xref: /minix/lib/libc/string/strndup.c (revision 00b67f09)
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 */
75