reg_errcode_t add_epsilon_src_nodes (re_dfa_t *dfa,
+                                            re_node_set *dest_nodes,
+                                            const re_node_set *candidates);
+static reg_errcode_t sub_epsilon_src_nodes (re_dfa_t *dfa, int node,
+                                            re_node_set *dest_nodes,
+                                            const re_node_set *and_nodes);
+static int check_dst_limits (re_dfa_t *dfa, re_node_set *limits,
+                             re_match_context_t *mctx, int dst_node,
+                             int dst_idx, int src_node, int src_idx);
+static int check_dst_limits_calc_pos (re_dfa_t *dfa, re_match_context_t *mctx,
+                                      int limit, re_node_set *eclosures,
+                                      int subexp_idx, int node, int str_idx);
+static reg_errcode_t check_subexp_limits (re_dfa_t *dfa,
+                                          re_node_set *dest_nodes,
+                                          const re_node_set *candidates,
+                                          re_node_set *limits,
+                                          struct re_backref_cache_entry *bkref_ents,
+                                          int str_idx);
+static reg_errcode_t search_subexp (const regex_t *preg,
+                                    re_match_context_t *mctx,
+                                    re_sift_context_t *sctx, int str_idx,
+                                    re_node_set *dest_nodes);
+static reg_errcode_t sift_states_bkref (const regex_t *preg,
+                                        re_match_context_t *mctx,
+                                        re_sift_context_t *sctx,
+                                        int str_idx, re_node_set *dest_nodes);
+static reg_errcode_t clean_state_log_if_need (re_match_context_t *mctx,
+                                              int next_state_log_idx);
+static reg_errcode_t merge_state_array (re_dfa_t *dfa, re_dfastate_t **dst,
+                                        re_dfastate_t **src, int num);
+static re_dfastate_t *transit_state (reg_errcode_t *err, const regex_t *preg,
+                                     re_match_context_t *mctx,
+                                     re_dfastate_t *state, int fl_search);
+static re_dfastate_t *transit_state_sb (reg_errcode_t *err, const regex_t *preg,
+                                        re_dfastate_t *pstate,
+                                        int fl_search,
+                                        re_match_context_t *mctx);
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t transit_state_mb (const regex_t *preg,
+                                       re_dfastate_t *pstate,
+                                       re_match_context_t *mctx);
+#endif /* RE_ENABLE_I18N */
+static reg_errcode_t transit_state_bkref (const regex_t *preg,
+                                          re_dfastate_t *pstate,
+                                          re_match_context_t *mctx);
+static reg_errcode_t transit_state_bkref_loop (const regex_t *preg,
+                                               re_node_set *nodes,
+                                               re_dfastate_t **work_state_log,
+                                               re_match_context_t *mctx);
+static re_dfastate_t **build_trtable (const regex_t *dfa,
+                                      const re_dfastate_t *state,
+                                      int fl_search);
+#ifdef RE_ENABLE_I18N
+static int check_node_accept_bytes (const regex_t *preg, int node_idx,
+                                    const re_string_t *input, int idx);
+# ifdef _LIBC
+static unsigned int find_collation_sequence_value (const unsigned char *mbs,
+                                                   size_t name_len);
+# endif /* _LIBC */
+#endif /* RE_ENABLE_I18N */
+static int group_nodes_into_DFAstates (const regex_t *dfa,
+                                       const re_dfastate_t *state,
+                                       re_node_set *states_node,
+                                       bitset *states_ch);
+static int check_node_accept (const regex_t *preg, const re_token_t *node,
+                              const re_match_context_t *mctx, int idx);
+static reg_errcode_t extend_buffers (re_match_context_t *mctx);
+
+/* Entry point for POSIX code.  */
+
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
+
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
+
+   EFLAGS specifies `execution flags' which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
+
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+
+int
+regexec (preg, string, nmatch, pmatch, eflags)
+    const regex_t *__restrict preg;
+    const char *__restrict string;
+    size_t nmatch;
+    regmatch_t pmatch[];
+    int eflags;
+{
+  reg_errcode_t err;
+  int length = strlen (string);
+  if (preg->no_sub)
+    err = re_search_internal (preg, string, length, 0, length, length, 0,
+                              NULL, eflags);
+  else
+    err = re_search_internal (preg, string, length, 0, length, length, nmatch,
+                              pmatch, eflags);
+  return err != REG_NOERROR;
+}
+#ifdef _LIBC
+weak_alias (__regexec, regexec)
+#endif
+
+/* Entry points for GNU code.  */
+
+/* re_match, re_search, re_match_2, re_search_2
+
+   The former two functions operate on STRING with length LENGTH,
+   while the later two operate on concatenation of STRING1 and STRING2
+   with lengths LENGTH1 and LENGTH2, respectively.
+
+   re_match() matches the compiled pattern in BUFP against the string,
+   starting at index START.
+
+   re_search() first tries matching at index START, then it tries to match
+   starting from index START + 1, and so on.  The last start position tried
+   is START + RANGE.  (Thus RANGE = 0 forces re_search to operate the same
+   way as re_match().)
+
+   The parameter STOP of re_{match,search}_2 specifies that no match exceeding
+   the first STOP characters of the concatenation of the strings should be
+   concerned.
+
+   If REGS is not NULL, and BUFP->no_sub is not set, the offsets of the match
+   and all groups is stroed in REGS.  (For the "_2" variants, the offsets are
+   computed relative to the concatenation, not relative to the individual
+   strings.)
+
+   On success, re_match* functions return the length of the match, re_search*
+   return the position of the start of the match.  Return value -1 means no
+   match was found and -2 indicates an internal error.  */
+
+int
+re_match (bufp, string, length, start, regs)
+    struct re_pattern_buffer *bufp;
+    const char *string;
+    int length, start;
+    struct re_registers *regs;
+{
+  return re_search_stub (bufp, string, length, start, 0, length, regs, 1);
+}
+#ifdef _LIBC
+weak_alias (__re_match, re_match)
+#endif
+
+int
+re_search (bufp, string, length, start, range, regs)
+    struct re_pattern_buffer *bufp;
+    const char *string;
+    int length, start, range;
+    struct re_registers *regs;
+{
+  return re_search_stub (bufp, string, length, start, range, length, regs, 0);
+}
+#ifdef _LIBC
+weak_alias (__re_search, re_search)
+#endif
+
+int
+re_match_2 (bufp, string1, length1, string2, length2, start, regs, stop)
+    struct re_pattern_buffer *bufp;
+    const char *string1, *string2;
+    int length1, length2, start, stop;
+    struct re_registers *regs;
+{
+  return re_search_2_stub (bufp, string1, length1, string2, length2,
+                           start, 0, regs, stop, 1);
+}
+#ifdef _LIBC
+weak_alias (__re_match_2, re_match_2)
+#endif
+
+int
+re_search_2 (bufp, string1, length1, string2, length2, start, range, regs, stop)
+    struct re_pattern_buffer *bufp;
+    const char *string1, *string2;
+    int length1, length2, start, range, stop;
+    struct re_registers *regs;
+{
+  return re_search_2_stub (bufp, string1, length1, string2, length2,
+                           start, range, regs, stop, 0);
+}
+#ifdef _LIBC
+weak_alias (__re_search_2, re_search_2)
+#endif
+
+static int
+re_search_2_stub (bufp, string1, length1, string2, length2, start, range, regs,
+                  stop, ret_len)
+    struct re_pattern_buffer *bufp;
+    const char *string1, *string2;
+    int length1, length2, start, range, stop, ret_len;
+    struct re_registers *regs;
+{
+  const char *str;
+  int rval;
+  int len = length1 + length2;
+  int free_str = 0;
+
+  if (BE (length1 < 0 || length2 < 0 || stop < 0, 0))
+    return -2;
+
+  /* Concatenate the strings.  */
+  if (length2 > 0)
+    if (length1 > 0)
+      {
+        char *s = re_malloc (char, len);
+
+        if (BE (s == NULL, 0))
+          return -2;
+        memcpy (s, string1, length1);
+        memcpy (s + length1, string2, length2);
+        str = s;
+        free_str = 1;
+      }
+    else
+      str = string2;
+  else
+    str = string1;
+
+  rval = re_search_stub (bufp, str, len, start, range, stop, regs,
+                         ret_len);
+  if (free_str)
+      re_free ((char *) str);
+  return rval;
+}
+
+/* The parameters have the same meaning as those of re_search.
+   Additional parameters:
+   If RET_LEN is nonzero the length of the match is returned (re_match style);
+   otherwise the position of the match is returned.  */
+
+static int
+re_search_stub (bufp, string, length, start, range, stop, regs, ret_len)
+    struct re_pattern_buffer *bufp;
+    const char *string;
+    int length, start, range, stop, ret_len;
+    struct re_registers *regs;
+{
+  reg_errcode_t result;
+  regmatch_t *pmatch;
+  int nregs, rval;
+  int eflags = 0;
+
+  /* Check for out-of-range.  */
+  if (BE (start < 0 || start > length, 0))
+    return -1;
+  if (BE (start + range > length, 0))
+    range = length - start;
+  else if (BE (start + range < 0, 0))
+    range = -start;
+
+  eflags |= (bufp->not_bol) ? REG_NOTBOL : 0;
+  eflags |= (bufp->not_eol) ? REG_NOTEOL : 0;
+
+  /* Compile fastmap if we haven't yet.  */
+  if (range > 0 && bufp->fastmap != NULL && !bufp->fastmap_accurate)
+    re_compile_fastmap (bufp);
+
+  if (BE (bufp->no_sub, 0))
+    regs = NULL;
+
+  /* We need at least 1 register.  */
+  if (regs == NULL)
+    nregs = 1;
+  else if (BE (bufp->regs_allocated == REGS_FIXED &&
+               regs->num_regs < bufp->re_nsub + 1, 0))
+    {
+      nregs = regs->num_regs;
+      if (BE (nregs < 1, 0))
+        {
+          /* Nothing can be copied to regs.  */
+          regs = NULL;
+          nregs = 1;
+        }
+    }
+  else
+    nregs = bufp->re_nsub + 1;
+  pmatch = re_malloc (regmatch_t, nregs);
+  if (BE (pmatch == NULL, 0))
+    return -2;
+
+  result = re_search_internal (bufp, string, length, start, range, stop,
+                               nregs, pmatch, eflags);
+
+  rval = 0;
+
+  /* I hope we needn't fill ther regs with -1's when no match was found.  */
+  if (result != REG_NOERROR)
+    rval = -1;
+  else if (regs != NULL)
+    {
+      /* If caller wants register contents data back, copy them.  */
+      bufp->regs_allocated = re_copy_regs (regs, pmatch, nregs,
+                                           bufp->regs_allocated);
+      if (BE (bufp->regs_allocated == REGS_UNALLOCATED, 0))
+        rval = -2;
+    }
+
+  if (BE (rval == 0, 1))
+    {
+      if (ret_len)
+        {
+          assert (pmatch[0].rm_so == start);
+          rval = pmatch[0].rm_eo - start;
+        }
+      else
+        rval = pmatch[0].rm_so;
+    }
+  re_free (pmatch);
+  return rval;
+}
+
+static unsigned
+re_copy_regs (regs, pmatch, nregs, regs_allocated)
+    struct re_registers *regs;
+    regmatch_t *pmatch;
+    int nregs, regs_allocated;
+{
+  int rval = REGS_REALLOCATE;
+  int i;
+  int need_regs = nregs + 1;
+  /* We need one extra element beyond `num_regs' for the `-1' marker GNU code
+     uses.  */
+
+  /* Have the register data arrays been allocated?  */
+  if (regs_allocated == REGS_UNALLOCATED)
+    { /* No.  So allocate them with malloc.  */
+      regs->start = re_malloc (regoff_t, need_regs);
+      if (BE (regs->start == NULL, 0))
+        return REGS_UNALLOCATED;
+      regs->end = re_malloc (regoff_t, need_regs);
+      if (BE (regs->end == NULL, 0))
+        {
+          re_free (regs->start);
+          return REGS_UNALLOCATED;
+        }
+      regs->num_regs = need_regs;
+    }
+  else if (regs_allocated == REGS_REALLOCATE)
+    { /* Yes.  If we need more elements than were already
+         allocated, reallocate them.  If we need fewer, just
+         leave it alone.  */
+      if (need_regs > regs->num_regs)
+        {
+          regs->start = re_realloc (regs->start, regoff_t, need_regs);
+          if (BE (regs->start == NULL, 0))
+            {
+              if (regs->end != NULL)
+                re_free (regs->end);
+              return REGS_UNALLOCATED;
+            }
+          regs->end = re_realloc (regs->end, regoff_t, need_regs);
+          if (BE (regs->end == NULL, 0))
+            {
+              re_free (regs->start);
+              return REGS_UNALLOCATED;
+            }
+          regs->num_regs = need_regs;
+        }
+    }
+  else
+    {
+      assert (regs_allocated == REGS_FIXED);
+      /* This function may not be called with REGS_FIXED and nregs too big.  */
+      assert (regs->num_regs >= nregs);
+      rval = REGS_FIXED;
+    }
+
+  /* Copy the regs.  */
+  for (i = 0; i < nregs; ++i)
+    {
+      regs->start[i] = pmatch[i].rm_so;
+      regs->end[i] = pmatch[i].rm_eo;
+    }
+  for ( ; i < regs->num_regs; ++i)
+    regs->start[i] = regs->end[i] = -1;
+
+  return rval;
+}
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+
+void
+re_set_registers (bufp, regs, num_regs, starts, ends)
+    struct re_pattern_buffer *bufp;
+    struct re_registers *regs;
+    unsigned num_regs;
+    regoff_t *starts, *ends;
+{
+  if (num_regs)
+    {
+      bufp->regs_allocated = REGS_REALLOCATE;
+      regs->num_regs = num_regs;
+      regs->start = starts;
+      regs->end = ends;
+    }
+  else
+    {
+      bufp->regs_allocated = REGS_UNALLOCATED;
+      regs->num_regs = 0;
+      regs->start = regs->end = (regoff_t *) 0;
+    }
+}
+#ifdef _LIBC
+weak_alias (__re_set_registers, re_set_registers)
+#endif
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+
+#if defined _REGEX_RE_COMP || defined _LIBC
+int
+# ifdef _LIBC
+weak_function
+# endif
+re_exec (s)
+     const char *s;
+{
+  return 0 == regexec (&re_comp_buf, s, 0, NULL, 0);
+}
+#endif /* _REGEX_RE_COMP */
+
+static re_node_set empty_set;
+
+/* Internal entry point.  */
+
+/* Searches for a compiled pattern PREG in the string STRING, whose
+   length is LENGTH.  NMATCH, PMATCH, and EFLAGS have the same
+   mingings with regexec.  START, and RANGE have the same meanings
+   with re_search.
