WSJT-X/lib/ldpc/extract.c

113 lines
2.5 KiB
C
Executable File

/* EXTRACT.C - Extract message bits from coded blocks. */
/* Copyright (c) 1995-2012 by Radford M. Neal.
*
* Permission is granted for anyone to copy, use, modify, and distribute
* these programs and accompanying documents for any purpose, provided
* this copyright notice is retained and prominently displayed, and note
* is made of any changes made to these programs. These programs and
* documents are distributed without any warranty, express or implied.
* As the programs were written for research purposes only, they have not
* been tested to the degree that would be advisable in any important
* application. All use of these programs is entirely at the user's own
* risk.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "alloc.h"
#include "blockio.h"
#include "open.h"
#include "mod2sparse.h"
#include "mod2dense.h"
#include "mod2convert.h"
#include "rcode.h"
void usage(void);
/* MAIN PROGRAM. */
int main
( int argc,
char **argv
)
{
char *gen_file, *coded_file, *ext_file;
FILE *codef, *extf;
char *cblk;
int i;
/* Look at arguments. */
if (!(gen_file = argv[1])
|| !(coded_file = argv[2])
|| !(ext_file = argv[3])
|| argv[4])
{ usage();
}
if ((strcmp(gen_file,"-")==0) + (strcmp(coded_file,"-")==0) > 1)
{ fprintf(stderr,"Can't read more than one stream from standard input\n");
exit(1);
}
/* Read generator matrix file, up to the point of finding out which
are the message bits. */
read_gen(gen_file,1,1);
/* Open decoded file. */
codef = open_file_std(coded_file,"r");
if (codef==NULL)
{ fprintf(stderr,"Can't open coded file: %s\n",coded_file);
exit(1);
}
/* Open file to write extracted message bits to. */
extf = open_file_std(ext_file,"w");
if (extf==NULL)
{ fprintf(stderr,"Can't create file for extracted bits: %s\n",ext_file);
exit(1);
}
cblk = chk_alloc (N, sizeof *cblk);
for (;;)
{
/* Read block from coded file. */
if (blockio_read(codef,cblk,N)==EOF) break;
/* Extract message bits and write to file, followed by newline to mark
block boundary. */
for (i = M; i<N; i++)
{ putc("01"[cblk[cols[i]]],extf);
}
putc('\n',extf);
}
if (ferror(extf) || fclose(extf)!=0)
{ fprintf(stderr,"Error writing extracted data to %s\n",ext_file);
exit(1);
}
return 0;
}
/* PRINT USAGE MESSAGE AND EXIT. */
void usage(void)
{ fprintf(stderr,
"Usage: extract gen-file decoded-file extracted-file\n");
exit(1);
}