// =================================================================================================
// ADOBE SYSTEMS INCORPORATED
// Copyright 2006 Adobe Systems Incorporated
// All Rights Reserved
//
// NOTICE:  Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
// =================================================================================================



package com.adobe.xmp.impl;

import java.util.Iterator;

import com.adobe.xmp.XMPConst;
import com.adobe.xmp.XMPError;
import com.adobe.xmp.XMPException;
import com.adobe.xmp.XMPMeta;
import com.adobe.xmp.XMPMetaFactory;
import com.adobe.xmp.XMPUtils;
import com.adobe.xmp.impl.xpath.XMPPath;
import com.adobe.xmp.impl.xpath.XMPPathParser;
import com.adobe.xmp.options.PropertyOptions;
import com.adobe.xmp.properties.XMPAliasInfo;



/**
 * @since 11.08.2006
 */
public class XMPUtilsImpl implements XMPConst
{
	/** */
	private static final int UCK_NORMAL = 0;
	/** */
	private static final int UCK_SPACE = 1;
	/** */
	private static final int UCK_COMMA = 2;
	/** */
	private static final int UCK_SEMICOLON = 3;
	/** */
	private static final int UCK_QUOTE = 4;
	/** */
	private static final int UCK_CONTROL = 5;


	/**
	 * Private constructor, as
	 */
	private XMPUtilsImpl()
	{
		// EMPTY
	}


	/**
	 * @see XMPUtils#catenateArrayItems(XMPMeta, String, String, String, String,
	 *      boolean)
	 * 
	 * @param xmp
	 *            The XMP object containing the array to be catenated.
	 * @param schemaNS
	 *            The schema namespace URI for the array. Must not be null or
	 *            the empty string.
	 * @param arrayName
	 *            The name of the array. May be a general path expression, must
	 *            not be null or the empty string. Each item in the array must
	 *            be a simple string value.
	 * @param separator
	 *            The string to be used to separate the items in the catenated
	 *            string. Defaults to "; ", ASCII semicolon and space
	 *            (U+003B, U+0020).
	 * @param quotes
	 *            The characters to be used as quotes around array items that
	 *            contain a separator. Defaults to '"'
	 * @param allowCommas
	 *            Option flag to control the catenation.
	 * @return Returns the string containing the catenated array items.
	 * @throws XMPException
	 *             Forwards the Exceptions from the metadata processing
	 */
	public static String catenateArrayItems(XMPMeta xmp, String schemaNS, String arrayName,
			String separator, String quotes, boolean allowCommas) throws XMPException
	{
		ParameterAsserts.assertSchemaNS(schemaNS);
		ParameterAsserts.assertArrayName(arrayName);
		ParameterAsserts.assertImplementation(xmp);
		if (separator == null  ||  separator.length() == 0)
		{
			separator = "; ";	
		}
		if (quotes == null  ||  quotes.length() == 0)
		{	
			quotes = "\"";
		}
		
		XMPMetaImpl xmpImpl = (XMPMetaImpl) xmp;
		XMPNode arrayNode = null;
		XMPNode currItem = null;

		// Return an empty result if the array does not exist, 
		// hurl if it isn't the right form.
		XMPPath arrayPath = XMPPathParser.expandXPath(schemaNS, arrayName);
		arrayNode = XMPNodeUtils.findNode(xmpImpl.getRoot(), arrayPath, false, null);
		if (arrayNode == null)
		{
			return "";
		}
		else if (!arrayNode.getOptions().isArray() || arrayNode.getOptions().isArrayAlternate())
		{
			throw new XMPException("Named property must be non-alternate array", XMPError.BADPARAM);
		}

		// Make sure the separator is OK.
		checkSeparator(separator);
		// Make sure the open and close quotes are a legitimate pair.
		char openQuote = quotes.charAt(0);
		char closeQuote = checkQuotes(quotes, openQuote);

		// Build the result, quoting the array items, adding separators.
		// Hurl if any item isn't simple.

