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