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	/*
	* Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.imageio.plugins.gif;

	import javax.imageio.metadata.IIOInvalidTreeException;
	import javax.imageio.metadata.IIOMetadata;
	import javax.imageio.metadata.IIOMetadataFormatImpl;
	import org.w3c.dom.Node;

	/**
	* Class which adds utility DOM element attribute access methods to
	* <code>IIOMetadata</code> for subclass use.
	*/
	abstract class GIFMetadata extends IIOMetadata {

	/**
	* Represents an undefined value of integer attributes.
	*/
	static final int UNDEFINED_INTEGER_VALUE = -1;

	//
	// Note: These attribute methods were shamelessly lifted from
	// com.sun.imageio.plugins.png.PNGMetadata and modified.
	//

	// Shorthand for throwing an IIOInvalidTreeException
	protected static void fatal(Node node, String reason)
	throws IIOInvalidTreeException {
	throw new IIOInvalidTreeException(reason, node);
	}

	// Get an integer-valued attribute
	protected static String getStringAttribute(Node node, String name,
	String defaultValue,
	boolean required,
	String[] range)
	throws IIOInvalidTreeException {
	Node attr = node.getAttributes().getNamedItem(name);
	if (attr == null) {
	if (!required) {
	return defaultValue;
	} else {
	fatal(node, "Required attribute " + name + " not present!");
	}
	}
	String value = attr.getNodeValue();

	if (range != null) {
	if (value == null) {
	fatal(node,
	"Null value for "+node.getNodeName()+
	" attribute "+name+"!");
	}
	boolean validValue = false;
	int len = range.length;
	for (int i = 0; i < len; i++) {
	if (value.equals(range[i])) {
	validValue = true;
	break;
	}
	}
	if (!validValue) {
	fatal(node,
	"Bad value for "+node.getNodeName()+
	" attribute "+name+"!");
	}
	}

	return value;
	}


	// Get an integer-valued attribute
	protected static int getIntAttribute(Node node, String name,
	int defaultValue, boolean required,
	boolean bounded, int min, int max)
	throws IIOInvalidTreeException {
	String value = getStringAttribute(node, name, null, required, null);
	if (value == null \|\| "".equals(value)) {
	return defaultValue;
	}

	int intValue = defaultValue;
	try {
	intValue = Integer.parseInt(value);
	} catch (NumberFormatException e) {
	fatal(node,
	"Bad value for "+node.getNodeName()+
	" attribute "+name+"!");
	}
	if (bounded && (intValue < min \|\| intValue > max)) {
	fatal(node,
	"Bad value for "+node.getNodeName()+
	" attribute "+name+"!");
	}
	return intValue;
	}

	// Get a float-valued attribute
	protected static float getFloatAttribute(Node node, String name,
	float defaultValue,
	boolean required)
	throws IIOInvalidTreeException {
	String value = getStringAttribute(node, name, null, required, null);
	if (value == null) {
	return defaultValue;
	}
	return Float.parseFloat(value);
	}

	// Get a required integer-valued attribute
	protected static int getIntAttribute(Node node, String name,
	boolean bounded, int min, int max)
	throws IIOInvalidTreeException {
	return getIntAttribute(node, name, -1, true, bounded, min, max);
	}

	// Get a required float-valued attribute
	protected static float getFloatAttribute(Node node, String name)
	throws IIOInvalidTreeException {
	return getFloatAttribute(node, name, -1.0F, true);
	}

	// Get a boolean-valued attribute
	protected static boolean getBooleanAttribute(Node node, String name,
	boolean defaultValue,
	boolean required)
	throws IIOInvalidTreeException {
	Node attr = node.getAttributes().getNamedItem(name);
	if (attr == null) {
	if (!required) {
	return defaultValue;
	} else {
	fatal(node, "Required attribute " + name + " not present!");
	}
	}
	String value = attr.getNodeValue();
	// Allow lower case booleans for backward compatibility, #5082756
	if (value.equals("TRUE") \|\| value.equals("true")) {
	return true;
	} else if (value.equals("FALSE") \|\| value.equals("false")) {
	return false;
	} else {
	fatal(node, "Attribute " + name + " must be 'TRUE' or 'FALSE'!");
	return false;
	}
	}

	// Get a required boolean-valued attribute
	protected static boolean getBooleanAttribute(Node node, String name)
	throws IIOInvalidTreeException {
	return getBooleanAttribute(node, name, false, true);
	}

