1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
*
* oFono - Open Source Telephony
*
* Copyright (C) 2008-2010 Intel Corporation. All rights reserved.
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#define _GNU_SOURCE
#include <string.h>
#include <glib.h>
#include "idmap.h"
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
struct idmap {
unsigned long *bits;
unsigned int size;
};
static inline int ffz(unsigned long word)
{
return __builtin_ctzl(~word);
}
/*
* Stolen from linux kernel lib/find_next_bit.c
*/
static unsigned int find_next_zero_bit(const unsigned long *addr,
unsigned int size,
unsigned int offset)
{
const unsigned long *p = addr + offset / BITS_PER_LONG;
unsigned int result = offset & ~(BITS_PER_LONG-1);
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset %= BITS_PER_LONG;
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (BITS_PER_LONG - offset);
if (size < BITS_PER_LONG)
goto found_first;
if (~tmp)
goto found_middle;
size -= BITS_PER_LONG;
result += BITS_PER_LONG;
}
while (size & ~(BITS_PER_LONG-1)) {
if (~(tmp = *(p++)))
goto found_middle;
size -= BITS_PER_LONG;
result += BITS_PER_LONG;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL << size;
if (tmp == ~0UL) /* Are any bits zero? */
return result + size; /* Nope. */
found_middle:
return result + ffz(tmp);
}
struct idmap *idmap_new(unsigned int size)
{
struct idmap *ret = g_new0(struct idmap, 1);
ret->bits = g_new0(unsigned long,
(size + BITS_PER_LONG - 1) / BITS_PER_LONG);
ret->size = size;
return ret;
}
void idmap_free(struct idmap *idmap)
{
g_free(idmap->bits);
g_free(idmap);
}
void idmap_put(struct idmap *idmap, unsigned int bit)
{
unsigned int offset = (bit - 1) / BITS_PER_LONG;
bit -= 1;
if (bit > idmap->size)
return;
bit %= BITS_PER_LONG;
idmap->bits[offset] &= ~(1 << bit);
}
unsigned int idmap_alloc(struct idmap *idmap)
{
unsigned int bit;
unsigned int offset;
bit = find_next_zero_bit(idmap->bits, idmap->size, 0);
if (bit >= idmap->size)
return 0;
offset = bit / BITS_PER_LONG;
idmap->bits[offset] |= 1 << (bit % BITS_PER_LONG);
return bit + 1;
}
/*
* Allocate the next bit skipping the first last bits
*/
unsigned int idmap_alloc_next(struct idmap *idmap, unsigned int last)
{
unsigned int bit;
unsigned int offset;
bit = find_next_zero_bit(idmap->bits, idmap->size, last);
if (bit >= idmap->size)
return idmap_alloc(idmap);
offset = bit / BITS_PER_LONG;
idmap->bits[offset] |= 1 << (bit % BITS_PER_LONG);
return bit + 1;
}
|
