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
|
/*
* Copyright (c) 2018-2024 Free Software Foundation, Inc.
*
* This file is part of libwget.
*
* Libwget is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Libwget 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with libwget. If not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <wget.h>
#include "private.h"
/**
* \file
* \brief Functions for bitmap
* \defgroup libwget-bitmap Bitmap management functions
*
* @{
*
* Bitmap (bit array) implementation.
*
* This is useful when you need a bitmap with more than 64 bits. Up to 64 bits you can
* use the C99 uint64_t as a standard C bitfield.
*
* As a usage example, Wget2 uses bitmaps for options with lists of HTTP status codes, which have values
* of 100-699.
*
*/
#define bitmap_type uint64_t
#define bitmap_bits (sizeof(bitmap_type) * 8)
#define bitmap_shift 6 // ln(bitmap_bits)/ln(2)
#define map(n) (((wget_bitmap *)b)->map[(n) >> bitmap_shift])
#define bit(n) (((bitmap_type) 1) << ((n) & (bitmap_bits - 1)))
struct wget_bitmap_st {
bitmap_type
bits;
bitmap_type
map[];
};
/**
* \param b Bitmap to act on
* \param n Number of the bit to set (0-...)
*
* Set the bit \p n in the bitmap \p b.
*/
void wget_bitmap_set(wget_bitmap *b, unsigned n)
{
if (b && n < ((wget_bitmap *) b)->bits)
map(n) |= bit(n);
}
/**
* \param b Bitmap to act on
* \param n Number of the bit to clear (0-...)
*
* Clear the bit \p n in the bitmap \p b.
*/
void wget_bitmap_clear(wget_bitmap *b, unsigned n)
{
if (b && n < ((wget_bitmap *) b)->bits)
map(n) &= ~bit(n);
}
/**
* \param[in] b Bitmap to read from
* \param[in] n Number of the bit of interest (0-...)
* \return
* 0 if bit \p n is cleared or if \p n is out of range
* 1 if bit \p is set
*
* Returns whether the bit \p n is set or not.
*/
bool wget_bitmap_get(const wget_bitmap *b, unsigned n)
{
if (b && n < ((wget_bitmap *) b)->bits)
return (map(n) & bit(n)) != 0;
return 0;
}
/**
* \param[out] b Pointer to the allocated bitmap
* \param[in] bits Number of bits
* \return A \ref wget_error value
*
* Allocates a bitmap with a capacity of \p bits.
* It must be freed by wget_bitmap_free() after usage.
*/
int wget_bitmap_init(wget_bitmap **b, unsigned bits)
{
if (!b)
return WGET_E_INVALID;
wget_bitmap *_b =
wget_calloc((bits + sizeof(bitmap_type) - 1) / sizeof(bitmap_type) + 1, sizeof(bitmap_type));
if (!_b)
return WGET_E_MEMORY;
_b->bits = bits;
*b = _b;
return WGET_E_SUCCESS;
}
/**
* \param[in] b Pointer to bitmap to free
*
* Frees and clears the bitmap pointed to by \p b.
*/
void wget_bitmap_free(wget_bitmap **b)
{
if (b)
xfree(*b);
}
/** @} */
|
