srsRAN_4G/srslte/lib/scrambling/scrambling.c

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2015 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of the srsLTE library.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE 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 Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "srslte/utils/bit.h"
#include "srslte/utils/vector.h"
#include "srslte/scrambling/scrambling.h"

void srslte_scrambling_f(srslte_sequence_t *s, float *data) {
  srslte_scrambling_f_offset(s, data, 0, s->len);
}

void srslte_scrambling_f_offset(srslte_sequence_t *s, float *data, int offset, int len) {
  assert (len + offset <= s->len);
  srslte_vec_prod_fff(data, &s->c_float[offset], data, len);
}

void srslte_scrambling_s(srslte_sequence_t *s, short *data) {
  srslte_scrambling_s_offset(s, data, 0, s->len);
}

void srslte_scrambling_s_offset(srslte_sequence_t *s, short *data, int offset, int len) {
  assert (len + offset <= s->len);
  srslte_vec_prod_sss(data, &s->c_short[offset], data, len);
}

void srslte_scrambling_c(srslte_sequence_t *s, cf_t *data) {
  srslte_scrambling_c_offset(s, data, 0, s->len);
}

void srslte_scrambling_c_offset(srslte_sequence_t *s, cf_t *data, int offset, int len) {
  assert (len + offset <= s->len);
  srslte_vec_prod_cfc(data, &s->c_float[offset], data, len);
}

void scrambling_b(uint8_t *c, uint8_t *data, int len) {
  int i;  
  for (i = 0; i < len; i++) {
    data[i] = (data[i] ^ c[i]);
  }  
}

void scrambling_b_word(uint8_t *c, uint8_t *data, int len) {
  // Do XOR every 64 bits 
  // FIXME: Use 32-bit in 32-bit machines
  uint64_t *x = (uint64_t*) data; 
  uint64_t *y = (uint64_t*) c;
  for (int i=0;i<len/8;i++) {
    x[i] = (x[i] ^ y[i]);
  }
  
  // Do XOR every 8 bits
  scrambling_b(&c[8*(len/8)], &data[8*(len/8)], len%8);
}


void srslte_scrambling_b(srslte_sequence_t *s, uint8_t *data) {
  scrambling_b_word(s->c, data, s->len);  
}

void srslte_scrambling_b_offset(srslte_sequence_t *s, uint8_t *data, int offset, int len) {
  if (offset%8) {
    // Do not load words if offset is not word-aligned
    scrambling_b(&s->c[offset], data, len);
  } else {
    scrambling_b_word(&s->c[offset], data, len);      
  }
}

void srslte_scrambling_bytes(srslte_sequence_t *s, uint8_t *data, int len) {
  scrambling_b_word(s->c_bytes, data, len/8);  
  // Scramble last bits
  if (len%8) {
    uint8_t tmp_bits[8];
    srslte_bit_unpack_vector(&data[len/8], tmp_bits, len%8);
    scrambling_b(&s->c[8*(len/8)], tmp_bits, len%8);
    srslte_bit_pack_vector(tmp_bits, &data[len/8], len%8);
  }    
}