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/*
** Extract a range of bytes from a file.
**
** Usage:
**
** extract FILENAME OFFSET AMOUNT
**
** The bytes are written to standard output.
*/
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv){
FILE *f;
char *zBuf;
int ofst;
int n;
size_t got;
if( argc!=4 ){
fprintf(stderr, "Usage: %s FILENAME OFFSET AMOUNT\n", *argv);
return 1;
}
f = fopen(argv[1], "rb");
if( f==0 ){
fprintf(stderr, "cannot open \"%s\"\n", argv[1]);
return 1;
}
ofst = atoi(argv[2]);
n = atoi(argv[3]);
zBuf = malloc( n );
if( zBuf==0 ){
fprintf(stderr, "out of memory\n");
return 1;
}
fseek(f, ofst, SEEK_SET);
got = fread(zBuf, 1, n, f);
fclose(f);
if( got<n ){
fprintf(stderr, "got only %d of %d bytes\n", got, n);
return 1;
}else{
fwrite(zBuf, 1, n, stdout);
}
return 0;
}
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