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Diffstat (limited to 'libjava/classpath/javax/imageio/plugins/jpeg/JPEGHuffmanTable.java')
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1 files changed, 282 insertions, 0 deletions
diff --git a/libjava/classpath/javax/imageio/plugins/jpeg/JPEGHuffmanTable.java b/libjava/classpath/javax/imageio/plugins/jpeg/JPEGHuffmanTable.java new file mode 100644 index 000000000..be718d4fc --- /dev/null +++ b/libjava/classpath/javax/imageio/plugins/jpeg/JPEGHuffmanTable.java @@ -0,0 +1,282 @@ +/* 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 + modules, and to copy and distribute the resulting executable under + terms of your choice, provided that you also meet, for each linked + independent module, the terms and conditions of the license of that + module. An independent module is a module which is not derived from + or based on this library. If you modify this library, you may extend + this exception to your version of the library, but you are not + obligated to do so. If you do not wish to do so, delete this + exception statement from your version. */ + + +package javax.imageio.plugins.jpeg; + +import gnu.java.lang.CPStringBuilder; + +/** + * 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() + { + CPStringBuilder buffer = new CPStringBuilder(); + + 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(); + } +} |