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/* 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.
*
*/
#include <errno.h>
#include <stdint.h>
#include <osmocore/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;
}
/* check if the bit is 0 or 1 for a given position inside a bitvec */
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;
}
/* check if the bit is L or H for a given position inside a bitvec */
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;
}
/* get the Nth set bit inside the bit vector */
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;
}
/* set the bit at a given position inside a bitvec */
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;
}
/* set the next bit inside a bitvec */
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;
}
/* 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;
}
/* set multiple bits (based on array of bitvals) at current pos */
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;
}
/* 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;
}
/* 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;
}
/* 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;
}
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