WSJT-X/lib/ftrsd/sfrsd.c

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/*
sfrsd.c
A soft-decision decoder for the JT65 (63,12) Reed-Solomon code.
This decoding scheme is built around Phil Karn's Berlekamp-Massey
errors and erasures decoder. The approach is inspired by a number of
publications, including the stochastic Chase decoder described
in "Stochastic Chase Decoding of Reed-Solomon Codes", by Leroux et al.,
IEEE Communications Letters, Vol. 14, No. 9, September 2010 and
"Soft-Decision Decoding of Reed-Solomon Codes Using Successive Error-
and-Erasure Decoding," by Soo-Woong Lee and B. V. K. Vijaya Kumar.
Steve Franke K9AN, Urbana IL, September 2015
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include "sfrsd2.h"
//***************************************************************************
void usage(void)
{
printf("Usage: sfrsd [options...] <path to kvasd.dat>\n");
printf(" input file should be in kvasd format\n");
printf("\n");
printf("Options:\n");
printf(" -n number of random erasure vectors to try\n");
printf(" -v verbose\n");
}
int main(int argc, char *argv[]){
extern char *optarg;
extern int optind;
int correct[63], indx[63], param[8];
int c,i;
char *infile;
FILE *datfile, *logfile;
int nsec, maxe, nads;
float xlambda;
int mrsym[63],mrprob[63],mr2sym[63],mr2prob[63];
int nsec2,ncount,dat4[12];
int ntrials, nverbose, ntry;
int nhard;
double tt;
ntrials=10000;
nverbose=1;
while ( (c = getopt(argc, argv, "n:qv")) !=-1 ) {
switch (c) {
case 'n':
ntrials=(int)strtof(optarg,NULL);
printf("ntrials set to %d\n",ntrials);
break;
case 'v':
nverbose=1;
break;
case 'q': //accept (and ignore) -q option for WSJT10 compatibility
break;
case '?':
usage();
exit(1);
}
}
if( optind+1 > argc) {
// usage();
// exit(1);
infile="kvasd.dat";
} else {
infile=argv[optind];
}
logfile=fopen("/tmp/sfrsd.log","a");
if( !logfile ) {
printf("Unable to open sfrsd.log\n");
exit(1);
}
datfile=fopen(infile,"rb");
if( !datfile ) {
printf("Unable to open kvasd.dat\n");
exit(1);
} else {
fread(&nsec,sizeof(int),1,datfile);
fread(&xlambda,sizeof(float),1,datfile);
fread(&maxe,sizeof(int),1,datfile);
fread(&nads,sizeof(int),1,datfile);
fread(&mrsym,sizeof(int),63,datfile);
fread(&mrprob,sizeof(int),63,datfile);
fread(&mr2sym,sizeof(int),63,datfile);
fread(&mr2prob,sizeof(int),63,datfile);
fread(&nsec2,sizeof(int),1,datfile);
fread(&ncount,sizeof(int),1,datfile);
fread(&dat4,sizeof(int),12,datfile);
fclose(datfile);
}
sfrsd2_(mrsym,mrprob,mr2sym,mr2prob,&ntrials,&nverbose,correct,param,indx,&tt,&ntry);
nhard=param[1];
if( nhard>=0 ) {
for (i=0; i<12; i++) {
dat4[i]=correct[11-i];
}
} else {
nhard=-1;
memset(dat4,0,12*sizeof(int));
}
datfile=fopen(infile,"wb");
if( !datfile ) {
printf("Unable to open kvasd.dat\n");
return 1;
} else {
fwrite(&nsec,sizeof(int),1,datfile);
fwrite(&xlambda,sizeof(float),1,datfile);
fwrite(&maxe,sizeof(int),1,datfile);
fwrite(&nads,sizeof(int),1,datfile);
fwrite(&mrsym,sizeof(int),63,datfile);
fwrite(&mrprob,sizeof(int),63,datfile);
fwrite(&mr2sym,sizeof(int),63,datfile);
fwrite(&mr2prob,sizeof(int),63,datfile);
fwrite(&nsec2,sizeof(int),1,datfile);
fwrite(&nhard,sizeof(int),1,datfile);
fwrite(&dat4,sizeof(int),12,datfile);
fclose(datfile);
}
exit(0);
}