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 <ctype.h>
30 #include <string.h>
31 
32 #include "libavutil/mem.h"
33 #include "libavutil/avstring.h"
34 #include "urldecode.h"
35 
36 char *ff_urldecode(const char *url)
37 {
38  int s = 0, d = 0, url_len = 0;
39  char c;
40  char *dest = NULL;
41 
42  if (!url)
43  return NULL;
44 
45  url_len = strlen(url) + 1;
46  dest = av_malloc(url_len);
47 
48  if (!dest)
49  return NULL;
50 
51  while (s < url_len) {
52  c = url[s++];
53 
54  if (c == '%' && s + 2 < url_len) {
55  char c2 = url[s++];
56  char c3 = url[s++];
57  if (isxdigit(c2) && isxdigit(c3)) {
58  c2 = av_tolower(c2);
59  c3 = av_tolower(c3);
60 
61  if (c2 <= '9')
62  c2 = c2 - '0';
63  else
64  c2 = c2 - 'a' + 10;
65 
66  if (c3 <= '9')
67  c3 = c3 - '0';
68  else
69  c3 = c3 - 'a' + 10;
70 
71  dest[d++] = 16 * c2 + c3;
72 
73  } else { /* %zz or something other invalid */
74  dest[d++] = c;
75  dest[d++] = c2;
76  dest[d++] = c3;
77  }
78  } else if (c == '+') {
79  dest[d++] = ' ';
80  } else {
81  dest[d++] = c;
82  }
83 
84  }
85 
86  return dest;
87 }