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/*
* Copyright 2002-2019 Drew Noakes and contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* More information about this project is available at:
*
* https://drewnoakes.com/code/exif/
* https://github.com/drewnoakes/metadata-extractor
*/
package com.drew.metadata.jpeg;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import com.drew.lang.annotations.NotNull;
import com.drew.metadata.Directory;
import com.drew.metadata.MetadataException;
/**
* Directory of tables for the DHT (Define Huffman Table(s)) segment.
*
* @author Nadahar
*/
@SuppressWarnings("WeakerAccess")
public class HuffmanTablesDirectory extends Directory
{
public static final int TAG_NUMBER_OF_TABLES = 1;
static final byte[] TYPICAL_LUMINANCE_DC_LENGTHS = {
(byte) 0x00, (byte) 0x01, (byte) 0x05, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01,
(byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00
};
static final byte[] TYPICAL_LUMINANCE_DC_VALUES = {
(byte) 0x00, (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x04, (byte) 0x05, (byte) 0x06, (byte) 0x07,
(byte) 0x08, (byte) 0x09, (byte) 0x0A, (byte) 0x0B
};
static final byte[] TYPICAL_CHROMINANCE_DC_LENGTHS = {
(byte) 0x00, (byte) 0x03, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01,
(byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00
};
static final byte[] TYPICAL_CHROMINANCE_DC_VALUES = {
(byte) 0x00, (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x04, (byte) 0x05, (byte) 0x06, (byte) 0x07,
(byte) 0x08, (byte) 0x09, (byte) 0x0A, (byte) 0x0B
};
static final byte[] TYPICAL_LUMINANCE_AC_LENGTHS = {
(byte) 0x00, (byte) 0x02, (byte) 0x01, (byte) 0x03, (byte) 0x03, (byte) 0x02, (byte) 0x04, (byte) 0x03,
(byte) 0x05, (byte) 0x05, (byte) 0x04, (byte) 0x04, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x7D
};
static final byte[] TYPICAL_LUMINANCE_AC_VALUES = {
(byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x00, (byte) 0x04, (byte) 0x11, (byte) 0x05, (byte) 0x12,
(byte) 0x21, (byte) 0x31, (byte) 0x41, (byte) 0x06, (byte) 0x13, (byte) 0x51, (byte) 0x61, (byte) 0x07,
(byte) 0x22, (byte) 0x71, (byte) 0x14, (byte) 0x32, (byte) 0x81, (byte) 0x91, (byte) 0xA1, (byte) 0x08,
(byte) 0x23, (byte) 0x42, (byte) 0xB1, (byte) 0xC1, (byte) 0x15, (byte) 0x52, (byte) 0xD1, (byte) 0xF0,
(byte) 0x24, (byte) 0x33, (byte) 0x62, (byte) 0x72, (byte) 0x82, (byte) 0x09, (byte) 0x0A, (byte) 0x16,
(byte) 0x17, (byte) 0x18, (byte) 0x19, (byte) 0x1A, (byte) 0x25, (byte) 0x26, (byte) 0x27, (byte) 0x28,
(byte) 0x29, (byte) 0x2A, (byte) 0x34, (byte) 0x35, (byte) 0x36, (byte) 0x37, (byte) 0x38, (byte) 0x39,
(byte) 0x3A, (byte) 0x43, (byte) 0x44, (byte) 0x45, (byte) 0x46, (byte) 0x47, (byte) 0x48, (byte) 0x49,
(byte) 0x4A, (byte) 0x53, (byte) 0x54, (byte) 0x55, (byte) 0x56, (byte) 0x57, (byte) 0x58, (byte) 0x59,
(byte) 0x5A, (byte) 0x63, (byte) 0x64, (byte) 0x65, (byte) 0x66, (byte) 0x67, (byte) 0x68, (byte) 0x69,
(byte) 0x6A, (byte) 0x73, (byte) 0x74, (byte) 0x75, (byte) 0x76, (byte) 0x77, (byte) 0x78, (byte) 0x79,
