mirror of https://github.com/PentHertz/srsLTE.git
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2015 Software Radio Systems Limited
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*
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* \section LICENSE
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*
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* This file is part of the srsLTE library.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <sys/time.h>
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#include <stdlib.h>
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#include <strings.h>
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#include "srslte/io/binsource.h"
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#include "srslte/utils/bit.h"
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#define DIV(a,b) ((a-1)/b+1)
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/* Internal functions */
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static int gen_seq_buff(srslte_binsource_t* q, int nwords) {
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if (q->seq_buff_nwords != nwords) {
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free(q->seq_buff);
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q->seq_buff_nwords = 0;
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}
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if (!q->seq_buff_nwords) {
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q->seq_buff = malloc(nwords*sizeof(uint32_t));
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if (!q->seq_buff) {
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return -1;
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}
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q->seq_buff_nwords = nwords;
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}
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for (int i=0;i<q->seq_buff_nwords;i++) {
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q->seq_buff[i] = rand_r(&q->seed);
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}
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return 0;
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}
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/* Low-level API */
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/**
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* Initializes the binsource object.
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*/
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void srslte_binsource_init(srslte_binsource_t* q) {
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bzero((void*) q,sizeof(srslte_binsource_t));
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}
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/**
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* Destroys binsource object
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*/
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void srslte_binsource_free(srslte_binsource_t* q) {
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if (q->seq_buff) {
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free(q->seq_buff);
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}
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bzero(q, sizeof(srslte_binsource_t));
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}
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/**
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* Sets a new seed
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*/
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void srslte_binsource_seed_set(srslte_binsource_t* q, uint32_t seed) {
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q->seed = seed;
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}
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/**
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* Sets local time as seed.
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*/
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void srslte_binsource_seed_time(srslte_binsource_t *q) {
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struct timeval t1;
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gettimeofday(&t1, NULL);
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q->seed = t1.tv_usec * t1.tv_sec;
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}
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/**
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* Generates a sequence of nbits random bits
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*/
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int srslte_binsource_cache_gen(srslte_binsource_t* q, int nbits) {
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if (gen_seq_buff(q,DIV(nbits,32))) {
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return -1;
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}
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q->seq_cache_nbits = nbits;
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q->seq_cache_rp = 0;
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return 0;
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}
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static int int_2_bits(uint32_t* src, uint8_t* dst, int nbits) {
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int n;
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n=nbits/32;
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for (int i=0;i<n;i++) {
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srslte_bit_unpack(src[i],&dst,32);
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}
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srslte_bit_unpack(src[n],&dst,nbits-n*32);
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return n;
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}
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/**
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* Copies the next random bits to the buffer bits from the array generated by srslte_binsource_cache_gen
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*/
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void srslte_binsource_cache_cpy(srslte_binsource_t* q, uint8_t *bits, int nbits) {
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q->seq_cache_rp += int_2_bits(&q->seq_buff[q->seq_cache_rp],bits,nbits);
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}
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/**
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* Stores in the bits buffer a sequence of nbits pseudo-random bits.
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* Overwrites the bits generated using srslte_binsource_cache_gen.
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*/
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int srslte_binsource_generate(srslte_binsource_t* q, uint8_t *bits, int nbits) {
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if (gen_seq_buff(q,DIV(nbits,32))) {
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return -1;
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}
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int_2_bits(q->seq_buff,bits,nbits);
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return 0;
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}
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