| /* (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 <stdlib.h> |
| #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 ยง 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; |
| } |
| |
| /*! @} */ |