133 lines
3.0 KiB
C
133 lines
3.0 KiB
C
/*-
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* Copyright (C) 1996
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* David L. Nugent. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <stdlib.h>
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#include <string.h>
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#include "bitmap.h"
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struct bitmap
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bm_alloc(int size)
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{
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struct bitmap bm;
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int szmap = (size / 8) + !!(size % 8);
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bm.size = size;
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bm.map = malloc(szmap);
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if (bm.map)
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memset(bm.map, 0, szmap);
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return bm;
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}
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void
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bm_dealloc(struct bitmap * bm)
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{
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if (bm->map)
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free(bm->map);
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}
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static void
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bm_getmask(int *pos, unsigned char *bmask)
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{
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*bmask = (unsigned char) (1 << (*pos % 8));
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*pos /= 8;
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}
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void
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bm_setbit(struct bitmap * bm, int pos)
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{
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unsigned char bmask;
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bm_getmask(&pos, &bmask);
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bm->map[pos] |= bmask;
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}
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void
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bm_clrbit(struct bitmap * bm, int pos)
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{
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unsigned char bmask;
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bm_getmask(&pos, &bmask);
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bm->map[pos] &= ~bmask;
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}
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int
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bm_isset(struct bitmap * bm, int pos)
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{
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unsigned char bmask;
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bm_getmask(&pos, &bmask);
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return !!(bm->map[pos] & bmask);
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}
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int
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bm_firstunset(struct bitmap * bm)
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{
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int szmap = (bm->size / 8) + !!(bm->size % 8);
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int at = 0;
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int pos = 0;
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while (pos < szmap) {
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unsigned char bmv = bm->map[pos++];
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unsigned char bmask = 1;
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while (bmask & 0xff) {
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if ((bmv & bmask) == 0)
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return at;
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bmask <<= 1;
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++at;
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}
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}
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return at;
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}
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int
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bm_lastset(struct bitmap * bm)
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{
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int szmap = (bm->size / 8) + !!(bm->size % 8);
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int at = 0;
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int pos = 0;
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int ofs = 0;
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while (pos < szmap) {
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unsigned char bmv = bm->map[pos++];
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unsigned char bmask = 1;
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while (bmask & 0xff) {
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if ((bmv & bmask) != 0)
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ofs = at;
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bmask <<= 1;
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++at;
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}
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}
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return ofs;
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}
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