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authorThomas Guyot-Sionnest <dermoth@aei.ca>2010-04-08 01:11:46 (GMT)
committerThomas Guyot-Sionnest <dermoth@aei.ca>2010-04-13 01:26:35 (GMT)
commit74da141e618ef99959d509cb2e7be35a348a39db (patch)
tree88ebc38b381a1021fc2d74864a71e230ae591c3d /gl/strstr.c
parentc63a4f726a0b6ad8cf6040f947754a81fd4683bb (diff)
downloadmonitoring-plugins-74da141e618ef99959d509cb2e7be35a348a39db.tar.gz
Sync with the latest Gnulib code (177f525)
Signed-off-by: Thomas Guyot-Sionnest <dermoth@aei.ca>
Diffstat (limited to 'gl/strstr.c')
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1/* Copyright (C) 1991, 1992, 1993, 1994, 1996, 1997, 1998, 2000, 2004, 2007,
2 2008, 2009, 2010 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18
19/* This particular implementation was written by Eric Blake, 2008. */
20
21#ifndef _LIBC
22# include <config.h>
23#endif
24
25/* Specification of strstr. */
26#include <string.h>
27
28#include <stdbool.h>
29
30#ifndef _LIBC
31# define __builtin_expect(expr, val) (expr)
32#endif
33
34#define RETURN_TYPE char *
35#define AVAILABLE(h, h_l, j, n_l) \
36 (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \
37 && ((h_l) = (j) + (n_l)))
38#include "str-two-way.h"
39
40/* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK
41 if NEEDLE is empty, otherwise NULL if NEEDLE is not found in
42 HAYSTACK. */
43char *
44strstr (const char *haystack_start, const char *needle_start)
45{
46 const char *haystack = haystack_start;
47 const char *needle = needle_start;
48 size_t needle_len; /* Length of NEEDLE. */
49 size_t haystack_len; /* Known minimum length of HAYSTACK. */
50 bool ok = true; /* True if NEEDLE is prefix of HAYSTACK. */
51
52 /* Determine length of NEEDLE, and in the process, make sure
53 HAYSTACK is at least as long (no point processing all of a long
54 NEEDLE if HAYSTACK is too short). */
55 while (*haystack && *needle)
56 ok &= *haystack++ == *needle++;
57 if (*needle)
58 return NULL;
59 if (ok)
60 return (char *) haystack_start;
61
62 /* Reduce the size of haystack using strchr, since it has a smaller
63 linear coefficient than the Two-Way algorithm. */
64 needle_len = needle - needle_start;
65 haystack = strchr (haystack_start + 1, *needle_start);
66 if (!haystack || __builtin_expect (needle_len == 1, 0))
67 return (char *) haystack;
68 needle -= needle_len;
69 haystack_len = (haystack > haystack_start + needle_len ? 1
70 : needle_len + haystack_start - haystack);
71
72 /* Perform the search. Abstract memory is considered to be an array
73 of 'unsigned char' values, not an array of 'char' values. See
74 ISO C 99 section 6.2.6.1. */
75 if (needle_len < LONG_NEEDLE_THRESHOLD)
76 return two_way_short_needle ((const unsigned char *) haystack,
77 haystack_len,
78 (const unsigned char *) needle, needle_len);
79 return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
80 (const unsigned char *) needle, needle_len);
81}
82
83#undef LONG_NEEDLE_THRESHOLD