osmo-msc/openbsc/src/bitvec.c

124 lines
2.5 KiB
C

/* 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 <sys/types.h>
#include <openbsc/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;
}
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);
u_int8_t bitval;
if (bytenum >= bv->data_len)
return -EINVAL;
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 -EINVAL;
}
/* first clear the bit */
bv->data[bytenum] &= ~(1 << bitnum);
/* then set it to desired value */
bv->data[bytenum] |= bitval;
return 0;
}
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;
}
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;
}
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;
}
/* 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;
}