| /* JPEGHuffmanTable.java -- |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
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| terms of your choice, provided that you also meet, for each linked |
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| exception statement from your version. */ |
| |
| |
| package javax.imageio.plugins.jpeg; |
| |
| /** |
| * The JPEGHuffmanTable class represents a Huffman table read from a |
| * JPEG image file. The standard JPEG AC and DC chrominance and |
| * luminance values are provided as static fields. |
| */ |
| public class JPEGHuffmanTable |
| { |
| /** |
| * Huffman code lengths. |
| */ |
| private short[] lengths; |
| |
| /** |
| * Huffman values. |
| */ |
| private short[] values; |
| |
| // The private constructors are used for these final fields to avoid |
| // unnecessary copying. |
| /** |
| * The standard JPEG AC chrominance Huffman table. |
| */ |
| public static final JPEGHuffmanTable StdACChrominance = |
| new JPEGHuffmanTable(new short[] { 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, |
| 4, 4, 0, 1, 2, 0x77 }, |
| new short[] { 0x00, 0x01, 0x02, 0x03, 0x11, |
| 0x04, 0x05, 0x21, 0x31, 0x06, |
| 0x12, 0x41, 0x51, 0x07, 0x61, |
| 0x71, 0x13, 0x22, 0x32, 0x81, |
| 0x08, 0x14, 0x42, 0x91, 0xa1, |
| 0xb1, 0xc1, 0x09, 0x23, 0x33, |
| 0x52, 0xf0, 0x15, 0x62, 0x72, |
| 0xd1, 0x0a, 0x16, 0x24, 0x34, |
| 0xe1, 0x25, 0xf1, 0x17, 0x18, |
| 0x19, 0x1a, 0x26, 0x27, 0x28, |
| 0x29, 0x2a, 0x35, 0x36, 0x37, |
| 0x38, 0x39, 0x3a, 0x43, 0x44, |
| 0x45, 0x46, 0x47, 0x48, 0x49, |
| 0x4a, 0x53, 0x54, 0x55, 0x56, |
| 0x57, 0x58, 0x59, 0x5a, 0x63, |
| 0x64, 0x65, 0x66, 0x67, 0x68, |
| 0x69, 0x6a, 0x73, 0x74, 0x75, |
| 0x76, 0x77, 0x78, 0x79, 0x7a, |
| 0x82, 0x83, 0x84, 0x85, 0x86, |
| 0x87, 0x88, 0x89, 0x8a, 0x92, |
| 0x93, 0x94, 0x95, 0x96, 0x97, |
| 0x98, 0x99, 0x9a, 0xa2, 0xa3, |
| 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, |
| 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, |
| 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, |
| 0xba, 0xc2, 0xc3, 0xc4, 0xc5, |
| 0xc6, 0xc7, 0xc8, 0xc9, 0xca, |
| 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, |
| 0xd7, 0xd8, 0xd9, 0xda, 0xe2, |
| 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, |
| 0xe8, 0xe9, 0xea, 0xf2, 0xf3, |
| 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, |
| 0xf9, 0xfa }, false); |
| |
| /** |
| * The standard JPEG AC luminance Huffman table. |
| */ |
| public static final JPEGHuffmanTable StdACLuminance = |
| new JPEGHuffmanTable(new short[] { 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, |
| 4, 4, 0, 0, 1, 0x7d }, |
| new short[] { 0x01, 0x02, 0x03, 0x00, 0x04, |
| 0x11, 0x05, 0x12, 0x21, 0x31, |
| 0x41, 0x06, 0x13, 0x51, 0x61, |
| 0x07, 0x22, 0x71, 0x14, 0x32, |
| 0x81, 0x91, 0xa1, 0x08, 0x23, |
| 0x42, 0xb1, 0xc1, 0x15, 0x52, |
| 0xd1, 0xf0, 0x24, 0x33, 0x62, |
| 0x72, 0x82, 0x09, 0x0a, 0x16, |
| 0x17, 0x18, 0x19, 0x1a, 0x25, |
| 0x26, 0x27, 0x28, 0x29, 0x2a, |
| 0x34, 0x35, 0x36, 0x37, 0x38, |
| 0x39, 0x3a, 0x43, 0x44, 0x45, |
| 0x46, 0x47, 0x48, 0x49, 0x4a, |
| 0x53, 0x54, 0x55, 0x56, 0x57, |
| 0x58, 0x59, 0x5a, 0x63, 0x64, |
| 0x65, 0x66, 0x67, 0x68, 0x69, |
| 0x6a, 0x73, 0x74, 0x75, 0x76, |
| 0x77, 0x78, 0x79, 0x7a, 0x83, |
| 0x84, 0x85, 0x86, 0x87, 0x88, |
| 0x89, 0x8a, 0x92, 0x93, 0x94, |
| 0x95, 0x96, 0x97, 0x98, 0x99, |
| 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, |
| 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, |
| 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, |
| 0xb7, 0xb8, 0xb9, 0xba, 0xc2, |
| 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, |
| 0xc8, 0xc9, 0xca, 0xd2, 0xd3, |
| 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, |
| 0xd9, 0xda, 0xe1, 0xe2, 0xe3, |
| 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, |
| 0xe9, 0xea, 0xf1, 0xf2, 0xf3, |
| 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, |
| 0xf9, 0xfa }, false); |
| |
| /** |
| * The standard JPEG DC chrominance Huffman table. |
| */ |
| public static final JPEGHuffmanTable StdDCChrominance = |
| new JPEGHuffmanTable(new short[] { 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 0, 0, 0, 0, 0 }, |
