strlcpy.c

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/*-------------------------------------------------------------------------
 *
 * strlcpy.c
 *    strncpy done right
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 *
 *
 * IDENTIFICATION
 *    src/port/strlcpy.c
 *
 * This file was taken from OpenBSD and is used on platforms that don't
 * provide strlcpy().  The OpenBSD copyright terms follow.
 *-------------------------------------------------------------------------
 */

/*  $OpenBSD: strlcpy.c,v 1.11 2006/05/05 15:27:38 millert Exp $    */

/*
 * Copyright (c) 1998 Todd C. Miller <[email protected]>
 *
 * 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 "c.h"


/*
 * Copy src to string dst of size siz.  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz == 0).
 * Returns strlen(src); if retval >= siz, truncation occurred.
 * Function creation history:  http://www.gratisoft.us/todd/papers/strlcpy.html
 */
size_t
strlcpy(char *dst, const char *src, size_t siz)
{
    char       *d = dst;
    const char *s = src;
    size_t      n = siz;

    /* Copy as many bytes as will fit */
    if (n != 0)
    {
        while (--n != 0)
        {
            if ((*d++ = *s++) == '\0')
                break;
        }
    }

    /* Not enough room in dst, add NUL and traverse rest of src */
    if (n == 0)
    {
        if (siz != 0)
            *d = '\0';          /* NUL-terminate dst */
        while (*s++)
            ;
    }

    return (s - src - 1);       /* count does not include NUL */
}