mirror of https://gerrit.osmocom.org/libosmocore
709 lines
18 KiB
C
709 lines
18 KiB
C
/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
|
|
* (C) 2012 Ivan Klyuchnikov
|
|
* (C) 2015 by sysmocom - s.f.m.c. GmbH
|
|
*
|
|
* All Rights Reserved
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*
|
|
* 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
|
|
* @{
|
|
* Osmocom bit vector abstraction utility routines.
|
|
*
|
|
* These functions assume a MSB (most significant bit) first layout of the
|
|
* bits, so that for instance the 5 bit number abcde (a is MSB) can be
|
|
* embedded into a byte sequence like in xxxxxxab cdexxxxx. The bit count
|
|
* starts with the MSB, so the bits in a byte are numbered (MSB) 01234567 (LSB).
|
|
* Note that there are other incompatible encodings, like it is used
|
|
* for the EGPRS RLC data block headers (there the bits are numbered from LSB
|
|
* to MSB).
|
|
*
|
|
* \file bitvec.c */
|
|
|
|
#include <errno.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <stdbool.h>
|
|
|
|
#include <osmocom/core/bits.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;
|
|
}
|
|
|
|
/*! 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
|
|
* \return value of the requested bit
|
|
*/
|
|
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
|
|
* \param[in] bv the bit vector on which to check
|
|
* \param[in] bitnr the bit number inside the bit vector to check
|
|
* \return value of the requested bit
|
|
*/
|
|
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
|
|
* \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;
|
|
}
|
|
|
|
/*! 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
|
|
* \returns 0 on success, negative value on error
|
|
*/
|
|
inline 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
|
|
* \param[in] bv bit vector to be used
|
|
* \param[in] bit value of the bit to be set
|
|
* \returns 0 on success, negative value on error
|
|
*/
|
|
inline 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
|
|
* \return value of th next bit in the vector */
|
|
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
|
|
* \param[in] bv bit vector
|
|
* \param[in] bits array of \ref bit_value
|
|
* \param[in] count number of bits to set
|
|
* \return 0 on success; negative in case of error */
|
|
int bitvec_set_bits(struct bitvec *bv, const enum bit_value *bits, unsigned 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.
|
|
* \param[in] bv bit vector.
|
|
* \param[in] v mask representing which bits needs to be set.
|
|
* \param[in] num_bits number of meaningful bits in the mask.
|
|
* \param[in] use_lh whether to interpret the bits as L/H values or as 0/1.
|
|
* \return 0 on success; negative in case of error. */
|
|
int bitvec_set_u64(struct bitvec *bv, uint64_t v, uint8_t num_bits, bool use_lh)
|
|
{
|
|
uint8_t i;
|
|
|
|
if (num_bits > 64)
|
|
return -E2BIG;
|
|
|
|
for (i = 0; i < num_bits; i++) {
|
|
int rc;
|
|
enum bit_value bit = use_lh ? L : 0;
|
|
|
|
if (v & ((uint64_t)1 << (num_bits - i - 1)))
|
|
bit = use_lh ? H : 1;
|
|
|
|
rc = bitvec_set_bit(bv, bit);
|
|
if (rc != 0)
|
|
return rc;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*! set multiple bits (based on numeric value) at current pos.
