lib/libc/string/memrchr.c

   1 /*
   2  * Copyright (c) 2007 Todd C. Miller <Todd.Miller@courtesan.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  *
  16  * $OpenBSD: memrchr.c,v 1.2 2007/11/27 16:22:12 martynas Exp $
  17  * $FreeBSD: src/lib/libc/string/memrchr.c,v 1.1 2008/04/10 00:12:44 delphij Exp $
  18  */
  19
  20 #include <string.h>
  21
  22 /*
  23  * Reverse memchr()
  24  * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
  25  */
  26 void *
  27 memrchr(const void *s, int c, size_t n)
  28 {
  29         const unsigned char *cp;
  30
  31         if (n != 0) {
  32                 cp = (unsigned char *)s + n;
  33                 do {
  34                         if (*(--cp) == (unsigned char)c)
  35                                 return((void *)cp);
  36                 } while (--n != 0);
  37         }
  38         return(NULL);
  39 }