Working examples for http://stackoverflow.com/questions/15177218

test.cpp

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cstring>

int main(int argc, char *argv[]) {
	(void)argc;

	bool good = true;

	if (argc < 4) {
		std::cout << "Wrong number of args: <size> <file1> <file2>" << std::endl;
		return 1;
	}

	int buff_size = atoi(argv[1]);
	int count = 0;

	char buff_1[buff_size];
	char buff_2[buff_size];

	std::ifstream file1(argv[2], std::ios::in | std::ios::binary);
	std::ifstream file2(argv[3], std::ios::in | std::ios::binary);

	if (!file1.good() || !file2.good()) {
		std::cout << "Error opening files" << std::endl;
		return 1;
	}

	std::streamsize read1 = 0, read2 = 0;

	do {
		count++;
		file1.read(buff_1, buff_size);
		file2.read(buff_2, buff_size);
		read1 = file1.gcount();
		read2 = file1.gcount();

		if (read1 != read2 || std::memcmp(buff_1, buff_2, read1) != 0) {
			good = false;
			break;
		}
	} while(file1.good() && file2.good());

	if (good) {
		std::cout << "Same, " << count << std::endl;
	} else {
		std::cout << "Different, " << count << std::endl;
	}

	return 0;
}

Test.java

import java.util.*;
import java.io.*;

public class Test {
	public static void main(String[] args) throws FileNotFoundException, IOException {
		boolean result = true;

		int count = 0;

		int size = Integer.parseInt(args[0]);

		InputStream is1 = new BufferedInputStream(new FileInputStream(args[1]));
		InputStream is2 = new BufferedInputStream(new FileInputStream(args[2]));

		byte[] buffer1 = new byte[size];
		byte[] buffer2 = new byte[size];

		int readBytesCount1 = 0, readBytesCount2 = 0;

		while (
			(readBytesCount1 = is1.read(buffer1)) != -1 &&
			(readBytesCount2 = is2.read(buffer2)) != -1
		) {
			if (Arrays.equals(buffer1, buffer2) && readBytesCount1 == readBytesCount2) {
				count++;
			} else {
				result = false;
				break;
			}
		}

		if (result) {
			System.out.println("Same, " + count);
		} else {
			System.out.println("Different, " + count);
		}
	}
}