1. /*

  2.  * @(#)JPEGHuffmanTable.java	1.7 00/02/02

  3.  *

  4.  * Copyright 1998-2000 Sun Microsystems, Inc. All Rights Reserved.

  5.  * 

  6.  * This software is the proprietary information of Sun Microsystems, Inc.  

  7.  * Use is subject to license terms.

  8.  * 

  9.  */

  10. 

  11. /**********************************************************************

  12.  **********************************************************************

  13.  **********************************************************************

  14.  *** COPYRIGHT (c) 1997-1998 Eastman Kodak Company.                 ***

  15.  *** As  an unpublished  work pursuant to Title 17 of the United    ***

  16.  *** States Code.  All rights reserved.                             ***

  17.  **********************************************************************

  18.  **********************************************************************

  19.  **********************************************************************/

  20. 

  21. package com.sun.image.codec.jpeg;

  22. 

  23. 

  24. /** A class to encapsulate a JPEG Huffman table.

  25.  * <p>

  26.  * Note that the classes in the com.sun.image.codec.jpeg package are not

  27.  * part of the core Java APIs.  They are a part of Sun's JDK and JRE

  28.  * distributions.  Although other licensees may choose to distribute these

  29.  * classes, developers cannot depend on their availability in non-Sun

  30.  * implementations.  We expect that equivalent functionality will eventually

  31.  * be available in a core API or standard extension.

  32.  * <p>

  33.  */

  34. public class JPEGHuffmanTable {

  35. 

  36. 	/** 

  37. 	 * The maximum number of symbol lengths

  38. 	 * (max symbol length in bits = 16) 

  39. 	 */

  40.     private static final int HUFF_MAX_LEN=17;

  41. 	

  42.     /** the maximum number of symbols */

  43.     private static final int HUFF_MAX_SYM=256;

  44. 	

  45.     /** bits[k] = number of symbols with length k bits	*/

  46.     private short lengths[];

  47. 	

  48.     /** Symbols in order of increasing length */

  49.     private short symbols[];

  50. 	

  51.     /** Standard Huffman table ( JPEG standard section K.3 ) */

  52. 	public static final JPEGHuffmanTable StdDCLuminance = 

  53. 		new JPEGHuffmanTable();

  54. 

  55. 	static {

  56. 		short lengths[] = { // 0-base

  57. 			0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };

  58. 		short symbols[] = {

  59. 			0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  60. 		

  61. 		StdDCLuminance.lengths = lengths;

  62. 		StdDCLuminance.symbols = symbols;

  63. 		StdDCLuminance.checkTable();

  64. 	}

  65. 	

  66. 	

  67.     /** Standard Huffman table ( JPEG standard section K.3 ) */

  68. 	public static final JPEGHuffmanTable StdDCChrominance = 

  69. 		new JPEGHuffmanTable();

  70. 	static {

  71. 		short lengths[] = { // 0-base

  72. 			0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };

  73. 		short symbols[] = {

  74. 			0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  75. 		

  76. 		StdDCChrominance.lengths = lengths;

  77. 		StdDCChrominance.symbols = symbols;

  78. 		StdDCChrominance.checkTable();

  79. 	}

  80. 	

  81. 	/** Standard Huffman table ( JPEG standard section K.3 ) */

  82. 	public static final JPEGHuffmanTable StdACLuminance = 

  83. 		new JPEGHuffmanTable();

  84. 	static {

  85. 		short lengths[] = { // 0-base

  86. 			0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };

  87. 		short symbols[] = { 

  88. 			0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

  89. 			0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

  90. 			0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,

  91. 			0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,

  92. 			0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,

  93. 			0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,

  94. 			0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

  95. 			0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

  96. 			0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

  97. 			0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

  98. 			0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

  99. 			0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

  100. 			0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

  101. 			0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,

  102. 			0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,

  103. 			0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,

  104. 			0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,

  105. 			0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,

  106. 			0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,

  107. 			0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  108. 			0xf9, 0xfa };

  109. 			

  110. 		StdACLuminance.lengths = lengths;

  111. 		StdACLuminance.symbols = symbols;

  112. 		StdACLuminance.checkTable();

  113. 	}

  114. 	

  115.     /** Standard Huffman table ( JPEG standard section K.3 ) */

  116. 	public static final JPEGHuffmanTable StdACChrominance = 

  117. 		new JPEGHuffmanTable();

  118. 	static {

  119. 		short lengths[] =  { // 0-base

  120. 			0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };

  121. 		short symbols[] = { 

  122. 			0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

  123. 			0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

  124. 			0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

  125. 			0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,

  126. 			0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,

  127. 			0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,

  128. 			0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,

  129. 			0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

  130. 			0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

  131. 			0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

  132. 			0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

  133. 			0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

  134. 			0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,

  135. 			0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,

  136. 			0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,

  137. 			0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,

  138. 			0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,

  139. 			0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,

  140. 			0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,

  141. 			0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,

  142. 			0xf9, 0xfa };

  143. 			

