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bsd memmem

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tg(x) 2011-04-24 17:23:44 +02:00
parent 2fb506abce
commit d52f1a90ee
1 changed files with 62 additions and 67 deletions
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src/memmem.c
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@ -1,67 +1,62 @@
#ifndef _GNU_SOURCE /*-
* Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
/* 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. * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
This program is free software; you can redistribute it and/or modify * are met:
it under the terms of the GNU General Public License as published by * 1. Redistributions of source code must retain the above copyright
the Free Software Foundation; either version 2, or (at your option) * notice, this list of conditions and the following disclaimer.
any later version. * 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
This program is distributed in the hope that it will be useful, * documentation and/or other materials provided with the distribution.
but WITHOUT ANY WARRANTY; without even the implied warranty of * 3. The name of the author may not be used to endorse or promote
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * products derived from this software without specific prior written
GNU General Public License for more details. * permission.
*
You should have received a copy of the GNU General Public License along * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
with this program; if not, write to the Free Software Foundation, * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
/* * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
#ifndef _LIBC * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# include <config.h> * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
#endif * 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
#include <stddef.h> * SUCH DAMAGE.
#include <string.h> */
#ifndef _LIBC #include <string.h>
# define __builtin_expect(expr, val) (expr)
#endif /*
* Find the first occurrence of the byte string s in byte string l.
#undef memmem */
/* Return the first occurrence of NEEDLE in HAYSTACK. */ void *
void * memmem(const void *l, size_t l_len, const void *s, size_t s_len)
memmem (haystack, haystack_len, needle, needle_len) {
const void *haystack; register char *cur, *last;
size_t haystack_len; const char *cl = (const char *)l;
const void *needle; const char *cs = (const char *)s;
size_t needle_len;
{ /* we need something to compare */
const char *begin; if (l_len == 0 || s_len == 0)
const char *const last_possible return NULL;
= (const char *) haystack + haystack_len - needle_len;
/* "s" must be smaller or equal to "l" */
if (needle_len == 0) if (l_len < s_len)
/* The first occurrence of the empty string is deemed to occur at return NULL;
the beginning of the string. */
return (void *) haystack; /* special case where s_len == 1 */
if (s_len == 1)
/* Sanity check, otherwise the loop might search through the whole return memchr(l, (int)*cs, l_len);
memory. */
if (__builtin_expect (haystack_len < needle_len, 0)) /* the last position where its possible to find "s" in "l" */
return NULL; last = (char *)cl + l_len - s_len;
for (begin = (const char *) haystack; begin <= last_possible; ++begin) for (cur = (char *)cl; cur <= last; cur++)
if (begin[0] == ((const char *) needle)[0] && if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
!memcmp ((const void *) &begin[1], return cur;
(const void *) ((const char *) needle + 1),
needle_len - 1)) return NULL;
return (void *) begin; }
return NULL;
}
#endif