awt/java/awt/image/DataBuffer.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.
 */
/**
 * @author Igor V. Stolyarov
 * @version $Revision$
 */
package java.awt.image;

import org.apache.harmony.awt.gl.image.DataBufferListener;
import org.apache.harmony.awt.internal.nls.Messages;

/**
 * The Class DataBuffer is a wrapper class for a data array
 * to be used for the situation where a suite of functionality
 * acts on a set of data in a consistent way even though the 
 * primitive type of the data may vary from one use to the next. 
 */
public abstract class DataBuffer {

    /** The Constant TYPE_BYTE. */
    public static final int TYPE_BYTE = 0;

    /** The Constant TYPE_USHORT. */
    public static final int TYPE_USHORT = 1;

    /** The Constant TYPE_SHORT. */
    public static final int TYPE_SHORT = 2;

    /** The Constant TYPE_INT. */
    public static final int TYPE_INT = 3;

    /** The Constant TYPE_FLOAT. */
    public static final int TYPE_FLOAT = 4;

    /** The Constant TYPE_DOUBLE. */
    public static final int TYPE_DOUBLE = 5;

    /** The Constant TYPE_UNDEFINED. */
    public static final int TYPE_UNDEFINED = 32;

    /** The data type indicates the primitive type of the 
     * data in this DataBuffer. */
    protected int dataType;

    /** The number of data arrays in this DataBuffer. */
    protected int banks;

    /** The starting index for reading the 
     * data from the first (or only) internal data array. */
    protected int offset;

    /** The length (number of elements) of the data arrays. */
    protected int size;

    /** The starting indices for reading the 
     * data from the internal data arrays. */
    protected int offsets[];
    
    /** The data changed. */
    boolean dataChanged = true;
    
    /** The data taken. */
    boolean dataTaken = false;
    
    /** The listener. */
    DataBufferListener listener;

    static {
        AwtImageBackdoorAccessorImpl.init();
    }

    /**
     * Instantiates a new data buffer.
     * 
     * @param dataType the data type
     * @param size the length (number of elements) of the data arrays
     * @param numBanks the number of data arrays to create
     * @param offsets the starting indices for reading the 
     * data from the internal data arrays
     */
    protected DataBuffer(int dataType, int size, int numBanks, int[] offsets) {
        this.dataType = dataType;
        this.size = size;
        this.banks = numBanks;
        this.offsets = offsets.clone();
        this.offset = offsets[0];
    }

    /**
     * Instantiates a new data buffer with all of the 
     * data arrays starting at the same index.
     * 
     * @param dataType the data type
     * @param size the length (number of elements) of the data arrays
     * @param numBanks the number of data arrays to create
     * @param offset the offset to use for all of the data arrays
     */
    protected DataBuffer(int dataType, int size, int numBanks, int offset) {
        this.dataType = dataType;
        this.size = size;
        this.banks = numBanks;
        this.offset = offset;
        this.offsets = new int[numBanks];
        int i = 0;
        while (i < numBanks) {
            offsets[i++] = offset;
        }
    }

    /**
     * Instantiates a new data buffer with all of the 
     * data arrays read from the beginning (at offset zero).
     * 
     * @param dataType the data type
     * @param size the length (number of elements) of the data arrays
     * @param numBanks the number of data arrays to create
     */
    protected DataBuffer(int dataType, int size, int numBanks) {
        this.dataType = dataType;
        this.size = size;
        this.banks = numBanks;
        this.offset = 0;
        this.offsets = new int[numBanks];
    }

    /**
     * Instantiates a new data buffer with one internal data array
     * read from the beginning (at offset zero).
     * 
     * @param dataType the data type
     * @param size the length (number of elements) of the data arrays
     */
    protected DataBuffer(int dataType, int size) {
        this.dataType = dataType;
        this.size = size;
        this.banks = 1;
        this.offset = 0;
        this.offsets = new int[1];
    }

    /**
     * Sets the data value in the specified array at the 
     * specified index.
     * 
     * @param bank the internal array to the data to
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public abstract void setElem(int bank, int i, int val);

    /**
     * Sets the float data value in the specified array at the 
     * specified index.
     * 
     * @param bank the internal array to the data to
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public void setElemFloat(int bank, int i, float val) {
        setElem(bank, i, (int) val);
    }