(byte) 0x7A, (byte) 0x83, (byte) 0x84, (byte) 0x85, (byte) 0x86, (byte) 0x87, (byte) 0x88, (byte) 0x89,
(byte) 0x8A, (byte) 0x92, (byte) 0x93, (byte) 0x94, (byte) 0x95, (byte) 0x96, (byte) 0x97, (byte) 0x98,
(byte) 0x99, (byte) 0x9A, (byte) 0xA2, (byte) 0xA3, (byte) 0xA4, (byte) 0xA5, (byte) 0xA6, (byte) 0xA7,
(byte) 0xA8, (byte) 0xA9, (byte) 0xAA, (byte) 0xB2, (byte) 0xB3, (byte) 0xB4, (byte) 0xB5, (byte) 0xB6,
(byte) 0xB7, (byte) 0xB8, (byte) 0xB9, (byte) 0xBA, (byte) 0xC2, (byte) 0xC3, (byte) 0xC4, (byte) 0xC5,
(byte) 0xC6, (byte) 0xC7, (byte) 0xC8, (byte) 0xC9, (byte) 0xCA, (byte) 0xD2, (byte) 0xD3, (byte) 0xD4,
(byte) 0xD5, (byte) 0xD6, (byte) 0xD7, (byte) 0xD8, (byte) 0xD9, (byte) 0xDA, (byte) 0xE1, (byte) 0xE2,
(byte) 0xE3, (byte) 0xE4, (byte) 0xE5, (byte) 0xE6, (byte) 0xE7, (byte) 0xE8, (byte) 0xE9, (byte) 0xEA,
(byte) 0xF1, (byte) 0xF2, (byte) 0xF3, (byte) 0xF4, (byte) 0xF5, (byte) 0xF6, (byte) 0xF7, (byte) 0xF8,
(byte) 0xF9, (byte) 0xFA
};
static final byte[] TYPICAL_CHROMINANCE_AC_LENGTHS = {
(byte) 0x00, (byte) 0x02, (byte) 0x01, (byte) 0x02, (byte) 0x04, (byte) 0x04, (byte) 0x03, (byte) 0x04,
(byte) 0x07, (byte) 0x05, (byte) 0x04, (byte) 0x04, (byte) 0x00, (byte) 0x01, (byte) 0x02, (byte) 0x77
};
static final byte[] TYPICAL_CHROMINANCE_AC_VALUES = {
(byte) 0x00, (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x11, (byte) 0x04, (byte) 0x05, (byte) 0x21,
(byte) 0x31, (byte) 0x06, (byte) 0x12, (byte) 0x41, (byte) 0x51, (byte) 0x07, (byte) 0x61, (byte) 0x71,
(byte) 0x13, (byte) 0x22, (byte) 0x32, (byte) 0x81, (byte) 0x08, (byte) 0x14, (byte) 0x42, (byte) 0x91,
(byte) 0xA1, (byte) 0xB1, (byte) 0xC1, (byte) 0x09, (byte) 0x23, (byte) 0x33, (byte) 0x52, (byte) 0xF0,
(byte) 0x15, (byte) 0x62, (byte) 0x72, (byte) 0xD1, (byte) 0x0A, (byte) 0x16, (byte) 0x24, (byte) 0x34,
(byte) 0xE1, (byte) 0x25, (byte) 0xF1, (byte) 0x17, (byte) 0x18, (byte) 0x19, (byte) 0x1A, (byte) 0x26,
(byte) 0x27, (byte) 0x28, (byte) 0x29, (byte) 0x2A, (byte) 0x35, (byte) 0x36, (byte) 0x37, (byte) 0x38,
(byte) 0x39, (byte) 0x3A, (byte) 0x43, (byte) 0x44, (byte) 0x45, (byte) 0x46, (byte) 0x47, (byte) 0x48,
(byte) 0x49, (byte) 0x4A, (byte) 0x53, (byte) 0x54, (byte) 0x55, (byte) 0x56, (byte) 0x57, (byte) 0x58,
(byte) 0x59, (byte) 0x5A, (byte) 0x63, (byte) 0x64, (byte) 0x65, (byte) 0x66, (byte) 0x67, (byte) 0x68,
(byte) 0x69, (byte) 0x6A, (byte) 0x73, (byte) 0x74, (byte) 0x75, (byte) 0x76, (byte) 0x77, (byte) 0x78,
(byte) 0x79, (byte) 0x7A, (byte) 0x82, (byte) 0x83, (byte) 0x84, (byte) 0x85, (byte) 0x86, (byte) 0x87,
(byte) 0x88, (byte) 0x89, (byte) 0x8A, (byte) 0x92, (byte) 0x93, (byte) 0x94, (byte) 0x95, (byte) 0x96,
(byte) 0x97, (byte) 0x98, (byte) 0x99, (byte) 0x9A, (byte) 0xA2, (byte) 0xA3, (byte) 0xA4, (byte) 0xA5,
(byte) 0xA6, (byte) 0xA7, (byte) 0xA8, (byte) 0xA9, (byte) 0xAA, (byte) 0xB2, (byte) 0xB3, (byte) 0xB4,
(byte) 0xB5, (byte) 0xB6, (byte) 0xB7, (byte) 0xB8, (byte) 0xB9, (byte) 0xBA, (byte) 0xC2, (byte) 0xC3,
(byte) 0xC4, (byte) 0xC5, (byte) 0xC6, (byte) 0xC7, (byte) 0xC8, (byte) 0xC9, (byte) 0xCA, (byte) 0xD2,
