kopia lustrzana https://github.com/projecthorus/wenet
111 wiersze
2.4 KiB
C
111 wiersze
2.4 KiB
C
/*
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LDPC Encoder, using a 'RA' encoder written by Bill Cowley VK5DSP in March 2016.
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Compile with:
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gcc -fPIC -shared -o ldpc_enc.so ldpc_enc.c
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*/
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#include<stdio.h>
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#include<string.h>
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#include<stdlib.h>
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/*
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LDPC Encoder Functions
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*/
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#define Nibits 2064
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#define Npbits 516
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#define Nwt 12
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unsigned short hrows[] = {
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// read from file created via make_Hrows_txt.m
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// use the new code of March 2016
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#include "Hrow2064.txt"
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};
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void encode(unsigned char *ibits, unsigned char *pbits) {
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unsigned int p, i, tmp, par, prev=0;
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char c;
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for (p=0; p<Npbits; p++) {
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par =0;
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for (i=0; i<Nwt; i++)
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par = par + ibits[hrows[p*Nwt+i]-1];
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// -1 as matlab arrays start from 1, C from 0
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tmp = par + prev;
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//printf(" p ind %d, parity %d \n", p, tmp);
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//c = getchar();
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tmp &= 1; // only retain the lsb
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prev = tmp;
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pbits[p] =tmp;
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}
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}
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/*
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Diagonal Interleaver Functions
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From fldigi
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Copyright (C) 2006
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Dave Freese, W1HKJ
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*/
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#define INTERLEAVE_FWD 0
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#define INTERLEAVE_REV 1
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#define PUNCTURE 0
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#define INTERLEAVER_SIZE 256
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#define INTERLEAVER_DEPTH 10
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int len, interleaver_direction = 0;
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unsigned char interleaver_table[INTERLEAVER_SIZE*INTERLEAVER_SIZE*INTERLEAVER_DEPTH];
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// Helper function for accessing interleaver table.
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unsigned char *tab(int i, int j, int k) {
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return &interleaver_table[(INTERLEAVER_SIZE * INTERLEAVER_SIZE * i) + (INTERLEAVER_SIZE * j) + k];
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}
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void interleaver_flush(void)
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{
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// Fill entire RX interleaver with punctures or 0 depending on whether
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// Rx or Tx
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if (interleaver_direction == INTERLEAVE_REV)
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memset(interleaver_table, 0, len);
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else
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memset(interleaver_table, PUNCTURE, len);
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}
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void interleave_symbols(unsigned char *psyms)
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{
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int i, j, k;
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for (k = 0; k < INTERLEAVER_DEPTH; k++) {
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for (i = 0; i < INTERLEAVER_SIZE; i++)
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for (j = 0; j < INTERLEAVER_SIZE - 1; j++)
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*tab(k, i, j) = *tab(k, i, j + 1);
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for (i = 0; i < INTERLEAVER_SIZE; i++)
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*tab(k, i, INTERLEAVER_SIZE - 1) = psyms[i];
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for (i = 0; i < INTERLEAVER_SIZE; i++) {
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if (interleaver_direction == INTERLEAVE_FWD)
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psyms[i] = *tab(k, i, INTERLEAVER_SIZE - i - 1);
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else
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psyms[i] = *tab(k, i, i);
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}
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}
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}
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void init_interleaver(int direction){
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len = INTERLEAVER_SIZE*INTERLEAVER_SIZE*INTERLEAVER_DEPTH;
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interleaver_direction = direction;
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interleaver_flush();
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} |