+   Return REG_NOERROR if we find a match, and REG_NOMATCH if not,
+   otherwise return the error code.
+   Note: We assume front end functions already check ranges.
+   (START + RANGE >= 0 && START + RANGE <= LENGTH)  */
+
+static reg_errcode_t
+re_search_internal (preg, string, length, start, range, stop, nmatch, pmatch,
+                    eflags)
+    const regex_t *preg;
+    const char *string;
+    int length, start, range, stop, eflags;
+    size_t nmatch;
+    regmatch_t pmatch[];
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  re_string_t input;
+  int left_lim, right_lim, incr;
+  int fl_longest_match, match_first, match_last = -1;
+  re_match_context_t mctx;
+  char *fastmap = ((preg->fastmap != NULL && preg->fastmap_accurate)
+                   ? preg->fastmap : NULL);
+
+  /* Check if the DFA haven't been compiled.  */
+  if (BE (preg->used == 0 || dfa->init_state == NULL
+          || dfa->init_state_word == NULL || dfa->init_state_nl == NULL
+          || dfa->init_state_begbuf == NULL, 0))
+    return REG_NOMATCH;
+
+  re_node_set_init_empty (&empty_set);
+
+  /* We must check the longest matching, if nmatch > 0.  */
+  fl_longest_match = (nmatch != 0);
+
+  err = re_string_allocate (&input, string, length, dfa->nodes_len + 1,
+                            preg->translate, preg->syntax & RE_ICASE);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  input.stop = stop;
+
+  err = match_ctx_init (&mctx, eflags, &input, dfa->nbackref * 2);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* We will log all the DFA states through which the dfa pass,
+     if nmatch > 1, or this dfa has "multibyte node", which is a
+     back-reference or a node which can accept multibyte character or
+     multi character collating element.  */
+  if (nmatch > 1 || dfa->has_mb_node)
+    {
+      mctx.state_log = re_malloc (re_dfastate_t *, dfa->nodes_len + 1);
+      if (BE (mctx.state_log == NULL, 0))
+        return REG_ESPACE;
+    }
+  else
+    mctx.state_log = NULL;
+
+#ifdef DEBUG
+  /* We assume front-end functions already check them.  */
+  assert (start + range >= 0 && start + range <= length);
+#endif
+
+  match_first = start;
+  input.tip_context = ((eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
+                       : CONTEXT_NEWLINE | CONTEXT_BEGBUF);
+
+  /* Check incrementally whether of not the input string match.  */
+  incr = (range < 0) ? -1 : 1;
+  left_lim = (range < 0) ? start + range : start;
+  right_lim = (range < 0) ? start : start + range;
+
+  for (;;)
+    {
+      /* At first get the current byte from input string.  */
+      int ch;
+      if (MB_CUR_MAX > 1 && (preg->syntax & RE_ICASE || preg->translate))
+        {
+          /* In this case, we can't determin easily the current byte,
+             since it might be a component byte of a multibyte character.
+             Then we use the constructed buffer instead.  */
+          /* If MATCH_FIRST is out of the valid range, reconstruct the
+             buffers.  */
+          if (input.raw_mbs_idx + input.valid_len <= match_first)
+            re_string_reconstruct (&input, match_first, eflags,
+                                   preg->newline_anchor);
+          /* If MATCH_FIRST is out of the buffer, leave it as '\0'.
+             Note that MATCH_FIRST must not be smaller than 0.  */
+          ch = ((match_first >= length) ? 0
+                : re_string_byte_at (&input, match_first - input.raw_mbs_idx));
+        }
+      else
+        {
+          /* We apply translate/conversion manually, since it is trivial
+             in this case.  */
+          /* If MATCH_FIRST is out of the buffer, leave it as '\0'.
+             Note that MATCH_FIRST must not be smaller than 0.  */
+          ch = (match_first < length) ? (unsigned char)string[match_first] : 0;
+          /* Apply translation if we need.  */
+          ch = preg->translate ? preg->translate[ch] : ch;
+          /* In case of case insensitive mode, convert to upper case.  */
+          ch = ((preg->syntax & RE_ICASE) && islower (ch)) ? toupper (ch) : ch;
+        }
+
+      /* Eliminate inappropriate one by fastmap.  */
+      if (preg->can_be_null || fastmap == NULL || fastmap[ch])
+        {
+          /* Reconstruct the buffers so that the matcher can assume that
+             the matching starts from the begining of the buffer.  */
+          re_string_reconstruct (&input, match_first, eflags,
+                                 preg->newline_anchor);
+#ifdef RE_ENABLE_I18N
+          /* Eliminate it when it is a component of a multibyte character
+             and isn't the head of a multibyte character.  */
+          if (MB_CUR_MAX == 1 || re_string_first_byte (&input, 0))
+#endif
+            {
+              /* It seems to be appropriate one, then use the matcher.  */
+              /* We assume that the matching starts from 0.  */
+              mctx.state_log_top = mctx.nbkref_ents = mctx.max_mb_elem_len = 0;
+              match_last = check_matching (preg, &mctx, 0, fl_longest_match);
+              if (match_last != -1)
+                {
+                  if (BE (match_last == -2, 0))
+                    return REG_ESPACE;
+                  else
+                    break; /* We found a matching.  */
+                }
+            }
+        }
+      /* Update counter.  */
+      match_first += incr;
+      if (match_first < left_lim || right_lim < match_first)
+        break;
+    }
+
+  /* Set pmatch[] if we need.  */
+  if (match_last != -1 && nmatch > 0)
+    {
+      int reg_idx;
+
+      /* Initialize registers.  */
+      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
+        pmatch[reg_idx].rm_so = pmatch[reg_idx].rm_eo = -1;
+
+      /* Set the points where matching start/end.  */
+      pmatch[0].rm_so = 0;
+      mctx.match_last = pmatch[0].rm_eo = match_last;
+
+      if (!preg->no_sub && nmatch > 1)
+        {
+          /* We need the ranges of all the subexpressions.  */
+          int halt_node;
+          re_dfastate_t **sifted_states;
+          re_dfastate_t **lim_states = NULL;
+          re_dfastate_t *pstate = mctx.state_log[match_last];
+          re_sift_context_t sctx;
+#ifdef DEBUG
+          assert (mctx.state_log != NULL);
+#endif
+          halt_node = check_halt_state_context (preg, pstate, &mctx,
+                                                match_last);
+          if (dfa->has_plural_match)
+            {
+              match_ctx_clear_flag (&mctx);
+              sifted_states = re_malloc (re_dfastate_t *, match_last + 1);
+              if (BE (sifted_states == NULL, 0))
+                return REG_ESPACE;
+              if (dfa->nbackref)
+                {
+                  lim_states = calloc (sizeof (re_dfastate_t *),
+                                       match_last + 1);
+                  if (BE (lim_states == NULL, 0))
+                    return REG_ESPACE;
+                }
+              sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
+                             mctx.match_last, 0);
+              err = sift_states_backward (preg, &mctx, &sctx);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+              if (lim_states != NULL)
+                {
+                  err = merge_state_array (dfa, sifted_states, lim_states,
+                                           match_last + 1);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                  re_free (lim_states);
+                }
+              re_node_set_free (&sctx.limits);
+              re_free (mctx.state_log);
+              mctx.state_log = sifted_states;
+            }
+          mctx.last_node = halt_node;
+          err = set_regs (preg, &mctx, nmatch, pmatch,
+                          dfa->has_plural_match && dfa->nbackref > 0);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+        }
+
+      /* At last, add the offset to the each registers, since we slided
+         the buffers so that We can assume that the matching starts from 0.  */
+      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
+        if (pmatch[reg_idx].rm_so != -1)
+          {
+            pmatch[reg_idx].rm_so += match_first;
+            pmatch[reg_idx].rm_eo += match_first;
+          }
+    }
+
+  re_free (mctx.state_log);
+  if (dfa->nbackref)
+    match_ctx_free (&mctx);
+  re_string_destruct (&input);
+
+  return (match_last == -1) ? REG_NOMATCH : REG_NOERROR;
+}
+
+/* Acquire an initial state and return it.
+   We must select appropriate initial state depending on the context,
+   since initial states may have constraints like "\<", "^", etc..  */
+
+static inline re_dfastate_t *
+acquire_init_state_context (err, preg, mctx, idx)
+     reg_errcode_t *err;
+     const regex_t *preg;
+     const re_match_context_t *mctx;
+     int idx;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+
+  *err = REG_NOERROR;
+  if (dfa->init_state->has_constraint)
+    {
+      unsigned int context;
+      context =  re_string_context_at (mctx->input, idx - 1, mctx->eflags,
+                                       preg->newline_anchor);
+      if (IS_WORD_CONTEXT (context))
+        return dfa->init_state_word;
+      else if (IS_ORDINARY_CONTEXT (context))
+        return dfa->init_state;
+      else if (IS_BEGBUF_CONTEXT (context) && IS_NEWLINE_CONTEXT (context))
+        return dfa->init_state_begbuf;
+      else if (IS_NEWLINE_CONTEXT (context))
+        return dfa->init_state_nl;
+      else if (IS_BEGBUF_CONTEXT (context))
+        {
+          /* It is relatively rare case, then calculate on demand.  */
+          return  re_acquire_state_context (err, dfa,
+                                            dfa->init_state->entrance_nodes,
+                                            context);
+        }
+      else
+        /* Must not happen?  */
+        return dfa->init_state;
+    }
+  else
+    return dfa->init_state;
+}
+
+/* Check whether the regular expression match input string INPUT or not,
+   and return the index where the matching end, return -1 if not match,
+   or return -2 in case of an error.
+   FL_SEARCH means we must search where the matching starts,
+   FL_LONGEST_MATCH means we want the POSIX longest matching.
+   Note that the matcher assume that the maching starts from the current
+   index of the buffer.  */
+
+static int
+check_matching (preg, mctx, fl_search, fl_longest_match)
+    const regex_t *preg;
+    re_match_context_t *mctx;
+    int fl_search, fl_longest_match;
+{
+  reg_errcode_t err;
+  int match = 0;
+  int match_last = -1;
+  int cur_str_idx = re_string_cur_idx (mctx->input);
+  re_dfastate_t *cur_state;
+
+  cur_state = acquire_init_state_context (&err, preg, mctx, cur_str_idx);
+  /* An initial state must not be NULL(invalid state).  */
+  if (BE (cur_state == NULL, 0))
+    return -2;
+  if (mctx->state_log != NULL)
+    mctx->state_log[cur_str_idx] = cur_state;
+
+  if (cur_state->has_backref)
+    {
+      int i;
+      re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+      for (i = 0; i < cur_state->nodes.nelem; ++i)
+        {
+          re_token_type_t type;
+          int node = cur_state->nodes.elems[i];
+          int entity = (dfa->nodes[node].type != OP_CONTEXT_NODE ? node
+                        : dfa->nodes[node].opr.ctx_info->entity);
+          type = dfa->nodes[entity].type;
+          if (type == OP_BACK_REF)
+            {
+              int clexp_idx;
+              for (clexp_idx = 0; clexp_idx < cur_state->nodes.nelem;
+                   ++clexp_idx)
+                {
+                  re_token_t *clexp_node;
+                  clexp_node = dfa->nodes + cur_state->nodes.elems[clexp_idx];
+                  if (clexp_node->type == OP_CLOSE_SUBEXP
+                      && clexp_node->opr.idx + 1== dfa->nodes[entity].opr.idx)
+                    {
+                      err = match_ctx_add_entry (mctx, node, 0, 0, 0);
+                      if (BE (err != REG_NOERROR, 0))
+                        return -2;
+                      break;
+                    }
+                }
+            }
+        }
+    }
+
+  /* If the RE accepts NULL string.  */
+  if (cur_state->halt)
+    {
+      if (!cur_state->has_constraint
+          || check_halt_state_context (preg, cur_state, mctx, cur_str_idx))
+        {
+          if (!fl_longest_match)
+            return cur_str_idx;
+          else
+            {
+              match_last = cur_str_idx;
+              match = 1;
+            }
+        }
+    }
+
+  while (!re_string_eoi (mctx->input))
+    {
+      cur_state = transit_state (&err, preg, mctx, cur_state,
+                                 fl_search && !match);
+      if (cur_state == NULL) /* Reached at the invalid state or an error.  */
+        {
+          cur_str_idx = re_string_cur_idx (mctx->input);
+          if (BE (err != REG_NOERROR, 0))
+            return -2;
+          if (fl_search && !match)
+            {
+              /* Restart from initial state, since we are searching
+                 the point from where matching start.  */
+#ifdef RE_ENABLE_I18N
+              if (MB_CUR_MAX == 1
+                  || re_string_first_byte (mctx->input, cur_str_idx))
+#endif /* RE_ENABLE_I18N */
+                cur_state = acquire_init_state_context (&err, preg, mctx,
+                                                        cur_str_idx);
+              if (BE (cur_state == NULL && err != REG_NOERROR, 0))
+                return -2;
+              if (mctx->state_log != NULL)
+                mctx->state_log[cur_str_idx] = cur_state;
+            }
+          else if (!fl_longest_match && match)
+            break;
+          else /* (fl_longest_match && match) || (!fl_search && !match)  */
+            {
+              if (mctx->state_log == NULL)
+                break;
+              else
+                {
+                  int max = mctx->state_log_top;
+                  for (; cur_str_idx <= max; ++cur_str_idx)
+                    if (mctx->state_log[cur_str_idx] != NULL)
+                      break;
+                  if (cur_str_idx > max)
+                    break;
+                }
+            }
+        }
+
+      if (cur_state != NULL && cur_state->halt)
+        {
+          /* Reached at a halt state.
