1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include <stdlib.h>
#include <string.h>
#ifndef HAVE_MEMMEM
#include "roken.h"
ROKEN_LIB_FUNCTION void * ROKEN_LIB_CALL
memmem(const void *haystack,
size_t haystacklen,
const void *needle,
size_t needlelen)
{
const unsigned char *hs = haystack;
const unsigned char *n = needle;
size_t hsi, ni;
if (haystacklen < needlelen || haystacklen == 0)
return NULL;
/*
* Imagine a haystack of length 5 and needle of length 2, then the largest
* index in the haystack at which we can bother looking for the needle is:
*
* 0 1 2 3 4
* +---------+
* |?|?|?|?|?|
* +---------+
* ^
* \
* here, at index 3, which is 5 - 2, and less than (5 - 2 + 1).
*/
for (hsi = 0, ni = 0; hsi < (haystacklen - needlelen + 1); hsi++, ni = 0) {
while (ni < needlelen && n[ni] == hs[hsi + ni])
ni++;
if (ni == needlelen)
return rk_UNCONST(&hs[hsi]);
}
return NULL;
}
#endif
|
