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1 /*******************************************************************************
2  * Copyright (c) 2000, 2005 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.swt.internal.image;
12
13
14 /**
15  * JPEGHuffmanTable class actually represents two types of object:
16  * 1) A DHT (Define Huffman Tables) segment, which may represent
17  * as many as 4 Huffman tables. In this case, the tables are
18  * stored in the allTables array.
19  * 2) A single Huffman table. In this case, the allTables array
20  * will be null.
21  * The 'reference' field is stored in both types of object, but
22  * 'initialize' is only called if the object represents a DHT.
23  */
24 final class JPEGHuffmanTable extends JPEGVariableSizeSegment {
25     JPEGHuffmanTable[] allTables;
26     int tableClass;
27     int tableIdentifier;
28     int[] dhMaxCodes;
29     int[] dhMinCodes;
30     int[] dhValPtrs;
31     int[] dhValues;
32     int[] ehCodes;
33     byte[] ehCodeLengths;
34     static byte[] DCLuminanceTable = {
35         (byte)255, (byte)196, 0, 31, 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
36         0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
37     };
38     static byte[] DCChrominanceTable = {
39         (byte)255, (byte)196, 0, 31, 1, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
40         0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
41     };
42     static byte[] ACLuminanceTable = {
43         (byte)255, (byte)196, 0, (byte)181, 16, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125,
44         1, 2, 3, 0, 4, 17, 5, 18, 33, 49, 65, 6, 19, 81, 97, 7, 34, 113, 20,
45         50, (byte)129, (byte)145, (byte)161, 8, 35, 66, (byte)177, (byte)193, 21, 82, (byte)209, (byte)240, 36, 51, 98,
46         114, (byte)130, 9, 10, 22, 23, 24, 25, 26, 37, 38, 39, 40, 41, 42, 52, 53,
47         54, 55, 56, 57, 58, 67, 68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87,
48         88, 89, 90, 99, 100, 101, 102, 103, 104, 105, 106, 115, 116, 117, 118,
49         119, 120, 121, 122, (byte)131, (byte)132, (byte)133, (byte)134, (byte)135, (byte)136, (byte)137, (byte)138, (byte)146, (byte)147, (byte)148,
50         (byte)149, (byte)150, (byte)151, (byte)152, (byte)153, (byte)154, (byte)162, (byte)163, (byte)164, (byte)165, (byte)166, (byte)167, (byte)168, (byte)169, (byte)170,
51         (byte)178, (byte)179, (byte)180, (byte)181, (byte)182, (byte)183, (byte)184, (byte)185, (byte)186, (byte)194, (byte)195, (byte)196, (byte)197, (byte)198, (byte)199,
52         (byte)200, (byte)201, (byte)202, (byte)210, (byte)211, (byte)212, (byte)213, (byte)214, (byte)215, (byte)216, (byte)217, (byte)218, (byte)225, (byte)226, (byte)227,
53         (byte)228, (byte)229, (byte)230, (byte)231, (byte)232, (byte)233, (byte)234, (byte)241, (byte)242, (byte)243, (byte)244, (byte)245, (byte)246, (byte)247, (byte)248,
54         (byte)249, (byte)250
55     };
56     static byte[] ACChrominanceTable = {
57         (byte)255, (byte)196, 0, (byte)181, 17, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0,
58         1, 2, 119, 0, 1, 2, 3, 17, 4, 5, 33, 49, 6, 18, 65, 81, 7, 97, 113, 19, 34,
59         50, (byte)129, 8, 20, 66, (byte)145, (byte)161, (byte)177, (byte)193, 9, 35,
60         51, 82, (byte)240, 21, 98, 114, (byte)209, 10, 22, 36, 52, (byte)225, 37,
61         (byte)241, 23, 24, 25, 26, 38, 39, 40, 41, 42, 53, 54, 55, 56, 57, 58, 67,
62         68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87, 88, 89, 90, 99, 100, 101, 102,
63         103, 104, 105, 106, 115, 116, 117, 118, 119, 120, 121, 122, (byte)130,
64         (byte)131, (byte)132, (byte)133, (byte)134, (byte)135, (byte)136, (byte)137,
65         (byte)138, (byte)146, (byte)147, (byte)148, (byte)149, (byte)150, (byte)151,