+             Check the halt state can satisfy the current context.  */
+          if (!cur_state->has_constraint
+              || check_halt_state_context (preg, cur_state, mctx,
+                                           re_string_cur_idx (mctx->input)))
+            {
+              /* We found an appropriate halt state.  */
+              match_last = re_string_cur_idx (mctx->input);
+              match = 1;
+              if (!fl_longest_match)
+                break;
+            }
+        }
+   }
+  return match_last;
+}
+
+/* Check NODE match the current context.  */
+
+static int check_halt_node_context (dfa, node, context)
+    const re_dfa_t *dfa;
+    int node;
+    unsigned int context;
+{
+  int entity;
+  re_token_type_t type = dfa->nodes[node].type;
+  if (type == END_OF_RE)
+    return 1;
+  if (type != OP_CONTEXT_NODE)
+    return 0;
+  entity = dfa->nodes[node].opr.ctx_info->entity;
+  if (dfa->nodes[entity].type != END_OF_RE
+      || NOT_SATISFY_NEXT_CONSTRAINT (dfa->nodes[node].constraint, context))
+    return 0;
+  return 1;
+}
+
+/* Check the halt state STATE match the current context.
+   Return 0 if not match, if the node, STATE has, is a halt node and
+   match the context, return the node.  */
+
+static int
+check_halt_state_context (preg, state, mctx, idx)
+    const regex_t *preg;
+    const re_dfastate_t *state;
+    const re_match_context_t *mctx;
+    int idx;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int i;
+  unsigned int context;
+#ifdef DEBUG
+  assert (state->halt);
+#endif
+  context = re_string_context_at (mctx->input, idx, mctx->eflags,
+                                  preg->newline_anchor);
+  for (i = 0; i < state->nodes.nelem; ++i)
+    if (check_halt_node_context (dfa, state->nodes.elems[i], context))
+      return state->nodes.elems[i];
+  return 0;
+}
+
+/* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
+   corresponding to the DFA).
+   Return the destination node, and update EPS_VIA_NODES, return -1 in case
+   of errors.  */
+
+static int
+proceed_next_node (preg, nregs, regs, mctx, pidx, node, eps_via_nodes, fs)
+    const regex_t *preg;
+    regmatch_t *regs;
+    const re_match_context_t *mctx;
+    int nregs, *pidx, node;
+    re_node_set *eps_via_nodes;
+    struct re_fail_stack_t *fs;
+{
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  int i, err, dest_node, cur_entity;
+  dest_node = -1;
+  cur_entity = ((dfa->nodes[node].type == OP_CONTEXT_NODE)
+                ? dfa->nodes[node].opr.ctx_info->entity : node);
+  if (IS_EPSILON_NODE (dfa->nodes[node].type))
+    {
+      int ndest, dest_nodes[2], dest_entities[2];
+      err = re_node_set_insert (eps_via_nodes, node);
+      if (BE (err < 0, 0))
+        return -1;
+      /* Pick up valid destinations.  */
+      for (ndest = 0, i = 0; i < mctx->state_log[*pidx]->nodes.nelem; ++i)
+        {
+          int candidate = mctx->state_log[*pidx]->nodes.elems[i];
+          int entity;
+          entity = ((dfa->nodes[candidate].type == OP_CONTEXT_NODE)
+                    ? dfa->nodes[candidate].opr.ctx_info->entity : candidate);
+          if (!re_node_set_contains (dfa->edests + node, entity))
+            continue;
+          dest_nodes[0] = (ndest == 0) ? candidate : dest_nodes[0];
+          dest_entities[0] = (ndest == 0) ? entity : dest_entities[0];
+          dest_nodes[1] = (ndest == 1) ? candidate : dest_nodes[1];
+          dest_entities[1] = (ndest == 1) ? entity : dest_entities[1];
+          ++ndest;
+        }
+      if (ndest <= 1)
+        return ndest == 0 ? -1 : (ndest == 1 ? dest_nodes[0] : 0);
+      if (dest_entities[0] > dest_entities[1])
+        {
+          int swap_work = dest_nodes[0];
+          dest_nodes[0] = dest_nodes[1];
+          dest_nodes[1] = swap_work;
+        }
+      /* In order to avoid infinite loop like "(a*)*".  */
+      if (re_node_set_contains (eps_via_nodes, dest_nodes[0]))
+        return dest_nodes[1];
+      if (fs != NULL)
+        push_fail_stack (fs, *pidx, dest_nodes, nregs, regs, eps_via_nodes);
+      return dest_nodes[0];
+    }
+  else
+    {
+      int naccepted = 0, entity = node;
+      re_token_type_t type = dfa->nodes[node].type;
+      if (type == OP_CONTEXT_NODE)
+        {
+          entity = dfa->nodes[node].opr.ctx_info->entity;
+          type = dfa->nodes[entity].type;
+        }
+
+#ifdef RE_ENABLE_I18N
+      if (ACCEPT_MB_NODE (type))
+        naccepted = check_node_accept_bytes (preg, entity, mctx->input, *pidx);
+      else
+#endif /* RE_ENABLE_I18N */
+      if (type == OP_BACK_REF)
+        {
+          int subexp_idx = dfa->nodes[entity].opr.idx;
+          naccepted = regs[subexp_idx].rm_eo - regs[subexp_idx].rm_so;
+          if (fs != NULL)
+            {
+              if (regs[subexp_idx].rm_so == -1 || regs[subexp_idx].rm_eo == -1)
+                return -1;
+              else if (naccepted)
+                {
+                  char *buf = re_string_get_buffer (mctx->input);
+                  if (strncmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
+                               naccepted) != 0)
+                    return -1;
+                }
+            }
+
+          if (naccepted == 0)
+            {
+              err = re_node_set_insert (eps_via_nodes, node);
+              if (BE (err < 0, 0))
+                return -2;
+              dest_node = dfa->nexts[node];
+              if (re_node_set_contains (&mctx->state_log[*pidx]->nodes,
+                                        dest_node))
+                return dest_node;
+              for (i = 0; i < mctx->state_log[*pidx]->nodes.nelem; ++i)
+                {
+                  dest_node = mctx->state_log[*pidx]->nodes.elems[i];
+                  if ((dfa->nodes[dest_node].type == OP_CONTEXT_NODE
+                       && (dfa->nexts[node]
+                           == dfa->nodes[dest_node].opr.ctx_info->entity)))
+                    return dest_node;
+                }
+            }
+        }
+
+      if (naccepted != 0
+          || check_node_accept (preg, dfa->nodes + node, mctx, *pidx))
+        {
+          dest_node = dfa->nexts[node];
+          *pidx = (naccepted == 0) ? *pidx + 1 : *pidx + naccepted;
+          if (fs && (*pidx > mctx->match_last || mctx->state_log[*pidx] == NULL
+                     || !re_node_set_contains (&mctx->state_log[*pidx]->nodes,
+                                               dest_node)))
+            return -1;
+          re_node_set_empty (eps_via_nodes);
+          return dest_node;
+        }
+    }
+  return -1;
+}
+
+static reg_errcode_t
+push_fail_stack (fs, str_idx, dests, nregs, regs, eps_via_nodes)
+     struct re_fail_stack_t *fs;
+     int str_idx, *dests, nregs;
+     regmatch_t *regs;
+     re_node_set *eps_via_nodes;
+{
+  reg_errcode_t err;
+  int num = fs->num++;
+  if (fs->num == fs->alloc)
+    {
+      fs->alloc *= 2;
+      fs->stack = realloc (fs->stack, (sizeof (struct re_fail_stack_ent_t)
+                                       * fs->alloc));
+      if (fs->stack == NULL)
+        return REG_ESPACE;
+    }
+  fs->stack[num].idx = str_idx;
+  fs->stack[num].node = dests[1];
+  fs->stack[num].regs = re_malloc (regmatch_t, nregs);
+  memcpy (fs->stack[num].regs, regs, sizeof (regmatch_t) * nregs);
+  err = re_node_set_init_copy (&fs->stack[num].eps_via_nodes, eps_via_nodes);
+  return err;
+}
+ 
+static int
+pop_fail_stack (fs, pidx, nregs, regs, eps_via_nodes)
+     struct re_fail_stack_t *fs;
+     int *pidx, nregs;
+     regmatch_t *regs;
+     re_node_set *eps_via_nodes;
+{
+  int num = --fs->num;
+  assert (num >= 0);
+ *pidx = fs->stack[num].idx;
+  memcpy (regs, fs->stack[num].regs, sizeof (regmatch_t) * nregs);
+  re_node_set_free (eps_via_nodes);
+  *eps_via_nodes = fs->stack[num].eps_via_nodes;
+  return fs->stack[num].node;
+}
+
+/* Set the positions where the subexpressions are starts/ends to registers
+   PMATCH.
+   Note: We assume that pmatch[0] is already set, and
+   pmatch[i].rm_so == pmatch[i].rm_eo == -1 (i > 1).  */
+
+static reg_errcode_t
+set_regs (preg, mctx, nmatch, pmatch, fl_backtrack)
+     const regex_t *preg;
+     const re_match_context_t *mctx;
+     size_t nmatch;
+     regmatch_t *pmatch;
+     int fl_backtrack;
+{
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  int idx, cur_node, real_nmatch;
+  re_node_set eps_via_nodes;
+  struct re_fail_stack_t *fs;
+  struct re_fail_stack_t fs_body = {0, 2, NULL};
+#ifdef DEBUG
+  assert (nmatch > 1);
+  assert (mctx->state_log != NULL);
+#endif
+  if (fl_backtrack)
+    {
+      fs = &fs_body;
+      fs->stack = re_malloc (struct re_fail_stack_ent_t, fs->alloc);
+    }
+  else
+    fs = NULL;
+  cur_node = dfa->init_node;
+  real_nmatch = (nmatch <= preg->re_nsub) ? nmatch : preg->re_nsub + 1;
+  re_node_set_init_empty (&eps_via_nodes);
+  for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
+    {
+      update_regs (dfa, pmatch, cur_node, idx, real_nmatch);
+      if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
+        {
+          int reg_idx;
+          if (fs)
+            {
+              for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
+                if (pmatch[reg_idx].rm_so > -1 && pmatch[reg_idx].rm_eo == -1)
+                  break;
+              if (reg_idx == nmatch)
+                return REG_NOERROR;
+              cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+                                         &eps_via_nodes);
+            }
+          else
+            return REG_NOERROR;
+        }
+
+      /* Proceed to next node.  */
+      cur_node = proceed_next_node (preg, nmatch, pmatch, mctx, &idx, cur_node,
+                                    &eps_via_nodes, fs);
+
+      if (BE (cur_node < 0, 0))
+        {
+          if (cur_node == -2)
+            return REG_ESPACE;
+          if (fs)
+            cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+                                       &eps_via_nodes);
+          else
+            return REG_NOMATCH;
+        }
+    }
+  re_node_set_free (&eps_via_nodes);
+  return REG_NOERROR;
+}
+
+static void
+update_regs (dfa, pmatch, cur_node, cur_idx, nmatch)
+     re_dfa_t *dfa;
+     regmatch_t *pmatch;
+     int cur_node, cur_idx, nmatch;
+{
+  int type = dfa->nodes[cur_node].type;
+  int reg_num;
+  if (type != OP_OPEN_SUBEXP && type != OP_CLOSE_SUBEXP)
+    return;
+  reg_num = dfa->nodes[cur_node].opr.idx + 1;
+  if (reg_num >= nmatch)
+    return;
+  if (type == OP_OPEN_SUBEXP)
+    {
+      /* We are at the first node of this sub expression.  */
+      pmatch[reg_num].rm_so = cur_idx;
+      pmatch[reg_num].rm_eo = -1;
+    }
+  else if (type == OP_CLOSE_SUBEXP)
+    /* We are at the first node of this sub expression.  */
+    pmatch[reg_num].rm_eo = cur_idx;
+}
+
+#define NUMBER_OF_STATE 1
+
+/* This function checks the STATE_LOG from the SCTX->last_str_idx to 0
+   and sift the nodes in each states according to the following rules.
+   Updated state_log will be wrote to STATE_LOG.
+
+   Rules: We throw away the Node `a' in the STATE_LOG[STR_IDX] if...
+     1. When STR_IDX == MATCH_LAST(the last index in the state_log):
+        If `a' isn't the LAST_NODE and `a' can't epsilon transit to
+        the LAST_NODE, we throw away the node `a'.
+     2. When 0 <= STR_IDX < MATCH_LAST and `a' accepts
+        string `s' and transit to `b':
+        i. If 'b' isn't in the STATE_LOG[STR_IDX+strlen('s')], we throw
+           away the node `a'.
+        ii. If 'b' is in the STATE_LOG[STR_IDX+strlen('s')] but 'b' is
+            throwed away, we throw away the node `a'.
+     3. When 0 <= STR_IDX < n and 'a' epsilon transit to 'b':
+        i. If 'b' isn't in the STATE_LOG[STR_IDX], we throw away the
+           node `a'.
