#define _XOPEN_SOURCE 500

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char **argv){
    int f1, f2, res;
    unsigned char c1, c2;
    unsigned long int l=0, pos, l1, l2, l3, l4;
    struct stat buf;
    
    f1=open("1.tar.bz2",O_RDONLY);
    if(f1 == -1){
	puts ("Err 1");
	exit(1);
    }
    f2=open("2.tar.bz2",O_RDONLY);
    if(f2 == -1){
	puts ("Err 1");
	exit(1);
    }
    
    fstat(f1, &buf);
    l1=buf.st_size;
    
    fstat(f2, &buf);
    l2=buf.st_size;
    
    if(l1 > l2){
	l3 = l2;
	l4 = l1-l2;
    } else {
	l3 = l1;
	l4 = l2-l1;
    }
    
    printf("Несовпадений=%ld,Архив1=%ld,Архив2=%ld,Минимум=%ld,Дельта=%ld\n",l,l1,l2,l3,l4);
    
    for(pos=0; pos<l3;pos++)
    {
	pread(f1, &c1, 1, pos);
	pread(f2, &c2, 1, pos);
	if(c1 != c2){
	    printf("%8ld: %3d %3d %c %c\n",pos, c1, c2, c1>=32?c1:' ', c2>=32?c2:' ');
	    l++;
	}
    }
    
    printf("Несовпадений=%ld,Архив1=%ld,Архив2=%ld,Минимум=%ld,Дельта=%ld\n",l,l1,l2,l3,l4);
    printf("Разница=%8.2f%%\n", (float)(l+l4)*100.0/(float)(l3+l4) );
}