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-rw-r--r-- | openbsd-compat/memmem.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/openbsd-compat/memmem.c b/openbsd-compat/memmem.c new file mode 100644 index 000000000..823443b08 --- /dev/null +++ b/openbsd-compat/memmem.c | |||
@@ -0,0 +1,64 @@ | |||
1 | /* $OpenBSD: memmem.c,v 1.4 2015/08/31 02:53:57 guenther Exp $ */ | ||
2 | /*- | ||
3 | * Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com> | ||
4 | * | ||
5 | * Redistribution and use in source and binary forms, with or without | ||
6 | * modification, are permitted provided that the following conditions | ||
7 | * are met: | ||
8 | * 1. Redistributions of source code must retain the above copyright | ||
9 | * notice, this list of conditions and the following disclaimer. | ||
10 | * 2. Redistributions in binary form must reproduce the above copyright | ||
11 | * notice, this list of conditions and the following disclaimer in the | ||
12 | * documentation and/or other materials provided with the distribution. | ||
13 | * 3. The name of the author may not be used to endorse or promote | ||
14 | * products derived from this software without specific prior written | ||
15 | * permission. | ||
16 | * | ||
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | ||
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | ||
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||
27 | * SUCH DAMAGE. | ||
28 | */ | ||
29 | |||
30 | #include <string.h> | ||
31 | |||
32 | /* | ||
33 | * Find the first occurrence of the byte string s in byte string l. | ||
34 | */ | ||
35 | |||
36 | void * | ||
37 | memmem(const void *l, size_t l_len, const void *s, size_t s_len) | ||
38 | { | ||
39 | const char *cur, *last; | ||
40 | const char *cl = l; | ||
41 | const char *cs = s; | ||
42 | |||
43 | /* a zero length needle should just return the haystack */ | ||
44 | if (s_len == 0) | ||
45 | return (void *)cl; | ||
46 | |||
47 | /* "s" must be smaller or equal to "l" */ | ||
48 | if (l_len < s_len) | ||
49 | return NULL; | ||
50 | |||
51 | /* special case where s_len == 1 */ | ||
52 | if (s_len == 1) | ||
53 | return memchr(l, *cs, l_len); | ||
54 | |||
55 | /* the last position where its possible to find "s" in "l" */ | ||
56 | last = cl + l_len - s_len; | ||
57 | |||
58 | for (cur = cl; cur <= last; cur++) | ||
59 | if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0) | ||
60 | return (void *)cur; | ||
61 | |||
62 | return NULL; | ||
63 | } | ||
64 | DEF_WEAK(memmem); | ||