2 Unix SMB/CIFS implementation.
3 simple bitmap functions
4 Copyright (C) Andrew Tridgell 1992-1998
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 /* these functions provide a simple way to allocate integers from a
23 pool without repetition */
25 /****************************************************************************
27 ****************************************************************************/
28 struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
32 bm = talloc(mem_ctx, struct bitmap);
37 bm->b = TALLOC_ZERO_ARRAY(bm, uint32, (n+31)/32);
45 /****************************************************************************
46 copy as much of the source bitmap as will fit in the destination bitmap.
47 ****************************************************************************/
49 int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
51 int count = MIN(dst->n, src->n);
53 SMB_ASSERT(dst->b != src->b);
54 memcpy(dst->b, src->b, sizeof(uint32)*((count+31)/32));
59 /****************************************************************************
61 ****************************************************************************/
62 bool bitmap_set(struct bitmap *bm, unsigned i)
65 DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
69 bm->b[i/32] |= (1<<(i%32));
73 /****************************************************************************
74 clear a bit in a bitmap
75 ****************************************************************************/
76 bool bitmap_clear(struct bitmap *bm, unsigned i)
79 DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
83 bm->b[i/32] &= ~(1<<(i%32));
87 /****************************************************************************
88 query a bit in a bitmap
89 ****************************************************************************/
90 bool bitmap_query(struct bitmap *bm, unsigned i)
92 if (i >= bm->n) return False;
93 if (bm->b[i/32] & (1<<(i%32))) {
99 /****************************************************************************
100 find a zero bit in a bitmap starting at the specified offset, with
102 ****************************************************************************/
103 int bitmap_find(struct bitmap *bm, unsigned ofs)
107 if (ofs > bm->n) ofs = 0;
111 if (~(bm->b[i/32])) {
114 if (!bitmap_query(bm, j)) return j;
116 } while (j & 31 && j < bm->n);
124 if (~(bm->b[i/32])) {
127 if (!bitmap_query(bm, j)) return j;
129 } while (j & 31 && j < bm->n);