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strlcat.c 2.5 KB

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  1. /* $OpenBSD: strlcat.c,v 1.5 2001/01/13 16:17:24 millert Exp $ */
  2. /*
  3. * Copyright (c) 1998 Todd C. Miller <[email protected]>
  4. * All rights reserved.
  5. *
  6. * Redistribution and use in source and binary forms, with or without
  7. * modification, are permitted provided that the following conditions
  8. * are met:
  9. * 1. Redistributions of source code must retain the above copyright
  10. * notice, this list of conditions and the following disclaimer.
  11. * 2. Redistributions in binary form must reproduce the above copyright
  12. * notice, this list of conditions and the following disclaimer in the
  13. * documentation and/or other materials provided with the distribution.
  14. * 3. The name of the author may not be used to endorse or promote products
  15. * derived from this software without specific prior written permission.
  16. *
  17. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  18. * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  19. * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  20. * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  21. * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  22. * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  23. * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  24. * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  25. * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  26. * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27. */
  28. #if defined(LIBC_SCCS) && !defined(lint)
  29. static char *rcsid = "$OpenBSD: strlcat.c,v 1.5 2001/01/13 16:17:24 millert Exp $";
  30. #endif /* LIBC_SCCS and not lint */
  31. #include <sys/types.h>
  32. #include <string.h>
  33. /*
  34. * Appends src to string dst of size siz (unlike strncat, siz is the
  35. * full size of dst, not space left). At most siz-1 characters
  36. * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
  37. * Returns strlen(initial dst) + strlen(src); if retval >= siz,
  38. * truncation occurred.
  39. */
  40. size_t strlcat(dst, src, siz)
  41. char *dst;
  42. const char *src;
  43. size_t siz;
  44. {
  45. register char *d = dst;
  46. register const char *s = src;
  47. register size_t n = siz;
  48. size_t dlen;
  49. /* Find the end of dst and adjust bytes left but don't go past end */
  50. while (n-- != 0 && *d != '\0')
  51. d++;
  52. dlen = d - dst;
  53. n = siz - dlen;
  54. if (n == 0)
  55. return(dlen + strlen(s));
  56. while (*s != '\0') {
  57. if (n != 1) {
  58. *d++ = *s;
  59. n--;
  60. }
  61. s++;
  62. }
  63. *d = '\0';
  64. return(dlen + (s - src)); /* count does not include NUL */
  65. }