DirectReadOnlyFloatBufferAdapter.java

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package java.nio;

import com.googlecode.gwtgl.array.ArrayBufferView;
import com.googlecode.gwtgl.array.Float32Array;

import com.googlecode.gwtquake.client.HasArrayBufferView;

/**
 * This class wraps a byte buffer to be a float buffer.
 * <p>
 * Implementation notice:
 * <ul>
 * <li>After a byte buffer instance is wrapped, it becomes privately owned by
 * the adapter. It must NOT be accessed outside the adapter any more.</li>
 * <li>The byte buffer's position and limit are NOT linked with the adapter.
 * The adapter extends Buffer, thus has its own position and limit.</li>
 * </ul>
 * </p>
 * 
 */
final class DirectReadOnlyFloatBufferAdapter extends FloatBuffer implements HasArrayBufferView {
//implements DirectBuffer {

    static FloatBuffer wrap(DirectByteBuffer byteBuffer) {
        return new DirectReadOnlyFloatBufferAdapter((DirectByteBuffer) byteBuffer.slice());
    }

    private final DirectByteBuffer byteBuffer;
    private final Float32Array floatArray;

    DirectReadOnlyFloatBufferAdapter(DirectByteBuffer byteBuffer) {
        super((byteBuffer.capacity() >> 2));
        this.byteBuffer = byteBuffer;
        this.byteBuffer.clear();
        this.floatArray = Float32Array.create(byteBuffer.byteArray.getBuffer(), 
        			byteBuffer.byteArray.getByteOffset(),
        			capacity);
    }

    @Override
    public FloatBuffer asReadOnlyBuffer() {
        DirectReadOnlyFloatBufferAdapter buf = new DirectReadOnlyFloatBufferAdapter(byteBuffer);
        buf.limit = limit;
        buf.position = position;
        buf.mark = mark;
        return buf;
    }

    @Override
    public FloatBuffer compact() {
        throw new ReadOnlyBufferException();
    }

    @Override
    public FloatBuffer duplicate() {
        DirectReadOnlyFloatBufferAdapter buf = new DirectReadOnlyFloatBufferAdapter(
        		(DirectByteBuffer) byteBuffer.duplicate());
        buf.limit = limit;
        buf.position = position;
        buf.mark = mark;
        return buf;
    }

    @Override
    public float get() {
//        if (position == limit) {
//            throw new BufferUnderflowException();
//        }
        return floatArray.get(position++);
    }

    @Override
    public float get(int index) {
//        if (index < 0 || index >= limit) {
//            throw new IndexOutOfBoundsException();
//        }
        return floatArray.get(index);
    }

    @Override
    public boolean isDirect() {
        return true;
    }

    @Override
    public boolean isReadOnly() {
        return true;
    }

    @Override
    public ByteOrder order() {
        return byteBuffer.order();
    }

    @Override
    float[] protectedArray() {
        throw new UnsupportedOperationException();
    }

    @Override
    int protectedArrayOffset() {
        throw new UnsupportedOperationException();
    }

    @Override boolean protectedHasArray() {
        return false;
    }

    @Override
    public FloatBuffer put(float c) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public FloatBuffer put(int index, float c) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public FloatBuffer slice() {
        byteBuffer.limit(limit << 2);
        byteBuffer.position(position << 2);
        FloatBuffer result = new DirectReadOnlyFloatBufferAdapter((DirectByteBuffer) byteBuffer.slice());
        byteBuffer.clear();
        return result;
    }

	public ArrayBufferView getTypedArray() {
		return floatArray;
	}

	public int getElementSize() {
		return 4;
	}
}