Java tutorial
/* * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* **************************************************************** ****************************************************************** ****************************************************************** *** COPYRIGHT (c) Eastman Kodak Company, 1997 *** As an unpublished work pursuant to Title 17 of the United *** States Code. All rights reserved. ****************************************************************** ****************************************************************** ******************************************************************/ package java.awt.image; import static sun.java2d.StateTrackable.State.*; /** * This class extends {@code DataBuffer} and stores data internally as bytes. * Values stored in the byte array(s) of this {@code DataBuffer} are treated as * unsigned values. * <p> * <a id="optimizations"> * Note that some implementations may function more efficiently * if they can maintain control over how the data for an image is * stored. * For example, optimizations such as caching an image in video * memory require that the implementation track all modifications * to that data. * Other implementations may operate better if they can store the * data in locations other than a Java array. * To maintain optimum compatibility with various optimizations * it is best to avoid constructors and methods which expose the * underlying storage as a Java array, as noted below in the * documentation for those methods. * </a> */ public final class DataBufferByte extends DataBuffer { /** The default data bank. */ byte[] data; /** All data banks */ byte[][] bankdata; /** * Constructs a byte-based {@code DataBuffer} with a single bank and the * specified size. * * @param size The size of the {@code DataBuffer}. */ public DataBufferByte(int size) { super(STABLE, TYPE_BYTE, size); data = new byte[size]; bankdata = new byte[1][]; bankdata[0] = data; } /** * Constructs a byte based {@code DataBuffer} with the specified number of * banks all of which are the specified size. * * @param size The size of the banks in the {@code DataBuffer}. * @param numBanks The number of banks in the a {@code DataBuffer}. */ public DataBufferByte(int size, int numBanks) { super(STABLE, TYPE_BYTE, size, numBanks); bankdata = new byte[numBanks][]; for (int i = 0; i < numBanks; i++) { bankdata[i] = new byte[size]; } data = bankdata[0]; } /** * Constructs a byte-based {@code DataBuffer} with a single bank using the * specified array. * Only the first {@code size} elements should be used by accessors of * this {@code DataBuffer}. {@code dataArray} must be large enough to * hold {@code size} elements. * <p> * Note that {@code DataBuffer} objects created by this constructor * may be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @param dataArray The byte array for the {@code DataBuffer}. * @param size The size of the {@code DataBuffer} bank. */ public DataBufferByte(byte[] dataArray, int size) { super(UNTRACKABLE, TYPE_BYTE, size); data = dataArray; bankdata = new byte[1][]; bankdata[0] = data; } /** * Constructs a byte-based {@code DataBuffer} with a single bank using the * specified array, size, and offset. {@code dataArray} must have at least * {@code offset} + {@code size} elements. Only elements {@code offset} * through {@code offset} + {@code size} - 1 * should be used by accessors of this {@code DataBuffer}. * <p> * Note that {@code DataBuffer} objects created by this constructor * may be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @param dataArray The byte array for the {@code DataBuffer}. * @param size The size of the {@code DataBuffer} bank. * @param offset The offset into the {@code dataArray}. {@code dataArray} * must have at least {@code offset} + {@code size} elements. */ public DataBufferByte(byte[] dataArray, int size, int offset) { super(UNTRACKABLE, TYPE_BYTE, size, 1, offset); data = dataArray; bankdata = new byte[1][]; bankdata[0] = data; } /** * Constructs a byte-based {@code DataBuffer} with the specified arrays. * The number of banks is equal to {@code dataArray.length}. * Only the first {@code size} elements of each array should be used by * accessors of this {@code DataBuffer}. * <p> * Note that {@code DataBuffer} objects created by this constructor * may be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @param dataArray The byte arrays for the {@code DataBuffer}. * @param size The size of the banks in the {@code DataBuffer}. */ public DataBufferByte(byte[][] dataArray, int size) { super(UNTRACKABLE, TYPE_BYTE, size, dataArray.length); bankdata = dataArray.clone(); data = bankdata[0]; } /** * Constructs a byte-based {@code DataBuffer} with the specified arrays, size, * and offsets. * The number of banks is equal to {@code dataArray.length}. Each array must * be at least as large as {@code size} + the corresponding {@code offset}. * There must be an entry in the {@code offset} array for each {@code dataArray} * entry. For each bank, only elements {@code offset} through * {@code offset} + {@code size} - 1 should be used by accessors of this * {@code DataBuffer}. * <p> * Note that {@code DataBuffer} objects created by this constructor * may be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @param dataArray The byte arrays for the {@code DataBuffer}. * @param size The size of the banks in the {@code DataBuffer}. * @param offsets The offsets into each array. */ public DataBufferByte(byte[][] dataArray, int size, int[] offsets) { super(UNTRACKABLE, TYPE_BYTE, size, dataArray.length, offsets); bankdata = dataArray.clone(); data = bankdata[0]; } /** * Returns the default (first) byte data array. * <p> * Note that calling this method may cause this {@code DataBuffer} * object to be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @return The first byte data array. */ public byte[] getData() { theTrackable.setUntrackable(); return data; } /** * Returns the data array for the specified bank. * <p> * Note that calling this method may cause this {@code DataBuffer} * object to be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @param bank The bank whose data array you want to get. * @return The data array for the specified bank. */ public byte[] getData(int bank) { theTrackable.setUntrackable(); return bankdata[bank]; } /** * Returns the data arrays for all banks. * <p> * Note that calling this method may cause this {@code DataBuffer} * object to be incompatible with <a href="#optimizations">performance * optimizations</a> used by some implementations (such as caching * an associated image in video memory). * * @return All of the data arrays. */ public byte[][] getBankData() { theTrackable.setUntrackable(); return bankdata.clone(); } /** * Returns the requested data array element from the first (default) bank. * * @param i The data array element you want to get. * @return The requested data array element as an integer. * @see #setElem(int, int) * @see #setElem(int, int, int) */ public int getElem(int i) { return (int) (data[i + offset]) & 0xff; } /** * Returns the requested data array element from the specified bank. * * @param bank The bank from which you want to get a data array element. * @param i The data array element you want to get. * @return The requested data array element as an integer. * @see #setElem(int, int) * @see #setElem(int, int, int) */ public int getElem(int bank, int i) { return (int) (bankdata[bank][i + offsets[bank]]) & 0xff; } /** * Sets the requested data array element in the first (default) bank * to the specified value. * * @param i The data array element you want to set. * @param val The integer value to which you want to set the data array element. * @see #getElem(int) * @see #getElem(int, int) */ public void setElem(int i, int val) { data[i + offset] = (byte) val; theTrackable.markDirty(); } /** * Sets the requested data array element in the specified bank * from the given integer. * @param bank The bank in which you want to set the data array element. * @param i The data array element you want to set. * @param val The integer value to which you want to set the specified data array element. * @see #getElem(int) * @see #getElem(int, int) */ public void setElem(int bank, int i, int val) { bankdata[bank][i + offsets[bank]] = (byte) val; theTrackable.markDirty(); } }