gpgme/gpgme/conversion.c

/* conversion.c - String conversion helper functions.
   Copyright (C) 2000 Werner Koch (dd9jn)
   Copyright (C) 2001, 2002 g10 Code GmbH
 
   This file is part of GPGME.

   GPGME is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
 
   GPGME 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
   General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with GPGME; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#if HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <sys/types.h>
#include <stdlib.h>

#include "gpgme.h"
#include "util.h"


int
_gpgme_hextobyte (const byte *str)
{
  int val = 0;
  int i;

#define NROFHEXDIGITS 2
  for (i = 0; i < NROFHEXDIGITS; i++)
    {
      if (*str >= '0' && *str <= '9')
	val += *str - '0';
      else if (*str >= 'A' && *str <= 'F')
	val += 10 + *str - 'A';
      else if (*str >= 'a' && *str <= 'f')
	val += 10 + *str - 'a';
      else
	return -1;
      if (i < NROFHEXDIGITS - 1)
	val *= 16;
      str++;
    }
  return val;
}


/* Decode the C formatted string SRC and store the result in the
   buffer *DESTP which is LEN bytes long.  If LEN is zero, then a
   large enough buffer is allocated with malloc and *DESTP is set to
   the result.  Currently, LEN is only used to specify if allocation
   is desired or not, the caller is expected to make sure that *DESTP
   is large enough if LEN is not zero.  */
GpgmeError
_gpgme_decode_c_string (const char *src, char **destp, int len)
{
  char *dest;

  if (len)
    dest = *destp;
  else
    {
      /* We can malloc a buffer of the same length, because the converted
	 string will never be larger.  */
      dest = malloc (strlen (src) + 1);
      if (!dest)
	return mk_error (Out_Of_Core);

      *destp = dest;
    }

  while (*src)
    {
      if (*src != '\\')
	*(dest++) = *(src++);
      else if (src[1] == '\\')
	{
	  src++;
	  *(dest++) = *(src++); 
        }
      else if (src[1] == 'n')
	{
	  src += 2;
	  *(dest++) = '\n'; 
        }
      else if (src[1] == 'r')
	{
	  src += 2;
	  *(dest++) = '\r'; 
        }
      else if (src[1] == 'v')
	{
	  src += 2;
	  *(dest++) = '\v'; 
        }
      else if (src[1] == 'b')
	{
	  src += 2;
	  *(dest++) = '\b'; 
        }
      else if (src[1] == '0')
	{
	  /* Hmmm: no way to express this */
	  src += 2;
	  *(dest++) = '\\';
	  *(dest++) = '\0'; 
        }
      else if (src[1] == 'x' && isxdigit (src[2]) && isxdigit (src[3]))
	{
	  int val = _gpgme_hextobyte (&src[2]);
	  if (val == -1)
	    {
	      /* Should not happen.  */
	      *(dest++) = *(src++);
	      *(dest++) = *(src++);
	      *(dest++) = *(src++);
	      *(dest++) = *(src++);
	    }
	  else
	    {
	      if (!val)
		{
		  *(dest++) = '\\';
		  *(dest++) = '\0'; 
		}
	      else 
		*(byte*)dest++ = val;
	      src += 4;
	    }
        }
      else
	{
	  /* should not happen */
	  src++;
	  *(dest++) = '\\'; 
	  *(dest++) = *(src++);
        } 
    }
  *(dest++) = 0;

  return 0;
}


GpgmeError
_gpgme_data_append (GpgmeData dh, const char *buffer, size_t length)
{
  if (!dh || !buffer)
    return mk_error (Invalid_Value);

  do
    {
      ssize_t amt = gpgme_data_write (dh, buffer, length);
      if (amt == 0 || (amt < 0 && errno != EINTR))
	return mk_error (File_Error);
      buffer += amt;
      length -= amt;
    }
  while (length > 0);

  return 0;
}


GpgmeError
_gpgme_data_append_string (GpgmeData dh, const char *str)
{
  if (!str)
    return 0;

  return _gpgme_data_append (dh, str, strlen (str));
}


GpgmeError
_gpgme_data_append_for_xml (GpgmeData dh, const char *buffer, size_t len)
{
  const char *text, *str;
  size_t count;
  int err = 0;

  if (!dh || !buffer)
    return mk_error (Invalid_Value);

  do
    {
      text = NULL;
      str = buffer;
      for (count = len; count && !text; str++, count--)
        {
          if (*str == '<')
            text = "&lt;";
          else if (*str == '>')
            text = "&gt;";  /* Not sure whether this is really needed.  */
          else if (*str == '&')
            text = "&amp;";
          else if (!*str)
            text = "&#00;";
        }
      if (text)
        {
          str--;
          count++;
        }
      if (str != buffer)
        err = _gpgme_data_append (dh, buffer, str - buffer);
      if (!err && text)
        {
          err = _gpgme_data_append_string (dh, text);
          str++;
          count--;
        }
      buffer = str;
      len = count;
    }
  while (!err && len);
  return err;
}


/* Append a string to DATA and convert it so that the result will be
   valid XML.  */
GpgmeError
_gpgme_data_append_string_for_xml (GpgmeData dh, const char *str)
{
  return _gpgme_data_append_for_xml (dh, str, strlen (str));
}


/* Append a string with percent style (%XX) escape characters as
   XML.  */
GpgmeError
_gpgme_data_append_percentstring_for_xml (GpgmeData dh, const char *str)
{
  const byte *src;
  byte *buf, *dst;
  int val;
  GpgmeError err;

  buf = malloc (strlen (str));
  dst = buf;
  for (src = str; *src; src++)
    {
      if (*src == '%' && (val = _gpgme_hextobyte (src + 1)) != -1)
        {
          *dst++ = val;
          src += 2;
        }
      else
        *dst++ = *src;
    }

  err = _gpgme_data_append_for_xml (dh, buf, dst - buf);
  free (buf);
  return err;
}