mirror of
https://github.com/samba-team/samba.git
synced 2024-12-23 17:34:34 +03:00
42f65b6d06
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Andreas Schneider <asn@samba.org>
145 lines
3.7 KiB
C
145 lines
3.7 KiB
C
/*
|
|
Unix SMB/CIFS implementation.
|
|
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 3 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, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "replace.h"
|
|
#include <talloc.h>
|
|
#include "lib/util/bitmap.h"
|
|
#include "lib/util/debug.h"
|
|
#include "lib/util/fault.h"
|
|
|
|
struct bitmap {
|
|
unsigned int n;
|
|
uint32_t b[1]; /* We allocate more */
|
|
};
|
|
|
|
/* these functions provide a simple way to allocate integers from a
|
|
pool without repetition */
|
|
|
|
/****************************************************************************
|
|
talloc a bitmap
|
|
****************************************************************************/
|
|
struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
|
|
{
|
|
struct bitmap *bm;
|
|
|
|
bm = (struct bitmap *)talloc_zero_size(
|
|
mem_ctx,
|
|
offsetof(struct bitmap, b) + sizeof(uint32_t)*((n+31)/32));
|
|
|
|
if (!bm) return NULL;
|
|
|
|
talloc_set_name_const(bm, "struct bitmap");
|
|
|
|
bm->n = n;
|
|
return bm;
|
|
}
|
|
|
|
/****************************************************************************
|
|
copy as much of the source bitmap as will fit in the destination bitmap.
|
|
****************************************************************************/
|
|
|
|
int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
|
|
{
|
|
int count = MIN(dst->n, src->n);
|
|
|
|
SMB_ASSERT(dst->b != src->b);
|
|
memcpy(dst->b, src->b, sizeof(uint32_t)*((count+31)/32));
|
|
|
|
return count;
|
|
}
|
|
|
|
/****************************************************************************
|
|
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)
|
|
{
|
|
unsigned 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;
|
|
}
|