+        ii. If 'b' is in the STATE_LOG[STR_IDX] but 'b' is throwed away,
+            we throw away the node `a'.  */
+
+#define STATE_NODE_CONTAINS(state,node) \
+  ((state) != NULL && re_node_set_contains (&(state)->nodes, node))
+
+static reg_errcode_t
+sift_states_backward (preg, mctx, sctx)
+     const regex_t *preg;
+     re_match_context_t *mctx;
+     re_sift_context_t *sctx;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  int null_cnt = 0;
+  int str_idx = sctx->last_str_idx;
+  re_node_set cur_dest;
+  re_node_set *cur_src; /* Points the state_log[str_idx]->nodes  */
+
+#ifdef DEBUG
+  assert (mctx->state_log != NULL && mctx->state_log[str_idx] != NULL);
+#endif
+  cur_src = &mctx->state_log[str_idx]->nodes;
+
+  /* Build sifted state_log[str_idx].  It has the nodes which can epsilon
+     transit to the last_node and the last_node itself.  */
+  err = re_node_set_init_1 (&cur_dest, sctx->last_node);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  err = update_cur_sifted_state (preg, mctx, sctx, str_idx, &cur_dest);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* Then check each states in the state_log.  */
+  while (str_idx > 0)
+    {
+      int i, ret;
+      /* Update counters.  */
+      null_cnt = (sctx->sifted_states[str_idx] == NULL) ? null_cnt + 1 : 0;
+      if (null_cnt > mctx->max_mb_elem_len)
+        {
+          memset (sctx->sifted_states, '\0',
+                  sizeof (re_dfastate_t *) * str_idx);
+          return REG_NOERROR;
+        }
+      re_node_set_empty (&cur_dest);
+      --str_idx;
+      cur_src = ((mctx->state_log[str_idx] == NULL) ? &empty_set
+                 : &mctx->state_log[str_idx]->nodes);
+
+      /* Then build the next sifted state.
+         We build the next sifted state on `cur_dest', and update
+         `sifted_states[str_idx]' with `cur_dest'.
+         Note:
+         `cur_dest' is the sifted state from `state_log[str_idx + 1]'.
+         `cur_src' points the node_set of the old `state_log[str_idx]'.  */
+      for (i = 0; i < cur_src->nelem; i++)
+        {
+          int prev_node = cur_src->elems[i];
+          int entity = prev_node;
+          int naccepted = 0;
+          re_token_type_t type = dfa->nodes[prev_node].type;
+
+          if (IS_EPSILON_NODE(type))
+            continue;
+          if (type == OP_CONTEXT_NODE)
+            {
+              entity = dfa->nodes[prev_node].opr.ctx_info->entity;
+              type = dfa->nodes[entity].type;
+            }
+#ifdef RE_ENABLE_I18N
+          /* If the node may accept `multi byte'.  */
+          if (ACCEPT_MB_NODE (type))
+            naccepted = sift_states_iter_mb (preg, mctx, sctx, entity, str_idx,
+                                             sctx->last_str_idx);
+
+#endif /* RE_ENABLE_I18N */
+          /* We don't check backreferences here.
+             See update_cur_sifted_state().  */
+
+          if (!naccepted
+              && check_node_accept (preg, dfa->nodes + prev_node, mctx,
+                                    str_idx)
+              && STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + 1],
+                                      dfa->nexts[prev_node]))
+            naccepted = 1;
+
+          if (naccepted == 0)
+            continue;
+
+          if (sctx->limits.nelem)
+            {
+              int to_idx = str_idx + naccepted;
+              if (check_dst_limits (dfa, &sctx->limits, mctx,
+                                    dfa->nexts[prev_node], to_idx,
+                                    prev_node, str_idx))
+                continue;
+            }
+          ret = re_node_set_insert (&cur_dest, prev_node);
+          if (BE (ret == -1, 0))
+            return err;
+        }
+
+      /* Add all the nodes which satisfy the following conditions:
+         - It can epsilon transit to a node in CUR_DEST.
+         - It is in CUR_SRC.
+         And update state_log.  */
+      err = update_cur_sifted_state (preg, mctx, sctx, str_idx, &cur_dest);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+
+  re_node_set_free (&cur_dest);
+  return REG_NOERROR;
+}
+
+/* Helper functions.  */
+
+static inline reg_errcode_t
+clean_state_log_if_need (mctx, next_state_log_idx)
+    re_match_context_t *mctx;
+    int next_state_log_idx;
+{
+  int top = mctx->state_log_top;
+
+  if (next_state_log_idx >= mctx->input->bufs_len
+      || (next_state_log_idx >= mctx->input->valid_len
+          && mctx->input->valid_len < mctx->input->len))
+    {
+      reg_errcode_t err;
+      err = extend_buffers (mctx);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+
+  if (top < next_state_log_idx)
+    {
+      memset (mctx->state_log + top + 1, '\0',
+              sizeof (re_dfastate_t *) * (next_state_log_idx - top));
+      mctx->state_log_top = next_state_log_idx;
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t merge_state_array (dfa, dst, src, num)
+     re_dfa_t *dfa;
+     re_dfastate_t **dst;
+     re_dfastate_t **src;
+     int num;
+{
+  int st_idx;
+  reg_errcode_t err;
+  for (st_idx = 0; st_idx < num; ++st_idx)
+    {
+      if (dst[st_idx] == NULL)
+        dst[st_idx] = src[st_idx];
+      else if (src[st_idx] != NULL)
+        {
+          re_node_set merged_set;
+          err = re_node_set_init_union (&merged_set, &dst[st_idx]->nodes,
+                                        &src[st_idx]->nodes);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+          dst[st_idx] = re_acquire_state (&err, dfa, &merged_set);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+          re_node_set_free (&merged_set);
+        }
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+update_cur_sifted_state (preg, mctx, sctx, str_idx, dest_nodes)
+     const regex_t *preg;
+     re_match_context_t *mctx;
+     re_sift_context_t *sctx;
+     int str_idx;
+     re_node_set *dest_nodes;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  const re_node_set *candidates;
+  candidates = ((mctx->state_log[str_idx] == NULL) ? &empty_set
+                : &mctx->state_log[str_idx]->nodes);
+
+  /* At first, add the nodes which can epsilon transit to a node in
+     DEST_NODE.  */
+  err = add_epsilon_src_nodes (dfa, dest_nodes, candidates);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* Then, check the limitations in the current sift_context.  */
+  if (sctx->limits.nelem)
+    {
+      err = check_subexp_limits (dfa, dest_nodes, candidates, &sctx->limits,
+                                 mctx->bkref_ents, str_idx);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+
+  /* Update state_log.  */
+  sctx->sifted_states[str_idx] = re_acquire_state (&err, dfa, dest_nodes);
+  if (BE (sctx->sifted_states[str_idx] == NULL && err != REG_NOERROR, 0))
+    return err;
+
+  /* If we are searching for the subexpression candidates.
+     Note that we were from transit_state_bkref_loop() in this case.  */
+  if (sctx->check_subexp)
+    {
+      err = search_subexp (preg, mctx, sctx, str_idx, dest_nodes);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+
+  if ((mctx->state_log[str_idx] != NULL
+       && mctx->state_log[str_idx]->has_backref))
+    {
+      err = sift_states_bkref (preg, mctx, sctx, str_idx, dest_nodes);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+add_epsilon_src_nodes (dfa, dest_nodes, candidates)
+     re_dfa_t *dfa;
+     re_node_set *dest_nodes;
+     const re_node_set *candidates;
+{
+  reg_errcode_t err;
+  int src_idx;
+  re_node_set src_copy;
+
+  err = re_node_set_init_copy (&src_copy, dest_nodes);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  for (src_idx = 0; src_idx < src_copy.nelem; ++src_idx)
+    {
+      err = re_node_set_add_intersect (dest_nodes, candidates,
+                                       dfa->inveclosures
+                                       + src_copy.elems[src_idx]);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+  re_node_set_free (&src_copy);
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+sub_epsilon_src_nodes (dfa, node, dest_nodes, candidates)
+     re_dfa_t *dfa;
+     int node;
+     re_node_set *dest_nodes;
+     const re_node_set *candidates;
+{
+    int ecl_idx;
+    reg_errcode_t err;
+    re_node_set *inv_eclosure = dfa->inveclosures + node;
+    re_node_set except_nodes;
+    re_node_set_init_empty (&except_nodes);
+    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
+      {
+        int cur_node = inv_eclosure->elems[ecl_idx];
+        if (cur_node == node)
+          continue;
+        if (dfa->edests[cur_node].nelem)
+          {
+            int edst1 = dfa->edests[cur_node].elems[0];
+            int edst2 = ((dfa->edests[cur_node].nelem > 1)
+                         ? dfa->edests[cur_node].elems[1] : -1);
+            if ((!re_node_set_contains (inv_eclosure, edst1)
+                 && re_node_set_contains (dest_nodes, edst1))
+                || (edst2 > 0
+                    && !re_node_set_contains (inv_eclosure, edst2)
+                    && re_node_set_contains (dest_nodes, edst2)))
+              {
+                err = re_node_set_add_intersect (&except_nodes, candidates,
+                                                 dfa->inveclosures + cur_node);
+                if (BE (err != REG_NOERROR, 0))
+                  return err;
+              }
+          }
+      }
+    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
+      {
+        int cur_node = inv_eclosure->elems[ecl_idx];
+        if (!re_node_set_contains (&except_nodes, cur_node))
+          {
+            int idx = re_node_set_contains (dest_nodes, cur_node) - 1;
+            re_node_set_remove_at (dest_nodes, idx);
+          }
+      }
+    re_node_set_free (&except_nodes);
+    return REG_NOERROR;
+}
+
+static int
+check_dst_limits (dfa, limits, mctx, dst_node, dst_idx, src_node, src_idx)
+     re_dfa_t *dfa;
+     re_node_set *limits;
+     re_match_context_t *mctx;
+     int dst_node, dst_idx, src_node, src_idx;
+{
+  int lim_idx, src_pos, dst_pos;
+
+  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
+    {
+      int bkref, subexp_idx/*, node_idx, cls_node*/;
+      struct re_backref_cache_entry *ent;
+      ent = mctx->bkref_ents + limits->elems[lim_idx];
+      bkref = (dfa->nodes[ent->node].type == OP_CONTEXT_NODE
+               ? dfa->nodes[ent->node].opr.ctx_info->entity : ent->node);
+      subexp_idx = dfa->nodes[bkref].opr.idx - 1;
+
+      dst_pos = check_dst_limits_calc_pos (dfa, mctx, limits->elems[lim_idx],
+                                           dfa->eclosures + dst_node,
+                                           subexp_idx, dst_node, dst_idx);
+      src_pos = check_dst_limits_calc_pos (dfa, mctx, limits->elems[lim_idx],
+                                           dfa->eclosures + src_node,
+                                           subexp_idx, src_node, src_idx);
+
+      /* In case of:
+         <src> <dst> ( <subexp> )
+         ( <subexp> ) <src> <dst>
+         ( <subexp1> <src> <subexp2> <dst> <subexp3> )  */
+      if (src_pos == dst_pos)
+        continue; /* This is unrelated limitation.  */
+      else
+        return 1;
+    }
+  return 0;
+}
+
+static int
+check_dst_limits_calc_pos (dfa, mctx, limit, eclosures, subexp_idx, node,
+                           str_idx)
+     re_dfa_t *dfa;
+     re_match_context_t *mctx;
+     re_node_set *eclosures;
+     int limit, subexp_idx, node, str_idx;
+{
+  struct re_backref_cache_entry *lim = mctx->bkref_ents + limit;
+  int pos = (str_idx < lim->subexp_from ? -1
+             : (lim->subexp_to < str_idx ? 1 : 0));
+  if (pos == 0
+      && (str_idx == lim->subexp_from || str_idx == lim->subexp_to))
+    {
+      int node_idx;
+      for (node_idx = 0; node_idx < eclosures->nelem; ++node_idx)
+        {
+          int node = eclosures->elems[node_idx];
+          int entity = node;
+          re_token_type_t type= dfa->nodes[node].type;
+          if (type == OP_CONTEXT_NODE)
+            {
+              entity = dfa->nodes[node].opr.ctx_info->entity;
+              type = dfa->nodes[entity].type;
+            }
+          if (type == OP_BACK_REF)
+            {
+              int bi;
+              for (bi = 0; bi < mctx->nbkref_ents; ++bi)
+                {
+                  struct re_backref_cache_entry *ent = mctx->bkref_ents + bi;
+                  if (ent->node == node && ent->subexp_from == ent->subexp_to
+                      && ent->str_idx == str_idx)
+                    {
+                      int cpos, dst;
+                      dst = dfa->nexts[node];
+                      cpos = check_dst_limits_calc_pos (dfa, mctx, limit,
+                                                        dfa->eclosures + dst,
+                                                        subexp_idx, dst,
+                                                        str_idx);
+                      if ((str_idx == lim->subexp_from && cpos == -1)
+                          || (str_idx == lim->subexp_to && cpos == 0))
+                        return cpos;
+                    }
+                }
+            }
+          if (type == OP_OPEN_SUBEXP && subexp_idx == dfa->nodes[node].opr.idx
+              && str_idx == lim->subexp_from)
+            {
+              pos = -1;
+              break;
+            }
+          if (type == OP_CLOSE_SUBEXP && subexp_idx == dfa->nodes[node].opr.idx
+              && str_idx == lim->subexp_to)
+            break;
+        }
+      if (node_idx == eclosures->nelem && str_idx == lim->subexp_to)
+        pos = 1;
+    }
+  return pos;
+}
+
+/* Check the limitations of sub expressions LIMITS, and remove the nodes
+   which are against limitations from DEST_NODES. */
+
+static reg_errcode_t
+check_subexp_limits (dfa, dest_nodes, candidates, limits, bkref_ents, str_idx)
+     re_dfa_t *dfa;
+     re_node_set *dest_nodes;
+     const re_node_set *candidates;
+     re_node_set *limits;
+     struct re_backref_cache_entry *bkref_ents;
+     int str_idx;
+{
+  reg_errcode_t err;
+  int node_idx, lim_idx;
+
+  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
+    {
+      int bkref, subexp_idx;
+      struct re_backref_cache_entry *ent;
+      ent = bkref_ents + limits->elems[lim_idx];
+
+      if (str_idx <= ent->subexp_from || ent->str_idx < str_idx)
+        continue; /* This is unrelated limitation.  */
+
+      bkref = (dfa->nodes[ent->node].type == OP_CONTEXT_NODE
+               ? dfa->nodes[ent->node].opr.ctx_info->entity : ent->node);
+      subexp_idx = dfa->nodes[bkref].opr.idx - 1;
+
+      if (ent->subexp_to == str_idx)
+        {
+          int ops_node = -1;
+          int cls_node = -1;
+          for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+            {
+              int node = dest_nodes->elems[node_idx];
+              re_token_type_t type= dfa->nodes[node].type;
+              if (type == OP_OPEN_SUBEXP
+                  && subexp_idx == dfa->nodes[node].opr.idx)
+                ops_node = node;
+              else if (type == OP_CLOSE_SUBEXP
+                       && subexp_idx == dfa->nodes[node].opr.idx)
+                cls_node = node;
+            }
+
+          /* Check the limitation of the open subexpression.  */
+          /* Note that (ent->subexp_to = str_idx != ent->subexp_from).  */
+          if (ops_node >= 0)
+            {
+              err = sub_epsilon_src_nodes(dfa, ops_node, dest_nodes,
+                                          candidates);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+            }
+          /* Check the limitation of the close subexpression.  */
+          for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+            {
+              int node = dest_nodes->elems[node_idx];
+              if (!re_node_set_contains (dfa->inveclosures + node, cls_node)
+                  && !re_node_set_contains (dfa->eclosures + node, cls_node))
+                {
+                  /* It is against this limitation.
