#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define BLOCK 2048

int main(int argc, char *argv[])
{
	FILE *img, *dir;
	char dirname[32];
	int i;	

	int offset;
	int size;
	char filename[24];
	FILE *file;
	char temp[BLOCK];

	if (argc < 2) {
		printf("Usage: %s img\n", argv[0]);
		exit(1);
	}
        if ((img = fopen(argv[1], "r")) == NULL) {
		printf("Couldn't open file: %s\n", argv[1]);
		exit(1);
	}

	i = strlen(argv[1]);
	strncpy(dirname, argv[1], i);
	dirname[i-1] = dirname[i-2] = dirname[i-3] = '\0';
	strcat(dirname, "dir");
	if ((dir = fopen(dirname, "r")) == NULL) {
		printf("Couldn't open file: %s\n", dirname);
		exit(1);
	}

	while (fread(&offset, 4, 1, dir) == 1) {
		fread(&size, 4, 1, dir);
		fread(filename, 1, 24, dir);
	
		if ((file = fopen(filename, "w")) == NULL) {
			printf("Couldn't open file: %s\n", filename);
			exit(1);
		}
		fseek(img, offset*BLOCK, 0);
		for (i = 0; i < size; i++) {
			fread(temp, BLOCK, 1, img);
			fwrite(temp, BLOCK, 1, file);	
		}
		fclose(file);
	} 
	fclose(img);
	fclose(dir);
	return 0;	
}