	// Get an enumerated attribute as an index into a String array
	protected static int getEnumeratedAttribute(Node node,
	String name,
	String[] legalNames,
	int defaultValue,
	boolean required)
	throws IIOInvalidTreeException {
	Node attr = node.getAttributes().getNamedItem(name);
	if (attr == null) {
	if (!required) {
	return defaultValue;
	} else {
	fatal(node, "Required attribute " + name + " not present!");
	}
	}
	String value = attr.getNodeValue();
	for (int i = 0; i < legalNames.length; i++) {
	if(value.equals(legalNames[i])) {
	return i;
	}
	}

	fatal(node, "Illegal value for attribute " + name + "!");
	return -1;
	}

	// Get a required enumerated attribute as an index into a String array
	protected static int getEnumeratedAttribute(Node node,
	String name,
	String[] legalNames)
	throws IIOInvalidTreeException {
	return getEnumeratedAttribute(node, name, legalNames, -1, true);
	}

	// Get a String-valued attribute
	protected static String getAttribute(Node node, String name,
	String defaultValue, boolean required)
	throws IIOInvalidTreeException {
	Node attr = node.getAttributes().getNamedItem(name);
	if (attr == null) {
	if (!required) {
	return defaultValue;
	} else {
	fatal(node, "Required attribute " + name + " not present!");
	}
	}
	return attr.getNodeValue();
	}

	// Get a required String-valued attribute
	protected static String getAttribute(Node node, String name)
	throws IIOInvalidTreeException {
	return getAttribute(node, name, null, true);
	}

	protected GIFMetadata(boolean standardMetadataFormatSupported,
	String nativeMetadataFormatName,
	String nativeMetadataFormatClassName,
	String[] extraMetadataFormatNames,
	String[] extraMetadataFormatClassNames) {
	super(standardMetadataFormatSupported,
	nativeMetadataFormatName,
	nativeMetadataFormatClassName,
	extraMetadataFormatNames,
	extraMetadataFormatClassNames);
	}

	public void mergeTree(String formatName, Node root)
	throws IIOInvalidTreeException {
	if (formatName.equals(nativeMetadataFormatName)) {
	if (root == null) {
	throw new IllegalArgumentException("root == null!");
	}
	mergeNativeTree(root);
	} else if (formatName.equals
	(IIOMetadataFormatImpl.standardMetadataFormatName)) {
	if (root == null) {
	throw new IllegalArgumentException("root == null!");
	}
	mergeStandardTree(root);
	} else {
	throw new IllegalArgumentException("Not a recognized format!");
	}
	}

	protected byte[] getColorTable(Node colorTableNode,
	String entryNodeName,
	boolean lengthExpected,
	int expectedLength)
	throws IIOInvalidTreeException {
	byte[] red = new byte[256];
	byte[] green = new byte[256];
	byte[] blue = new byte[256];
	int maxIndex = -1;

	Node entry = colorTableNode.getFirstChild();
	if (entry == null) {
	fatal(colorTableNode, "Palette has no entries!");
	}

	while (entry != null) {
	if (!entry.getNodeName().equals(entryNodeName)) {
	fatal(colorTableNode,
	"Only a "+entryNodeName+" may be a child of a "+
	entry.getNodeName()+"!");
	}

	int index = getIntAttribute(entry, "index", true, 0, 255);
	if (index > maxIndex) {
	maxIndex = index;
	}
	red[index] = (byte)getIntAttribute(entry, "red", true, 0, 255);
	green[index] = (byte)getIntAttribute(entry, "green", true, 0, 255);
	blue[index] = (byte)getIntAttribute(entry, "blue", true, 0, 255);

	entry = entry.getNextSibling();
	}

	int numEntries = maxIndex + 1;

	if (lengthExpected && numEntries != expectedLength) {
	fatal(colorTableNode, "Unexpected length for palette!");
	}

	byte[] colorTable = new byte[3*numEntries];
	for (int i = 0, j = 0; i < numEntries; i++) {
	colorTable[j++] = red[i];
	colorTable[j++] = green[i];
	colorTable[j++] = blue[i];
	}

	return colorTable;
	}

	protected abstract void mergeNativeTree(Node root)
	throws IIOInvalidTreeException;

	protected abstract void mergeStandardTree(Node root)
	throws IIOInvalidTreeException;
	}

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