(byte) 0xD3, (byte) 0xD4, (byte) 0xD5, (byte) 0xD6, (byte) 0xD7, (byte) 0xD8, (byte) 0xD9, (byte) 0xDA,
(byte) 0xE2, (byte) 0xE3, (byte) 0xE4, (byte) 0xE5, (byte) 0xE6, (byte) 0xE7, (byte) 0xE8, (byte) 0xE9,
(byte) 0xEA, (byte) 0xF2, (byte) 0xF3, (byte) 0xF4, (byte) 0xF5, (byte) 0xF6, (byte) 0xF7, (byte) 0xF8,
(byte) 0xF9, (byte) 0xFA
};
@NotNull
protected final List tables = new ArrayList(4);
@NotNull
private static final HashMap _tagNameMap = new HashMap();
static
{
_tagNameMap.put(TAG_NUMBER_OF_TABLES, "Number of Tables");
}
public HuffmanTablesDirectory()
{
this.setDescriptor(new HuffmanTablesDescriptor(this));
}
@Override
@NotNull
public String getName()
{
return "Huffman";
}
@Override
@NotNull
protected HashMap getTagNameMap()
{
return _tagNameMap;
}
/**
* @param tableNumber The zero-based index of the table. This number is normally between 0 and 3.
* Use {@link #getNumberOfTables} for bounds-checking.
* @return The {@link HuffmanTable} having the specified number.
*/
@NotNull
public HuffmanTable getTable(int tableNumber)
{
return tables.get(tableNumber);
}
/**
* @return The number of Huffman tables held by this {@link HuffmanTablesDirectory} instance.
*/
public int getNumberOfTables() throws MetadataException
{
return getInt(HuffmanTablesDirectory.TAG_NUMBER_OF_TABLES);
}
/**
* @return The {@link List} of {@link HuffmanTable}s in this
* {@link Directory}.
*/
@NotNull
protected List getTables()
{
return tables;
}
/**
* Evaluates whether all the tables in this {@link HuffmanTablesDirectory}
* are "typical" Huffman tables.
*
* "Typical" has a special meaning in this context as the JPEG standard
* (ISO/IEC 10918 or ITU-T T.81) defines 4 Huffman tables that has been
* developed from the average statistics of a large set of images with 8-bit
* precision. Using these instead of calculating the optimal Huffman tables
* for a given image is faster, and is preferred by many hardware encoders
* and some hardware decoders.
*
* Even though the JPEG standard doesn't define these as "standard tables"
* and requires a decoder to be able to read any valid Huffman tables, some
* are in reality limited decoding images using these "typical" tables.
* Standards like DCF (Design rule for Camera File system) and DLNA (Digital
* Living Network Alliance) actually requires any compliant JPEG to use only
* the "typical" Huffman tables.
*
* This is also related to the term "optimized" JPEG. An "optimized" JPEG is
* a JPEG that doesn't use the "typical" Huffman tables.
*
* @return Whether or not all the tables in this
* {@link HuffmanTablesDirectory} are the predefined "typical"
* Huffman tables.
*/
public boolean isTypical()
{
if (tables.size() == 0) {
return false;
}
for (HuffmanTable table : tables) {
if (!table.isTypical()) {
return false;
}
}
return true;
}
/**
* The opposite of {@link #isTypical()}.
*
* @return Whether or not the tables in this {@link HuffmanTablesDirectory}
* are "optimized" - which means that at least one of them aren't
* one of the "typical" Huffman tables.