|
|
* \return 0 in case of success; negative in case of error. */
|
|
int bitvec_set_uint(struct bitvec *bv, unsigned int ui, unsigned int num_bits)
|
|
{
|
|
return bitvec_set_u64(bv, ui, num_bits, false);
|
|
}
|
|
|
|
/*! get multiple bits (num_bits) from beginning of vector (MSB side)
|
|
* \return 16bit signed integer retrieved from bit vector */
|
|
int16_t bitvec_get_int16_msb(const struct bitvec *bv, unsigned int num_bits)
|
|
{
|
|
if (num_bits > 15 || bv->cur_bit < num_bits)
|
|
return -EINVAL;
|
|
|
|
if (num_bits < 9)
|
|
return bv->data[0] >> (8 - num_bits);
|
|
|
|
return osmo_load16be(bv->data) >> (16 - num_bits);
|
|
}
|
|
|
|
/*! get multiple bits (based on numeric value) from current pos
|
|
* \return integer value retrieved from bit vector */
|
|
int bitvec_get_uint(struct bitvec *bv, unsigned 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;
|
|
}
|
|
|
|
/*! fill num_bits with \fill starting from the current position
|
|
* \return 0 on success; negative otherwise (out of vector boundary)
|
|
*/
|
|
int bitvec_fill(struct bitvec *bv, unsigned int num_bits, enum bit_value fill)
|
|
{
|
|
unsigned i, stop = bv->cur_bit + num_bits;
|
|
for (i = bv->cur_bit; i < stop; i++)
|
|
if (bitvec_set_bit(bv, fill) < 0)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*! pad all remaining bits up to num_bits
|
|
* \return 0 on success; negative otherwise */
|
|
int bitvec_spare_padding(struct bitvec *bv, unsigned int up_to_bit)
|
|
{
|
|
int n = up_to_bit - bv->cur_bit + 1;
|
|
if (n < 1)
|
|
return 0;
|
|
|
|
return bitvec_fill(bv, n, L);
|
|
}
|
|
|
|
/*! find first bit set in bit vector
|
|
* \return 0 on success; negative otherwise */
|
|
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;
|
|
}
|
|
|
|
/*! get multiple bytes from current pos
|
|
* Assumes MSB first encoding.
|
|
* \param[in] bv bit vector
|
|
* \param[in] bytes array
|
|
* \param[in] count number of bytes to copy
|
|
* \return 0 on success; negative otherwise
|
|
*/
|
|
int bitvec_get_bytes(struct bitvec *bv, uint8_t *bytes, unsigned int count)
|
|
{
|
|
int byte_offs = bytenum_from_bitnum(bv->cur_bit);
|
|
int bit_offs = bv->cur_bit % 8;
|
|
uint8_t c, last_c;
|
|
int i;
|
|
uint8_t *src;
|
|
|
|
if (byte_offs + count + (bit_offs ? 1 : 0) > bv->data_len)
|
|
return -EINVAL;
|
|
|
|
if (bit_offs == 0) {
|
|
memcpy(bytes, bv->data + byte_offs, count);
|
|
} else {
|
|
src = bv->data + byte_offs;
|
|
last_c = *(src++);
|
|
for (i = count; i > 0; i--) {
|
|
c = *(src++);
|
|
*(bytes++) =
|
|
(last_c << bit_offs) |
|
|
(c >> (8 - bit_offs));
|
|
last_c = c;
|
|
}
|
|
}
|
|
|
|
bv->cur_bit += count * 8;
|
|
return 0;
|
|
}
|
|
|
|
/*! set multiple bytes at current pos
|
|
* Assumes MSB first encoding.
|
|
* \param[in] bv bit vector
|
|
* \param[in] bytes array
|
|
* \param[in] count number of bytes to copy
|
|
* \return 0 on success; negative otherwise
|
|
*/
|
|
int bitvec_set_bytes(struct bitvec *bv, const uint8_t *bytes, unsigned int count)
|
|
{
|
|
int byte_offs = bytenum_from_bitnum(bv->cur_bit);
|
|
int bit_offs = bv->cur_bit % 8;
|
|
uint8_t c, last_c;
|
|
int i;
|
|
uint8_t *dst;
|
|
|
|
if (byte_offs + count + (bit_offs ? 1 : 0) > bv->data_len)
|
|
return -EINVAL;
|
|
|
