/* ENCODE.C - Encode message blocks. *//* Copyright (c) 2000, 2001 by Radford M. Neal  * * Permission is granted for anyone to copy, use, or modify this program  * for purposes of research or education, provided this copyright notice  * is retained, and note is made of any changes that have been made.  * * This program is distributed without any warranty, express or implied. * As this program was written for research purposes only, it has not been * tested to the degree that would be advisable in any important application. * All use of this program is entirely at the user's own risk. */#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h>#include "rand.h"#include "alloc.h"#include "blockio.h"#include "open.h"#include "mod2sparse.h"#include "mod2dense.h"#include "mod2convert.h"#include "rcode.h"#include "enc.h"void usage(void);/* MAIN PROGRAM. */int main( int argc, char **argv){  char *source_file, *encoded_file;  char *pchk_file, *gen_file;  mod2dense *u, *v;  FILE *srcf, *encf;  char *sblk, *cblk, *chks;//sourceblock???codeblock???  int i, n;  /* Look at arguments. */  if (!(pchk_file = argv[1]) || !(gen_file = argv[2]) || !(source_file = argv[3])|| !(encoded_file = argv[4])|| argv[5])  { 
	  usage();  }  if ((strcmp(pchk_file,"-")==0) + (strcmp(gen_file,"-")==0) + (strcmp(source_file,"-")==0) > 1)  { 
	fprintf(stderr,"Can't read more than one stream from standard input\n");    exit(1);  }  /* Read parity check file */  read_pchk(pchk_file);  if (N<=M)  { 
	  fprintf(stderr, "Can't encode if number of bits (%d) not greater than number of checks (%d)\n", N,M);      exit(1);  }  /* Read generator matrix file. */  read_gen(gen_file,0,0);  /* Allocate needed space. */  if (type=='d')  { 
	u = mod2dense_allocate(N-M,1);    v = mod2dense_allocate(M,1);  }  if (type=='m')  {
	u = mod2dense_allocate(M,1);    v = mod2dense_allocate(M,1);  }  /* Open source file. */  srcf = open_file_std(source_file,"r");  if (srcf==NULL)  { 
	fprintf(stderr,"Can't open source file: %s\n",source_file);    exit(1);  }  /* Create encoded output file. */  encf = open_file_std(encoded_file,"w");  if (encf==NULL)  { 
    fprintf(stderr,"Can't create file for encoded data: %s\n",encoded_file);    exit(1);  }  sblk = chk_alloc (N-M, sizeof *sblk);//  cblk = chk_alloc (N, sizeof *cblk);  chks = chk_alloc (M, sizeof *chks);  /* Encode successive blocks. */  for (n = 0; ; n++)  { 		/* Read block from source file. */		if (blockio_read(srcf,sblk,N-M)==EOF) 		{ 
			break;		}		/* Compute encoded block. */		switch (type)		{ 
		  case 's':		  { 
			sparse_encode (sblk, cblk);			break;		  }		  case 'd':		  { 
			dense_encode (sblk, cblk, u, v);			break;		  }		  case 'm':		  { 
			mixed_encode (sblk, cblk, u, v);			break;		  }		}		/* Check that encoded block is a code word. */		mod2sparse_mulvec (H, cblk, chks);		for (i = 0; i<M; i++) 		{ 
		  if (chks[i]==1)		  { 
			fprintf(stderr,"Output block %d is not a code word!  (Fails check %d)\n",n,i);			abort(); 		  }		}		/* Write encoded block to encoded output file. */		blockio_write(encf,cblk,N);  }  fprintf(stderr, "Encoded %d blocks, source block size %d, encoded block size %d\n",n,N-M,N);  if (ferror(encf) || fclose(encf)!=0)  { 
	fprintf(stderr,"Error writing encoded blocks to %s\n",encoded_file);    exit(1);  }  return 0;}/* PRINT USAGE MESSAGE AND EXIT. */void usage(void){ 
  fprintf(stderr, "Usage:  encode pchk-file gen-file source-file encoded-file\n");  exit(1);}