aboutsummaryrefslogtreecommitdiff
path: root/src/daemon/https/lgl/memmem.c
blob: 9a0e67d2289aac2d3ec23adc5bf04af9056d1463 (plain) (blame)
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
/* Copyright (C) 1991,92,93,94,96,97,98,2000,2004,2007 Free Software Foundation, Inc.
 This file is part of the GNU C Library.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation; either version 2.1, or (at your option)
 any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public License along
 with this program; if not, write to the Free Software Foundation,
 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifndef _LIBC
#include "MHD_config.h"
#endif

#include <stddef.h>
#include <string.h>

#ifndef _LIBC
# define __builtin_expect(expr, val)   (expr)
#endif

#undef memmem

/* Return the first occurrence of NEEDLE in HAYSTACK.  */
void *
memmem (haystack, haystack_len, needle, needle_len)
     const void *haystack;
     size_t haystack_len;
     const void *needle;
     size_t needle_len;
{
  const char *begin;
  const char *const last_possible = (const char *) haystack + haystack_len
    - needle_len;

  if (needle_len == 0)
    /* The first occurrence of the empty string is deemed to occur at
       the beginning of the string.  */
    return (void *) haystack;

  /* Sanity check, otherwise the loop might search through the whole
     memory.  */
  if (__builtin_expect (haystack_len < needle_len, 0))
    return NULL;

  for (begin = (const char *) haystack; begin <= last_possible; ++begin)
    if (begin[0] == ((const char *) needle)[0]
        && !memcmp ((const void *) &begin[1],
                    (const void *) ((const char *) needle + 1),
                    needle_len - 1))
      return (void *) begin;

  return NULL;
}