|
if (bit_offs == 0) {
|
|
memcpy(bv->data + byte_offs, bytes, count);
|
|
} else if (count > 0) {
|
|
dst = bv->data + byte_offs;
|
|
/* Get lower bits of first dst byte */
|
|
last_c = *dst >> (8 - bit_offs);
|
|
for (i = count; i > 0; i--) {
|
|
c = *(bytes++);
|
|
*(dst++) =
|
|
(last_c << (8 - bit_offs)) |
|
|
(c >> bit_offs);
|
|
last_c = c;
|
|
}
|
|
/* Overwrite lower bits of N+1 dst byte */
|
|
*dst = (*dst & ((1 << (8 - bit_offs)) - 1)) |
|
|
(last_c << (8 - bit_offs));
|
|
}
|
|
|
|
bv->cur_bit += count * 8;
|
|
return 0;
|
|
}
|
|
|
|
/*! Allocate a bit vector
|
|
* \param[in] size Number of bits in the vector
|
|
* \param[in] ctx Context from which to allocate
|
|
* \return pointer to allocated vector; NULL in case of error */
|
|
struct bitvec *bitvec_alloc(unsigned int size, TALLOC_CTX *ctx)
|
|
{
|
|
struct bitvec *bv = talloc_zero(ctx, struct bitvec);
|
|
if (!bv)
|
|
return NULL;
|
|
|
|
bv->data = talloc_zero_array(bv, uint8_t, size);
|
|
if (!(bv->data)) {
|
|
talloc_free(bv);
|
|
return NULL;
|
|
}
|
|
|
|
bv->data_len = size;
|
|
bv->cur_bit = 0;
|
|
return bv;
|
|
}
|
|
|
|
/*! Free a bit vector (release its memory)
|
|
* \param[in] bit vector to free */
|
|
void bitvec_free(struct bitvec *bv)
|
|
{
|
|
talloc_free(bv->data);
|
|
talloc_free(bv);
|
|
}
|
|
|
|
/*! Export a bit vector to a buffer
|
|
* \param[in] bitvec (unpacked bits)
|
|
* \param[out] buffer for the unpacked bits
|
|
* \return number of bytes (= bits) copied */
|
|
unsigned int bitvec_pack(const struct bitvec *bv, uint8_t *buffer)
|
|
{
|
|
unsigned int i = 0;
|
|
for (i = 0; i < bv->data_len; i++)
|
|
buffer[i] = bv->data[i];
|
|
|
|
return i;
|
|
}
|
|
|
|
/*! Copy buffer of unpacked bits into bit vector
|
|
* \param[in] buffer unpacked input bits
|
|
* \param[out] bv unpacked bit vector
|
|
* \return number of bytes (= bits) copied */
|
|
unsigned int bitvec_unpack(struct bitvec *bv, const uint8_t *buffer)
|
|
{
|
|
unsigned int i = 0;
|
|
for (i = 0; i < bv->data_len; i++)
|
|
bv->data[i] = buffer[i];
|
|
|
|
return i;
|
|
}
|
|
|
|
/*! read hexadecimap string into a bit vector
|
|
* \param[in] src string containing hex digits
|
|
* \param[out] bv unpacked bit vector
|
|
* \return 0 in case of success; 1 in case of error
|
|
*/
|
|
int bitvec_unhex(struct bitvec *bv, const char *src)
|
|
{
|
|
unsigned i;
|
|
unsigned val;
|
|
unsigned write_index = 0;
|
|
unsigned digits = bv->data_len * 2;
|
|
|
|
for (i = 0; i < digits; i++) {
|
|
if (sscanf(src + i, "%1x", &val) < 1) {
|
|
return 1;
|
|
}
|
|
bitvec_write_field(bv, &write_index, val, 4);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*! read part of the vector
|
|
* \param[in] bv The boolean vector to work on
|
|
* \param[in,out] read_index Where reading supposed to start in the vector
|
|
* \param[in] len How many bits to read from vector
|
|
* \returns read bits or negative value on error
|
|
*/
|
|
uint64_t bitvec_read_field(struct bitvec *bv, unsigned int *read_index, unsigned int len)
|
|
{
|
|
unsigned int i;
|
|
uint64_t ui = 0;
|
|
bv->cur_bit = *read_index;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
int bit = bitvec_get_bit_pos((const struct bitvec *)bv, bv->cur_bit);
|
|
if (bit < 0)
|
|
