/*
 * $Id$
 *
 * DEBUG: 
 * AUTHOR: Harvest Derived
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program 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.
 *  
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "rfc1738.h"

/*  
 *  RFC 1738 defines that these characters should be escaped, as well
 *  any non-US-ASCII character or anything between 0x00 - 0x1F.
 */
static char rfc1738_unsafe_chars[] = {
  (char) 0x3C,			/* < */
  (char) 0x3E,			/* > */
  (char) 0x22,			/* " */
  (char) 0x23,			/* # */
#if 0				/* done in code */
  (char) 0x25,			/* % */
#endif
  (char) 0x7B,			/* { */
  (char) 0x7D,			/* } */
  (char) 0x7C,			/* | */
  (char) 0x5C,			/* \ */
  (char) 0x5E,			/* ^ */
  (char) 0x7E,			/* ~ */
  (char) 0x5B,			/* [ */
  (char) 0x5D,			/* ] */
  (char) 0x60,			/* ` */
  (char) 0x27,			/* ' */
  (char) 0x20			/* space */
};

static char rfc1738_reserved_chars[] = {
  (char) 0x3b,			/* ; */
  (char) 0x2f,			/* / */
  (char) 0x3f,			/* ? */
  (char) 0x3a,			/* : */
  (char) 0x40,			/* @ */
  (char) 0x3d,			/* = */
  (char) 0x26			/* & */
};

/*
 *  rfc1738_escape - Returns a static buffer contains the RFC 1738 
 *  compliant, escaped version of the given url.
 */
static char *
rfc1738_do_escape (const char *url, int encode_reserved)
{
  static char *buf;
  static size_t bufsize = 0;
  const char *p;
  char *q;
  unsigned int i, do_escape;

  if (buf == NULL || strlen (url) * 3 > bufsize)
    {
      delete[] buf;
      bufsize = strlen (url) * 3 + 1;
      buf = new char [bufsize];
    }
  for (p = url, q = buf; *p != '\0'; p++, q++)
    {
      do_escape = 0;

      /* RFC 1738 defines these chars as unsafe */
      for (i = 0; i < sizeof (rfc1738_unsafe_chars); i++)
	{
	  if (*p == rfc1738_unsafe_chars[i])
	    {
	      do_escape = 1;
	      break;
	    }
	}
      /* Handle % separately */
      if (encode_reserved >= 0 && *p == '%')
	do_escape = 1;
      /* RFC 1738 defines these chars as reserved */
      for (i = 0; i < sizeof (rfc1738_reserved_chars) && encode_reserved > 0;
	   i++)
	{
	  if (*p == rfc1738_reserved_chars[i])
	    {
	      do_escape = 1;
	      break;
	    }
	}
      /* RFC 1738 says any control chars (0x00-0x1F) are encoded */
      if ((unsigned char) *p <= (unsigned char) 0x1F)
	{
	  do_escape = 1;
	}
      /* RFC 1738 says 0x7f is encoded */
      if (*p == (char) 0x7F)
	{
	  do_escape = 1;
	}
      /* RFC 1738 says any non-US-ASCII are encoded */
      if ((unsigned char) *p >= (unsigned char) 0x80)
	{
	  do_escape = 1;
	}
      /* Do the triplet encoding, or just copy the char */
      /* note: we do not need snprintf here as q is appropriately
       * allocated - KA */

      if (do_escape == 1)
	{
	  (void) sprintf (q, "%%%02x", (unsigned char) *p);
	  q += sizeof (char) * 2;
	}
      else
	{
	  *q = *p;
	}
    }
  *q = '\0';
  return (buf);
}

/*
 * rfc1738_escape - Returns a static buffer that contains the RFC
 * 1738 compliant, escaped version of the given url.
 */
char const *
rfc1738_escape (const char *url)
{
  return rfc1738_do_escape (url, 0);
}

/*
 * rfc1738_escape_unescaped - Returns a static buffer that contains
 * the RFC 1738 compliant, escaped version of the given url.
 */
char *
rfc1738_escape_unescaped (const char *url)
{
  return rfc1738_do_escape (url, -1);
}

/*
 * rfc1738_escape_part - Returns a static buffer that contains the
 * RFC 1738 compliant, escaped version of the given url segment.
 */
char const *
rfc1738_escape_part (const char *url)
{
  return rfc1738_do_escape (url, 1);
}
String
rfc1738_escape_part (String const &url)
{
  char const *t = rfc1738_do_escape (url.cstr_oneuse(), 1);
  return String (t);
}

/*
 *  rfc1738_unescape() - Converts escaped characters (%xy numbers) in 
 *  given the string.  %% is a %. %ab is the 8-bit hexadecimal number "ab"
 */
void
rfc1738_unescape (char *s)
{
  char hexnum[3];
  int i, j;			/* i is write, j is read */
  unsigned int x;
  for (i = j = 0; s[j]; i++, j++)
    {
      s[i] = s[j];
      if (s[i] != '%')
	continue;
      if (s[j + 1] == '%')
	{			/* %% case */
	  j++;
	  continue;
	}
      if (s[j + 1] && s[j + 2])
	{
	  hexnum[0] = s[j + 1];
	  hexnum[1] = s[j + 2];
	  hexnum[2] = '\0';
	  if (1 == sscanf (hexnum, "%x", &x))
	    {
	      s[i] = (char) (0x0ff & x);
	      j += 2;
	    }
	}
    }
  s[i] = '\0';
}

String
rfc1738_unescape_part (String const &url)
{
  char *t = url.cstr();
  rfc1738_unescape (t);
  String rv (t);
  delete[] t;
  return rv;
}