+                     Remove it form the current sifted state.  */
+                  err = sub_epsilon_src_nodes(dfa, node, dest_nodes,
+                                              candidates);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                  --node_idx;
+                }
+            }
+        }
+      else /* (ent->subexp_to != str_idx)  */
+        {
+          for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+            {
+              int node = dest_nodes->elems[node_idx];
+              re_token_type_t type= dfa->nodes[node].type;
+              if (type == OP_CLOSE_SUBEXP || type == OP_OPEN_SUBEXP)
+                {
+                  if (subexp_idx != dfa->nodes[node].opr.idx)
+                    continue;
+                  if ((type == OP_CLOSE_SUBEXP && ent->subexp_to != str_idx)
+                      || (type == OP_OPEN_SUBEXP))
+                    {
+                      /* It is against this limitation.
+                         Remove it form the current sifted state.  */
+                      err = sub_epsilon_src_nodes(dfa, node, dest_nodes,
+                                                  candidates);
+                      if (BE (err != REG_NOERROR, 0))
+                        return err;
+                    }
+                }
+            }
+        }
+    }
+  return REG_NOERROR;
+}
+
+/* Search for the top (in case of sctx->check_subexp < 0) or the
+   bottom (in case of sctx->check_subexp > 0) of the subexpressions
+   which the backreference sctx->cur_bkref can match.  */
+
+static reg_errcode_t
+search_subexp (preg, mctx, sctx, str_idx, dest_nodes)
+     const regex_t *preg;
+     re_match_context_t *mctx;
+     re_sift_context_t *sctx;
+     int str_idx;
+     re_node_set *dest_nodes;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  re_sift_context_t local_sctx;
+  int node_idx, node=0; /* gnupg */
+  const re_node_set *candidates;
+  re_dfastate_t **lim_states = NULL;
+  candidates = ((mctx->state_log[str_idx] == NULL) ? &empty_set
+                : &mctx->state_log[str_idx]->nodes);
+  local_sctx.sifted_states = NULL; /* Mark that it hasn't been initialized.  */
+
+  for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+    {
+      re_token_type_t type;
+      int entity;
+      node = dest_nodes->elems[node_idx];
+      type = dfa->nodes[node].type;
+      entity = (type != OP_CONTEXT_NODE ? node
+                : dfa->nodes[node].opr.ctx_info->entity);
+      type = (type != OP_CONTEXT_NODE ? type : dfa->nodes[entity].type);
+
+      if (type == OP_CLOSE_SUBEXP
+          && sctx->check_subexp == dfa->nodes[node].opr.idx + 1)
+        {
+          re_dfastate_t *cur_state;
+          /* Found the bottom of the subexpression, then search for the
+             top of it.  */
+          if (local_sctx.sifted_states == NULL)
+            {
+              /* It hasn't been initialized yet, initialize it now.  */
+              local_sctx = *sctx;
+              err = re_node_set_init_copy (&local_sctx.limits, &sctx->limits);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+            }
+          local_sctx.check_subexp = -sctx->check_subexp;
+          local_sctx.limited_states = sctx->limited_states;
+          local_sctx.last_node = node;
+          local_sctx.last_str_idx = local_sctx.cls_subexp_idx = str_idx;
+          cur_state = local_sctx.sifted_states[str_idx];
+          err = sift_states_backward (preg, mctx, &local_sctx);
+          local_sctx.sifted_states[str_idx] = cur_state;
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+          /* There must not 2 same node in a node set.  */
+          break;
+        }
+      else if (type == OP_OPEN_SUBEXP
+               && -sctx->check_subexp == dfa->nodes[node].opr.idx + 1)
+        {
+          /* Found the top of the subexpression, check that the
+             backreference can match the input string.  */
+          char *buf;
+          int dest_str_idx;
+          int bkref_str_idx = re_string_cur_idx (mctx->input);
+          int subexp_len = sctx->cls_subexp_idx - str_idx;
+          if (subexp_len < 0 || bkref_str_idx + subexp_len > mctx->input->len)
+            break;
+
+          if (bkref_str_idx + subexp_len > mctx->input->valid_len
+              && mctx->input->valid_len < mctx->input->len)
+            {
+              reg_errcode_t err;
+              err = extend_buffers (mctx);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+            }
+          buf = (char *) re_string_get_buffer (mctx->input);
+          if (strncmp (buf + str_idx, buf + bkref_str_idx, subexp_len) != 0)
+            break;
+
+          if (sctx->limits.nelem && str_idx > 0)
+            {
+              re_dfastate_t *cur_state = sctx->sifted_states[str_idx];
+              if (lim_states == NULL)
+                {
+                  lim_states = re_malloc (re_dfastate_t *, str_idx + 1);
+                }
+              if (local_sctx.sifted_states == NULL)
+                {
+                  /* It hasn't been initialized yet, initialize it now.  */
+                  local_sctx = *sctx;
+                  if (BE (lim_states == NULL, 0))
+                    return REG_ESPACE;
+                  err = re_node_set_init_copy (&local_sctx.limits,
+                                               &sctx->limits);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                }
+              local_sctx.check_subexp = 0;
+              local_sctx.last_node = node;
+              local_sctx.last_str_idx = str_idx;
+              local_sctx.limited_states = lim_states;
+              memset (lim_states, '\0',
+                      sizeof (re_dfastate_t*) * (str_idx + 1));
+              err = sift_states_backward (preg, mctx, &local_sctx);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+              if (local_sctx.sifted_states[0] == NULL
+                  && local_sctx.limited_states[0] == NULL)
+                {
+                  sctx->sifted_states[str_idx] = cur_state;
+                  break;
+                }
+              sctx->sifted_states[str_idx] = cur_state;
+            }
+          /* Successfully matched, add a new cache entry.  */
+          dest_str_idx = bkref_str_idx + subexp_len;
+          err = match_ctx_add_entry (mctx, sctx->cur_bkref, bkref_str_idx,
+                                     str_idx, sctx->cls_subexp_idx);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+          err = clean_state_log_if_need (mctx, dest_str_idx);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+          break;
+        }
+    }
+
+  /* Remove the top/bottom of the sub expression we processed.  */
+  if (node_idx < dest_nodes->nelem)
+    {
+      err = sub_epsilon_src_nodes(dfa, node, dest_nodes, candidates);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+      /* Update state_log.  */
+      sctx->sifted_states[str_idx] = re_acquire_state (&err, dfa, dest_nodes);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+    }
+
+  if (local_sctx.sifted_states != NULL)
+    re_node_set_free (&local_sctx.limits);
+  if (lim_states != NULL)
+    re_free (lim_states);
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+sift_states_bkref (preg, mctx, sctx, str_idx, dest_nodes)
+     const regex_t *preg;
+     re_match_context_t *mctx;
+     re_sift_context_t *sctx;
+     int str_idx;
+     re_node_set *dest_nodes;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
+  int node_idx, node;
+  re_sift_context_t local_sctx;
+  const re_node_set *candidates;
+  candidates = ((mctx->state_log[str_idx] == NULL) ? &empty_set
+                : &mctx->state_log[str_idx]->nodes);
+  local_sctx.sifted_states = NULL; /* Mark that it hasn't been initialized.  */
+
+  for (node_idx = 0; node_idx < candidates->nelem; ++node_idx)
+    {
+      int entity;
+      int cur_bkref_idx = re_string_cur_idx (mctx->input);
+      re_token_type_t type;
+      node = candidates->elems[node_idx];
+      type = dfa->nodes[node].type;
+      entity = (type != OP_CONTEXT_NODE ? node
+                : dfa->nodes[node].opr.ctx_info->entity);
+      type = (type != OP_CONTEXT_NODE ? type : dfa->nodes[entity].type);
+      if (node == sctx->cur_bkref && str_idx == cur_bkref_idx)
+        continue;
+      /* Avoid infinite loop for the REs like "()\1+".  */
+      if (node == sctx->last_node && str_idx == sctx->last_str_idx)
+        continue;
+      if (type == OP_BACK_REF)
+        {
+          int enabled_idx;
+          for (enabled_idx = 0; enabled_idx < mctx->nbkref_ents; ++enabled_idx)
+            {
+              int disabled_idx, subexp_len, to_idx;
+              struct re_backref_cache_entry *entry;
+              entry = mctx->bkref_ents + enabled_idx;
+              subexp_len = entry->subexp_to - entry->subexp_from;
+              to_idx = str_idx + subexp_len;
+
+              if (entry->node != node || entry->str_idx != str_idx
+                  || to_idx > sctx->last_str_idx
+                  || sctx->sifted_states[to_idx] == NULL)
+                continue;
+              if (!STATE_NODE_CONTAINS (sctx->sifted_states[to_idx],
+                                        dfa->nexts[node]))
+                {
+                  int dst_idx;
+                  re_node_set *dsts = &sctx->sifted_states[to_idx]->nodes;
+                  for (dst_idx = 0; dst_idx < dsts->nelem; ++dst_idx)
+                    {
+                      int dst_node = dsts->elems[dst_idx];
+                      if (dfa->nodes[dst_node].type == OP_CONTEXT_NODE
+                          && (dfa->nodes[dst_node].opr.ctx_info->entity
+                              == dfa->nexts[node]))
+                        break;
+                    }
+                  if (dst_idx == dsts->nelem)
+                    continue;
+                }
+
+              if (check_dst_limits (dfa, &sctx->limits, mctx, node,
+                                    str_idx, dfa->nexts[node], to_idx))
+                continue;
+              if (sctx->check_subexp == dfa->nodes[entity].opr.idx)
+                {
+                  char *buf;
+                  buf = (char *) re_string_get_buffer (mctx->input);
+                  if (strncmp (buf + entry->subexp_from,
+                               buf + cur_bkref_idx, subexp_len) != 0)
+                    continue;
+                  err = match_ctx_add_entry (mctx, sctx->cur_bkref,
+                                             cur_bkref_idx, entry->subexp_from,
+                                             entry->subexp_to);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                  err = clean_state_log_if_need (mctx, cur_bkref_idx
+                                                 + subexp_len);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                }
+              else
+                {
+                  re_dfastate_t *cur_state;
+                  entry->flag = 0;
+                  for (disabled_idx = enabled_idx + 1;
+                       disabled_idx < mctx->nbkref_ents; ++disabled_idx)
+                    {
+                      struct re_backref_cache_entry *entry2;
+                      entry2 = mctx->bkref_ents + disabled_idx;
+                      if (entry2->node != node || entry2->str_idx != str_idx)
+                        continue;
+                      entry2->flag = 1;
+                    }
+
+                  if (local_sctx.sifted_states == NULL)
+                    {
+                      local_sctx = *sctx;
+                      err = re_node_set_init_copy (&local_sctx.limits,
+                                                   &sctx->limits);
+                      if (BE (err != REG_NOERROR, 0))
+                        return err;
+                    }
+                  local_sctx.last_node = node;
+                  local_sctx.last_str_idx = str_idx;
+                  err = re_node_set_insert (&local_sctx.limits, enabled_idx);
+                  if (BE (err < 0, 0))
+                    return REG_ESPACE;
+                  cur_state = local_sctx.sifted_states[str_idx];
+                  err = sift_states_backward (preg, mctx, &local_sctx);
+                  if (BE (err != REG_NOERROR, 0))
+                    return err;
+                  if (sctx->limited_states != NULL)
+                    {
+                      err = merge_state_array (dfa, sctx->limited_states,
+                                               local_sctx.sifted_states,
+                                               str_idx + 1);
+                      if (BE (err != REG_NOERROR, 0))
+                        return err;
+                    }
+                  local_sctx.sifted_states[str_idx] = cur_state;
+                  re_node_set_remove_at (&local_sctx.limits,
+                                         local_sctx.limits.nelem - 1);
+                  entry->flag = 1;
+                }
+            }
+          for (enabled_idx = 0; enabled_idx < mctx->nbkref_ents; ++enabled_idx)
+            {
+              struct re_backref_cache_entry *entry;
+              entry = mctx->bkref_ents + enabled_idx;
+              if (entry->node == node && entry->str_idx == str_idx)
+                entry->flag = 0;
+            }
+        }
+    }
+  if (local_sctx.sifted_states != NULL)
+    {
+      re_node_set_free (&local_sctx.limits);
+    }
+
+  return REG_NOERROR;
+}
+
+
+#ifdef RE_ENABLE_I18N
+static int
+sift_states_iter_mb (preg, mctx, sctx, node_idx, str_idx, max_str_idx)
+    const regex_t *preg;
+    const re_match_context_t *mctx;
+    re_sift_context_t *sctx;
+    int node_idx, str_idx, max_str_idx;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int naccepted;
+  /* Check the node can accept `multi byte'.  */
+  naccepted = check_node_accept_bytes (preg, node_idx, mctx->input, str_idx);
+  if (naccepted > 0 && str_idx + naccepted <= max_str_idx &&
+      !STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + naccepted],
+                            dfa->nexts[node_idx]))
+    /* The node can't accept the `multi byte', or the
+       destination was already throwed away, then the node
+       could't accept the current input `multi byte'.   */
+    naccepted = 0;
+  /* Otherwise, it is sure that the node could accept
+     `naccepted' bytes input.  */
+  return naccepted;
+}
+#endif /* RE_ENABLE_I18N */
+
+
+/* Functions for state transition.  */
+
+/* Return the next state to which the current state STATE will transit by
+   accepting the current input byte, and update STATE_LOG if necessary.
