strlcat.c 1.8 KB

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  1. /* $OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $ */
  2. /*
  3. * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
  4. *
  5. * Permission to use, copy, modify, and distribute this software for any
  6. * purpose with or without fee is hereby granted, provided that the above
  7. * copyright notice and this permission notice appear in all copies.
  8. *
  9. * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10. * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11. * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12. * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13. * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14. * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15. * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16. */
  17. #if defined(LIBC_SCCS) && !defined(lint)
  18. static char *rcsid = "$OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $";
  19. #endif /* LIBC_SCCS and not lint */
  20. #include <sys/types.h>
  21. #include <string.h>
  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. register char *d = dst;
  33. register const char *s = src;
  34. register 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. }