1 files changed, 103 insertions, 0 deletions
diff --git a/src/parsetlv.c b/src/parsetlv.c
new file mode 100644
index 00000000..70c95189
--- /dev/null
+++ b/src/parsetlv.c
@@ -0,0 +1,103 @@
+/* parsetlv.c -  ASN.1 TLV functions
+ * Copyright (C) 2005, 2007, 2008, 2012 g10 Code GmbH
+ *
+ * This file 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.
+ *
+ * This file 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parsetlv.h"
+
+
+/* Simple but pretty complete ASN.1 BER parser.  Parse the data at the
+   address of BUFFER with a length given at the address of SIZE.  On
+   success return 0 and update BUFFER and SIZE to point to the value.
+   Do not update them on error.  The information about the object are
+   stored in the caller allocated TI structure.  */
+int
+_gpgme_parse_tlv (char const **buffer, size_t *size, tlvinfo_t *ti)
+{
+  int c;
+  unsigned long tag;
+  const unsigned char *buf = (const unsigned char *)(*buffer);
+  size_t length = *size;
+
+  ti->cls = 0;
+  ti->tag = 0;
+  ti->is_cons = 0;
+  ti->is_ndef = 0;
+  ti->length = 0;
+  ti->nhdr = 0;
+
+  if (!length)
+    return -1;
+  c = *buf++; length--; ++ti->nhdr;
+
+  ti->cls = (c & 0xc0) >> 6;
+  ti->is_cons = !!(c & 0x20);
+  tag = c & 0x1f;
+
+  if (tag == 0x1f)
+    {
+      tag = 0;
+      do
+        {
+          tag <<= 7;
+          if (!length)
+            return -1;
+          c = *buf++; length--; ++ti->nhdr;
+          tag |= c & 0x7f;
+        }
+      while (c & 0x80);
+    }
+  ti->tag = tag;
+
+  if (!length)
+    return -1;
+  c = *buf++; length--; ++ti->nhdr;
+
+  if ( !(c & 0x80) )
+    ti->length = c;
+  else if (c == 0x80)
+    ti->is_ndef = 1;
+  else if (c == 0xff)
+    return -1;
+  else
+    {
+      unsigned long len = 0;
+      int count = (c & 0x7f);
+
+      if (count > sizeof (len) || count > sizeof (size_t))
+        return -1;
+
+      for (; count; count--)
+        {
+          len <<= 8;
+          if (!length)
+            return -1;
+          c = *buf++; length--; ++ti->nhdr;
+          len |= c & 0xff;
+        }
+      ti->length = len;
+    }
+
+  *buffer = (void*)buf;
+  *size = length;
+  return 0;
+}