lib/libc/string/strndup.c

   1 /*      $NetBSD: strndup.c,v 1.4 2007/07/03 12:11:09 nakayama Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 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 #if HAVE_NBTOOL_CONFIG_H
  33 #include "nbtool_config.h"
  34 #endif
  35
  36 #include <sys/cdefs.h>
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 #if 0
  39 static char sccsid[] = "@(#)strdup.c    8.1 (Berkeley) 6/4/93";
  40 #else
  41 __RCSID("$NetBSD: strndup.c,v 1.4 2007/07/03 12:11:09 nakayama Exp $");
  42 #endif
  43 #endif /* LIBC_SCCS and not lint */
  44
  45 #include "namespace.h"
  46
  47 #include <assert.h>
  48 #include <errno.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51
  52 #ifdef __weak_alias
  53 __weak_alias(strndup,_strndup)
  54 #endif
  55
  56 #if !HAVE_STRNDUP
  57 char *
  58 strndup(const char *str, size_t n)
  59 {
  60         size_t len;
  61         char *copy;
  62
  63         _DIAGASSERT(str != NULL);
  64
  65         for (len = 0; len < n && str[len]; len++)
  66                 continue;
  67
  68         if (!(copy = malloc(len + 1)))
  69                 return (NULL);
  70         memcpy(copy, str, len);
  71         copy[len] = '\0';
  72         return (copy);
  73 }
  74 #endif /* !HAVE_STRNDUP */