Function http_copy_decode

cups/http-support.c:2165–2231

 */

static const char *			/* O - New source pointer or NULL on error */
http_copy_decode(char       *dst,	/* O - Destination buffer */
                 const char *src,	/* I - Source pointer */
		 int        dstsize,	/* I - Destination size */
		 const char *term,	/* I - Terminating characters */
		 int        decode)	/* I - Decode %-encoded values */
{
  char	*ptr,				/* Pointer into buffer */
	*end;				/* End of buffer */
  int	quoted;				/* Quoted character */


 /*
  * Copy the src to the destination until we hit a terminating character
  * or the end of the string.
  */

  for (ptr = dst, end = dst + dstsize - 1;
       *src && (!term || !strchr(term, *src));
       src ++)
    if (ptr < end)
    {
      if (*src == '%' && decode)
      {
        if (isxdigit(src[1] & 255) && isxdigit(src[2] & 255))
	{
	 /*
	  * Grab a hex-encoded character...
	  */

          src ++;
	  if (isalpha(*src))
	    quoted = (tolower(*src) - 'a' + 10) << 4;
	  else
	    quoted = (*src - '0') << 4;

          src ++;
	  if (isalpha(*src))
	    quoted |= tolower(*src) - 'a' + 10;
	  else
	    quoted |= *src - '0';

          *ptr++ = (char)quoted;
	}
	else
	{
	 /*
	  * Bad hex-encoded character...
	  */

	  *ptr = '\0';
	  return (NULL);
	}
      }
      else if ((*src & 255) <= 0x20 || (*src & 255) >= 0x7f)
      {
        *ptr = '\0';
        return (NULL);