88 lines
3.0 KiB
C
88 lines
3.0 KiB
C
/* $NetBSD: memmem.c,v 1.1 2005/03/13 14:47:02 perry Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 2005 The NetBSD Foundation, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to The NetBSD Foundation
|
|
* by Perry E. Metzger of Metzger, Dowdeswell & Co. LLC.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the NetBSD
|
|
* Foundation, Inc. and its contributors.
|
|
* 4. Neither the name of The NetBSD Foundation nor the names of its
|
|
* contributors may be used to endorse or promote products derived
|
|
* from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) 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 SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
__RCSID("$NetBSD: memmem.c,v 1.1 2005/03/13 14:47:02 perry Exp $");
|
|
#endif /* LIBC_SCCS and not lint */
|
|
|
|
#if !defined(_KERNEL) && !defined(_STANDALONE)
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
#else
|
|
#include <lib/libkern/libkern.h>
|
|
#define _DIAGASSERT(x) (void)0
|
|
#define NULL ((void *)0)
|
|
#endif
|
|
|
|
void *
|
|
memmem(const void *block, size_t blen, const void *pat, size_t plen)
|
|
{
|
|
const unsigned char *bp, *pp, *endp;
|
|
|
|
_DIAGASSERT(block != NULL);
|
|
_DIAGASSERT(pat != NULL);
|
|
|
|
/*
|
|
* Following the precedent in ststr(3) and glibc, a zero
|
|
* length pattern matches the start of block.
|
|
*/
|
|
if (plen == 0)
|
|
return __UNCONST(block);
|
|
|
|
if (blen < plen)
|
|
return NULL;
|
|
|
|
bp = block;
|
|
pp = pat;
|
|
endp = bp + (blen - plen) + 1;
|
|
|
|
/*
|
|
* As a cheezy optimization, check that the first chars are
|
|
* the same before calling memcmp. Really we should use bm(3)
|
|
* to speed this up if blen is large enough.
|
|
*/
|
|
while (bp < endp) {
|
|
if ((*bp == *pp) && (memcmp(bp, pp, plen) == 0))
|
|
return __UNCONST(bp);
|
|
bp++;
|
|
}
|
|
|
|
return NULL;
|
|
}
|