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C

/**
*
* \section COPYRIGHT
*
* Copyright 2013-2014 The libLTE Developers. See the
* COPYRIGHT file at the top-level directory of this distribution.
*
* \section LICENSE
*
* This file is part of the libLTE library.
*
* libLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* libLTE 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 Lesser General Public License for more details.
*
* A copy of the GNU Lesser 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 <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include "liblte/phy/fec/convcoder.h"
#include "parity.h"
int convcoder_encode(convcoder_t *q, char *input, char *output, uint32_t frame_length) {
uint32_t sr;
uint32_t i,j;
uint32_t len = q->tail_biting ? frame_length : (frame_length + q->K - 1);
if (q != NULL &&
input != NULL &&
output != NULL &&
frame_length > q->K + 1)
{
if (q->tail_biting) {
sr = 0;
for (i=frame_length - q->K + 1; i<frame_length; i++) {
sr = (sr << 1) | (input[i] & 1);
}
} else {
sr = 0;
}
for (i = 0; i < len; i++) {
char bit = (i < frame_length) ? (input[i] & 1) : 0;
sr = (sr << 1) | bit;
for (j=0;j<q->R;j++) {
output[q->R * i + j] = parity(sr & q->poly[j]);
}
}
return q->R*len;
} else {
return LIBLTE_ERROR_INVALID_INPUTS;
}
}
int convcoder_initialize(convcoder_hl* h) {
return 0;
}
int convcoder_work(convcoder_hl* hl) {
hl->obj.K = hl->ctrl_in.constraint_length;
hl->obj.R = hl->ctrl_in.rate;
hl->obj.poly[0] = hl->ctrl_in.generator_0;
hl->obj.poly[1] = hl->ctrl_in.generator_1;
hl->obj.poly[2] = hl->ctrl_in.generator_2;
hl->obj.tail_biting = hl->ctrl_in.tail_bitting?true:false;
hl->out_len = convcoder_encode(&hl->obj, hl->input, hl->output, hl->in_len);
return 0;
}
int convcoder_stop(convcoder_hl* h) {
return 0;
}