/*
  * Simple URL decoding function
  * Copyright (c) 2012 Antti Seppälä
  *
  * References:
  *  RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
  *       T. Berners-Lee et al. The Internet Society, 2005
  *
  * based on http://www.icosaedro.it/apache/urldecode.c
  *          from Umberto Salsi (salsi@icosaedro.it)
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg 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.
  *

  * FFmpeg 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 FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <string.h>
 
 #include "libavutil/mem.h"
 #include "libavutil/avstring.h"
 #include "urldecode.h"
 
 char *ff_urldecode(const char *url)
 {
     int s = 0, d = 0, url_len = 0;
     char c;
     char *dest = NULL;
 
     if (!url)
         return NULL;
 
     url_len = strlen(url) + 1;
     dest = av_malloc(url_len);
 
     if (!dest)
         return NULL;
 
     while (s < url_len) {
         c = url[s++];
 
         if (c == '%' && s + 2 < url_len) {
             char c2 = url[s++];
             char c3 = url[s++];

             if (av_isxdigit(c2) && av_isxdigit(c3)) {

                 c2 = av_tolower(c2);
                 c3 = av_tolower(c3);
 
                 if (c2 <= '9')
                     c2 = c2 - '0';
                 else
                     c2 = c2 - 'a' + 10;
 
                 if (c3 <= '9')
                     c3 = c3 - '0';
                 else
                     c3 = c3 - 'a' + 10;
 
                 dest[d++] = 16 * c2 + c3;
 
             } else { /* %zz or something other invalid */
                 dest[d++] = c;
                 dest[d++] = c2;
                 dest[d++] = c3;
             }
         } else if (c == '+') {
             dest[d++] = ' ';
         } else {
             dest[d++] = c;
         }
 
     }
 
     return dest;
 }