FFmpeg
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urldecode.c
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1 /*
2  * Simple URL decoding function
3  * Copyright (c) 2012 Antti Seppälä
4  *
5  * References:
6  * RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
7  * T. Berners-Lee et al. The Internet Society, 2005
8  *
9  * based on http://www.icosaedro.it/apache/urldecode.c
10  * from Umberto Salsi (salsi@icosaedro.it)
11  *
12  * This file is part of FFmpeg.
13  *
14  * FFmpeg is free software; you can redistribute it and/or
15  * modify it under the terms of the GNU Lesser General Public
16  * License as published by the Free Software Foundation; either
17  * version 2.1 of the License, or (at your option) any later version.
18  *
19  * FFmpeg is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22  * Lesser General Public License for more details.
23  *
24  * You should have received a copy of the GNU Lesser General Public
25  * License along with FFmpeg; if not, write to the Free Software
26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27  */
28 
29 #include <string.h>
30 
31 #include "libavutil/mem.h"
32 #include "libavutil/avstring.h"
33 #include "urldecode.h"
34 
35 char *ff_urldecode(const char *url)
36 {
37  int s = 0, d = 0, url_len = 0;
38  char c;
39  char *dest = NULL;
40 
41  if (!url)
42  return NULL;
43 
44  url_len = strlen(url) + 1;
45  dest = av_malloc(url_len);
46 
47  if (!dest)
48  return NULL;
49 
50  while (s < url_len) {
51  c = url[s++];
52 
53  if (c == '%' && s + 2 < url_len) {
54  char c2 = url[s++];
55  char c3 = url[s++];
56  if (av_isxdigit(c2) && av_isxdigit(c3)) {
57  c2 = av_tolower(c2);
58  c3 = av_tolower(c3);
59 
60  if (c2 <= '9')
61  c2 = c2 - '0';
62  else
63  c2 = c2 - 'a' + 10;
64 
65  if (c3 <= '9')
66  c3 = c3 - '0';
67  else
68  c3 = c3 - 'a' + 10;
69 
70  dest[d++] = 16 * c2 + c3;
71 
72  } else { /* %zz or something other invalid */
73  dest[d++] = c;
74  dest[d++] = c2;
75  dest[d++] = c3;
76  }
77  } else if (c == '+') {
78  dest[d++] = ' ';
79  } else {
80  dest[d++] = c;
81  }
82 
83  }
84 
85  return dest;
86 }