| new short[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, |
| 10, 11 }, false); |
| |
| /** |
| * The standard JPEG DC luminance Huffman table. |
| */ |
| public static final JPEGHuffmanTable StdDCLuminance = |
| new JPEGHuffmanTable(new short[] { 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, |
| 0, 0, 0, 0, 0, 0 }, |
| new short[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, |
| 10, 11 }, false); |
| |
| /** |
| * Construct and initialize a Huffman table. Copies are created of |
| * the array arguments. lengths[index] stores the number of Huffman |
| * values with Huffman codes of length index + 1. The values array |
| * stores the Huffman values in order of increasing code length. |
| * |
| * @param lengths an array of Huffman code lengths |
| * @param values a sorted array of Huffman values |
| * @throws IllegalArgumentException if either parameter is null, if |
| * lengths.length > 16 or values.length > 256, if any value in |
| * length or values is negative, or if the parameters do not |
| * describe a valid Huffman table |
| */ |
| public JPEGHuffmanTable(short[] lengths, short[] values) |
| { |
| // Create copies of the lengths and values arguments. |
| this(checkLengths(lengths), checkValues(values, lengths), true); |
| } |
| |
| /** |
| * Private constructor that avoids unnecessary copying and argument |
| * checking. |
| * |
| * @param lengths an array of Huffman code lengths |
| * @param values a sorted array of Huffman values |
| * @param copy true if copies should be created of the given arrays |
| */ |
| private JPEGHuffmanTable(short[] lengths, short[] values, boolean copy) |
| { |
| this.lengths = copy ? (short[]) lengths.clone() : lengths; |
| this.values = copy ? (short[]) values.clone() : values; |
| } |
| |
| private static short[] checkLengths(short[] lengths) |
| { |
| if (lengths == null || lengths.length > 16) |
| throw new IllegalArgumentException("invalid length array"); |
| |
| for (int i = 0; i < lengths.length; i++) |
| { |
| if (lengths[i] < 0) |
| throw new IllegalArgumentException("negative length"); |
| } |
| |
| int sum = 0; |
| for (int i = 0; i < lengths.length; i++) |
| { |
| if (lengths[i] > ((1 << (i + 1)) - 1)) |
| throw new IllegalArgumentException("invalid number of codes" |
| + " for code length " + (i + 1)); |
| sum += lengths[i]; |
| } |
| |
| return lengths; |
| } |
| |
| private static short[] checkValues(short[] values, short[] lengths) |
| { |
| if (values == null || values.length > 256) |
| throw new IllegalArgumentException("invalid values array"); |
| |
| for (int i = 0; i < values.length; i++) |
| { |
| if (values[i] < 0) |
| throw new IllegalArgumentException("negative value"); |
| } |
| // lengths is known-valid by this point. |
| int sum = 0; |
| for (int i = 0; i < lengths.length; i++) |
| sum += lengths[i]; |
| |
| if (values.length != sum) |
| throw new IllegalArgumentException("invalid number of values" |
| + " for number of codes"); |
| |
| return values; |
| } |
| |
| /** |
| * Retrieve a copy of the array of Huffman code lengths. If the |
| * returned array is called lengthcount, there are |
| * lengthcount[index] codes of length index + 1. |
| * |
| * @return a copy of the array of Huffman code lengths |
| */ |
| public short[] getLengths() |
| { |
| return (short[]) lengths.clone(); |
| } |
| |
| /** |
| * Retrieve a copy of the array of Huffman values, sorted in order |
| * of increasing code length. |
| * |
| * @return a copy of the array of Huffman values |
| */ |
| public short[] getValues() |
| { |
| return (short[]) values.clone(); |
| } |
| |
| /** |
| * Create a string representation of this JPEG Huffman table. |
| * |
| * @return a string representation of this JPEG Huffman table. |
| */ |
| public String toString() |
| { |
| StringBuffer buffer = new StringBuffer(); |
| |
| buffer.append("JPEGHuffmanTable:\nlengths:"); |
| |
| for (int i = 0; i < lengths.length; i++) |
| buffer.append(" " + lengths[i]); |
| |
| buffer.append("\nvalues:"); |
| |
| for (int i = 0; i < values.length; i++) |
| buffer.append(" " + values[i]); |
| |
| return buffer.toString(); |
| } |
| } |