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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package com.sun.imageio.plugins.jpeg;

import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.plugins.jpeg.JPEGHuffmanTable;

import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.NamedNodeMap;

A DHT (Define Huffman Table) marker segment.
/** * A DHT (Define Huffman Table) marker segment. */
class DHTMarkerSegment extends MarkerSegment { List<Htable> tables = new ArrayList<>(); DHTMarkerSegment(boolean needFour) { super(JPEG.DHT); tables.add(new Htable(JPEGHuffmanTable.StdDCLuminance, true, 0)); if (needFour) { tables.add(new Htable(JPEGHuffmanTable.StdDCChrominance, true, 1)); } tables.add(new Htable(JPEGHuffmanTable.StdACLuminance, false, 0)); if (needFour) { tables.add(new Htable(JPEGHuffmanTable.StdACChrominance, false, 1)); } } DHTMarkerSegment(JPEGBuffer buffer) throws IOException { super(buffer); int count = length; while (count > 0) { Htable newGuy = new Htable(buffer); tables.add(newGuy); count -= 1 + 16 + newGuy.values.length; } buffer.bufAvail -= length; } DHTMarkerSegment(JPEGHuffmanTable[] dcTables, JPEGHuffmanTable[] acTables) { super(JPEG.DHT); for (int i = 0; i < dcTables.length; i++) { tables.add(new Htable(dcTables[i], true, i)); } for (int i = 0; i < acTables.length; i++) { tables.add(new Htable(acTables[i], false, i)); } } DHTMarkerSegment(Node node) throws IIOInvalidTreeException { super(JPEG.DHT); NodeList children = node.getChildNodes(); int size = children.getLength(); if ((size < 1) || (size > 4)) { throw new IIOInvalidTreeException("Invalid DHT node", node); } for (int i = 0; i < size; i++) { tables.add(new Htable(children.item(i))); } } protected Object clone() { DHTMarkerSegment newGuy = (DHTMarkerSegment) super.clone(); newGuy.tables = new ArrayList<>(tables.size()); Iterator<Htable> iter = tables.iterator(); while (iter.hasNext()) { Htable table = iter.next(); newGuy.tables.add((Htable) table.clone()); } return newGuy; } IIOMetadataNode getNativeNode() { IIOMetadataNode node = new IIOMetadataNode("dht"); for (int i= 0; i<tables.size(); i++) { Htable table = tables.get(i); node.appendChild(table.getNativeNode()); } return node; }
Writes the data for this segment to the stream in valid JPEG format.
/** * Writes the data for this segment to the stream in * valid JPEG format. */
void write(ImageOutputStream ios) throws IOException { // We don't write DHT segments; the IJG library does. } void print() { printTag("DHT"); System.out.println("Num tables: " + Integer.toString(tables.size())); for (int i= 0; i<tables.size(); i++) { Htable table = tables.get(i); table.print(); } System.out.println(); } Htable getHtableFromNode(Node node) throws IIOInvalidTreeException { return new Htable(node); } void addHtable(JPEGHuffmanTable table, boolean isDC, int id) { tables.add(new Htable(table, isDC, id)); }
A Huffman table within a DHT marker segment.
/** * A Huffman table within a DHT marker segment. */
class Htable implements Cloneable { int tableClass; // 0 == DC, 1 == AC int tableID; // 0 - 4 private static final int NUM_LENGTHS = 16; // # of codes of each length short [] numCodes = new short[NUM_LENGTHS]; short [] values; Htable(JPEGBuffer buffer) { tableClass = buffer.buf[buffer.bufPtr] >>> 4; tableID = buffer.buf[buffer.bufPtr++] & 0xf; for (int i = 0; i < NUM_LENGTHS; i++) { numCodes[i] = (short) (buffer.buf[buffer.bufPtr++] & 0xff); } int numValues = 0; for (int i = 0; i < NUM_LENGTHS; i++) { numValues += numCodes[i]; } values = new short[numValues]; for (int i = 0; i < numValues; i++) { values[i] = (short) (buffer.buf[buffer.bufPtr++] & 0xff); } } Htable(JPEGHuffmanTable table, boolean isDC, int id) { tableClass = isDC ? 0 : 1; tableID = id; numCodes = table.getLengths(); values = table.getValues(); } Htable(Node node) throws IIOInvalidTreeException { if (node.getNodeName().equals("dhtable")) { NamedNodeMap attrs = node.getAttributes(); int count = attrs.getLength(); if (count != 2) { throw new IIOInvalidTreeException ("dhtable node must have 2 attributes", node); } tableClass = getAttributeValue(node, attrs, "class", 0, 1, true); tableID = getAttributeValue(node, attrs, "htableId", 0, 3, true); if (node instanceof IIOMetadataNode) { IIOMetadataNode ourNode = (IIOMetadataNode) node; JPEGHuffmanTable table = (JPEGHuffmanTable) ourNode.getUserObject(); if (table == null) { throw new IIOInvalidTreeException ("dhtable node must have user object", node); } numCodes = table.getLengths(); values = table.getValues(); } else { throw new IIOInvalidTreeException ("dhtable node must have user object", node); } } else { throw new IIOInvalidTreeException ("Invalid node, expected dqtable", node); } } protected Object clone() { Htable newGuy = null; try { newGuy = (Htable) super.clone(); } catch (CloneNotSupportedException e) {} // won't happen if (numCodes != null) { newGuy.numCodes = numCodes.clone(); } if (values != null) { newGuy.values = values.clone(); } return newGuy; } IIOMetadataNode getNativeNode() { IIOMetadataNode node = new IIOMetadataNode("dhtable"); node.setAttribute("class", Integer.toString(tableClass)); node.setAttribute("htableId", Integer.toString(tableID)); node.setUserObject(new JPEGHuffmanTable(numCodes, values)); return node; } void print() { System.out.println("Huffman Table"); System.out.println("table class: " + ((tableClass == 0) ? "DC":"AC")); System.out.println("table id: " + Integer.toString(tableID)); (new JPEGHuffmanTable(numCodes, values)).toString(); /* System.out.print("Lengths:"); for (int i=0; i<16; i++) { System.out.print(" " + Integer.toString(numCodes[i])); } int count = 0; if (values.length > 16) { System.out.println("\nFirst 16 Values:"); count = 16; } else { System.out.println("\nValues:"); count = values.length; } for (int i=0; i<count; i++) { System.out.println(Integer.toString(values[i]&0xff)); } */ } } }