return bit;
|
|
if (bit)
|
|
ui |= ((uint64_t)1 << (len - i - 1));
|
|
bv->cur_bit++;
|
|
}
|
|
*read_index += len;
|
|
return ui;
|
|
}
|
|
|
|
/*! write into the vector
|
|
* \param[in] bv The boolean vector to work on
|
|
* \param[in,out] write_index Where writing supposed to start in the vector
|
|
* \param[in] len How many bits to write
|
|
* \returns next write index or negative value on error
|
|
*/
|
|
int bitvec_write_field(struct bitvec *bv, unsigned int *write_index, uint64_t val, unsigned int len)
|
|
{
|
|
int rc;
|
|
|
|
bv->cur_bit = *write_index;
|
|
|
|
rc = bitvec_set_u64(bv, val, len, false);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
*write_index += len;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*! convert enum to corresponding character
|
|
* \param v input value (bit)
|
|
* \return single character, either 0, 1, L or H */
|
|
char bit_value_to_char(enum bit_value v)
|
|
{
|
|
switch (v) {
|
|
case ZERO: return '0';
|
|
case ONE: return '1';
|
|
case L: return 'L';
|
|
case H: return 'H';
|
|
default: abort();
|
|
}
|
|
}
|
|
|
|
/*! prints bit vector to provided string
|
|
* It's caller's responsibility to ensure that we won't shoot him in the foot:
|
|
* the provided buffer should be at lest cur_bit + 1 bytes long
|
|
*/
|
|
void bitvec_to_string_r(const struct bitvec *bv, char *str)
|
|
{
|
|
unsigned i, pos = 0;
|
|
char *cur = str;
|
|
for (i = 0; i < bv->cur_bit; i++) {
|
|
if (0 == i % 8)
|
|
*cur++ = ' ';
|
|
*cur++ = bit_value_to_char(bitvec_get_bit_pos(bv, i));
|
|
pos++;
|
|
}
|
|
*cur = 0;
|
|
}
|
|
|
|
/* we assume that x have at least 1 non-b bit */
|
|
static inline unsigned leading_bits(uint8_t x, bool b)
|
|
{
|
|
if (b) {
|
|
if (x < 0x80) return 0;
|
|
if (x < 0xC0) return 1;
|
|
if (x < 0xE0) return 2;
|
|
if (x < 0xF0) return 3;
|
|
if (x < 0xF8) return 4;
|
|
if (x < 0xFC) return 5;
|
|
if (x < 0xFE) return 6;
|
|
} else {
|
|
if (x > 0x7F) return 0;
|
|
if (x > 0x3F) return 1;
|
|
if (x > 0x1F) return 2;
|
|
if (x > 0xF) return 3;
|
|
if (x > 7) return 4;
|
|
if (x > 3) return 5;
|
|
if (x > 1) return 6;
|
|
}
|
|
return 7;
|
|
}
|
|
/*! force bit vector to all 0 and current bit to the beginnig of the vector */
|
|
void bitvec_zero(struct bitvec *bv)
|
|
{
|
|
bv->cur_bit = 0;
|
|
memset(bv->data, 0, bv->data_len);
|
|
}
|
|
|
|
/*! Return number (bits) of uninterrupted bit run in vector starting from the MSB
|
|
* \param[in] bv The boolean vector to work on
|
|
* \param[in] b The boolean, sequence of which is looked at from the vector start
|
|
* \returns Number of consecutive bits of \p b in \p bv
|
|
*/
|
|
unsigned bitvec_rl(const struct bitvec *bv, bool b)
|
|
{
|
|
unsigned i;
|
|
for (i = 0; i < (bv->cur_bit % 8 ? bv->cur_bit / 8 + 1 : bv->cur_bit / 8); i++) {
|
|
if ( (b ? 0xFF : 0) != bv->data[i])
|
|
return i * 8 + leading_bits(bv->data[i], b);
|
|
}
|
|
|
|
return bv->cur_bit;
|
|
}
|
|
|
|
/*! Return number (bits) of uninterrupted bit run in vector
|
|
* starting from the current bit
|
|
* \param[in] bv The boolean vector to work on
|
|
* \param[in] b The boolean, sequence of 1's or 0's to be checked
|
|
* \param[in] max_bits Total Number of Uncmopresed bits
|
|
