strlcat.c (1815B)
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 TODD C. MILLER DISCLAIMS ALL 9 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE 11 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 13 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 14 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 #ifdef HAVE_DIX_CONFIG_H 18 #include <dix-config.h> 19 #endif 20 21 #include <sys/types.h> 22 #include <string.h> 23 #include "os.h" 24 25 /* 26 * Appends src to string dst of size siz (unlike strncat, siz is the 27 * full size of dst, not space left). At most siz-1 characters 28 * will be copied. Always NUL terminates (unless siz <= strlen(dst)). 29 * Returns strlen(src) + MIN(siz, strlen(initial dst)). 30 * If retval >= siz, truncation occurred. 31 */ 32 size_t 33 strlcat(char *dst, const char *src, size_t siz) 34 { 35 register char *d = dst; 36 register const char *s = src; 37 register size_t n = siz; 38 size_t dlen; 39 40 /* Find the end of dst and adjust bytes left but don't go past end */ 41 while (n-- != 0 && *d != '\0') 42 d++; 43 dlen = d - dst; 44 n = siz - dlen; 45 46 if (n == 0) 47 return (dlen + strlen(s)); 48 while (*s != '\0') { 49 if (n != 1) { 50 *d++ = *s; 51 n--; 52 } 53 s++; 54 } 55 *d = '\0'; 56 57 return (dlen + (s - src)); /* count does not include NUL */ 58 }