1/* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18package javax.imageio.plugins.jpeg; 19 20/** 21 * The JPEGHuffmanTable class represents a single JPEG Huffman table. It 22 * contains the standard tables from the JPEG specification. 23 * 24 * @since Android 1.0 25 */ 26public class JPEGHuffmanTable { 27 28 /** 29 * The standard DC luminance Huffman table . 30 */ 31 public static final JPEGHuffmanTable StdDCLuminance = new JPEGHuffmanTable(new short[] { 32 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 33 }, new short[] { 34 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0x0A, 0x0B 35 }, false); 36 37 /** 38 * The standard DC chrominance Huffman table. 39 */ 40 public static final JPEGHuffmanTable StdDCChrominance = new JPEGHuffmanTable(new short[] { 41 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 42 }, new short[] { 43 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0x0A, 0x0B 44 }, false); 45 46 /** 47 * The standard AC luminance Huffman table. 48 */ 49 public static final JPEGHuffmanTable StdACLuminance = new JPEGHuffmanTable(new short[] { 50 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7D 51 }, new short[] { 52 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 53 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08, 0x23, 0x42, 0xB1, 0xC1, 54 0x15, 0x52, 0xD1, 0xF0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16, 0x17, 0x18, 55 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 56 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 57 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73, 0x74, 0x75, 58 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x92, 59 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 60 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 61 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 62 0xD9, 0xDA, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 63 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA 64 }, false); 65 66 /** 67 * The standard AC chrominance Huffman table. 68 */ 69 public static final JPEGHuffmanTable StdACChrominance = new JPEGHuffmanTable(new short[] { 70 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 71 }, new short[] { 72 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 73 0x61, 0x71, 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1, 0x09, 74 0x23, 0x33, 0x52, 0xF0, 0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34, 0xE1, 0x25, 75 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38, 76 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 77 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73, 0x74, 78 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 79 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 80 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 81 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 82 0xD7, 0xD8, 0xD9, 0xDA, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF2, 83 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA 84 }, false); 85 86 /** 87 * The lengths. 88 */ 89 private short lengths[]; 90 91 /** 92 * The values. 93 */ 94 private short values[]; 95 96 /** 97 * Instantiates a new jPEG huffman table. 98 * 99 * @param lengths 100 * the lengths 101 * @param values 102 * the values 103 * @param copy 104 * the copy 105 */ 106 JPEGHuffmanTable(short[] lengths, short[] values, boolean copy) { 107 // Construction of standard tables without checks 108 // The third param is dummy 109 // Could be also used for copying of the existing tables 110 this.lengths = lengths; 111 this.values = values; 112 } 113 114 /** 115 * Instantiates a new JPEGHuffmanTable. 116 * 117 * @param lengths 118 * the array of shorts lengths. 119 * @param values 120 * the array of shorts containing the values in order of 121 * increasing code length. 122 */ 123 public JPEGHuffmanTable(short[] lengths, short[] values) { 124 if (lengths == null) { 125 throw new IllegalArgumentException("lengths array is null!"); 126 } 127 if (values == null) { 128 throw new IllegalArgumentException("values array is null!"); 129 } 130 if (lengths.length > 16) { // According to the spec 131 throw new IllegalArgumentException("lengths array is too long!"); 132 } 133 if (values.length > 256) { // According to the spec 134 throw new IllegalArgumentException("values array is too long"); 135 } 136 for (short length : lengths) { 137 if (length < 0) { 138 throw new IllegalArgumentException("Values in lengths array must be non-negative."); 139 } 140 } 141 for (short value : values) { 142 if (value < 0) { 143 throw new IllegalArgumentException("Values in values array must be non-negative."); 144 } 145 } 146 147 checkHuffmanTable(lengths, values); 148 149 this.lengths = new short[lengths.length]; 150 this.values = new short[values.length]; 151 System.arraycopy(lengths, 0, this.lengths, 0, lengths.length); 152 System.arraycopy(values, 0, this.values, 0, values.length); 153 } 154 155 /** 156 * Gets an array of lengths in the Huffman table. 157 * 158 * @return the array of short values representing the length values in the 159 * Huffman table. 160 */ 161 public short[] getLengths() { 162 short newLengths[] = new short[lengths.length]; 163 System.arraycopy(lengths, 0, newLengths, 0, lengths.length); 164 return newLengths; 165 } 166 167 /** 168 * Gets an array of values represented by increasing length of their codes. 169 * 170 * @return the array of values. 171 */ 172 public short[] getValues() { 173 short newValues[] = new short[values.length]; 174 System.arraycopy(values, 0, newValues, 0, values.length); 175 return newValues; 176 } 177 178 /** 179 * Check huffman table. 180 * 181 * @param lengths 182 * the lengths. 183 * @param values 184 * the values. 185 */ 186 private static void checkHuffmanTable(short[] lengths, short[] values) { 187 int numLeaves = 0; 188 int possibleLeaves = 2; 189 for (short length : lengths) { 190 numLeaves += length; 191 possibleLeaves -= length; 192 if (possibleLeaves < 0) { 193 throw new IllegalArgumentException( 194 "Invalid Huffman table provided, lengths are incorrect."); 195 } 196 possibleLeaves <<= 1; 197 } 198 199 if (values.length != numLeaves) { 200 throw new IllegalArgumentException( 201 "Invalid Huffman table provided, sum of lengths != values."); 202 } 203 } 204 205 /** 206 * Returns the string representation of this JPEGHuffmanTable object. 207 * 208 * @return the string representation of this JPEGHuffmanTable object. 209 */ 210 @Override 211 public String toString() { 212 StringBuffer sb = new StringBuffer(); 213 214 sb.append("JPEGHuffmanTable:\nlengths:"); 215 for (short length : lengths) { 216 sb.append(' ').append(length); 217 } 218 219 sb.append("\nvalues:"); 220 for (short value : values) { 221 sb.append(' ').append(value); 222 } 223 224 return sb.toString(); 225 } 226} 227