package unimelb.utils;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.zip.CRC32;
import java.util.zip.CheckedInputStream;

public class ChecksumUtils {

    public static long getCRC32Value(Path f) throws Throwable {
        return getCRC32Value(f.toFile());
    }

    public static long getCRC32Value(File f) throws Throwable {
        InputStream in = new BufferedInputStream(new FileInputStream(f));
        try {
            return getCRC32Value(in);
        } finally {
            in.close();
        }
    };

    public static long getCRC32Value(InputStream in) throws Throwable {
        CheckedInputStream cin = new CheckedInputStream(
                (in instanceof BufferedInputStream) ? in : new BufferedInputStream(in), new CRC32());
        byte[] buffer = new byte[1024];
        try {
            while (cin.read(buffer) != -1) {
                // Read file in completely
            }
        } finally {
            cin.close();
            in.close();
        }
        return cin.getChecksum().getValue();
    }
    
    public static String getCRC32(Path f) throws Throwable {
        return getCRC32(f.toFile());
    }
    
        public static String getCRC32(Path f) throws Throwable {
        return getCRC32(f.toFile());
    }

    public static String getCRC32(File f) throws Throwable {
        InputStream in = new BufferedInputStream(new FileInputStream(f));
        try {
            return getCRC32(in);
        } finally {
            in.close();
        }
    }

    public static String getCRC32(InputStream in) throws Throwable {
        CheckedInputStream cin = new CheckedInputStream(
                (in instanceof BufferedInputStream) ? in : new BufferedInputStream(in), new CRC32());
        byte[] buffer = new byte[1024];
        try {
            while (cin.read(buffer) != -1) {
                // Read file in completely
            }
        } finally {
            cin.close();
            in.close();
        }
        long value = cin.getChecksum().getValue();
        return Long.toHexString(value);
    }
    
    
}