lib/dbm/src/memmove.c
author Daiki Ueno <dueno@redhat.com>
Fri, 15 Sep 2017 15:57:31 +0200
changeset 13593 279b257c6433f1972d49c529247e6ed2633b979f
parent 12490 de6b0f33d1ab3f94e2e7025bce727f15ebb075e8
permissions -rw-r--r--
Bug 1395495, modutil: Initialize DB with empty password on -create, r=kaie

#if defined(__sun) && !defined(__SVR4)
/*-
 * Copyright (c) 1990, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. ***REMOVED*** - see
 *    ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */

#include <string.h>

/*
 * sizeof(word) MUST BE A POWER OF TWO
 * SO THAT wmask BELOW IS ALL ONES
 */
typedef int word; /* "word" used for optimal copy speed */

#define wsize sizeof(word)
#define wmask (wsize - 1)

/*
 * Copy a block of memory, handling overlap.
 * This is the routine that actually implements
 * (the portable versions of) bcopy, memcpy, and memmove.
 */
#ifdef MEMCOPY
void *
    memcpy(dst0, src0, length)
#else
#ifdef MEMMOVE
void *
    memmove(dst0, src0, length)
#else
void
    bcopy(src0, dst0, length)
#endif
#endif
        void *dst0;
const void *src0;
register size_t length;
{
    register char *dst = dst0;
    register const char *src = src0;
    register size_t t;

    if (length == 0 || dst == src) /* nothing to do */
        goto done;

/*
     * Macros: loop-t-times; and loop-t-times, t>0
     */
#define TLOOP(s) \
    if (t)       \
    TLOOP1(s)
#define TLOOP1(s) \
    do {          \
        s;        \
    } while (--t)

    if ((unsigned long)dst < (unsigned long)src) {
        /*
         * Copy forward.
         */
        t = (int)src; /* only need low bits */
        if ((t | (int)dst) & wmask) {
            /*
             * Try to align operands.  This cannot be done
             * unless the low bits match.
             */
            if ((t ^ (int)dst) & wmask || length < wsize)
                t = length;
            else
                t = wsize - (t & wmask);
            length -= t;
            TLOOP1(*dst++ = *src++);
        }
        /*
         * Copy whole words, then mop up any trailing bytes.
         */
        t = length / wsize;
        TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
        t = length & wmask;
        TLOOP(*dst++ = *src++);
    } else {
        /*
         * Copy backwards.  Otherwise essentially the same.
         * Alignment works as before, except that it takes
         * (t&wmask) bytes to align, not wsize-(t&wmask).
         */
        src += length;
        dst += length;
        t = (int)src;
        if ((t | (int)dst) & wmask) {
            if ((t ^ (int)dst) & wmask || length <= wsize)
                t = length;
            else
                t &= wmask;
            length -= t;
            TLOOP1(*--dst = *--src);
        }
        t = length / wsize;
        TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
        t = length & wmask;
        TLOOP(*--dst = *--src);
    }
done:
#if defined(MEMCOPY) || defined(MEMMOVE)
    return (dst0);
#else
    return;
#endif
}
#endif /* no __sgi */

/* Some compilers don't like an empty source file. */
static int dummy = 0;