xref: /netbsd-src/external/bsd/am-utils/dist/libamu/strlcat.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: strlcat.c,v 1.1.1.2 2009/03/20 20:26:56 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997-2009 Erez Zadok
5  * Copyright (c) 1990 Jan-Simon Pendry
6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
7  * Copyright (c) 1990 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to Berkeley by
11  * Jan-Simon Pendry at Imperial College, London.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgment:
23  *      This product includes software developed by the University of
24  *      California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *
42  * File: am-utils/libamu/strlcat.c
43  *
44  */
45 
46 #ifdef HAVE_CONFIG_H
47 # include <config.h>
48 #endif /* HAVE_CONFIG_H */
49 #include <am_defs.h>
50 #include <amu.h>
51 
52 /*
53  * Implementation of strlcat(3) from OpenBSD/NetBSD.
54  */
55 
56 /*
57  * Appends src to string dst of size siz (unlike strncat, siz is the
58  * full size of dst, not space left).  At most siz-1 characters
59  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
60  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
61  * If retval >= siz, truncation occurred.
62  */
63 size_t
64 strlcat(char *dst, const char *src, size_t siz)
65 {
66   char *d = dst;
67   const char *s = src;
68   size_t n = siz;
69   size_t dlen;
70 
71   /* Find the end of dst and adjust bytes left but don't go past end */
72   while (n-- != 0 && *d != '\0')
73     d++;
74   dlen = d - dst;
75   n = siz - dlen;
76 
77   if (n == 0)
78     return(dlen + strlen(s));
79   while (*s != '\0') {
80     if (n != 1) {
81       *d++ = *s;
82       n--;
83     }
84     s++;
85   }
86   *d = '\0';
87 
88   return(dlen + (s - src));	/* count does not include NUL */
89 }
90