+   If STATE can accept a multibyte char/collating element/back reference
+   update the destination of STATE_LOG.  */
+
+static re_dfastate_t *
+transit_state (err, preg, mctx, state, fl_search)
+     reg_errcode_t *err;
+     const regex_t *preg;
+     re_match_context_t *mctx;
+     re_dfastate_t *state;
+     int fl_search;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  re_dfastate_t **trtable, *next_state;
+  unsigned char ch;
+
+  if (re_string_cur_idx (mctx->input) + 1 >= mctx->input->bufs_len
+      || (re_string_cur_idx (mctx->input) + 1 >= mctx->input->valid_len
+          && mctx->input->valid_len < mctx->input->len))
+    {
+      *err = extend_buffers (mctx);
+      if (BE (*err != REG_NOERROR, 0))
+        return NULL;
+    }
+
+  *err = REG_NOERROR;
+  if (state == NULL)
+    {
+      next_state = state;
+      re_string_skip_bytes (mctx->input, 1);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      /* If the current state can accept multibyte.  */
+      if (state->accept_mb)
+        {
+          *err = transit_state_mb (preg, state, mctx);
+          if (BE (*err != REG_NOERROR, 0))
+            return NULL;
+        }
+#endif /* RE_ENABLE_I18N */
+
+      /* Then decide the next state with the single byte.  */
+      if (1)
+        {
+          /* Use transition table  */
+          ch = re_string_fetch_byte (mctx->input);
+          trtable = fl_search ? state->trtable_search : state->trtable;
+          if (trtable == NULL)
+            {
+              trtable = build_trtable (preg, state, fl_search);
+              if (fl_search)
+                state->trtable_search = trtable;
+              else
+                state->trtable = trtable;
+            }
+          next_state = trtable[ch];
+        }
+      else
+        {
+          /* don't use transition table  */
+          next_state = transit_state_sb (err, preg, state, fl_search, mctx);
+          if (BE (next_state == NULL && err != REG_NOERROR, 0))
+            return NULL;
+        }
+    }
+
+  /* Update the state_log if we need.  */
+  if (mctx->state_log != NULL)
+    {
+      int cur_idx = re_string_cur_idx (mctx->input);
+      if (cur_idx > mctx->state_log_top)
+        {
+          mctx->state_log[cur_idx] = next_state;
+          mctx->state_log_top = cur_idx;
+        }
+      else if (mctx->state_log[cur_idx] == 0)
+        {
+          mctx->state_log[cur_idx] = next_state;
+        }
+      else
+        {
+          re_dfastate_t *pstate;
+          unsigned int context;
+          re_node_set next_nodes, *log_nodes, *table_nodes = NULL;
+          /* If (state_log[cur_idx] != 0), it implies that cur_idx is
+             the destination of a multibyte char/collating element/
+             back reference.  Then the next state is the union set of
+             these destinations and the results of the transition table.  */
+          pstate = mctx->state_log[cur_idx];
+          log_nodes = pstate->entrance_nodes;
+          if (next_state != NULL)
+            {
+              table_nodes = next_state->entrance_nodes;
+              *err = re_node_set_init_union (&next_nodes, table_nodes,
+                                             log_nodes);
+              if (BE (*err != REG_NOERROR, 0))
+                return NULL;
+            }
+          else
+            next_nodes = *log_nodes;
+          /* Note: We already add the nodes of the initial state,
+                   then we don't need to add them here.  */
+
+          context = re_string_context_at (mctx->input,
+                                          re_string_cur_idx (mctx->input) - 1,
+                                          mctx->eflags, preg->newline_anchor);
+          next_state = mctx->state_log[cur_idx]
+            = re_acquire_state_context (err, dfa, &next_nodes, context);
+          /* We don't need to check errors here, since the return value of
+             this function is next_state and ERR is already set.  */
+
+          if (table_nodes != NULL)
+            re_node_set_free (&next_nodes);
+        }
+      /* If the next state has back references.  */
+      if (next_state != NULL && next_state->has_backref)
+        {
+          *err = transit_state_bkref (preg, next_state, mctx);
+          if (BE (*err != REG_NOERROR, 0))
+            return NULL;
+          next_state = mctx->state_log[cur_idx];
+        }
+    }
+  return next_state;
+}
+
+/* Helper functions for transit_state.  */
+
+/* Return the next state to which the current state STATE will transit by
+   accepting the current input byte.  */
+
+static re_dfastate_t *
+transit_state_sb (err, preg, state, fl_search, mctx)
+     reg_errcode_t *err;
+     const regex_t *preg;
+     re_dfastate_t *state;
+     int fl_search;
+     re_match_context_t *mctx;
+{
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  re_node_set next_nodes;
+  re_dfastate_t *next_state;
+  int node_cnt, cur_str_idx = re_string_cur_idx (mctx->input);
+  unsigned int context;
+
+  *err = re_node_set_alloc (&next_nodes, state->nodes.nelem + 1);
+  if (BE (*err != REG_NOERROR, 0))
+    return NULL;
+  for (node_cnt = 0; node_cnt < state->nodes.nelem; ++node_cnt)
+    {
+      int cur_node = state->nodes.elems[node_cnt];
+      if (check_node_accept (preg, dfa->nodes + cur_node, mctx, cur_str_idx))
+        {
+          *err = re_node_set_merge (&next_nodes,
+                                    dfa->eclosures + dfa->nexts[cur_node]);
+          if (BE (*err != REG_NOERROR, 0))
+            return NULL;
+        }
+    }
+  if (fl_search)
+    {
+#ifdef RE_ENABLE_I18N
+      int not_initial = 0;
+      if (MB_CUR_MAX > 1)
+        for (node_cnt = 0; node_cnt < next_nodes.nelem; ++node_cnt)
+          if (dfa->nodes[next_nodes.elems[node_cnt]].type == CHARACTER)
+            {
+              not_initial = dfa->nodes[next_nodes.elems[node_cnt]].mb_partial;
+              break;
+            }
+      if (!not_initial)
+#endif
+        {
+          *err = re_node_set_merge (&next_nodes,
+                                    dfa->init_state->entrance_nodes);
+          if (BE (*err != REG_NOERROR, 0))
+            return NULL;
+        }
+    }
+  context = re_string_context_at (mctx->input, cur_str_idx, mctx->eflags,
+                                  preg->newline_anchor);
+  next_state = re_acquire_state_context (err, dfa, &next_nodes, context);
+  /* We don't need to check errors here, since the return value of
+     this function is next_state and ERR is already set.  */
+
+  re_node_set_free (&next_nodes);
+  re_string_skip_bytes (mctx->input, 1);
+  return next_state;
+}
+
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t
+transit_state_mb (preg, pstate, mctx)
+    const regex_t *preg;
+    re_dfastate_t *pstate;
+    re_match_context_t *mctx;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int i;
+
+  for (i = 0; i < pstate->nodes.nelem; ++i)
+    {
+      re_node_set dest_nodes, *new_nodes;
+      int cur_node_idx = pstate->nodes.elems[i];
+      int naccepted = 0, dest_idx;
+      unsigned int context;
+      re_dfastate_t *dest_state;
+
+      if (dfa->nodes[cur_node_idx].type == OP_CONTEXT_NODE)
+        {
+          context = re_string_context_at (mctx->input,
+                                          re_string_cur_idx (mctx->input),
+                                          mctx->eflags, preg->newline_anchor);
+          if (NOT_SATISFY_NEXT_CONSTRAINT (dfa->nodes[cur_node_idx].constraint,
+                                        context))
+            continue;
+          cur_node_idx = dfa->nodes[cur_node_idx].opr.ctx_info->entity;
+        }
+
+      /* How many bytes the node can accepts?  */
+      if (ACCEPT_MB_NODE (dfa->nodes[cur_node_idx].type))
+        naccepted = check_node_accept_bytes (preg, cur_node_idx, mctx->input,
+                                             re_string_cur_idx (mctx->input));
+      if (naccepted == 0)
+        continue;
+
+      /* The node can accepts `naccepted' bytes.  */
+      dest_idx = re_string_cur_idx (mctx->input) + naccepted;
+      mctx->max_mb_elem_len = ((mctx->max_mb_elem_len < naccepted) ? naccepted
+                               : mctx->max_mb_elem_len);
+      err = clean_state_log_if_need (mctx, dest_idx);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+#ifdef DEBUG
+      assert (dfa->nexts[cur_node_idx] != -1);
+#endif
+      /* `cur_node_idx' may point the entity of the OP_CONTEXT_NODE,
+         then we use pstate->nodes.elems[i] instead.  */
+      new_nodes = dfa->eclosures + dfa->nexts[pstate->nodes.elems[i]];
+
+      dest_state = mctx->state_log[dest_idx];
+      if (dest_state == NULL)
+        dest_nodes = *new_nodes;
+      else
+        {
+          err = re_node_set_init_union (&dest_nodes,
+                                        dest_state->entrance_nodes, new_nodes);
+          if (BE (err != REG_NOERROR, 0))
+            return err;
+        }
+      context = re_string_context_at (mctx->input, dest_idx - 1, mctx->eflags,
+                                      preg->newline_anchor);
+      mctx->state_log[dest_idx]
+        = re_acquire_state_context (&err, dfa, &dest_nodes, context);
+      if (BE (mctx->state_log[dest_idx] == NULL && err != REG_NOERROR, 0))
+        return err;
+      if (dest_state != NULL)
+        re_node_set_free (&dest_nodes);
+    }
+  return REG_NOERROR;
+}
+#endif /* RE_ENABLE_I18N */
+
+static reg_errcode_t
+transit_state_bkref (preg, pstate, mctx)
+    const regex_t *preg;
+    re_dfastate_t *pstate;
+    re_match_context_t *mctx;
+{
+  reg_errcode_t err;
+  re_dfastate_t **work_state_log;
+
+  work_state_log = re_malloc (re_dfastate_t *,
+                              re_string_cur_idx (mctx->input) + 1);
+  if (BE (work_state_log == NULL, 0))
+    return REG_ESPACE;
+
+  err = transit_state_bkref_loop (preg, &pstate->nodes, work_state_log, mctx);
+  re_free (work_state_log);
+  return err;
+}
+
+/* Caller must allocate `work_state_log'.  */
+
+static reg_errcode_t
+transit_state_bkref_loop (preg, nodes, work_state_log, mctx)
+    const regex_t *preg;
+    re_node_set *nodes;
+    re_dfastate_t **work_state_log;
+    re_match_context_t *mctx;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int i;
+  regmatch_t *cur_regs = re_malloc (regmatch_t, preg->re_nsub + 1);
+  int cur_str_idx = re_string_cur_idx (mctx->input);
+  if (BE (cur_regs == NULL, 0))
+    return REG_ESPACE;
+
+  for (i = 0; i < nodes->nelem; ++i)
+    {
+      int dest_str_idx, subexp_idx, prev_nelem, bkc_idx;
+      int node_idx = nodes->elems[i];
+      unsigned int context;
+      re_token_t *node = dfa->nodes + node_idx;
+      re_node_set *new_dest_nodes;
+      re_sift_context_t sctx;
+
+      /* Check whether `node' is a backreference or not.  */
+      if (node->type == OP_BACK_REF)
+        subexp_idx = node->opr.idx;
+      else if (node->type == OP_CONTEXT_NODE &&
+               dfa->nodes[node->opr.ctx_info->entity].type == OP_BACK_REF)
+        {
+          context = re_string_context_at (mctx->input, cur_str_idx,
+                                          mctx->eflags, preg->newline_anchor);
+          if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
+            continue;
+          subexp_idx = dfa->nodes[node->opr.ctx_info->entity].opr.idx;
+        }
+      else
+        continue;
+
+      /* `node' is a backreference.
