common/lib/libc/string/strchr.c

   1 /*      $NetBSD: strchr.c,v 1.4 2009/07/17 19:37:57 dsl Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)index.c     8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: strchr.c,v 1.4 2009/07/17 19:37:57 dsl Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #if !defined(_KERNEL) && !defined(_STANDALONE)
  42 #include "namespace.h"
  43 #include <assert.h>
  44 #include <string.h>
  45 #else
  46 #include <lib/libkern/libkern.h>
  47 #endif
  48
  49 __strong_alias(index, strchr)
  50 char *
  51 strchr(const char *p, int ch)
  52 {
  53         const char cmp = ch;
  54         _DIAGASSERT(p != NULL);
  55
  56         for (;; ++p) {
  57                 if (*p == cmp) {
  58                         /* LINTED const cast-away */
  59                         return(__UNCONST(p));
  60                 }
  61                 if (!*p)
  62                         return((char *)NULL);
  63         }
  64         /* NOTREACHED */
  65 }