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Annotation of sys/lib/libkern/memcmp.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: memcmp.c,v 1.4 2004/08/07 00:38:32 deraadt Exp $      */
                      2:
                      3: /*-
                      4:  * Copyright (c) 1990 The Regents of the University of California.
                      5:  * All rights reserved.
                      6:  *
                      7:  * This code is derived from software contributed to Berkeley by
                      8:  * Chris Torek.
                      9:  *
                     10:  * Redistribution and use in source and binary forms, with or without
                     11:  * modification, are permitted provided that the following conditions
                     12:  * are met:
                     13:  * 1. Redistributions of source code must retain the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer.
                     15:  * 2. Redistributions in binary form must reproduce the above copyright
                     16:  *    notice, this list of conditions and the following disclaimer in the
                     17:  *    documentation and/or other materials provided with the distribution.
                     18:  * 3. Neither the name of the University nor the names of its contributors
                     19:  *    may be used to endorse or promote products derived from this software
                     20:  *    without specific prior written permission.
                     21:  *
                     22:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     23:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     24:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     25:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     26:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     27:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     28:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     29:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     30:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     31:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     32:  * SUCH DAMAGE.
                     33:  */
                     34:
                     35: #if defined(LIBC_SCCS) && !defined(lint)
                     36: static char *rcsid = "$OpenBSD: memcmp.c,v 1.4 2004/08/07 00:38:32 deraadt Exp $";
                     37: #endif /* LIBC_SCCS and not lint */
                     38:
                     39: #if !defined(_KERNEL) && !defined(_STANDALONE)
                     40: #include <string.h>
                     41: #else
                     42: #include <lib/libkern/libkern.h>
                     43: #endif
                     44:
                     45: /*
                     46:  * Compare memory regions.
                     47:  */
                     48: int
                     49: memcmp(const void *s1, const void *s2, size_t n)
                     50: {
                     51:        if (n != 0) {
                     52:                const unsigned char *p1 = s1, *p2 = s2;
                     53:
                     54:                do {
                     55:                        if (*p1++ != *p2++)
                     56:                                return (*--p1 - *--p2);
                     57:                } while (--n != 0);
                     58:        }
                     59:        return (0);
                     60: }