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/*
Unix SMB/Netbios implementation.
Version 1.9.
simple bitmap functions
Copyright (C) Andrew Tridgell 1992-1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
/* these functions provide a simple way to allocate integers from a
pool without repitition */
/****************************************************************************
allocate a bitmap of the specified size
****************************************************************************/
struct bitmap *bitmap_allocate(int n)
{
struct bitmap *bm;
bm = (struct bitmap *)malloc(sizeof(*bm));
if (!bm) return NULL;
bm->n = n;
bm->b = (uint32 *)malloc(sizeof(bm->b[0])*(n+31)/32);
if (!bm->b) {
SAFE_FREE(bm);
return NULL;
}
memset(bm->b, 0, sizeof(bm->b[0])*(n+31)/32);
return bm;
}
/****************************************************************************
free a bitmap.
****************************************************************************/
void bitmap_free(struct bitmap *bm)
{
if (!bm)
return;
SAFE_FREE(bm->b);
SAFE_FREE(bm);
}
/****************************************************************************
set a bit in a bitmap
****************************************************************************/
BOOL bitmap_set(struct bitmap *bm, unsigned i)
{
if (i >= bm->n) {
DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
i, bm->n));
return False;
}
bm->b[i/32] |= (1<<(i%32));
return True;
}
/****************************************************************************
clear a bit in a bitmap
****************************************************************************/
BOOL bitmap_clear(struct bitmap *bm, unsigned i)
{
if (i >= bm->n) {
DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
i, bm->n));
return False;
}
bm->b[i/32] &= ~(1<<(i%32));
return True;
}
/****************************************************************************
query a bit in a bitmap
****************************************************************************/
BOOL bitmap_query(struct bitmap *bm, unsigned i)
{
if (i >= bm->n) return False;
if (bm->b[i/32] & (1<<(i%32))) {
return True;
}
return False;
}
/****************************************************************************
find a zero bit in a bitmap starting at the specified offset, with
wraparound
****************************************************************************/
int bitmap_find(struct bitmap *bm, unsigned ofs)
{
int i, j;
if (ofs > bm->n) ofs = 0;
i = ofs;
while (i < bm->n) {
if (~(bm->b[i/32])) {
j = i;
do {
if (!bitmap_query(bm, j)) return j;
j++;
} while (j & 31 && j < bm->n);
}
i += 32;
i &= ~31;
}
i = 0;
while (i < ofs) {
if (~(bm->b[i/32])) {
j = i;
do {
if (!bitmap_query(bm, j)) return j;
j++;
} while (j & 31 && j < bm->n);
}
i += 32;
i &= ~31;
}
return -1;
}
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