1 /**************************************************************************
2 *
3 * Copyright 2017 Valve Corporation
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 THE AUTHORS 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 /* Allocator of IDs (e.g. OpenGL object IDs), or simply an allocator of
29 * numbers.
30 *
31 * The allocator uses a bit array to track allocated IDs.
32 */
33
34 #ifndef U_IDALLOC_H
35 #define U_IDALLOC_H
36
37 #include <inttypes.h>
38 #include <stdbool.h>
39 #include "simple_mtx.h"
40 #include "bitscan.h"
41
42 #ifdef __cplusplus
43 extern "C" {
44 #endif
45
46 struct util_idalloc
47 {
48 uint32_t *data;
49 unsigned num_elements; /* number of allocated elements of "data" */
50 unsigned num_set_elements; /* the last non-zero element of "data" + 1 */
51 unsigned lowest_free_idx;
52 };
53
54 void
55 util_idalloc_init(struct util_idalloc *buf, unsigned initial_num_ids);
56
57 void
58 util_idalloc_fini(struct util_idalloc *buf);
59
60 unsigned
61 util_idalloc_alloc(struct util_idalloc *buf);
62
63 unsigned
64 util_idalloc_alloc_range(struct util_idalloc *buf, unsigned num);
65
66 void
67 util_idalloc_free(struct util_idalloc *buf, unsigned id);
68
69 void
70 util_idalloc_reserve(struct util_idalloc *buf, unsigned id);
71
72 static inline bool
util_idalloc_exists(struct util_idalloc * buf,unsigned id)73 util_idalloc_exists(struct util_idalloc *buf, unsigned id)
74 {
75 return id / 32 < buf->num_set_elements &&
76 buf->data[id / 32] & BITFIELD_BIT(id % 32);
77 }
78
79 #define util_idalloc_foreach(buf, id) \
80 for (uint32_t i = 0, mask = (buf)->num_set_elements ? (buf)->data[0] : 0, id, \
81 count = (buf)->num_used; \
82 i < count; mask = ++i < count ? (buf)->data[i] : 0) \
83 while (mask) \
84 if ((id = i * 32 + u_bit_scan(&mask)), true)
85
86 /* This allows freeing IDs while iterating, excluding ID=0. */
87 #define util_idalloc_foreach_no_zero_safe(buf, id) \
88 for (uint32_t i = 0, bit, id, count = (buf)->num_set_elements, \
89 mask = count ? (buf)->data[0] & ~0x1 : 0; \
90 i < count; mask = ++i < count ? (buf)->data[i] : 0) \
91 while (mask) \
92 if ((bit = u_bit_scan(&mask), id = i * 32 + bit), \
93 (buf)->data[i] & BITFIELD_BIT(bit))
94
95 /* Thread-safe variant. */
96 struct util_idalloc_mt {
97 struct util_idalloc buf;
98 simple_mtx_t mutex;
99 bool skip_zero;
100 };
101
102 void
103 util_idalloc_mt_init(struct util_idalloc_mt *buf,
104 unsigned initial_num_ids, bool skip_zero);
105
106 void
107 util_idalloc_mt_init_tc(struct util_idalloc_mt *buf);
108
109 void
110 util_idalloc_mt_fini(struct util_idalloc_mt *buf);
111
112 unsigned
113 util_idalloc_mt_alloc(struct util_idalloc_mt *buf);
114
115 void
116 util_idalloc_mt_free(struct util_idalloc_mt *buf, unsigned id);
117
118
119 #ifdef __cplusplus
120 }
121 #endif
122
123 #endif /* U_IDALLOC_H */
124