strlcat.c (2557B)
1 /* $OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> 5 * 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. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 19 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 20 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 21 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 22 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 24 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 27 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char *rcsid = "$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $"; 32 #endif /* LIBC_SCCS and not lint */ 33 34 #include <sys/types.h> 35 #include <string.h> 36 37 /* 38 * Appends src to string dst of size siz (unlike strncat, siz is the 39 * full size of dst, not space left). At most siz-1 characters 40 * will be copied. Always NUL terminates (unless siz <= strlen(dst)). 41 * Returns strlen(src) + MIN(siz, strlen(initial dst)). 42 * If retval >= siz, truncation occurred. 43 */ 44 size_t 45 strlcat(char *dst, const char *src, size_t siz) 46 { 47 register char *d = dst; 48 register const char *s = src; 49 register size_t n = siz; 50 size_t dlen; 51 52 /* Find the end of dst and adjust bytes left but don't go past end */ 53 while (n-- != 0 && *d != '\0') 54 d++; 55 dlen = d - dst; 56 n = siz - dlen; 57 58 if (n == 0) 59 return(dlen + strlen(s)); 60 while (*s != '\0') { 61 if (n != 1) { 62 *d++ = *s; 63 n--; 64 } 65 s++; 66 } 67 *d = '\0'; 68 69 return(dlen + (s - src)); /* count does not include NUL */ 70 }