    /**
     * Sets the double data value in the specified array at the 
     * specified index.
     * 
     * @param bank the internal array to the data to
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public void setElemDouble(int bank, int i, double val) {
        setElem(bank, i, (int) val);
    }

    /**
     * Sets the data value in the first array at the 
     * specified index.
     * 
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public void setElem(int i, int val) {
        setElem(0, i, val);
    }

    /**
     * Gets the data value from the specified data array at the 
     * specified index.
     * 
     * @param bank the data array to read from
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public abstract int getElem(int bank, int i);

    /**
     * Gets the float-type data value from the specified 
     * data array at the specified index.
     * 
     * @param bank the data array to read from
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public float getElemFloat(int bank, int i) {
        return getElem(bank, i);
    }

    /**
     * Gets the double-type data value from the specified 
     * data array at the specified index.
     * 
     * @param bank the data array to read from
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public double getElemDouble(int bank, int i) {
        return getElem(bank, i);
    }

    /**
     * Sets the float data value in the first array at the 
     * specified index.
     * 
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public void setElemFloat(int i, float val) {
        setElemFloat(0, i, val);
    }

    /**
     * Sets the double data value in the first array at the 
     * specified index.
     * 
     * @param i the index within the array where the data
     * should be written
     * @param val the value to write into the array
     */
    public void setElemDouble(int i, double val) {
        setElemDouble(0, i, val);
    }

    /**
     * Gets the data value from the first 
     * data array at the specified index and returns it
     * as an int.
     * 
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public int getElem(int i) {
        return getElem(0, i);
    }

    /**
     * Gets the data value from the first 
     * data array at the specified index and returns it
     * as a float.
     * 
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public float getElemFloat(int i) {
        return getElem(0, i);
    }

    /**
     * Gets the data value from the first 
     * data array at the specified index and returns it
     * as a double.
     * 
     * @param i the index within the array where the data
     * should be read
     * 
     * @return the data element
     */
    public double getElemDouble(int i) {
        return getElem(i);
    }

    /**
     * Gets the array giving the offsets corresponding 
     * to the internal data arrays.
     * 
     * @return the array of offsets
     */
    public int[] getOffsets() {
        return offsets;
    }

    /**
     * Gets the size in bits of the primitive data type.
     * 
     * @return the size in bits of the primitive data type

     */
    public int getSize() {
        return size;
    }

    /**
     * Gets the offset corresponding to the first internal 
     * data array.
     * 
     * @return the offset
     */
    public int getOffset() {
        return offset;
    }

    /**
     * Gets the number of data arrays in this DataBuffer.
     * 
     * @return the number of data arrays
     */
    public int getNumBanks() {
        return banks;
    }

    /**
     * Gets the primitive type of this buffer's data.
     * 
     * @return the data type
     */
    public int getDataType() {
        return this.dataType;
    }

    /**
     * Gets the size in bits of the primitive data type.
     * 
     * @param type the primitive type
     * 
     * @return the size in bits of the primitive data type
     */
    public static int getDataTypeSize(int type) {
        switch (type) {

        case TYPE_BYTE:
            return 8;

        case TYPE_USHORT:
        case TYPE_SHORT:
            return 16;

        case TYPE_INT:
        case TYPE_FLOAT:
            return 32;

        case TYPE_DOUBLE:
            return 64;

        default:
            // awt.22C=Unknown data type {0}
            throw new IllegalArgumentException(Messages.getString("awt.22C", type)); //$NON-NLS-1$
        }
    }
    
    /**
     * Notifies the listener that the data has changed.
     */
    void notifyChanged(){
        if(listener != null && !dataChanged){
            dataChanged = true;
            listener.dataChanged();
        }
    }
    
    /**
     * Notifies the listener that the data has been released.
     */
    void notifyTaken(){
        if(listener != null && !dataTaken){
            dataTaken = true;
            listener.dataTaken();
        }
    }
    
    /**
     * Release the data.
     */
    void releaseData(){
        if(listener != null && dataTaken){
            dataTaken = false;
            listener.dataReleased();
        }
    }
    
    /**
     * Adds the data buffer listener.
     * 
     * @param listener the listener
     */
    void addDataBufferListener(DataBufferListener listener){
        this.listener = listener;
    }
    
    /**
     * Removes the data buffer listener.
     */
    void removeDataBufferListener(){
        listener = null;
    }
    
    /**
     * Validate.
     */
    void validate(){
        dataChanged = false;
    }
    
}