1/*
2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup lwext4
30 * @{
31 */
32/**
33 * @file ext4_bitmap.c
34 * @brief Block/inode bitmap allocator.
35 */
36
37#include <ext4_config.h>
38#include <ext4_types.h>
39#include <ext4_misc.h>
40#include <ext4_errno.h>
41#include <ext4_debug.h>
42
43#include <ext4_bitmap.h>
44
45void ext4_bmap_bits_free(uint8_t *bmap, uint32_t sbit, uint32_t bcnt)
46{
47 uint32_t i = sbit;
48
49 while (i & 7) {
50
51 if (!bcnt)
52 return;
53
54 ext4_bmap_bit_clr(bmap, bit: i);
55
56 bcnt--;
57 i++;
58 }
59 sbit = i;
60 bmap += (sbit >> 3);
61
62#if CONFIG_UNALIGNED_ACCESS
63 while (bcnt >= 32) {
64 *(uint32_t *)bmap = 0;
65 bmap += 4;
66 bcnt -= 32;
67 sbit += 32;
68 }
69
70 while (bcnt >= 16) {
71 *(uint16_t *)bmap = 0;
72 bmap += 2;
73 bcnt -= 16;
74 sbit += 16;
75 }
76#endif
77
78 while (bcnt >= 8) {
79 *bmap = 0;
80 bmap += 1;
81 bcnt -= 8;
82 sbit += 8;
83 }
84
85 for (i = 0; i < bcnt; ++i) {
86 ext4_bmap_bit_clr(bmap, bit: i);
87 }
88}
89
90int ext4_bmap_bit_find_clr(uint8_t *bmap, uint32_t sbit, uint32_t ebit,
91 uint32_t *bit_id)
92{
93 uint32_t i;
94 uint32_t bcnt = ebit - sbit;
95
96 i = sbit;
97
98 while (i & 7) {
99
100 if (!bcnt)
101 return ENOSPC;
102
103 if (ext4_bmap_is_bit_clr(bmap, bit: i)) {
104 *bit_id = sbit;
105 return EOK;
106 }
107
108 i++;
109 bcnt--;
110 }
111
112 sbit = i;
113 bmap += (sbit >> 3);
114
115#if CONFIG_UNALIGNED_ACCESS
116 while (bcnt >= 32) {
117 if (*(uint32_t *)bmap != 0xFFFFFFFF)
118 goto finish_it;
119
120 bmap += 4;
121 bcnt -= 32;
122 sbit += 32;
123 }
124
125 while (bcnt >= 16) {
126 if (*(uint16_t *)bmap != 0xFFFF)
127 goto finish_it;
128
129 bmap += 2;
130 bcnt -= 16;
131 sbit += 16;
132 }
133finish_it:
134#endif
135 while (bcnt >= 8) {
136 if (*bmap != 0xFF) {
137 for (i = 0; i < 8; ++i) {
138 if (ext4_bmap_is_bit_clr(bmap, bit: i)) {
139 *bit_id = sbit + i;
140 return EOK;
141 }
142 }
143 }
144
145 bmap += 1;
146 bcnt -= 8;
147 sbit += 8;
148 }
149
150 for (i = 0; i < bcnt; ++i) {
151 if (ext4_bmap_is_bit_clr(bmap, bit: i)) {
152 *bit_id = sbit + i;
153 return EOK;
154 }
155 }
156
157 return ENOSPC;
158}
159
160/**
161 * @}
162 */
163