strlcat.c (1631B)
1 /* 2 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 #include <string.h> 18 #include <sys/types.h> 19 20 #include "util.h" 21 22 /* 23 * Appends src to string dst of size siz (unlike strncat, siz is the 24 * full size of dst, not space left). At most siz-1 characters 25 * will be copied. Always NUL terminates (unless siz <= strlen(dst)). 26 * Returns strlen(src) + MIN(siz, strlen(initial dst)). 27 * If retval >= siz, truncation occurred. 28 */ 29 size_t 30 strlcat(char *dst, const char *src, size_t siz) 31 { 32 char *d = dst; 33 const char *s = src; 34 size_t n = siz; 35 size_t dlen; 36 /* Find the end of dst and adjust bytes left but don't go past end */ 37 while (n-- != 0 && *d != '\0') 38 d++; 39 dlen = d - dst; 40 n = siz - dlen; 41 if (n == 0) 42 return(dlen + strlen(s)); 43 while (*s != '\0') { 44 if (n != 1) { 45 *d++ = *s; 46 n--; 47 } 48 s++; 49 } 50 *d = '\0'; 51 return(dlen + (s - src)); /* count does not include NUL */ 52 }