WritableFormChunk.java

/*
 * $Id: WritableFormChunk.java 536 2008-02-19 06:03:27Z weiju $
 * 
 * Created on 2005/09/23
 * Copyright 2005-2008 by Wei-ju Wu
 * This file is part of The Z-machine Preservation Project (ZMPP).
 *
 * ZMPP is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ZMPP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ZMPP.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.zmpp.iff;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import org.zmpp.base.DefaultMemory;
import org.zmpp.base.Memory;

public class WritableFormChunk implements FormChunk {

    private byte[] subId;
    private static final byte[] FORM_ID = "FORM".getBytes();

    private List<Chunk> subChunks;

    /**
     * Constructor.
     *
     * @param subId the sub id
     */
    public WritableFormChunk(final byte[] subId) {

        super();
        this.subId = subId;
        this.subChunks = new ArrayList<Chunk>();
    }

    /**
     * Adds a sub chunk.
     *
     * @param chunk the sub chunk to add
     */
    public void addChunk(final Chunk chunk) {

        subChunks.add(chunk);
    }

    /**
     * {@inheritDoc}
     */
    public byte[] getSubId() {

        return subId;
    }

    /**
     * {@inheritDoc}
     */
    public Iterator<Chunk> getSubChunks() {

        return subChunks.iterator();
    }

    /**
     * {@inheritDoc}
     */
    public Chunk getSubChunk(final byte[] id) {

        for (Chunk chunk : subChunks) {

            if (Arrays.equals(chunk.getId(), id)) {

                return chunk;
            }
        }
        return null;
    }

    /**
     * {@inheritDoc}
     */
    public Chunk getSubChunk(final int address) {

        // We do not need to implement this
        return null;
    }

    /**
     * {@inheritDoc}
     */
    public byte[] getId() {

        return FORM_ID;
    }

    /**
     * {@inheritDoc}
     */
    public int getSize() {

        int size = subId.length;

        for (Chunk chunk : subChunks) {

            int chunkSize = chunk.getSize();
            if ((chunkSize % 2) != 0) {
                chunkSize++; // pad if necessary
            }
            size += (Chunk.CHUNK_HEADER_LENGTH + chunkSize);
        }
        return size;
    }

    /**
     * {@inheritDoc}
     */
    public boolean isValid() {

        return true;
    }

    /**
     * {@inheritDoc}
     */
    public Memory getMemory() {

        return new DefaultMemory(getBytes());
    }

    /**
     * Returns the data of this chunk.
     *
     * @return the chunk data
     */
    public byte[] getBytes() {

        final int datasize = Chunk.CHUNK_HEADER_LENGTH + getSize();
        final byte[] data = new byte[datasize];
        final Memory memory = new DefaultMemory(data);
        memory.writeByte(0, (byte) 'F');
        memory.writeByte(1, (byte) 'O');
        memory.writeByte(2, (byte) 'R');
        memory.writeByte(3, (byte) 'M');
        memory.writeUnsigned32(4, getSize());

        int offset = Chunk.CHUNK_HEADER_LENGTH;

        // Write sub id
        for (int i = 0; i < subId.length; i++) {

            memory.writeByte(offset++, subId[i]);
        }

        // Write sub chunk data
        for (Chunk chunk : subChunks) {

            //System.out.println("Chunk: " + (new String(chunk.getId())));
            final byte[] chunkId = chunk.getId();
            final int chunkSize = chunk.getSize();

            // Write id
            for (int i = 0; i < chunkId.length; i++) {

                memory.writeByte(offset++, chunkId[i]);
            }

            // Write chunk size
            memory.writeUnsigned32(offset, chunkSize);
            offset += 4; // add the size word length

            // Write chunk data
            final Memory chunkMem = chunk.getMemory();
            for (int i = 0; i < chunkSize; i++) {

                memory.writeByte(offset++,
                        chunkMem.readByte(Chunk.CHUNK_HEADER_LENGTH + i));
            }

            // Pad if necessary
            if ((chunkSize % 2) != 0) {
                memory.writeByte(offset++, (byte) 0);
            }
        }

        return data;
    }

    /**
     * {@inheritDoc}
     */
    public int getAddress() {
        return 0;
    }

}