66         (byte)152, (byte)153, (byte)154, (byte)162, (byte)163, (byte)164, (byte)165,
67         (byte)166, (byte)167, (byte)168, (byte)169, (byte)170, (byte)178, (byte)179,
68         (byte)180, (byte)181, (byte)182, (byte)183, (byte)184, (byte)185, (byte)186,
69         (byte)194, (byte)195, (byte)196, (byte)197, (byte)198, (byte)199, (byte)200,
70         (byte)201, (byte)202, (byte)210, (byte)211, (byte)212, (byte)213, (byte)214,
71         (byte)215, (byte)216, (byte)217, (byte)218, (byte)226, (byte)227, (byte)228,
72         (byte)229, (byte)230, (byte)231, (byte)232, (byte)233, (byte)234, (byte)242,
73         (byte)243, (byte)244, (byte)245, (byte)246, (byte)247, (byte)248, (byte)249,
74         (byte)250
75     };
76     
77 public JPEGHuffmanTable(byte[] reference) {
78     super(reference);
79 }
80
81 public JPEGHuffmanTable(LEDataInputStream byteStream) {
82     super(byteStream);
83     initialize();
84 }
85
86 public JPEGHuffmanTable[] getAllTables() {
87     return allTables;
88 }
89
90 public static JPEGHuffmanTable getDefaultACChrominanceTable() {
91     JPEGHuffmanTable result = new JPEGHuffmanTable(ACChrominanceTable);
92     result.initialize();
93     return result;
94 }
95
96 public static JPEGHuffmanTable getDefaultACLuminanceTable() {
97     JPEGHuffmanTable result = new JPEGHuffmanTable(ACLuminanceTable);
98     result.initialize();
99     return result;
100 }
101
102 public static JPEGHuffmanTable getDefaultDCChrominanceTable() {
103     JPEGHuffmanTable result = new JPEGHuffmanTable(DCChrominanceTable);
104     result.initialize();
105     return result;
106 }
107
108 public static JPEGHuffmanTable getDefaultDCLuminanceTable() {
109     JPEGHuffmanTable result = new JPEGHuffmanTable(DCLuminanceTable);
110     result.initialize();
111     return result;
112 }
113
114 public int[] getDhMaxCodes() {
115     return dhMaxCodes;
116 }
117
118 public int[] getDhMinCodes() {
119     return dhMinCodes;
120 }
121
122 public int[] getDhValPtrs() {
123     return dhValPtrs;
124 }
125
126 public int[] getDhValues() {
127     return dhValues;
128 }
129
130 public int getTableClass() {
131     return tableClass;
132 }
133
134 public int getTableIdentifier() {
135     return tableIdentifier;
136 }
137
138 void initialize() {
139     int totalLength = getSegmentLength() - 2;
140     int ofs = 4;
141     int[] bits = new int[16];
142     JPEGHuffmanTable[] huffTables = new JPEGHuffmanTable[8]; // maximum is 4 AC + 4 DC
143 int huffTableCount = 0;
144     while (totalLength > 0) {
145         int tc = (reference[ofs] & 0xFF) >> 4; // table class: AC (1) or DC (0)
146 int tid = reference[ofs] & 0xF; // table id: 0-1 baseline, 0-3 prog/ext
147 ofs++;
148         
149         /* Read the 16 count bytes and add them together to get the table size. */
150         int count = 0;
151         for (int i = 0; i < bits.length; i++) {
152             int bCount = reference[ofs + i] & 0xFF;
153             bits[i] = bCount;
154             count += bCount;
155         }
156         ofs += 16;
157         totalLength -= 17;
158         
159         /* Read the table. */
160         int[] huffVals = new int[count];
161         for (int i = 0; i < count; i++) {
162             huffVals[i] = reference[ofs + i] & 0xFF;
163         }
164         ofs += count;
165         totalLength -= count;
166         
167         /* Calculate the lengths. */
168         int[] huffCodeLengths = new int[50]; // start with 50 and increment as needed
169 int huffCodeLengthsIndex = 0;
170         for (int i = 0; i < 16; i++) {
171             for (int j = 0; j < bits[i]; j++) {
172                 if (huffCodeLengthsIndex >= huffCodeLengths.length) {
173                     int[] newHuffCodeLengths = new int[huffCodeLengths.length + 50];
