94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
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/* MAKE-PCHK.C - Make a parity check matrix explicitly. */
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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 "intio.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 **bit_specs;
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char *file;
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FILE *f;
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int i, j, k;
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char junk;
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if (!(file = argv[1])
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|| !argv[2] || sscanf(argv[2],"%d%c",&M,&junk)!=1 || M<=0
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|| !argv[3] || sscanf(argv[3],"%d%c",&N,&junk)!=1 || N<=0)
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{ usage();
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}
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bit_specs = argv+4;
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if (bit_specs[0]==0)
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{ usage();
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}
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H = mod2sparse_allocate(M,N);
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for (k = 0; bit_specs[k]!=0; k++)
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{ if (sscanf(bit_specs[k],"%d:%d%c",&i,&j,&junk)!=2 || i<0 || j<0)
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{ usage();
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}
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if (i>=M || j>=N)
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{ fprintf(stderr,"Bit %d:%d is out of range\n",i,j);
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exit(1);
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}
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mod2sparse_insert(H,i,j);
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}
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f = open_file_std(file,"wb");
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if (f==NULL)
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{ fprintf(stderr,"Can't create parity check file: %s\n",file);
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exit(1);
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}
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intio_write(f,('P'<<8)+0x80);
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if (ferror(f) || !mod2sparse_write(f,H) || fclose(f)!=0)
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{ fprintf(stderr,"Error writing to parity check file %s\n",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,"Usage: make-pchk pchk-file n-checks n-bits row:col ...\n");
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exit(1);
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}
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