kopia lustrzana https://github.com/pabr/leansdr
Split generic RS implementation from DVB-specific code
pabr
rodzic
adc50bf825
commit
17c5918a7c
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@ -4,6 +4,7 @@
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#include "leansdr/viterbi.h"
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#include "leansdr/convolutional.h"
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#include "leansdr/sdr.h"
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#include "leansdr/rs.h"
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namespace leansdr {
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@ -856,6 +857,112 @@ namespace leansdr {
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struct tspacket { u8 data[SIZE_TSPACKET]; };
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// RS ENCODER
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struct rs_encoder : runnable {
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rs_encoder(scheduler *sch,
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pipebuf<tspacket> &_in, pipebuf< rspacket<u8> > &_out)
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: runnable(sch, "RS encoder"),
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in(_in), out(_out) { }
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void run() {
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while ( in.readable()>=1 && out.writable()>=1 ) {
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u8 *pin = in.rd()->data;
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u8 *pout = out.wr()->data;
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// The first 188 bytes are the uncoded message P(X)
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memcpy(pout, pin, SIZE_TSPACKET);
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// Append 16 RS parity bytes R(X) = - (P(X)*X^16 mod G(X))
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// so that G(X) divides the coded message S(X) = P(X)*X^16 - R(X).
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rs.encode(pout);
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in.read(1);
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out.written(1);
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}
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}
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private:
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rs_engine rs;
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pipereader<tspacket> in;
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pipewriter< rspacket<u8> > out;
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}; // rs_encoder
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// RS DECODER
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template<typename Tbyte, int BYTE_ERASED>
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struct rs_decoder : runnable {
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rs_engine rs;
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rs_decoder(scheduler *sch,
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pipebuf< rspacket<Tbyte> > &_in,
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pipebuf<tspacket> &_out,
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pipebuf<int> *_bitcount=NULL,
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pipebuf<int> *_errcount=NULL)
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: runnable(sch, "RS decoder"),
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in(_in), out(_out) {
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bitcount = _bitcount ? new pipewriter<int>(*_bitcount) : NULL;
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errcount = _errcount ? new pipewriter<int>(*_errcount) : NULL;
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}
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void run() {
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if ( bitcount && bitcount->writable()<1 ) return;
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if ( errcount && errcount->writable()<1 ) return;
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int nbits=0, nerrs=0;
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while ( in.readable()>=1 && out.writable()>=1 ) {
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Tbyte *pin = in.rd()->data;
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u8 *pout = out.wr()->data;
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nbits += SIZE_RSPACKET * 8;
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// The message is the first 188 bytes.
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if ( sizeof(Tbyte) == 1 )
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memcpy(pout, pin, SIZE_TSPACKET);
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else
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fail("Erasures not implemented");
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u8 synd[16];
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bool corrupted = rs.syndromes(pin, synd);
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#if 0
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if ( ! corrupted ) {
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// Test BM
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fprintf(stderr, "Simulating errors\n");
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pin[203] ^= 42;
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pin[202] ^= 99;
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corrupted = rs.syndromes(pin, synd);
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}
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#endif
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if ( ! corrupted ) {
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if ( sch->debug )
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fprintf(stderr, "_"); // Packet received without errors.
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} else {
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corrupted = rs.correct(synd, pout, pin, &nerrs);
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if ( sch->debug ) {
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if ( ! corrupted )
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fprintf(stderr, "."); // Errors were corrected.
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else
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fprintf(stderr, "!"); // Packet still corrupted.
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}
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}
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in.read(1);
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// Output corrupted packets (with a special mark)
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// otherwise the derandomizer will lose synchronization.
