/*
* @(#)JPEGHuffmanTable.java 1.10 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
/**********************************************************************
**********************************************************************
**********************************************************************
*** COPYRIGHT (c) 1997-1998 Eastman Kodak Company. ***
*** As an unpublished work pursuant to Title 17 of the United ***
*** States Code. All rights reserved. ***
**********************************************************************
**********************************************************************
**********************************************************************/
package com.sun.image.codec.jpeg;
/** A class to encapsulate a JPEG Huffman table.
* <p>
* Note that the classes in the com.sun.image.codec.jpeg package are not
* part of the core Java APIs. They are a part of Sun's JDK and JRE
* distributions. Although other licensees may choose to distribute these
* classes, developers cannot depend on their availability in non-Sun
* implementations. We expect that equivalent functionality will eventually
* be available in a core API or standard extension.
* <p>
*/
public class JPEGHuffmanTable {
/**
* The maximum number of symbol lengths
* (max symbol length in bits = 16)
*/
private static final int HUFF_MAX_LEN=17;
/** the maximum number of symbols */
private static final int HUFF_MAX_SYM=256;
/** bits[k] = number of symbols with length k bits */
private short lengths[];
/** Symbols in order of increasing length */
private short symbols[];
/** Standard Huffman table ( JPEG standard section K.3 ) */
public static final JPEGHuffmanTable StdDCLuminance =
new JPEGHuffmanTable();
static {
short lengths[] = { // 0-base
0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
short symbols[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
StdDCLuminance.lengths = lengths;
StdDCLuminance.symbols = symbols;
StdDCLuminance.checkTable();
}
/** Standard Huffman table ( JPEG standard section K.3 ) */
public static final JPEGHuffmanTable StdDCChrominance =
new JPEGHuffmanTable();
static {
short lengths[] = { // 0-base
0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
short symbols[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
StdDCChrominance.lengths = lengths;
StdDCChrominance.symbols = symbols;
StdDCChrominance.checkTable();
}
/** Standard Huffman table ( JPEG standard section K.3 ) */
public static final JPEGHuffmanTable StdACLuminance =
new JPEGHuffmanTable();
static {
short lengths[] = { // 0-base
0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
short symbols[] = {
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 };
StdACLuminance.lengths = lengths;
StdACLuminance.symbols = symbols;
StdACLuminance.checkTable();
}
/** Standard Huffman table ( JPEG standard section K.3 ) */
public static final JPEGHuffmanTable StdACChrominance =
new JPEGHuffmanTable();
static {
short lengths[] = { // 0-base
0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
short symbols[] = {
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 };
StdACChrominance.lengths = lengths;
StdACChrominance.symbols = symbols;
StdACChrominance.checkTable();
}
/**
* Private constructor used to construct the Standard Huffman tables
*/
private JPEGHuffmanTable() {
lengths = null;
symbols = null;
}
/**
* Creates a Huffman Table and initializes it.
* @param lengths lengths[k] = # of symbols with codes of length k
* bits; lengths[0] is ignored
* @param symbols symbols in order of increasing code length
* @exception IllegalArgumentException if the length of
* <code>lengths</code> is greater than 17
* @exception IllegalArgumentException if the length of
* <code>symbols</code> is greater than 256
* @exception IllegalArgumentException if any of the values in
* <code>lengths</code> or <code>symbols</code> is less than zero
*/
public JPEGHuffmanTable( short lengths[], short symbols[] ) {
if ( lengths.length > HUFF_MAX_LEN )
throw new IllegalArgumentException( "lengths array is too long" );
for (int i=1; i < lengths.length; i++)
if (lengths[i] < 0)
throw new IllegalArgumentException
( "Values in lengths array must be non-negative." );
if ( symbols.length > HUFF_MAX_SYM )
throw new IllegalArgumentException( "symbols array is too long" );
for (int i=0; i < symbols.length; i++)
if (symbols[i] < 0)
throw new IllegalArgumentException
( "Values in symbols array must be non-negative." );
this.lengths = new short[lengths.length];
this.symbols = new short[symbols.length];
System.arraycopy( lengths, 0, this.lengths, 0, lengths.length );
System.arraycopy( symbols, 0, this.symbols, 0, symbols.length );
checkTable();
}
/**
* This checks that the table they gave us isn't 'illegal' It
* checks that the symbol length counts are possible, and that
* they gave us at least enough symbols for the symbol length
* counts. Eventually this might check that there aren't duplicate
* symbols.
*/
private void checkTable() {
int numVals=2;
int sum=0;
for (int i=1; i<lengths.length; i++) {
sum += lengths[i];
numVals -= lengths[i];
numVals *= 2;
}
//System.out.println("NumVals: " + numVals);
//System.out.println("Sum: " + sum + " Symbols: " + symbols.length);
if (numVals < 0)
throw new IllegalArgumentException
("Invalid Huffman Table provided, lengths are incorrect.");
// I'll let them go if they gave us 'extra' symbols...
if (sum > symbols.length)
throw new IllegalArgumentException
("Invalid Huffman Table provided, not enough symbols.");
}
/**
* Return a copy of the array containing the number of symbols
* for each length in the Huffman table.
* @return A short array where array[k] = # of symbols in the
* table of length k. array[0] is unused
*/
public short[] getLengths() {
short[] ret = new short[ lengths.length];
System.arraycopy( lengths, 0, ret, 0, lengths.length);
return ret;
}
/**
* Return an array containing the Huffman symbols arranged by
* increasing length. To make use of this array you must refer
* the the lengths array.
* @return A short array of Huffman symbols
*/
public short[] getSymbols() {
short[] ret = new short[symbols.length];
System.arraycopy( symbols, 0, ret, 0, symbols.length);
return ret;
}
}
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