freebsd-dev/lib/libc/string/memset.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

131 lines
3.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Hibler and 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. 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[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <limits.h>
#define wsize sizeof(u_int)
#define wmask (wsize - 1)
#ifdef BZERO
#include <strings.h>
#define RETURN return
#define VAL 0
#define WIDEVAL 0
void
bzero(void *dst0, size_t length)
#else
#include <string.h>
#define RETURN return (dst0)
#define VAL c0
#define WIDEVAL c
void *
memset(void *dst0, int c0, size_t length)
#endif
{
size_t t;
#ifndef BZERO
u_int c;
#endif
u_char *dst;
dst = dst0;
/*
* If not enough words, just fill bytes. A length >= 2 words
* guarantees that at least one of them is `complete' after
* any necessary alignment. For instance:
*
* |-----------|-----------|-----------|
* |00|01|02|03|04|05|06|07|08|09|0A|00|
* ^---------------------^
* dst dst+length-1
*
* but we use a minimum of 3 here since the overhead of the code
* to do word writes is substantial.
*/
if (length < 3 * wsize) {
while (length != 0) {
*dst++ = VAL;
--length;
}
RETURN;
}
#ifndef BZERO
if ((c = (u_char)c0) != 0) { /* Fill the word. */
c = (c << 8) | c; /* u_int is 16 bits. */
#if UINT_MAX > 0xffff
c = (c << 16) | c; /* u_int is 32 bits. */
#endif
#if UINT_MAX > 0xffffffff
c = (c << 32) | c; /* u_int is 64 bits. */
#endif
}
#endif
/* Align destination by filling in bytes. */
if ((t = (long)dst & wmask) != 0) {
t = wsize - t;
length -= t;
do {
*dst++ = VAL;
} while (--t != 0);
}
/* Fill words. Length was >= 2*words so we know t >= 1 here. */
t = length / wsize;
do {
*(u_int *)dst = WIDEVAL;
dst += wsize;
} while (--t != 0);
/* Mop up trailing bytes, if any. */
t = length & wmask;
if (t != 0)
do {
*dst++ = VAL;
} while (--t != 0);
RETURN;
}