+         Check the substring which the substring matched.  */
+      sift_ctx_init (&sctx, work_state_log, NULL, node_idx, cur_str_idx,
+                     subexp_idx);
+      sctx.cur_bkref = node_idx;
+      match_ctx_clear_flag (mctx);
+      err = sift_states_backward (preg, mctx, &sctx);
+      if (BE (err != REG_NOERROR, 0))
+        return err;
+
+      /* And add the epsilon closures (which is `new_dest_nodes') of
+         the backreference to appropriate state_log.  */
+#ifdef DEBUG
+      assert (dfa->nexts[node_idx] != -1);
+#endif
+      for (bkc_idx = 0; bkc_idx < mctx->nbkref_ents; ++bkc_idx)
+        {
+          int subexp_len;
+          re_dfastate_t *dest_state;
+          struct re_backref_cache_entry *bkref_ent;
+          bkref_ent = mctx->bkref_ents + bkc_idx;
+          if (bkref_ent->node != node_idx || bkref_ent->str_idx != cur_str_idx)
+            continue;
+          subexp_len = bkref_ent->subexp_to - bkref_ent->subexp_from;
+          new_dest_nodes = ((node->type == OP_CONTEXT_NODE && subexp_len == 0)
+                            ? dfa->nodes[node_idx].opr.ctx_info->bkref_eclosure
+                            : dfa->eclosures + dfa->nexts[node_idx]);
+          dest_str_idx = (cur_str_idx + bkref_ent->subexp_to
+                          - bkref_ent->subexp_from);
+          context = (IS_WORD_CHAR (re_string_byte_at (mctx->input,
+                                                      dest_str_idx - 1))
+                     ? CONTEXT_WORD : 0);
+          dest_state = mctx->state_log[dest_str_idx];
+          prev_nelem = ((mctx->state_log[cur_str_idx] == NULL) ? 0
+                        : mctx->state_log[cur_str_idx]->nodes.nelem);
+          /* Add `new_dest_node' to state_log.  */
+          if (dest_state == NULL)
+            {
+              mctx->state_log[dest_str_idx]
+                = re_acquire_state_context (&err, dfa, new_dest_nodes,
+                                            context);
+              if (BE (mctx->state_log[dest_str_idx] == NULL
+                      && err != REG_NOERROR, 0))
+                return err;
+            }
+          else
+            {
+              re_node_set dest_nodes;
+              err = re_node_set_init_union (&dest_nodes,
+                                            dest_state->entrance_nodes,
+                                            new_dest_nodes);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+              mctx->state_log[dest_str_idx]
+                = re_acquire_state_context (&err, dfa, &dest_nodes, context);
+              if (BE (mctx->state_log[dest_str_idx] == NULL
+                      && err != REG_NOERROR, 0))
+                return err;
+              re_node_set_free (&dest_nodes);
+            }
+          /* We need to check recursively if the backreference can epsilon
+             transit.  */
+          if (subexp_len == 0
+              && mctx->state_log[cur_str_idx]->nodes.nelem > prev_nelem)
+            {
+              err = transit_state_bkref_loop (preg, new_dest_nodes,
+                                              work_state_log, mctx);
+              if (BE (err != REG_NOERROR, 0))
+                return err;
+            }
+        }
+    }
+  re_free (cur_regs);
+  return REG_NOERROR;
+}
+
+/* Build transition table for the state.
+   Return the new table if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t **
+build_trtable (preg, state, fl_search)
+    const regex_t *preg;
+    const re_dfastate_t *state;
+    int fl_search;
+{
+  reg_errcode_t err;
+  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int i, j, k, ch;
+  int ndests; /* Number of the destination states from `state'.  */
+  re_dfastate_t **trtable, **dest_states, **dest_states_word, **dest_states_nl;
+  re_node_set follows, *dests_node;
+  bitset *dests_ch;
+  bitset acceptable;
+
+  /* We build DFA states which corresponds to the destination nodes
+     from `state'.  `dests_node[i]' represents the nodes which i-th
+     destination state contains, and `dests_ch[i]' represents the
+     characters which i-th destination state accepts.  */
+  dests_node = re_malloc (re_node_set, SBC_MAX);
+  dests_ch = re_malloc (bitset, SBC_MAX);
+
+  /* Initialize transiton table.  */
+  trtable = (re_dfastate_t **) calloc (sizeof (re_dfastate_t *), SBC_MAX);
+  if (BE (dests_node == NULL || dests_ch == NULL || trtable == NULL, 0))
+    return NULL;
+
+  /* At first, group all nodes belonging to `state' into several
+     destinations.  */
+  ndests = group_nodes_into_DFAstates (preg, state, dests_node, dests_ch);
+  if (BE (ndests <= 0, 0))
+    {
+      re_free (dests_node);
+      re_free (dests_ch);
+      /* Return NULL in case of an error, trtable otherwise.  */
+      return (ndests < 0) ? NULL : trtable;
+    }
+
+  dest_states = re_malloc (re_dfastate_t *, ndests);
+  dest_states_word = re_malloc (re_dfastate_t *, ndests);
+  dest_states_nl = re_malloc (re_dfastate_t *, ndests);
+  bitset_empty (acceptable);
+
+  err = re_node_set_alloc (&follows, ndests + 1);
+  if (BE (dest_states == NULL || dest_states_word == NULL
+          || dest_states_nl == NULL || err != REG_NOERROR, 0))
+    return NULL;
+
+  /* Then build the states for all destinations.  */
+  for (i = 0; i < ndests; ++i)
+    {
+      int next_node;
+      re_node_set_empty (&follows);
+      /* Merge the follows of this destination states.  */
+      for (j = 0; j < dests_node[i].nelem; ++j)
+        {
+          next_node = dfa->nexts[dests_node[i].elems[j]];
+          if (next_node != -1)
+            {
+              err = re_node_set_merge (&follows, dfa->eclosures + next_node);
+              if (BE (err != REG_NOERROR, 0))
+                return NULL;
+            }
+        }
+      /* If search flag is set, merge the initial state.  */
+      if (fl_search)
+        {
+#ifdef RE_ENABLE_I18N
+          int not_initial = 0;
+          for (j = 0; j < follows.nelem; ++j)
+            if (dfa->nodes[follows.elems[j]].type == CHARACTER)
+              {
+                not_initial = dfa->nodes[follows.elems[j]].mb_partial;
+                break;
+              }
+          if (!not_initial)
+#endif
+            {
+              err = re_node_set_merge (&follows,
+                                       dfa->init_state->entrance_nodes);
+              if (BE (err != REG_NOERROR, 0))
+                return NULL;
+            }
+        }
+      dest_states[i] = re_acquire_state_context (&err, dfa, &follows, 0);
+      if (BE (dest_states[i] == NULL && err != REG_NOERROR, 0))
+        return NULL;
+      /* If the new state has context constraint,
+         build appropriate states for these contexts.  */
+      if (dest_states[i]->has_constraint)
+        {
+          dest_states_word[i] = re_acquire_state_context (&err, dfa, &follows,
+                                                          CONTEXT_WORD);
+          if (BE (dest_states_word[i] == NULL && err != REG_NOERROR, 0))
+            return NULL;
+          dest_states_nl[i] = re_acquire_state_context (&err, dfa, &follows,
+                                                        CONTEXT_NEWLINE);
+          if (BE (dest_states_nl[i] == NULL && err != REG_NOERROR, 0))
+            return NULL;
+        }
+      else
+        {
+          dest_states_word[i] = dest_states[i];
+          dest_states_nl[i] = dest_states[i];
+        }
+      bitset_merge (acceptable, dests_ch[i]);
+    }
+
+  /* Update the transition table.  */
+  /* For all characters ch...:  */
+  for (i = 0, ch = 0; i < BITSET_UINTS; ++i)
+    for (j = 0; j < UINT_BITS; ++j, ++ch)
+      if ((acceptable[i] >> j) & 1)
+        {
+          /* The current state accepts the character ch.  */
+          if (IS_WORD_CHAR (ch))
+            {
+              for (k = 0; k < ndests; ++k)
+                if ((dests_ch[k][i] >> j) & 1)
+                  {
+                    /* k-th destination accepts the word character ch.  */
+                    trtable[ch] = dest_states_word[k];
+                    /* There must be only one destination which accepts
+                       character ch.  See group_nodes_into_DFAstates.  */
+                    break;
+                  }
+            }
+          else /* not WORD_CHAR */
+            {
+              for (k = 0; k < ndests; ++k)
+                if ((dests_ch[k][i] >> j) & 1)
+                  {
+                    /* k-th destination accepts the non-word character ch.  */
+                    trtable[ch] = dest_states[k];
+                    /* There must be only one destination which accepts
+                       character ch.  See group_nodes_into_DFAstates.  */
+                    break;
+                  }
+            }
+        }
+  /* new line */
+  if (bitset_contain (acceptable, NEWLINE_CHAR))
+    {
+      /* The current state accepts newline character.  */
+      for (k = 0; k < ndests; ++k)
+        if (bitset_contain (dests_ch[k], NEWLINE_CHAR))
+          {
+            /* k-th destination accepts newline character.  */
+            trtable[NEWLINE_CHAR] = dest_states_nl[k];
+            /* There must be only one destination which accepts
+               newline.  See group_nodes_into_DFAstates.  */
+            break;
+          }
+    }
+
+  re_free (dest_states_nl);
+  re_free (dest_states_word);
+  re_free (dest_states);
+
+  re_node_set_free (&follows);
+  for (i = 0; i < ndests; ++i)
+    re_node_set_free (dests_node + i);
+
+  re_free (dests_ch);
+  re_free (dests_node);
+
+  return trtable;
+}
+
+/* Group all nodes belonging to STATE into several destinations.
+   Then for all destinations, set the nodes belonging to the destination
+   to DESTS_NODE[i] and set the characters accepted by the destination
+   to DEST_CH[i].  This function return the number of destinations.  */
+
+static int
+group_nodes_into_DFAstates (preg, state, dests_node, dests_ch)
+    const regex_t *preg;
+    const re_dfastate_t *state;
+    re_node_set *dests_node;
+    bitset *dests_ch;
+{
+  reg_errcode_t err;
+  const re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  int i, j, k;
+  int ndests; /* Number of the destinations from `state'.  */
+  bitset accepts; /* Characters a node can accept.  */
+  const re_node_set *cur_nodes = &state->nodes;
+  bitset_empty (accepts);
+  ndests = 0;
+
+  /* For all the nodes belonging to `state',  */
+  for (i = 0; i < cur_nodes->nelem; ++i)
+    {
+      unsigned int constraint = 0;
+      re_token_t *node = &dfa->nodes[cur_nodes->elems[i]];
+      re_token_type_t type = node->type;
+
+      if (type == OP_CONTEXT_NODE)
+        {
+          constraint = node->constraint;
+          node = dfa->nodes + node->opr.ctx_info->entity;
+          type = node->type;
+        }
+
+      /* Enumerate all single byte character this node can accept.  */
+      if (type == CHARACTER)
+        bitset_set (accepts, node->opr.c);
+      else if (type == SIMPLE_BRACKET)
+        {
+          bitset_merge (accepts, node->opr.sbcset);
+        }
+      else if (type == OP_PERIOD)
+        {
+          bitset_set_all (accepts);
+          if (!(preg->syntax & RE_DOT_NEWLINE))
+            bitset_clear (accepts, '\n');
+          if (preg->syntax & RE_DOT_NOT_NULL)
+            bitset_clear (accepts, '\0');
+        }
+      else
+        continue;
+
+      /* Check the `accepts' and sift the characters which are not
+         match it the context.  */
+      if (constraint)
+        {
+          if (constraint & NEXT_WORD_CONSTRAINT)
+            for (j = 0; j < BITSET_UINTS; ++j)
+              accepts[j] &= dfa->word_char[j];
+          else if (constraint & NEXT_NOTWORD_CONSTRAINT)
+            for (j = 0; j < BITSET_UINTS; ++j)
+              accepts[j] &= ~dfa->word_char[j];
+          else if (constraint & NEXT_NEWLINE_CONSTRAINT)
+            {
+              int accepts_newline = bitset_contain (accepts, NEWLINE_CHAR);
+              bitset_empty (accepts);
+              if (accepts_newline)
+                bitset_set (accepts, NEWLINE_CHAR);
+              else
+                continue;
+            }
+        }
+
+      /* Then divide `accepts' into DFA states, or create a new
+         state.  */
+      for (j = 0; j < ndests; ++j)
+        {
+          bitset intersec; /* Intersection sets, see below.  */
+          bitset remains;
+          /* Flags, see below.  */
+          int has_intersec, not_subset, not_consumed;
+
+          /* Optimization, skip if this state doesn't accept the character.  */
+          if (type == CHARACTER && !bitset_contain (dests_ch[j], node->opr.c))
+            continue;
+
+          /* Enumerate the intersection set of this state and `accepts'.  */
+          has_intersec = 0;
+          for (k = 0; k < BITSET_UINTS; ++k)
+            has_intersec |= intersec[k] = accepts[k] & dests_ch[j][k];
+          /* And skip if the intersection set is empty.  */
+          if (!has_intersec)
+            continue;
+
+          /* Then check if this state is a subset of `accepts'.  */
+          not_subset = not_consumed = 0;
+          for (k = 0; k < BITSET_UINTS; ++k)
+            {
+              not_subset |= remains[k] = ~accepts[k] & dests_ch[j][k];
+              not_consumed |= accepts[k] = accepts[k] & ~dests_ch[j][k];
+            }
+
+          /* If this state isn't a subset of `accepts', create a
+             new group state, which has the `remains'. */
+          if (not_subset)
+            {
+              bitset_copy (dests_ch[ndests], remains);
+              bitset_copy (dests_ch[j], intersec);
+              err = re_node_set_init_copy (dests_node + ndests, &dests_node[j]);
+              if (BE (err != REG_NOERROR, 0))
+                return -1;
+              ++ndests;
+            }
+
+          /* Put the position in the current group. */
+          err = re_node_set_insert (&dests_node[j], cur_nodes->elems[i]);
+          if (BE (err < 0, 0))
+            return -1;
+
+          /* If all characters are consumed, go to next node. */
+          if (!not_consumed)
+            break;
+        }
+      /* Some characters remain, create a new group. */
+      if (j == ndests)
+        {
+          bitset_copy (dests_ch[ndests], accepts);
+          err = re_node_set_init_1 (dests_node + ndests, cur_nodes->elems[i]);
+          if (BE (err != REG_NOERROR, 0))
+            return -1;
+          ++ndests;
+          bitset_empty (accepts);
+        }
+    }
+  return ndests;
+}
+
+#ifdef RE_ENABLE_I18N
+/* Check how many bytes the node `dfa->nodes[node_idx]' accepts.
