/*
* Copyright 2007 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package javax.imageio.plugins.jpeg;
import java.util.Arrays;
/**
* A class encapsulating a single JPEG Huffman table.
* Fields are provided for the "standard" tables taken
* from Annex K of the JPEG specification.
* These are the tables used as defaults.
* <p>
* For more information about the operation of the standard JPEG plug-in,
* see the <A HREF="../../metadata/doc-files/jpeg_metadata.html">JPEG
* metadata format specification and usage notes</A>
*/
public class JPEGHuffmanTable {
/* The data for the publically defined tables, as specified in ITU T.81
* JPEG specification section K3.3 and used in the IJG library.
*/
private static final short[] StdDCLuminanceLengths = {
0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
private static final short[] StdDCLuminanceValues = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b,
};
private static final short[] StdDCChrominanceLengths = {
0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
};
private static final short[] StdDCChrominanceValues = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b,
};
private static final short[] StdACLuminanceLengths = {
0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03,
0x05, 0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7d,
};
private static final short[] StdACLuminanceValues = {
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,
};
private static final short[] StdACChrominanceLengths = {
0x00, 0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04,
0x07, 0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77,
};
private static final short[] StdACChrominanceValues = {
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,
};
/**
* The standard DC luminance Huffman table.
*/
public static final JPEGHuffmanTable
StdDCLuminance = new JPEGHuffmanTable(StdDCLuminanceLengths,
StdDCLuminanceValues, false);
/**
* The standard DC chrominance Huffman table.
*/
public static final JPEGHuffmanTable
StdDCChrominance = new JPEGHuffmanTable(StdDCChrominanceLengths,
StdDCChrominanceValues, false);
/**
* The standard AC luminance Huffman table.
*/
public static final JPEGHuffmanTable
StdACLuminance = new JPEGHuffmanTable(StdACLuminanceLengths,
StdACLuminanceValues, false);
/**
* The standard AC chrominance Huffman table.
*/
public static final JPEGHuffmanTable
StdACChrominance = new JPEGHuffmanTable(StdACChrominanceLengths,
StdACChrominanceValues, false);
private short[] lengths;
private short[] values;
/**
* Creates a Huffman table and initializes it. The input arrays are copied.
* The arrays must describe a possible Huffman table.
* For example, 3 codes cannot be expressed with a single bit.
*
* @param lengths an array of {@code short}s where <code>lengths[k]</code>
* is equal to the number of values with corresponding codes of
* length <code>k + 1</code> bits.
* @param values an array of shorts containing the values in
* order of increasing code length.
* @throws IllegalArgumentException if <code>lengths</code> or
* <code>values</code> are null, the length of <code>lengths</code> is
* greater than 16, the length of <code>values</code> is greater than 256,
* if any value in <code>lengths</code> or <code>values</code> is less
* than zero, or if the arrays do not describe a valid Huffman table.
*/
public JPEGHuffmanTable(short[] lengths, short[] values) {
if (lengths == null || values == null ||
lengths.length == 0 || values.length == 0 ||
lengths.length > 16 || values.length > 256) {
throw new IllegalArgumentException("Illegal lengths or values");
}
for (int i = 0; i<lengths.length; i++) {
if (lengths[i] < 0) {
throw new IllegalArgumentException("lengths["+i+"] < 0");
}
}
for (int i = 0; i<values.length; i++) {
if (values[i] < 0) {
throw new IllegalArgumentException("values["+i+"] < 0");
}
}
this.lengths = Arrays.copyOf(lengths, lengths.length);
this.values = Arrays.copyOf(values, values.length);
validate();
}
private void validate() {
int sumOfLengths = 0;
for (int i=0; i<lengths.length; i++) {
sumOfLengths += lengths[i];
}
if (sumOfLengths != values.length) {
throw new IllegalArgumentException("lengths do not correspond " +
"to length of value table");
}
}
/* Internal version which avoids the overhead of copying and checking */
private JPEGHuffmanTable(short[] lengths, short[] values, boolean copy) {
if (copy) {
this.lengths = Arrays.copyOf(lengths, lengths.length);
this.values = Arrays.copyOf(values, values.length);
} else {
this.lengths = lengths;
this.values = values;
}
}
/**
* Returns an array of <code>short</code>s containing the number of values
* for each length in the Huffman table. The returned array is a copy.
*
* @return a <code>short</code> array where <code>array[k-1]</code>
* is equal to the number of values in the table of length <code>k</code>.
* @see #getValues
*/
public short[] getLengths() {
return Arrays.copyOf(lengths, lengths.length);
}
/**
* Returns an array of <code>short</code>s containing the values arranged
* by increasing length of their corresponding codes.
* The interpretation of the array is dependent on the values returned
* from <code>getLengths</code>. The returned array is a copy.
*
* @return a <code>short</code> array of values.
* @see #getLengths
*/
public short[] getValues() {
return Arrays.copyOf(values, values.length);
}
/**
* Returns a {@code String} representing this Huffman table.
* @return a {@code String} representing this Huffman table.
*/
public String toString() {
String ls = System.getProperty("line.separator", "\n");
StringBuilder sb = new StringBuilder("JPEGHuffmanTable");
sb.append(ls).append("lengths:");
for (int i=0; i<lengths.length; i++) {
sb.append(" ").append(lengths[i]);
}
sb.append(ls).append("values:");
for (int i=0; i<values.length; i++) {
sb.append(" ").append(values[i]);
}
return sb.toString();
}
}