*/
public boolean isOptimized()
{
return !isTypical();
}
/**
* An instance of this class holds a JPEG Huffman table.
*/
public static class HuffmanTable
{
private final int _tableLength;
private final HuffmanTableClass _tableClass;
private final int _tableDestinationId;
private final byte[] _lengthBytes;
private final byte[] _valueBytes;
@SuppressWarnings("ConstantConditions")
public HuffmanTable(
@NotNull HuffmanTableClass tableClass,
int tableDestinationId,
@NotNull byte[] lengthBytes,
@NotNull byte[] valueBytes)
{
if (lengthBytes == null)
throw new IllegalArgumentException("lengthBytes cannot be null.");
if (valueBytes == null)
throw new IllegalArgumentException("valueBytes cannot be null.");
_tableClass = tableClass;
_tableDestinationId = tableDestinationId;
_lengthBytes = lengthBytes;
_valueBytes = valueBytes;
_tableLength = _valueBytes.length + 17;
}
/**
* @return The table length in bytes.
*/
public int getTableLength()
{
return _tableLength;
}
/**
* @return The {@link HuffmanTableClass} of this table.
*/
public HuffmanTableClass getTableClass()
{
return _tableClass;
}
/**
* @return the the destination identifier for this table.
*/
public int getTableDestinationId()
{
return _tableDestinationId;
}
/**
* @return A byte array with the L values for this table.
*/
@NotNull
public byte[] getLengthBytes()
{
byte[] result = new byte[_lengthBytes.length];
System.arraycopy(_lengthBytes, 0, result, 0, _lengthBytes.length);
return result;
}
/**
* @return A byte array with the V values for this table.
*/
@NotNull
public byte[] getValueBytes()
{
byte[] result = new byte[_valueBytes.length];
System.arraycopy(_valueBytes, 0, result, 0, _valueBytes.length);
return result;
}
/**
* Evaluates whether this table is a "typical" Huffman table.
*
* "Typical" has a special meaning in this context as the JPEG standard
* (ISO/IEC 10918 or ITU-T T.81) defines 4 Huffman tables that has been
* developed from the average statistics of a large set of images with
* 8-bit precision. Using these instead of calculating the optimal
* Huffman tables for a given image is faster, and is preferred by many
* hardware encoders and some hardware decoders.
*
* Even though the JPEG standard doesn't define these as
* "standard tables" and requires a decoder to be able to read any valid
* Huffman tables, some are in reality limited decoding images using
* these "typical" tables. Standards like DCF (Design rule for Camera
* File system) and DLNA (Digital Living Network Alliance) actually
* requires any compliant JPEG to use only the "typical" Huffman tables.
*
* This is also related to the term "optimized" JPEG. An "optimized"
* JPEG is a JPEG that doesn't use the "typical" Huffman tables.
*
* @return Whether or not this table is one of the predefined "typical"
* Huffman tables.
*/
public boolean isTypical()
{
if (_tableClass == HuffmanTableClass.DC) {
return
Arrays.equals(_lengthBytes, TYPICAL_LUMINANCE_DC_LENGTHS) &&
Arrays.equals(_valueBytes, TYPICAL_LUMINANCE_DC_VALUES) ||
Arrays.equals(_lengthBytes, TYPICAL_CHROMINANCE_DC_LENGTHS) &&
Arrays.equals(_valueBytes, TYPICAL_CHROMINANCE_DC_VALUES);
} else if (_tableClass == HuffmanTableClass.AC) {
return
Arrays.equals(_lengthBytes, TYPICAL_LUMINANCE_AC_LENGTHS) &&
Arrays.equals(_valueBytes, TYPICAL_LUMINANCE_AC_VALUES) ||
Arrays.equals(_lengthBytes, TYPICAL_CHROMINANCE_AC_LENGTHS) &&
Arrays.equals(_valueBytes, TYPICAL_CHROMINANCE_AC_VALUES);
}
return false;
}
/**
* The opposite of {@link #isTypical()}.
*
* @return Whether or not this table is "optimized" - which means that
* it isn't one of the "typical" Huffman tables.
*/
public boolean isOptimized()
{
return !isTypical();
}
public enum HuffmanTableClass
{
DC,
AC,
UNKNOWN;
public static HuffmanTableClass typeOf(int value)
{
switch (value) {
case 0:
return DC;
case 1:
return AC;
default:
return UNKNOWN;
}
}
}
}
}