package de.bablokb.crypto;
 
import java.io.*;
import java.security.*;
import sun.misc.*;

public class Digest {
    private static final String DEFAULT_MD = "SHA-1";
    private static final int    BUF_SIZE   = 8192;
    
    public static void main(String[] args) throws Exception {
	
	if (args.length < 1 || args.length > 2) {
	    usage();
	    System.exit(3);
	}
	
	String algorithm = DEFAULT_MD;
	if (args.length == 2)
	    algorithm = args[1];
	
	MessageDigest md = MessageDigest.getInstance(algorithm);
	FileInputStream stream = new FileInputStream(args[0]);
	byte[] sbuf = new byte[BUF_SIZE];
	int length;
	while ((length=stream.read(sbuf)) != -1)
	    md.update(sbuf,0,length);
	stream.close();
	
	BASE64Encoder enc = new BASE64Encoder();
	String out = enc.encode(md.digest());
	System.err.println("Document fingerprint ("+algorithm+"):");
	System.out.println(out);
	System.exit(0);
    }
    
    private static void usage() {
	System.out.println("usage: de.bablokb.crypto.Digest filename [algorithm]");
    }
}