mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
94 lines
3.1 KiB
C
94 lines
3.1 KiB
C
/* Return the offset of one string within another.
|
|
Copyright (C) 1994-2019 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library 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 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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 the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* This particular implementation was written by Eric Blake, 2008. */
|
|
|
|
#ifndef _LIBC
|
|
# include <config.h>
|
|
#endif
|
|
|
|
/* Specification of strstr. */
|
|
#include <string.h>
|
|
|
|
#include <stdbool.h>
|
|
|
|
#ifndef _LIBC
|
|
# define __builtin_expect(expr, val) (expr)
|
|
#endif
|
|
|
|
#define RETURN_TYPE char *
|
|
#define AVAILABLE(h, h_l, j, n_l) \
|
|
(((j) + (n_l) <= (h_l)) \
|
|
|| ((h_l) += __strnlen ((void*)((h) + (h_l)), (n_l) + 512), \
|
|
(j) + (n_l) <= (h_l)))
|
|
#define CHECK_EOL (1)
|
|
#define RET0_IF_0(a) if (!a) goto ret0
|
|
#define FASTSEARCH(S,C,N) (void*) strchr ((void*)(S), (C))
|
|
#include "str-two-way.h"
|
|
|
|
#undef strstr
|
|
|
|
#ifndef STRSTR
|
|
#define STRSTR strstr
|
|
#endif
|
|
|
|
/* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK
|
|
if NEEDLE is empty, otherwise NULL if NEEDLE is not found in
|
|
HAYSTACK. */
|
|
char *
|
|
STRSTR (const char *haystack, const char *needle)
|
|
{
|
|
size_t needle_len; /* Length of NEEDLE. */
|
|
size_t haystack_len; /* Known minimum length of HAYSTACK. */
|
|
|
|
/* Handle empty NEEDLE special case. */
|
|
if (needle[0] == '\0')
|
|
return (char *) haystack;
|
|
|
|
/* Skip until we find the first matching char from NEEDLE. */
|
|
haystack = strchr (haystack, needle[0]);
|
|
if (haystack == NULL || needle[1] == '\0')
|
|
return (char *) haystack;
|
|
|
|
/* Ensure HAYSTACK length is at least as long as NEEDLE length.
|
|
Since a match may occur early on in a huge HAYSTACK, use strnlen
|
|
and read ahead a few cachelines for improved performance. */
|
|
needle_len = strlen (needle);
|
|
haystack_len = __strnlen (haystack, needle_len + 256);
|
|
if (haystack_len < needle_len)
|
|
return NULL;
|
|
|
|
/* Check whether we have a match. This improves performance since we avoid
|
|
the initialization overhead of the two-way algorithm. */
|
|
if (memcmp (haystack, needle, needle_len) == 0)
|
|
return (char *) haystack;
|
|
|
|
/* Perform the search. Abstract memory is considered to be an array
|
|
of 'unsigned char' values, not an array of 'char' values. See
|
|
ISO C 99 section 6.2.6.1. */
|
|
if (needle_len < LONG_NEEDLE_THRESHOLD)
|
|
return two_way_short_needle ((const unsigned char *) haystack,
|
|
haystack_len,
|
|
(const unsigned char *) needle, needle_len);
|
|
return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
|
|
(const unsigned char *) needle, needle_len);
|
|
}
|
|
libc_hidden_builtin_def (strstr)
|
|
|
|
#undef LONG_NEEDLE_THRESHOLD
|