  144. 		StdACChrominance.lengths = lengths;

  145. 		StdACChrominance.symbols = symbols;

  146. 		StdACChrominance.checkTable();

  147. 	}

  148. 	

  149. 	/**

  150. 	 * Private constructor used to construct the Standard Huffman tables

  151. 	 */

  152.     private JPEGHuffmanTable() {

  153. 		lengths = null;

  154. 		symbols = null;

  155. 	}

  156. 

  157.     /** 

  158.      * Creates a Huffman Table and initializes it.

  159.      * @param lengths lengths[k] = # of symbols with codes of length k

  160.      * bits; lengths[0] is ignored

  161.      * @param symbols symbols in order of increasing code length

  162.      * @exception IllegalArgumentException if the length of 

  163.      * <code>lengths</code> is greater than 17

  164.      * @exception IllegalArgumentException if the length of

  165.      * <code>symbols</code> is greater than 256

  166.      * @exception IllegalArgumentException if any of the values in 

  167.      * <code>lengths</code> or <code>symbols</code> is less than zero

  168.      */

  169.     public JPEGHuffmanTable( short lengths[], short symbols[] ) {

  170. 		if ( lengths.length > HUFF_MAX_LEN )

  171. 			throw new IllegalArgumentException( "lengths array is too long" );

  172. 		for (int i=1; i < lengths.length; i++)

  173. 			if (lengths[i] < 0)

  174. 				throw new IllegalArgumentException

  175. 					( "Values in lengths array must be non-negative." );

  176. 

  177. 		

  178. 		if ( symbols.length > HUFF_MAX_SYM )

  179. 			throw new IllegalArgumentException( "symbols array is too long" );

  180. 		for (int i=0; i < symbols.length; i++)

  181. 			if (symbols[i] < 0)

  182. 				throw new IllegalArgumentException

  183. 					( "Values in symbols array must be non-negative." );

  184. 		

  185. 		this.lengths = new short[lengths.length];

  186. 		this.symbols = new short[symbols.length];

  187. 		

  188. 		System.arraycopy( lengths, 0, this.lengths, 0, lengths.length );

  189. 		System.arraycopy( symbols, 0, this.symbols, 0, symbols.length );

  190. 

  191. 		checkTable();

  192.     }

  193. 

  194. 	/**

  195. 	 * This checks that the table they gave us isn't 'illegal' It

  196. 	 * checks that the symbol length counts are possible, and that

  197. 	 * they gave us at least enough symbols for the symbol length

  198. 	 * counts. Eventually this might check that there aren't duplicate

  199. 	 * symbols.

  200. 	 */

  201. 	private void checkTable() {

  202. 		int numVals=2;

  203. 		int sum=0;

  204. 		for (int i=1; i<lengths.length; i++) {

  205. 			sum     += lengths[i];

  206. 			numVals -= lengths[i];

  207. 			numVals *= 2;

  208. 		}

  209. 

  210. 		//System.out.println("NumVals: " + numVals);

  211. 		//System.out.println("Sum: " + sum + " Symbols: " + symbols.length);

  212. 

  213. 		if (numVals < 0) 

  214. 			throw new IllegalArgumentException

  215. 				("Invalid Huffman Table provided, lengths are incorrect.");

  216. 

  217. 		// I'll let them go if they gave us 'extra' symbols...

  218. 		if (sum > symbols.length)

  219. 			throw new IllegalArgumentException

  220. 				("Invalid Huffman Table provided, not enough symbols.");

  221. 	}

  222. 

  223. 	/** 

  224. 	 * Return a copy of the array containing the number of symbols

  225. 	 * for each length in the Huffman table.

  226. 	 * @return A short array where array[k] = # of symbols in the

  227. 	 *         table of length k. array[0] is unused

  228. 	 */

  229.     public short[] getLengths() {

  230. 		short[] ret = new short[ lengths.length];

  231. 		System.arraycopy( lengths, 0, ret, 0, lengths.length);

  232. 		return ret;

  233.     }

  234. 

  235.     /** 

  236. 	 * Return an array containing the Huffman symbols arranged by

  237. 	 * increasing length.  To make use of this array you must refer

  238. 	 * the the lengths array.

  239. 	 * @return A short array of Huffman symbols

  240.      */

  241.     public short[] getSymbols() {

  242. 		short[] ret = new short[symbols.length];

  243. 		System.arraycopy( symbols, 0, ret, 0, symbols.length);

  244. 		return ret;

  245.     }

  246. }