package example5_3javaiodecorator;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;

/**
 * @author hornick
 * This output stream decorator encrypts an wrapped output stream
 */

public class EncryptedOutputStream extends FilterOutputStream {
	private String encryptionKey;	  // the "key" to use for encryption
	private Queue<Character> shifter; // Encryption "barrel". Note: Queue is abstract

	/**
	 * constructs the output stream encrypter
	 * @param key (ignored currently)
	 * @param wrappedStream
	 */
	public EncryptedOutputStream(String key, OutputStream wrappedStream) {
		super(wrappedStream);

        // TODO: This shifter is unused. Use it.
		// fill the barrel with the encryption key
		shifter = new LinkedList<Character>();
		encryptionKey = key;
		for( int c = 0; c<encryptionKey.length(); c++ )
			shifter.offer(encryptionKey.charAt(c));
	}

	/**
	 * encrypt an array of bytes and forward them to the wrapped output stream
	 */
	@Override
	public void write( byte[] b ) throws IOException {
		for( int c: b ) { //
			int k = c+5;
			out.write(k); // forward encrypted chars to the wrapped os
		}
	}


	/**
	 * encrypt an array of bytes and forward them to the wrapped output stream
	 */
	@Override
	public void write( byte[] b, int offset, int len ) throws IOException {
		// encryption algorithm
		for( int index=offset; index<offset+len; index++ ) {
			char k = (char)(5 + b[index]);
			out.write(k);// forward encrypted chars to the wrapped os
		}
	}


}