u_bitmask.h revision 4a49301e 
1/**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28/**
29 * @file
30 * Generic bitmask.
31 *
32 * @author Jose Fonseca <jfonseca@vmware.com>
33 */
34
35#ifndef U_HANDLE_BITMASK_H_
36#define U_HANDLE_BITMASK_H_
37
38
39#ifdef __cplusplus
40extern "C" {
41#endif
42
43
44#define UTIL_BITMASK_INVALID_INDEX (~0U)
45
46
47/**
48 * Abstract data type to represent arbitrary set of bits.
49 */
50struct util_bitmask;
51
52
53struct util_bitmask *
54util_bitmask_create(void);
55
56
57/**
58 * Search a cleared bit and set it.
59 *
60 * It searches for the first cleared bit.
61 *
62 * Returns the bit index on success, or UTIL_BITMASK_INVALID_INDEX on out of
63 * memory growing the bitmask.
64 */
65unsigned
66util_bitmask_add(struct util_bitmask *bm);
67
68/**
69 * Set a bit.
70 *
71 * Returns the input index on success, or UTIL_BITMASK_INVALID_INDEX on out of
72 * memory growing the bitmask.
73 */
74unsigned
75util_bitmask_set(struct util_bitmask *bm,
76                 unsigned index);
77
78void
79util_bitmask_clear(struct util_bitmask *bm,
80                   unsigned index);
81
82boolean
83util_bitmask_get(struct util_bitmask *bm,
84                 unsigned index);
85
86
87void
88util_bitmask_destroy(struct util_bitmask *bm);
89
90
91/**
92 * Search for the first set bit.
93 *
94 * Returns UTIL_BITMASK_INVALID_INDEX if a set bit cannot be found.
95 */
96unsigned
97util_bitmask_get_first_index(struct util_bitmask *bm);
98
99
100/**
101 * Search for the first set bit, starting from the giving index.
102 *
103 * Returns UTIL_BITMASK_INVALID_INDEX if a set bit cannot be found.
104 */
105unsigned
106util_bitmask_get_next_index(struct util_bitmask *bm,
107                            unsigned index);
108
109
110#ifdef __cplusplus
111}
112#endif
113
114#endif /* U_HANDLE_BITMASK_H_ */
115