package util;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriterTester {
    public static void main(String[] args) throws IOException {
        long l = 4657646574646L;
        FileWriter writer = new FileWriter("D:/temp");
        writer.write(longToChar(l));
        writer.flush();
        writer.close();
        FileReader reader = new FileReader("D:/temp");
        char[] c = new char[4];
        reader.read(c);
        reader.close();
        System.err.println(charToLong(c) == l);
        new File("D:/temp").delete();
    }

    public static char[] longToChar(long l) {
        char[] chars = new char[4];
        for (int i = 0; i < 4; i++) {
            chars[i] = (char) (l << (i * 16) >> (16 * 3));
        }
        return chars;
    }

    public static long charToLong(char[] c) {
        long result = 0;
        for (int i = 0; i < 4; i++) {
            long temp = c[i];
            result |= temp << (16 * (3 - i));
        }
        return result;
    }
}