xref: /third_party/curl/lib/curl_memrchr.c (revision 13498266)
1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25#include "curl_setup.h"
26
27#include <curl/curl.h>
28
29#include "curl_memrchr.h"
30#include "curl_memory.h"
31
32/* The last #include file should be: */
33#include "memdebug.h"
34
35#ifndef HAVE_MEMRCHR
36
37/*
38 * Curl_memrchr()
39 *
40 * Our memrchr() function clone for systems which lack this function. The
41 * memrchr() function is like the memchr() function, except that it searches
42 * backwards from the end of the n bytes pointed to by s instead of forward
43 * from the beginning.
44 */
45
46void *
47Curl_memrchr(const void *s, int c, size_t n)
48{
49  if(n > 0) {
50    const unsigned char *p = s;
51    const unsigned char *q = s;
52
53    p += n - 1;
54
55    while(p >= q) {
56      if(*p == (unsigned char)c)
57        return (void *)p;
58      p--;
59    }
60  }
61  return NULL;
62}
63
64#endif /* HAVE_MEMRCHR */
65