* \returns Number of consecutive bits of \p b in \p bv and cur_bit will
|
|
* \go to cur_bit + number of consecutive bit
|
|
*/
|
|
unsigned bitvec_rl_curbit(struct bitvec *bv, bool b, int max_bits)
|
|
{
|
|
unsigned i = 0;
|
|
unsigned j = 8;
|
|
int temp_res = 0;
|
|
int count = 0;
|
|
unsigned readIndex = bv->cur_bit;
|
|
unsigned remaining_bits = max_bits % 8;
|
|
unsigned remaining_bytes = max_bits / 8;
|
|
unsigned byte_mask = 0xFF;
|
|
|
|
if (readIndex % 8) {
|
|
for (j -= (readIndex % 8) ; j > 0 ; j--) {
|
|
if (readIndex < max_bits && bitvec_read_field(bv, &readIndex, 1) == b)
|
|
temp_res++;
|
|
else {
|
|
bv->cur_bit--;
|
|
return temp_res;
|
|
}
|
|
}
|
|
}
|
|
for (i = (readIndex / 8);
|
|
i < (remaining_bits ? remaining_bytes + 1 : remaining_bytes);
|
|
i++, count++) {
|
|
if ((b ? byte_mask : 0) != bv->data[i]) {
|
|
bv->cur_bit = (count * 8 +
|
|
leading_bits(bv->data[i], b) + readIndex);
|
|
return count * 8 +
|
|
leading_bits(bv->data[i], b) + temp_res;
|
|
}
|
|
}
|
|
bv->cur_bit = (temp_res + (count * 8)) + readIndex;
|
|
if (bv->cur_bit > max_bits)
|
|
bv->cur_bit = max_bits;
|
|
return (bv->cur_bit - readIndex + temp_res);
|
|
}
|
|
|
|
/*! Shifts bitvec to the left, n MSB bits lost */
|
|
void bitvec_shiftl(struct bitvec *bv, unsigned n)
|
|
{
|
|
if (0 == n)
|
|
return;
|
|
if (n >= bv->cur_bit) {
|
|
bitvec_zero(bv);
|
|
return;
|
|
}
|
|
|
|
memmove(bv->data, bv->data + n / 8, bv->data_len - n / 8);
|
|
|
|
uint8_t tmp[2];
|
|
unsigned i;
|
|
for (i = 0; i < bv->data_len - 2; i++) {
|
|
uint16_t t = osmo_load16be(bv->data + i);
|
|
osmo_store16be(t << (n % 8), &tmp);
|
|
bv->data[i] = tmp[0];
|
|
}
|
|
|
|
bv->data[bv->data_len - 1] <<= (n % 8);
|
|
bv->cur_bit -= n;
|
|
}
|
|
|
|
/*! Add given array to bitvec
|
|
* \param[in,out] bv bit vector to work with
|
|
* \param[in] array elements to be added
|
|
* \param[in] array_len length of array
|
|
* \param[in] dry_run indicates whether to return number of bits required
|
|
* instead of adding anything to bv for real
|
|
* \param[in] num_bits number of bits to consider in each element of array
|
|
* \returns number of bits necessary to add array elements if dry_run is true,
|
|
* 0 otherwise (only in this case bv is actually changed)
|
|
*
|
|
* N. B: no length checks are performed on bv - it's caller's job to ensure
|
|
* enough space is available - for example by calling with dry_run = true first.
|
|
*
|
|
* Useful for common pattern in CSN.1 spec which looks like:
|
|
* { 1 < XXX : bit (num_bits) > } ** 0
|
|
* which means repeat any times (between 0 and infinity),
|
|
* start each repetition with 1, mark end of repetitions with 0 bit
|
|
* see app. note in 3GPP TS 24.007 § B.2.1 Rule A2
|
|
*/
|
|
unsigned int bitvec_add_array(struct bitvec *bv, const uint32_t *array,
|
|
unsigned int array_len, bool dry_run,
|
|
unsigned int num_bits)
|
|
{
|
|
unsigned i, bits = 1; /* account for stop bit */
|
|
for (i = 0; i < array_len; i++) {
|
|
if (dry_run) {
|
|
bits += (1 + num_bits);
|
|
} else {
|
|
bitvec_set_bit(bv, 1);
|
|
bitvec_set_uint(bv, array[i], num_bits);
|
|
}
|
|
}
|
|
|
|
if (dry_run)
|
|
return bits;
|
|
|
|
bitvec_set_bit(bv, 0); /* stop bit - end of the sequence */
|
|
return 0;
|
|
}
|
|
|
|
/*! @} */
|