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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
|
/* bit vector utility routines */
/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
*
* 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 as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
/*! \addtogroup bitvec
* @{
*/
/*! \file bitvec.c
* \brief Osmocom bit vector abstraction
*/
#include <errno.h>
#include <stdint.h>
#include <osmocom/core/bitvec.h>
#define BITNUM_FROM_COMP(byte, bit) ((byte*8)+bit)
static inline unsigned int bytenum_from_bitnum(unsigned int bitnum)
{
unsigned int bytenum = bitnum / 8;
return bytenum;
}
/* convert ZERO/ONE/L/H to a bitmask at given pos in a byte */
static uint8_t bitval2mask(enum bit_value bit, uint8_t bitnum)
{
int bitval;
switch (bit) {
case ZERO:
bitval = (0 << bitnum);
break;
case ONE:
bitval = (1 << bitnum);
break;
case L:
bitval = ((0x2b ^ (0 << bitnum)) & (1 << bitnum));
break;
case H:
bitval = ((0x2b ^ (1 << bitnum)) & (1 << bitnum));
break;
default:
return 0;
}
return bitval;
}
/*! \brief check if the bit is 0 or 1 for a given position inside a bitvec
* \param[in] bv the bit vector on which to check
* \param[in] bitnr the bit number inside the bit vector to check
* \returns
*/
enum bit_value bitvec_get_bit_pos(const struct bitvec *bv, unsigned int bitnr)
{
unsigned int bytenum = bytenum_from_bitnum(bitnr);
unsigned int bitnum = 7 - (bitnr % 8);
uint8_t bitval;
if (bytenum >= bv->data_len)
return -EINVAL;
bitval = bitval2mask(ONE, bitnum);
if (bv->data[bytenum] & bitval)
return ONE;
return ZERO;
}
/*! \brief check if the bit is L or H for a given position inside a bitvec
* \param[in] bv the bit vector on which to check
* \param[in] bitnr the bit number inside the bit vector to check
*/
enum bit_value bitvec_get_bit_pos_high(const struct bitvec *bv,
unsigned int bitnr)
{
unsigned int bytenum = bytenum_from_bitnum(bitnr);
unsigned int bitnum = 7 - (bitnr % 8);
uint8_t bitval;
if (bytenum >= bv->data_len)
return -EINVAL;
bitval = bitval2mask(H, bitnum);
if ((bv->data[bytenum] & (1 << bitnum)) == bitval)
return H;
return L;
}
/*! \brief get the Nth set bit inside the bit vector
* \param[in] bv the bit vector to use
* \param[in] n the bit number to get
* \returns the bit number (offset) of the Nth set bit in \a bv
*/
unsigned int bitvec_get_nth_set_bit(const struct bitvec *bv, unsigned int n)
{
unsigned int i, k = 0;
for (i = 0; i < bv->data_len*8; i++) {
if (bitvec_get_bit_pos(bv, i) == ONE) {
k++;
if (k == n)
return i;
}
}
return 0;
}
/*! \brief set a bit at given position in a bit vector
* \param[in] bv bit vector on which to operate
* \param[in] bitnr number of bit to be set
* \param[in] bit value to which the bit is to be set
*/
int bitvec_set_bit_pos(struct bitvec *bv, unsigned int bitnr,
enum bit_value bit)
{
unsigned int bytenum = bytenum_from_bitnum(bitnr);
unsigned int bitnum = 7 - (bitnr % 8);
uint8_t bitval;
if (bytenum >= bv->data_len)
return -EINVAL;
/* first clear the bit */
bitval = bitval2mask(ONE, bitnum);
bv->data[bytenum] &= ~bitval;
/* then set it to desired value */
bitval = bitval2mask(bit, bitnum);
bv->data[bytenum] |= bitval;
return 0;
}
/*! \brief set the next bit inside a bitvec
* \param[in] bv bit vector to be used
* \param[in] bit value of the bit to be set
*/
int bitvec_set_bit(struct bitvec *bv, enum bit_value bit)
{
int rc;
rc = bitvec_set_bit_pos(bv, bv->cur_bit, bit);
if (!rc)
bv->cur_bit++;
return rc;
}
/*! \brief get the next bit (low/high) inside a bitvec */
int bitvec_get_bit_high(struct bitvec *bv)
{
int rc;
rc = bitvec_get_bit_pos_high(bv, bv->cur_bit);
if (rc >= 0)
bv->cur_bit++;
return rc;
}
/*! \brief set multiple bits (based on array of bitvals) at current pos
* \param[in] bv bit vector
* \param[in] bits array of \ref bit_value
* \param[in] count number of bits to set
*/
int bitvec_set_bits(struct bitvec *bv, enum bit_value *bits, int count)
{
int i, rc;
for (i = 0; i < count; i++) {
rc = bitvec_set_bit(bv, bits[i]);
if (rc)
return rc;
}
return 0;
}
/*! \brief set multiple bits (based on numeric value) at current pos */
int bitvec_set_uint(struct bitvec *bv, unsigned int ui, int num_bits)
{
int i, rc;
for (i = 0; i < num_bits; i++) {
int bit = 0;
if (ui & (1 << (num_bits - i - 1)))
bit = 1;
rc = bitvec_set_bit(bv, bit);
if (rc)
return rc;
}
return 0;
}
/*! \brief get multiple bits (based on numeric value) from current pos */
int bitvec_get_uint(struct bitvec *bv, int num_bits)
{
int i;
unsigned int ui = 0;
for (i = 0; i < num_bits; i++) {
int bit = bitvec_get_bit_pos(bv, bv->cur_bit);
if (bit < 0)
return bit;
if (bit)
ui |= (1 << (num_bits - i - 1));
bv->cur_bit++;
}
return ui;
}
/*! \brief pad all remaining bits up to num_bits */
int bitvec_spare_padding(struct bitvec *bv, unsigned int up_to_bit)
{
unsigned int i;
for (i = bv->cur_bit; i <= up_to_bit; i++)
bitvec_set_bit(bv, L);
return 0;
}
/*! \brief find first bit set in bit vector */
int bitvec_find_bit_pos(const struct bitvec *bv, unsigned int n,
enum bit_value val)
{
unsigned int i;
for (i = n; i < bv->data_len*8; i++) {
if (bitvec_get_bit_pos(bv, i) == val)
return i;
}
return -1;
}
/*! @} */
|
