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UbixOS / sys / lib / memset.c
/*-
 * Copyright (c) 2002-2018 The UbixOS Project.
 * All rights reserved.
 *
 * This was developed by Christopher W. Olsen for the UbixOS Project.
 *
 * 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, the following disclaimer and the list of authors.
 * 2) Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors in the documentation and/or
 *    other materials provided with the distribution.
 * 3) Neither the name of the UbixOS Project 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 AUTHOR 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 COPYRIGHT OWNER 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.
 */

#include <string.h>

#define wsize   sizeof(uInt)
#define wmask   (wsize - 1)
#define VAL     c0
#define WIDEVAL c

void *memset(void *dst0, int c0, size_t length) {
  size_t t;
  uInt c;
  uInt8 *dst;

  dst = dst0;

  if (length < 3 * wsize) {
    while (length != 0) {
      *dst++ = VAL;
      --length;
    }
    return (dst0);
  }

  if ((c = (uInt8) c0) != 0) { /* Fill the word. */
    c = (c << 8) | c; /* u_int is 16 bits. */
    c = (c << 16) | c; /* u_int is 32 bits. */
  }

  /* 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 (dst0);
}

/***
 $Log: memset.c,v $
 Revision 1.1.1.1  2006/06/01 12:46:16  reddawg
 ubix2

 Revision 1.2  2005/10/12 00:13:37  reddawg
 Removed

 Revision 1.1.1.1  2005/09/26 17:24:12  reddawg
 no message

 Revision 1.1  2004/07/28 16:20:10  reddawg
 forgot this file

 END
 ***/