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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
/*
* Copyright (c) 2015 Damien Miller <djm@mindrot.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include "bitmap.h"
#define BITMAP_WTYPE u_int
#define BITMAP_MAX (1<<24)
#define BITMAP_BYTES (sizeof(BITMAP_WTYPE))
#define BITMAP_BITS (sizeof(BITMAP_WTYPE) * 8)
#define BITMAP_WMASK ((BITMAP_WTYPE)BITMAP_BITS - 1)
struct bitmap {
BITMAP_WTYPE *d;
size_t len; /* number of words allocated */
size_t top; /* index of top word allocated */
};
struct bitmap *
bitmap_new(void)
{
struct bitmap *ret;
if ((ret = calloc(1, sizeof(*ret))) == NULL)
return NULL;
if ((ret->d = calloc(1, BITMAP_BYTES)) == NULL) {
free(ret);
return NULL;
}
ret->len = 1;
ret->top = 0;
return ret;
}
void
bitmap_free(struct bitmap *b)
{
if (b != NULL && b->d != NULL) {
explicit_bzero(b->d, b->len);
free(b->d);
}
free(b);
}
void
bitmap_zero(struct bitmap *b)
{
memset(b->d, 0, b->len * BITMAP_BYTES);
b->top = 0;
}
int
bitmap_test_bit(struct bitmap *b, u_int n)
{
if (b->top >= b->len)
return 0; /* invalid */
if (b->len == 0 || (n / BITMAP_BITS) > b->top)
return 0;
return (b->d[n / BITMAP_BITS] >> (n & BITMAP_WMASK)) & 1;
}
static int
reserve(struct bitmap *b, u_int n)
{
BITMAP_WTYPE *tmp;
size_t nlen;
if (b->top >= b->len || n > BITMAP_MAX)
return -1; /* invalid */
nlen = (n / BITMAP_BITS) + 1;
if (b->len < nlen) {
if ((tmp = reallocarray(b->d, nlen, BITMAP_BYTES)) == NULL)
return -1;
b->d = tmp;
memset(b->d + b->len, 0, (nlen - b->len) * BITMAP_BYTES);
b->len = nlen;
}
return 0;
}
int
bitmap_set_bit(struct bitmap *b, u_int n)
{
int r;
size_t offset;
if ((r = reserve(b, n)) != 0)
return r;
offset = n / BITMAP_BITS;
if (offset > b->top)
b->top = offset;
b->d[offset] |= (BITMAP_WTYPE)1 << (n & BITMAP_WMASK);
return 0;
}
/* Resets b->top to point to the most significant bit set in b->d */
static void
retop(struct bitmap *b)
{
if (b->top >= b->len)
return;
while (b->top > 0 && b->d[b->top] == 0)
b->top--;
}
void
bitmap_clear_bit(struct bitmap *b, u_int n)
{
size_t offset;
if (b->top >= b->len || n > BITMAP_MAX)
return; /* invalid */
offset = n / BITMAP_BITS;
if (offset > b->top)
return;
b->d[offset] &= ~((BITMAP_WTYPE)1 << (n & BITMAP_WMASK));
/* The top may have changed as a result of the clear */
retop(b);
}
size_t
bitmap_nbits(struct bitmap *b)
{
size_t bits;
BITMAP_WTYPE w;
retop(b);
if (b->top >= b->len)
return 0; /* invalid */
if (b->len == 0 || (b->top == 0 && b->d[0] == 0))
return 0;
/* Find MSB set */
w = b->d[b->top];
bits = (b->top + 1) * BITMAP_BITS;
while (!(w & ((BITMAP_WTYPE)1 << (BITMAP_BITS - 1)))) {
w <<= 1;
bits--;
}
return bits;
}
size_t
bitmap_nbytes(struct bitmap *b)
{
return (bitmap_nbits(b) + 7) / 8;
}
int
bitmap_to_string(struct bitmap *b, void *p, size_t l)
{
u_char *s = (u_char *)p;
size_t i, j, k, need = bitmap_nbytes(b);
if (l < need || b->top >= b->len)
return -1;
if (l > need)
l = need;
/* Put the bytes from LSB backwards */
for (i = k = 0; i < b->top + 1; i++) {
for (j = 0; j < BITMAP_BYTES; j++) {
if (k >= l)
break;
s[need - 1 - k++] = (b->d[i] >> (j * 8)) & 0xff;
}
}
return 0;
}
int
bitmap_from_string(struct bitmap *b, const void *p, size_t l)
{
int r;
size_t i, offset, shift;
u_char *s = (u_char *)p;
if (l > BITMAP_MAX / 8)
return -1;
if ((r = reserve(b, l * 8)) != 0)
return r;
bitmap_zero(b);
if (l == 0)
return 0;
b->top = offset = ((l + (BITMAP_BYTES - 1)) / BITMAP_BYTES) - 1;
shift = ((l + (BITMAP_BYTES - 1)) % BITMAP_BYTES) * 8;
for (i = 0; i < l; i++) {
b->d[offset] |= (BITMAP_WTYPE)s[i] << shift;
if (shift == 0) {
offset--;
shift = BITMAP_BITS - 8;
} else
shift -= 8;
}
retop(b);
return 0;
}
|
