mirror of git://git.psyc.eu/libpsyc
bsd memmem
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src/memmem.c
129
src/memmem.c
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#ifndef _GNU_SOURCE
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/* Copyright (C) 1991,92,93,94,96,97,98,2000,2004,2007 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/*
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#ifndef _LIBC
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# include <config.h>
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#endif
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*/
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#include <stddef.h>
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#include <string.h>
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#ifndef _LIBC
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# define __builtin_expect(expr, val) (expr)
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#endif
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#undef memmem
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/* Return the first occurrence of NEEDLE in HAYSTACK. */
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void *
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memmem (haystack, haystack_len, needle, needle_len)
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const void *haystack;
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size_t haystack_len;
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const void *needle;
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size_t needle_len;
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{
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const char *begin;
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const char *const last_possible
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= (const char *) haystack + haystack_len - needle_len;
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if (needle_len == 0)
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/* The first occurrence of the empty string is deemed to occur at
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the beginning of the string. */
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return (void *) haystack;
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/* Sanity check, otherwise the loop might search through the whole
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memory. */
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if (__builtin_expect (haystack_len < needle_len, 0))
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return NULL;
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for (begin = (const char *) haystack; begin <= last_possible; ++begin)
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if (begin[0] == ((const char *) needle)[0] &&
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!memcmp ((const void *) &begin[1],
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(const void *) ((const char *) needle + 1),
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needle_len - 1))
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return (void *) begin;
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return NULL;
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}
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#endif
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/*-
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* Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <string.h>
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/*
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* Find the first occurrence of the byte string s in byte string l.
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*/
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void *
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memmem(const void *l, size_t l_len, const void *s, size_t s_len)
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{
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register char *cur, *last;
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const char *cl = (const char *)l;
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const char *cs = (const char *)s;
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/* we need something to compare */
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if (l_len == 0 || s_len == 0)
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return NULL;
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/* "s" must be smaller or equal to "l" */
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if (l_len < s_len)
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return NULL;
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/* special case where s_len == 1 */
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if (s_len == 1)
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return memchr(l, (int)*cs, l_len);
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/* the last position where its possible to find "s" in "l" */
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last = (char *)cl + l_len - s_len;
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for (cur = (char *)cl; cur <= last; cur++)
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if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
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return cur;
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return NULL;
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}
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