source: trunk/server/lib/util/bitmap.c@ 987

Last change on this file since 987 was 922, checked in by Silvan Scherrer, 9 years ago

Samba Server: move bitmap.c to the right location, remove generated files, update build.cmd

File size: 3.6 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 simple bitmap functions
4 Copyright (C) Andrew Tridgell 1992-1998
5
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.
10
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.
15
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/>.
18*/
19
20#include "includes.h"
21#include "lib/util/bitmap.h"
22
23/* these functions provide a simple way to allocate integers from a
24 pool without repetition */
25
26/****************************************************************************
27talloc a bitmap
28****************************************************************************/
29struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
30{
31 struct bitmap *bm;
32
33 bm = talloc_zero(mem_ctx, struct bitmap);
34
35 if (!bm) return NULL;
36
37 bm->n = n;
38 bm->b = talloc_zero_array(bm, uint32_t, (n+31)/32);
39 if (!bm->b) {
40 TALLOC_FREE(bm);
41 return NULL;
42 }
43 return bm;
44}
45
46/****************************************************************************
47copy as much of the source bitmap as will fit in the destination bitmap.
48****************************************************************************/
49
50int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
51{
52 int count = MIN(dst->n, src->n);
53
54 SMB_ASSERT(dst->b != src->b);
55 memcpy(dst->b, src->b, sizeof(uint32_t)*((count+31)/32));
56
57 return count;
58}
59
60/****************************************************************************
61set a bit in a bitmap
62****************************************************************************/
63bool bitmap_set(struct bitmap *bm, unsigned i)
64{
65 if (i >= bm->n) {
66 DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
67 i, bm->n));
68 return false;
69 }
70 bm->b[i/32] |= (1<<(i%32));
71 return true;
72}
73
74/****************************************************************************
75clear a bit in a bitmap
76****************************************************************************/
77bool bitmap_clear(struct bitmap *bm, unsigned i)
78{
79 if (i >= bm->n) {
80 DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
81 i, bm->n));
82 return false;
83 }
84 bm->b[i/32] &= ~(1<<(i%32));
85 return true;
86}
87
88/****************************************************************************
89query a bit in a bitmap
90****************************************************************************/
91bool bitmap_query(struct bitmap *bm, unsigned i)
92{
93 if (i >= bm->n) return false;
94 if (bm->b[i/32] & (1<<(i%32))) {
95 return true;
96 }
97 return false;
98}
99
100/****************************************************************************
101find a zero bit in a bitmap starting at the specified offset, with
102wraparound
103****************************************************************************/
104int bitmap_find(struct bitmap *bm, unsigned ofs)
105{
106 unsigned int i, j;
107
108 if (ofs > bm->n) ofs = 0;
109
110 i = ofs;
111 while (i < bm->n) {
112 if (~(bm->b[i/32])) {
113 j = i;
114 do {
115 if (!bitmap_query(bm, j)) return j;
116 j++;
117 } while (j & 31 && j < bm->n);
118 }
119 i += 32;
120 i &= ~31;
121 }
122
123 i = 0;
124 while (i < ofs) {
125 if (~(bm->b[i/32])) {
126 j = i;
127 do {
128 if (!bitmap_query(bm, j)) return j;
129 j++;
130 } while (j & 31 && j < bm->n);
131 }
132 i += 32;
133 i &= ~31;
134 }
135
136 return -1;
137}
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