#include "config.h"

/* $NetBSD$ */
 
/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by 
 *
 * 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.
 */

// Function renamed by Adam Chlipala in 2016.

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD$");
#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            ((char *)0)
#endif

/*
 * urweb_memmem() returns the location of the first occurence of data
 * pattern b2 of size len2 in memory block b1 of size len1 or
 * NULL if none is found.
 */
void *
urweb_memmem(const void *b1, size_t len1, const void *b2, size_t len2)
{
        /* Sanity check */
        if(!(b1 != NULL && b2 != NULL && len1 != 0 && len2 != 0))
                return NULL;

        /* Initialize search pointer */
        char *sp = (char *) b1;

        /* Initialize pattern pointer */
        char *pp = (char *) b2;

        /* Intialize end of search address space pointer */
        char *eos   = sp + len1 - len2;

        while (sp <= eos) {
                if (*sp == *pp)
                        if (memcmp(sp, pp, len2) == 0)
                                return sp;

                sp++;
        }

        return NULL;
}