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_P(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
);