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if ( corrupted ) pout[0] ^= MPEG_SYNC_CORRUPTED;
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out.written(1);
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}
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if ( nbits ) {
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if ( bitcount ) { *bitcount->wr()=nbits; bitcount->written(1); }
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if ( errcount ) { *errcount->wr()=nerrs; errcount->written(1); }
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}
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}
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private:
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pipereader< rspacket<Tbyte> > in;
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pipewriter<tspacket> out;
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pipewriter<int> *bitcount, *errcount;
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}; // rs_decoder
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// RANDOMIZER
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struct randomizer : runnable {
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106
src/leansdr/rs.h
106
src/leansdr/rs.h
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@ -254,112 +254,6 @@ namespace leansdr {
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};
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// RS ENCODER
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struct rs_encoder : runnable {
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rs_encoder(scheduler *sch,
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pipebuf<tspacket> &_in, pipebuf< rspacket<u8> > &_out)
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: runnable(sch, "RS encoder"),
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in(_in), out(_out) { }
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void run() {
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while ( in.readable()>=1 && out.writable()>=1 ) {
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u8 *pin = in.rd()->data;
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u8 *pout = out.wr()->data;
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// The first 188 bytes are the uncoded message P(X)
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memcpy(pout, pin, SIZE_TSPACKET);
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// Append 16 RS parity bytes R(X) = - (P(X)*X^16 mod G(X))
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// so that G(X) divides the coded message S(X) = P(X)*X^16 - R(X).
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rs.encode(pout);
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in.read(1);
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out.written(1);
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}
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}
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private:
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rs_engine rs;
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pipereader<tspacket> in;
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pipewriter< rspacket<u8> > out;
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}; // rs_encoder
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// RS DECODER
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template<typename Tbyte, int BYTE_ERASED>
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struct rs_decoder : runnable {
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rs_engine rs;
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rs_decoder(scheduler *sch,
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pipebuf< rspacket<Tbyte> > &_in,
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pipebuf<tspacket> &_out,
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pipebuf<int> *_bitcount=NULL,
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pipebuf<int> *_errcount=NULL)
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: runnable(sch, "RS decoder"),
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in(_in), out(_out) {
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bitcount = _bitcount ? new pipewriter<int>(*_bitcount) : NULL;
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errcount = _errcount ? new pipewriter<int>(*_errcount) : NULL;
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}
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void run() {
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if ( bitcount && bitcount->writable()<1 ) return;
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if ( errcount && errcount->writable()<1 ) return;
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int nbits=0, nerrs=0;
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while ( in.readable()>=1 && out.writable()>=1 ) {
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Tbyte *pin = in.rd()->data;
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u8 *pout = out.wr()->data;
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nbits += SIZE_RSPACKET * 8;
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// The message is the first 188 bytes.
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if ( sizeof(Tbyte) == 1 )
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memcpy(pout, pin, SIZE_TSPACKET);
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else
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fail("Erasures not implemented");
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u8 synd[16];
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bool corrupted = rs.syndromes(pin, synd);
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#if 0
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if ( ! corrupted ) {
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// Test BM
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fprintf(stderr, "Simulating errors\n");
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pin[203] ^= 42;
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pin[202] ^= 99;
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corrupted = rs.syndromes(pin, synd);
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}
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#endif
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if ( ! corrupted ) {
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if ( sch->debug )
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fprintf(stderr, "_"); // Packet received without errors.
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} else {
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corrupted = rs.correct(synd, pout, pin, &nerrs);
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if ( sch->debug ) {
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if ( ! corrupted )
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fprintf(stderr, "."); // Errors were corrected.
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else
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fprintf(stderr, "!"); // Packet still corrupted.
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}
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}
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in.read(1);
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// Output corrupted packets (with a special mark)
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// otherwise the derandomizer will lose synchronization.
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if ( corrupted ) pout[0] ^= MPEG_SYNC_CORRUPTED;
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out.written(1);
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}
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if ( nbits ) {
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if ( bitcount ) { *bitcount->wr()=nbits; bitcount->written(1); }
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if ( errcount ) { *errcount->wr()=nerrs; errcount->written(1); }
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}
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}
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private:
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pipereader< rspacket<Tbyte> > in;
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pipewriter<tspacket> out;
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pipewriter<int> *bitcount, *errcount;
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}; // rs_decoder
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} // namespace
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#endif // LEANSDR_RS_H
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