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