+   Return the number of the bytes the node accepts.
+   STR_IDX is the current index of the input string.
+
+   This function handles the nodes which can accept one character, or
+   one collating element like '.', '[a-z]', opposite to the other nodes
+   can only accept one byte.  */
+
+static int
+check_node_accept_bytes (preg, node_idx, input, str_idx)
+    const regex_t *preg;
+    int node_idx, str_idx;
+    const re_string_t *input;
+{
+  const re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  const re_token_t *node = dfa->nodes + node_idx;
+  int elem_len = re_string_elem_size_at (input, str_idx);
+  int char_len = re_string_char_size_at (input, str_idx);
+  int i;
+# ifdef _LIBC
+  int j;
+  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+# endif /* _LIBC */
+  if (elem_len <= 1 && char_len <= 1)
+    return 0;
+  if (node->type == OP_PERIOD)
+    {
+      /* '.' accepts any one character except the following two cases.  */
+      if ((!(preg->syntax & RE_DOT_NEWLINE) &&
+           re_string_byte_at (input, str_idx) == '\n') ||
+          ((preg->syntax & RE_DOT_NOT_NULL) &&
+           re_string_byte_at (input, str_idx) == '\0'))
+        return 0;
+      return char_len;
+    }
+  else if (node->type == COMPLEX_BRACKET)
+    {
+      const re_charset_t *cset = node->opr.mbcset;
+# ifdef _LIBC
+      const unsigned char *pin = re_string_get_buffer (input) + str_idx;
+# endif /* _LIBC */
+      int match_len = 0;
+      wchar_t wc = ((cset->nranges || cset->nchar_classes || cset->nmbchars)
+                    ? re_string_wchar_at (input, str_idx) : 0);
+
+      /* match with multibyte character?  */
+      for (i = 0; i < cset->nmbchars; ++i)
+        if (wc == cset->mbchars[i])
+          {
+            match_len = char_len;
+            goto check_node_accept_bytes_match;
+          }
+      /* match with character_class?  */
+      for (i = 0; i < cset->nchar_classes; ++i)
+        {
+          wctype_t wt = cset->char_classes[i];
+          if (__iswctype (wc, wt))
+            {
+              match_len = char_len;
+              goto check_node_accept_bytes_match;
+            }
+        }
+
+# ifdef _LIBC
+      if (nrules != 0)
+        {
+          unsigned int in_collseq = 0;
+          const int32_t *table, *indirect;
+          const unsigned char *weights, *extra;
+          const char *collseqwc;
+          int32_t idx;
+          /* This #include defines a local function!  */
+#  include <locale/weight.h>
+
+          /* match with collating_symbol?  */
+          if (cset->ncoll_syms)
+            extra = (const unsigned char *)
+              _NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
+          for (i = 0; i < cset->ncoll_syms; ++i)
+            {
+              const unsigned char *coll_sym = extra + cset->coll_syms[i];
+              /* Compare the length of input collating element and
+                 the length of current collating element.  */
+              if (*coll_sym != elem_len)
+                continue;
+              /* Compare each bytes.  */
+              for (j = 0; j < *coll_sym; j++)
+                if (pin[j] != coll_sym[1 + j])
+                  break;
+              if (j == *coll_sym)
+                {
+                  /* Match if every bytes is equal.  */
+                  match_len = j;
+                  goto check_node_accept_bytes_match;
+                }
+            }
+
+          if (cset->nranges)
+            {
+              if (elem_len <= char_len)
+                {
+                  collseqwc = _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQWC);
+                  in_collseq = collseq_table_lookup (collseqwc, wc);
+                }
+              else
+                in_collseq = find_collation_sequence_value (pin, elem_len);
+            }
+          /* match with range expression?  */
+          for (i = 0; i < cset->nranges; ++i)
+            if (cset->range_starts[i] <= in_collseq
+                && in_collseq <= cset->range_ends[i])
+              {
+                match_len = elem_len;
+                goto check_node_accept_bytes_match;
+              }
+
+          /* match with equivalence_class?  */
+          if (cset->nequiv_classes)
+            {
+              const unsigned char *cp = pin;
+              table = (const int32_t *)
+                _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+              weights = (const unsigned char *)
+                _NL_CURRENT (LC_COLLATE, _NL_COLLATE_WEIGHTMB);
+              extra = (const unsigned char *)
+                _NL_CURRENT (LC_COLLATE, _NL_COLLATE_EXTRAMB);
+              indirect = (const int32_t *)
+                _NL_CURRENT (LC_COLLATE, _NL_COLLATE_INDIRECTMB);
+              idx = findidx (&cp);
+              if (idx > 0)
+                for (i = 0; i < cset->nequiv_classes; ++i)
+                  {
+                    int32_t equiv_class_idx = cset->equiv_classes[i];
+                    size_t weight_len = weights[idx];
+                    if (weight_len == weights[equiv_class_idx])
+                      {
+                        int cnt = 0;
+                        while (cnt <= weight_len
+                               && (weights[equiv_class_idx + 1 + cnt]
+                                   == weights[idx + 1 + cnt]))
+                          ++cnt;
+                        if (cnt > weight_len)
+                          {
+                            match_len = elem_len;
+                            goto check_node_accept_bytes_match;
+                          }
+                      }
+                  }
+            }
+        }
+      else
+# endif /* _LIBC */
+        {
+          /* match with range expression?  */
+#if __GNUC__ >= 2
+          wchar_t cmp_buf[] = {L'\0', L'\0', wc, L'\0', L'\0', L'\0'};
+#else
+          wchar_t cmp_buf[] = {L'\0', L'\0', L'\0', L'\0', L'\0', L'\0'};
+          cmp_buf[2] = wc;
+#endif
+          for (i = 0; i < cset->nranges; ++i)
+            {
+              cmp_buf[0] = cset->range_starts[i];
+              cmp_buf[4] = cset->range_ends[i];
+              if (wcscoll (cmp_buf, cmp_buf + 2) <= 0
+                  && wcscoll (cmp_buf + 2, cmp_buf + 4) <= 0)
+                {
+                  match_len = char_len;
+                  goto check_node_accept_bytes_match;
+                }
+            }
+        }
+    check_node_accept_bytes_match:
+      if (!cset->non_match)
+        return match_len;
+      else
+        {
+          if (match_len > 0)
+            return 0;
+          else
+            return (elem_len > char_len) ? elem_len : char_len;
+        }
+    }
+  return 0;
+}
+
+# ifdef _LIBC
+static unsigned int
+find_collation_sequence_value (mbs, mbs_len)
+    const unsigned char *mbs;
+    size_t mbs_len;
+{
+  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules == 0)
+    {
+      if (mbs_len == 1)
+        {
+          /* No valid character.  Match it as a single byte character.  */
+          const unsigned char *collseq = (const unsigned char *)
+            _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQMB);
+          return collseq[mbs[0]];
+        }
+      return UINT_MAX;
+    }
+  else
+    {
+      int32_t idx;
+      const unsigned char *extra = (const unsigned char *)
+        _NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
+
+      for (idx = 0; ;)
+        {
+          int mbs_cnt, found = 0;
+          int32_t elem_mbs_len;
+          /* Skip the name of collating element name.  */
+          idx = idx + extra[idx] + 1;
+          elem_mbs_len = extra[idx++];
+          if (mbs_len == elem_mbs_len)
+            {
+              for (mbs_cnt = 0; mbs_cnt < elem_mbs_len; ++mbs_cnt)
+                if (extra[idx + mbs_cnt] != mbs[mbs_cnt])
+                  break;
+              if (mbs_cnt == elem_mbs_len)
+                /* Found the entry.  */
+                found = 1;
+            }
+          /* Skip the byte sequence of the collating element.  */
+          idx += elem_mbs_len;
+          /* Adjust for the alignment.  */
+          idx = (idx + 3) & ~3;
+          /* Skip the collation sequence value.  */
+          idx += sizeof (uint32_t);
+          /* Skip the wide char sequence of the collating element.  */
+          idx = idx + sizeof (uint32_t) * (extra[idx] + 1);
+          /* If we found the entry, return the sequence value.  */
+          if (found)
+            return *(uint32_t *) (extra + idx);
+          /* Skip the collation sequence value.  */
+          idx += sizeof (uint32_t);
+        }
+    }
+}
+# endif /* _LIBC */
+#endif /* RE_ENABLE_I18N */
+
+/* Check whether the node accepts the byte which is IDX-th
+   byte of the INPUT.  */
+
+static int
+check_node_accept (preg, node, mctx, idx)
+    const regex_t *preg;
+    const re_token_t *node;
+    const re_match_context_t *mctx;
+    int idx;
+{
+  const re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
+  const re_token_t *cur_node;
+  unsigned char ch;
+  if (node->type == OP_CONTEXT_NODE)
+    {
+      /* The node has constraints.  Check whether the current context
+         satisfies the constraints.  */
+      unsigned int context = re_string_context_at (mctx->input, idx,
+                                                   mctx->eflags,
+                                                   preg->newline_anchor);
+      if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
+        return 0;
+      cur_node = dfa->nodes + node->opr.ctx_info->entity;
+    }
+  else
+    cur_node = node;
+
+  ch = re_string_byte_at (mctx->input, idx);
+  if (cur_node->type == CHARACTER)
+    return cur_node->opr.c == ch;
+  else if (cur_node->type == SIMPLE_BRACKET)
+    return bitset_contain (cur_node->opr.sbcset, ch);
+  else if (cur_node->type == OP_PERIOD)
+    return !((ch == '\n' && !(preg->syntax & RE_DOT_NEWLINE))
+             || (ch == '\0' && (preg->syntax & RE_DOT_NOT_NULL)));
+  else
+    return 0;
+}
+
+/* Extend the buffers, if the buffers have run out.  */
+
+static reg_errcode_t
+extend_buffers (mctx)
+     re_match_context_t *mctx;
+{
+  reg_errcode_t ret;
+  re_string_t *pstr = mctx->input;
+
+  /* Double the lengthes of the buffers.  */
+  ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  if (mctx->state_log != NULL)
+    {
+      /* And double the length of state_log.  */
+      mctx->state_log = re_realloc (mctx->state_log, re_dfastate_t *,
+                                    pstr->bufs_len * 2);
+      if (BE (mctx->state_log == NULL, 0))
+        return REG_ESPACE;
+    }
+
+  /* Then reconstruct the buffers.  */
+  if (pstr->icase)
+    {
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        build_wcs_upper_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+        build_upper_buffer (pstr);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      if (MB_CUR_MAX > 1)
+        build_wcs_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+        {
+          if (pstr->trans != NULL)
+            re_string_translate_buffer (pstr);
+          else
+            pstr->valid_len = pstr->bufs_len;
+        }
+    }
+  return REG_NOERROR;
+}
+
+
+/* Functions for matching context.  */
+
+static reg_errcode_t
+match_ctx_init (mctx, eflags, input, n)
+    re_match_context_t *mctx;
+    int eflags, n;
+    re_string_t *input;
+{
+  mctx->eflags = eflags;
+  mctx->input = input;
+  mctx->match_last = -1;
+  if (n > 0)
+    {
+      mctx->bkref_ents = re_malloc (struct re_backref_cache_entry, n);
+      if (BE (mctx->bkref_ents == NULL, 0))
+        return REG_ESPACE;
+    }
+  else
+    mctx->bkref_ents = NULL;
+  mctx->nbkref_ents = 0;
+  mctx->abkref_ents = n;
+  mctx->max_mb_elem_len = 0;
+  return REG_NOERROR;
+}
+
+static void
+match_ctx_free (mctx)
+    re_match_context_t *mctx;
+{
+  re_free (mctx->bkref_ents);
+}
+
+/* Add a new backreference entry to the cache.  */
+
+static reg_errcode_t
+match_ctx_add_entry (mctx, node, str_idx, from, to)
+    re_match_context_t *mctx;
+    int node, str_idx, from, to;
+{
+  if (mctx->nbkref_ents >= mctx->abkref_ents)
+    {
+      mctx->bkref_ents = re_realloc (mctx->bkref_ents,
+                                     struct re_backref_cache_entry,
+                                     mctx->abkref_ents * 2);
+      if (BE (mctx->bkref_ents == NULL, 0))
+        return REG_ESPACE;
+      memset (mctx->bkref_ents + mctx->nbkref_ents, '\0',
+             sizeof (struct re_backref_cache_entry) * mctx->abkref_ents);
+      mctx->abkref_ents *= 2;
+    }
+  mctx->bkref_ents[mctx->nbkref_ents].node = node;
+  mctx->bkref_ents[mctx->nbkref_ents].str_idx = str_idx;
+  mctx->bkref_ents[mctx->nbkref_ents].subexp_from = from;
+  mctx->bkref_ents[mctx->nbkref_ents].subexp_to = to;
+  mctx->bkref_ents[mctx->nbkref_ents++].flag = 0;
+  if (mctx->max_mb_elem_len < to - from)
+    mctx->max_mb_elem_len = to - from;
+  return REG_NOERROR;
+}
+
+static void
+match_ctx_clear_flag (mctx)
+     re_match_context_t *mctx;
+{
+  int i;
+  for (i = 0; i < mctx->nbkref_ents; ++i)
+    {
+      mctx->bkref_ents[i].flag = 0;
+    }
+}
+
+static void
+sift_ctx_init (sctx, sifted_sts, limited_sts, last_node, last_str_idx,
+               check_subexp)
+    re_sift_context_t *sctx;
+    re_dfastate_t **sifted_sts, **limited_sts;
+    int last_node, last_str_idx, check_subexp;
+{
+  sctx->sifted_states = sifted_sts;
+  sctx->limited_states = limited_sts;
+  sctx->last_node = last_node;
+  sctx->last_str_idx = last_str_idx;
+  sctx->check_subexp = check_subexp;
+  re_node_set_init_empty (&sctx->limits);
+}