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

136 lines
3.3 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 table iterator
Copyright 2018 Ahmet Inan <xdsopl@gmail.com>
*/
#ifndef LDPC_HH
#define LDPC_HH
namespace ldpctool {
struct LDPCInterface
{
virtual LDPCInterface *clone() = 0;
virtual int code_len() = 0;
virtual int data_len() = 0;
virtual int group_len() = 0;
virtual int links_total() = 0;
virtual int links_max_cn() = 0;
virtual int bit_deg() = 0;
virtual int *acc_pos() = 0;
virtual void first_bit() = 0;
virtual void next_bit() = 0;
virtual ~LDPCInterface() = default;
static const char *mc_tabnames[2][32];
};
template <typename TABLE>
class LDPC : public LDPCInterface
{
static const int M = TABLE::M;
static const int N = TABLE::N;
static const int K = TABLE::K;
static const int R = N-K;
static const int q = R/M;
int acc_pos_[TABLE::DEG_MAX];
const int *row_ptr;
int bit_deg_;
int grp_num;
int grp_len;
int grp_cnt;
int row_cnt;
void next_group()
{
if (grp_cnt >= grp_len) {
grp_len = TABLE::LEN[grp_num];
bit_deg_ = TABLE::DEG[grp_num];
grp_cnt = 0;
++grp_num;
}
for (int i = 0; i < bit_deg_; ++i)
acc_pos_[i] = row_ptr[i];
row_ptr += bit_deg_;
++grp_cnt;
}
public:
LDPCInterface *clone()
{
return new LDPC<TABLE>();
}
int code_len()
{
return N;
}
int data_len()
{
return K;
}
int group_len()
{
return M;
}
int links_total()
{
return TABLE::LINKS_TOTAL;
}
int links_max_cn()
{
return TABLE::LINKS_MAX_CN;
}
int bit_deg()
{
return bit_deg_;
}
int *acc_pos()
{
return acc_pos_;
}
void next_bit()
{
if (++row_cnt < M) {
for (int i = 0; i < bit_deg_; ++i)
acc_pos_[i] += q;
for (int i = 0; i < bit_deg_; ++i)
acc_pos_[i] %= R;
} else {
next_group();
row_cnt = 0;
}
}
void first_bit()
{
grp_num = 0;
grp_len = 0;
grp_cnt = 0;
row_cnt = 0;
row_ptr = TABLE::POS;
next_group();
}
};
LDPCInterface *create_ldpc(char *standard, char prefix, int number);
} // namespace ldpctool
#endif