174                     System.arraycopy(huffCodeLengths, 0, newHuffCodeLengths, 0, huffCodeLengths.length);
175                     huffCodeLengths = newHuffCodeLengths;
176                 }
177                 huffCodeLengths[huffCodeLengthsIndex] = i + 1;
178                 huffCodeLengthsIndex++;
179             }
180         }
181         
182         /* Truncate huffCodeLengths to the correct size. */
183         if (huffCodeLengthsIndex < huffCodeLengths.length) {
184             int[] newHuffCodeLengths = new int[huffCodeLengthsIndex];
185             System.arraycopy(huffCodeLengths, 0, newHuffCodeLengths, 0, huffCodeLengthsIndex);
186             huffCodeLengths = newHuffCodeLengths;
187         }
188         
189         /* Calculate the Huffman codes. */
190         int[] huffCodes = new int[50]; // start with 50 and increment as needed
191 int huffCodesIndex = 0;
192         int k = 1;
193         int code = 0;
194         int si = huffCodeLengths[0];
195         int p = 0;
196         while (p < huffCodeLengthsIndex) {
197             while ((p < huffCodeLengthsIndex) && (huffCodeLengths[p] == si)) {
198                 if (huffCodesIndex >= huffCodes.length) {
199                     int[] newHuffCodes = new int[huffCodes.length + 50];
200                     System.arraycopy(huffCodes, 0, newHuffCodes, 0, huffCodes.length);
201                     huffCodes = newHuffCodes;
202                 }
203                 huffCodes[huffCodesIndex] = code;
204                 huffCodesIndex++;
205                 code++;
206                 p++;
207             }
208             code *= 2;
209             si++;
210         }
211         
212         /* Truncate huffCodes to the correct size. */
213         if (huffCodesIndex < huffCodes.length) {
214             int[] newHuffCodes = new int[huffCodesIndex];
215             System.arraycopy(huffCodes, 0, newHuffCodes, 0, huffCodesIndex);
216             huffCodes = newHuffCodes;
217         }
218         
219         /* Calculate the maximum and minimum codes */
220         k = 0;
221         int[] maxCodes = new int[16];
222         int[] minCodes = new int[16];
223         int[] valPtrs = new int[16];
224         for (int i = 0; i < 16; i++) {
225             int bSize = bits[i];
226             if (bSize == 0) {
227                 maxCodes[i] = -1;
228             } else {
229                 valPtrs[i] = k;
230                 minCodes[i] = huffCodes[k];
231                 k += bSize;
232                 maxCodes[i] = huffCodes[k - 1];
233             }
234         }
235         
236         /* Calculate the eHuffman codes and lengths. */
237         int[] eHuffCodes = new int[256];
238         byte[] eHuffSize = new byte[256];
239         for (int i = 0; i < huffCodesIndex; i++) {
240             eHuffCodes[huffVals[i]] = huffCodes[i];
241             eHuffSize[huffVals[i]] = (byte)huffCodeLengths[i];
242         }
243         
244         /* Create the new JPEGHuffmanTable and add it to the allTables array. */
245         JPEGHuffmanTable dhtTable = new JPEGHuffmanTable(reference);
246         dhtTable.tableClass = tc;
247         dhtTable.tableIdentifier = tid;
248         dhtTable.dhValues = huffVals;
249         dhtTable.dhMinCodes = minCodes;
250         dhtTable.dhMaxCodes = maxCodes;
251         dhtTable.dhValPtrs = valPtrs;
252         dhtTable.ehCodes = eHuffCodes;
253         dhtTable.ehCodeLengths = eHuffSize;
254         huffTables[huffTableCount] = dhtTable;
255         huffTableCount++;
256     }
257     allTables = new JPEGHuffmanTable[huffTableCount];
258     System.arraycopy(huffTables, 0, allTables, 0, huffTableCount);
259 }
260
261 public int signature() {
262     return JPEGFileFormat.DHT;
263 }
264 }
265
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