strlcat.c

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/*      $OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $    */

/*
 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "RConfig.h"            /* for HAS_STRLCPY */

#ifndef HAS_STRLCPY

#if defined(LIBC_SCCS) && !defined(lint)
static char *rcsid = "$OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $";
#endif /* LIBC_SCCS and not lint */

#ifndef WIN32
#   include <unistd.h>
#else
#   include <sys/types.h>
#endif
#include <string.h>

/*
 * Appends src to string dst of size siz (unlike strncat, siz is the
 * full size of dst, not space left).  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
 * If retval >= siz, truncation occurred.
 */
size_t
strlcat(char *dst, const char *src, size_t siz)
{
        register char *d = dst;
        register const char *s = src;
        register size_t n = siz;
        size_t dlen;

        /* Find the end of dst and adjust bytes left but don't go past end */
        while (n-- != 0 && *d != '\0')
                d++;
        dlen = d - dst;
        n = siz - dlen;

        if (n == 0)
                return(dlen + strlen(s));
        while (*s != '\0') {
                if (n != 1) {
                        *d++ = *s;
                        n--;
                }
                s++;
        }
        *d = '\0';

        return(dlen + (s - src));       /* count does not include NUL */
}

#endif /* HAS_STRLCPY */

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