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 2 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, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 /* these functions provide a simple way to allocate integers from a
24 pool without repetition */
26 /****************************************************************************
27 allocate a bitmap of the specified size
28 ****************************************************************************/
29 struct bitmap *bitmap_allocate(int n)
33 bm = SMB_MALLOC_P(struct bitmap);
38 bm->b = SMB_MALLOC_ARRAY(uint32, (n+31)/32);
44 memset(bm->b, 0, sizeof(bm->b[0])*(n+31)/32);
49 /****************************************************************************
51 ****************************************************************************/
53 void bitmap_free(struct bitmap *bm)
62 /****************************************************************************
64 ****************************************************************************/
65 struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
69 if (!mem_ctx) return NULL;
71 bm = TALLOC_P(mem_ctx, struct bitmap);
76 bm->b = TALLOC_ARRAY(mem_ctx, uint32, (n+31)/32);
81 memset(bm->b, 0, sizeof(bm->b[0])*(n+31)/32);
86 /****************************************************************************
87 copy as much of the source bitmap as will fit in the destination bitmap.
88 ****************************************************************************/
90 int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
92 int count = MIN(dst->n, src->n);
94 SMB_ASSERT(dst->b != src->b);
95 memcpy(dst->b, src->b, sizeof(dst->b[0])*(count+31)/32);
100 /****************************************************************************
101 set a bit in a bitmap
102 ****************************************************************************/
103 BOOL bitmap_set(struct bitmap *bm, unsigned i)
106 DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
110 bm->b[i/32] |= (1<<(i%32));
114 /****************************************************************************
115 clear a bit in a bitmap
116 ****************************************************************************/
117 BOOL bitmap_clear(struct bitmap *bm, unsigned i)
120 DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
124 bm->b[i/32] &= ~(1<<(i%32));
128 /****************************************************************************
129 query a bit in a bitmap
130 ****************************************************************************/
131 BOOL bitmap_query(struct bitmap *bm, unsigned i)
133 if (i >= bm->n) return False;
134 if (bm->b[i/32] & (1<<(i%32))) {
140 /****************************************************************************
141 find a zero bit in a bitmap starting at the specified offset, with
143 ****************************************************************************/
144 int bitmap_find(struct bitmap *bm, unsigned ofs)
148 if (ofs > bm->n) ofs = 0;
152 if (~(bm->b[i/32])) {
155 if (!bitmap_query(bm, j)) return j;
157 } while (j & 31 && j < bm->n);
165 if (~(bm->b[i/32])) {
168 if (!bitmap_query(bm, j)) return j;
170 } while (j & 31 && j < bm->n);