SKIPBYTE.C Tony Lawrence:

I must have needed something like "dd" for Dos, so I wrote this. It only allows specification of the number of bytes to skip and the total number of bytes to copy before quitting. I can't remember what I needed this for, but I do remember using it frequently.

#include <stdio.h>
char buf[4096];

main(int argc, char **argv)
{
long skip=0;
unsigned long total=0;
unsigned long outp=0;
FILE *of,*nf;

int x;
size_t count=1;

if (argc < 4 || argc > 5)
  help_exit(1);

 skip=atol(argv[3]);
 if (argc == 5)
   total=atol(argv[3]);

if ((of=fopen(argv[1],"rb"))==NULL)
     {
     printf("No %s file??\n",argv[0]);
     help_exit(1);
     }
if ((nf=fopen(argv[2],"w"))==NULL)
     {
     printf("No %s file??\n",argv[0]);
     help_exit(1);
     }
if(skip)
 fseek(of,skip,SEEK_SET);
if (!total)
{
while (1)
{
long bread;

bread=fread(buf,4096,1,of);
printf(" %d ",bread);
if( !bread) break;
fwrite(buf,bread,1,nf);
printf(".");
}
}
else
{
 while (outp < total)
 {
 long bsize;
 long bread;
 
 bsize=4096;
 if (total - outp < 4096)
   bsize=total-outp;

bread=fread(buf,bsize,1,of);
printf(" %d ",bread);
if( !bread) break;
fwrite(buf,bsize,1,nf);
printf(".");
outp += bread;
 }
}
fclose(of);
fclose(nf);
printf("\n");
exit(0);
}

help_exit(int arg)
{
 printf("\n\nSKIPBYTE oldfile newfile skip-bytes [total-bytes]\n");
 printf("Reads 'oldfile' skipping 'skip-bytes' bytes and stopping\n");
 printf("after 'total-bytes' are copied (copied to newfile, not read\n");
 printf("from oldfile\n");
 printf("'total-bytes' is optional\n");
 printf("\n\n(C)1993 Lawrence & Clark, Inc (781) 784-5537 (206) 323-2864\n\n\n");
 exit(arg);
}

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© 2011-05-08 Tony Lawrence

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