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 /****************************************************************************
26 allocate a bitmap of the specified size
27 ****************************************************************************/
28 struct bitmap *bitmap_allocate(int n)
32 bm = SMB_MALLOC_P(struct bitmap);
37 bm->b = SMB_MALLOC_ARRAY(uint32, (n+31)/32);
43 memset(bm->b, 0, sizeof(uint32)*((n+31)/32));
48 /****************************************************************************
50 ****************************************************************************/
52 void bitmap_free(struct bitmap *bm)
61 /****************************************************************************
63 ****************************************************************************/
64 struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
68 if (!mem_ctx) return NULL;
70 bm = TALLOC_P(mem_ctx, struct bitmap);
75 bm->b = TALLOC_ARRAY(mem_ctx, uint32, (n+31)/32);
80 memset(bm->b, 0, sizeof(uint32)*((n+31)/32));
85 /****************************************************************************
86 copy as much of the source bitmap as will fit in the destination bitmap.
87 ****************************************************************************/
89 int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
91 int count = MIN(dst->n, src->n);
93 SMB_ASSERT(dst->b != src->b);
94 memcpy(dst->b, src->b, sizeof(uint32)*((count+31)/32));
99 /****************************************************************************
100 set a bit in a bitmap
101 ****************************************************************************/
102 bool bitmap_set(struct bitmap *bm, unsigned i)
105 DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
109 bm->b[i/32] |= (1<<(i%32));
113 /****************************************************************************
114 clear a bit in a bitmap
115 ****************************************************************************/
116 bool bitmap_clear(struct bitmap *bm, unsigned i)
119 DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
123 bm->b[i/32] &= ~(1<<(i%32));
127 /****************************************************************************
128 query a bit in a bitmap
129 ****************************************************************************/
130 bool bitmap_query(struct bitmap *bm, unsigned i)
132 if (i >= bm->n) return False;
133 if (bm->b[i/32] & (1<<(i%32))) {
139 /****************************************************************************
140 find a zero bit in a bitmap starting at the specified offset, with
142 ****************************************************************************/
143 int bitmap_find(struct bitmap *bm, unsigned ofs)
147 if (ofs > bm->n) ofs = 0;
151 if (~(bm->b[i/32])) {
154 if (!bitmap_query(bm, j)) return j;
156 } while (j & 31 && j < bm->n);
164 if (~(bm->b[i/32])) {
167 if (!bitmap_query(bm, j)) return j;
169 } while (j & 31 && j < bm->n);