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63 lines
1.2 KiB
C++
63 lines
1.2 KiB
C++
/*
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LDPC SISO encoder
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Copyright 2018 Ahmet Inan <inan@aicodix.de>
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*/
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#ifndef LDPC_ENCODER_HH
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#define LDPC_ENCODER_HH
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namespace CODE {
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template <typename TABLE>
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class LDPCEncoder
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{
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static const int M = TABLE::M;
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static const int N = TABLE::N;
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static const int K = TABLE::K;
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static const int R = N-K;
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static const int q = R/M;
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static const int CNC = TABLE::LINKS_MAX_CN - 2;
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uint16_t pos[R * CNC];
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uint8_t cnc[R];
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public:
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LDPCEncoder()
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{
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for (int i = 0; i < R; ++i)
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cnc[i] = 0;
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int bit_pos = 0;
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const int *row_ptr = TABLE::POS;
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for (int g = 0; TABLE::LEN[g]; ++g) {
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int bit_deg = TABLE::DEG[g];
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for (int r = 0; r < TABLE::LEN[g]; ++r) {
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int acc_pos[bit_deg];
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for (int d = 0; d < bit_deg; ++d)
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acc_pos[d] = row_ptr[d];
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row_ptr += bit_deg;
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for (int j = 0; j < M; ++j) {
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for (int d = 0; d < bit_deg; ++d) {
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int n = acc_pos[d];
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pos[CNC*n+cnc[n]++] = bit_pos;
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}
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++bit_pos;
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for (int d = 0; d < bit_deg; ++d)
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acc_pos[d] = (acc_pos[d] + q) % R;
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}
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}
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}
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}
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void operator()(int8_t *data, int8_t *parity)
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{
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int8_t tmp = 1;
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for (int i = 0; i < R; ++i) {
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for (int j = 0; j < cnc[i]; ++j)
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tmp *= data[pos[CNC*i+j]];
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parity[i] = tmp;
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}
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}
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};
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}
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#endif
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