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sdrangel/plugins/channelrx/demoddatv/ldpctool/encoder2.h

99 lines
2.7 KiB
C++

///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
// //
// 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 as version 3 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 V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////////
/*
LDPC SISO encoder v2
Copyright 2018 Ahmet Inan <xdsopl@gmail.com>
*/
#ifndef ENCODER_HH
#define ENCODER_HH
#include "ldpc.h"
namespace ldpctool {
template <typename TYPE>
class LDPCEncoder
{
uint16_t *pos;
uint8_t *cnc;
int R, CNL;
bool initialized;
TYPE one()
{
return 1;
}
TYPE sign(TYPE a, TYPE b)
{
return b < TYPE(0) ? -a : b > TYPE(0) ? a : TYPE(0);
}
public:
LDPCEncoder() : initialized(false)
{
}
void init(LDPCInterface *it)
{
if (initialized) {
delete[] pos;
delete[] cnc;
}
initialized = true;
LDPCInterface *ldpc = it->clone();
int N = ldpc->code_len();
int K = ldpc->data_len();
R = N - K;
CNL = ldpc->links_max_cn() - 2;
pos = new uint16_t[R * CNL];
cnc = new uint8_t[R];
for (int i = 0; i < R; ++i)
cnc[i] = 0;
ldpc->first_bit();
for (int j = 0; j < K; ++j) {
int *acc_pos = ldpc->acc_pos();
int bit_deg = ldpc->bit_deg();
for (int n = 0; n < bit_deg; ++n) {
int i = acc_pos[n];
pos[CNL*i+cnc[i]++] = j;
}
ldpc->next_bit();
}
delete ldpc;
}
void operator()(TYPE *data, TYPE *parity)
{
TYPE tmp = one();
for (int i = 0; i < R; ++i) {
for (int j = 0; j < cnc[i]; ++j)
tmp = sign(tmp, data[pos[CNL*i+j]]);
parity[i] = tmp;
}
}
~LDPCEncoder()
{
if (initialized) {
delete[] pos;
delete[] cnc;
}
}
};
} // namespace ldpctool
#endif