		StringBuffer catinatedString = new StringBuffer();

		for (Iterator it = arrayNode.iterateChildren(); it.hasNext();)
		{
			currItem = (XMPNode) it.next();
			if (currItem.getOptions().isCompositeProperty())
			{
				throw new XMPException("Array items must be simple", XMPError.BADPARAM);
			}
			String str = applyQuotes(currItem.getValue(), openQuote, closeQuote, allowCommas);

			catinatedString.append(str);
			if (it.hasNext())
			{
				catinatedString.append(separator);
			}
		}

		return catinatedString.toString();
	}


	/**
	 * see {@link XMPUtils#separateArrayItems(XMPMeta, String, String, String, 
	 * PropertyOptions, boolean)}
	 * 
	 * @param xmp
	 *            The XMP object containing the array to be updated.
	 * @param schemaNS
	 *            The schema namespace URI for the array. Must not be null or
	 *            the empty string.
	 * @param arrayName
	 *            The name of the array. May be a general path expression, must
	 *            not be null or the empty string. Each item in the array must
	 *            be a simple string value.
	 * @param catedStr
	 *            The string to be separated into the array items.
	 * @param arrayOptions
	 *            Option flags to control the separation.
	 * @param preserveCommas
	 *            Flag if commas shall be preserved
	 * 
	 * @throws XMPException
	 *             Forwards the Exceptions from the metadata processing
	 */
	public static void separateArrayItems(XMPMeta xmp, String schemaNS, String arrayName,
			String catedStr, PropertyOptions arrayOptions, boolean preserveCommas)
			throws XMPException
	{
		ParameterAsserts.assertSchemaNS(schemaNS);
		ParameterAsserts.assertArrayName(arrayName);
		if (catedStr == null)
		{
			throw new XMPException("Parameter must not be null", XMPError.BADPARAM);
		}
		ParameterAsserts.assertImplementation(xmp);
		XMPMetaImpl xmpImpl = (XMPMetaImpl) xmp;

		// Keep a zero value, has special meaning below.
		XMPNode arrayNode = separateFindCreateArray(schemaNS, arrayName, arrayOptions, xmpImpl);

		// Extract the item values one at a time, until the whole input string is done.
		String itemValue;
		int itemStart, itemEnd;
		int nextKind = UCK_NORMAL, charKind = UCK_NORMAL;
		char ch = 0, nextChar = 0;
		
		itemEnd = 0;
		int endPos = catedStr.length();
		while (itemEnd < endPos)
		{
			// Skip any leading spaces and separation characters. Always skip commas here.
			// They can be kept when within a value, but not when alone between values.
			for (itemStart = itemEnd; itemStart < endPos; itemStart++)
			{
				ch = catedStr.charAt(itemStart);
				charKind = classifyCharacter(ch);
				if (charKind == UCK_NORMAL || charKind == UCK_QUOTE)
				{
					break;
				}
			}
			if (itemStart >= endPos)
			{
				break;
			}

			if (charKind != UCK_QUOTE)
			{
				// This is not a quoted value. Scan for the end, create an array
				// item from the substring.
				for (itemEnd = itemStart; itemEnd < endPos; itemEnd++)
				{
					ch = catedStr.charAt(itemEnd);
					charKind = classifyCharacter(ch);

					if (charKind == UCK_NORMAL || charKind == UCK_QUOTE  ||
						(charKind == UCK_COMMA && preserveCommas))
					{
						continue;
					}
					else if (charKind != UCK_SPACE)
					{
						break;
					}
					else if ((itemEnd + 1) < endPos)
					{
						ch = catedStr.charAt(itemEnd + 1);
						nextKind = classifyCharacter(ch);
						if (nextKind == UCK_NORMAL  ||  nextKind == UCK_QUOTE  ||
							(nextKind == UCK_COMMA && preserveCommas))
						{
							continue;
						}
					}
					
					// Anything left?
					break; // Have multiple spaces, or a space followed by a
							// separator.
				}
				itemValue = catedStr.substring(itemStart, itemEnd);
			}
			else
			{
				// Accumulate quoted values into a local string, undoubling
				// internal quotes that
				// match the surrounding quotes. Do not undouble "unmatching"
				// quotes.

				char openQuote = ch;
				char closeQuote = getClosingQuote(openQuote);

				itemStart++; // Skip the opening quote;
				itemValue = "";

				for (itemEnd = itemStart; itemEnd < endPos; itemEnd++)
				{
					ch = catedStr.charAt(itemEnd);
					charKind = classifyCharacter(ch);

					if (charKind != UCK_QUOTE || !isSurroundingQuote(ch, openQuote, closeQuote))
					{
						// This is not a matching quote, just append it to the
						// item value.
						itemValue += ch;
					}
					else
					{
						// This is a "matching" quote. Is it doubled, or the
						// final closing quote?
						// Tolerate various edge cases like undoubled opening
						// (non-closing) quotes,
						// or end of input.

						if ((itemEnd + 1) < endPos)
						{
							nextChar = catedStr.charAt(itemEnd + 1);
							nextKind = classifyCharacter(nextChar);
						}
						else
						{
							nextKind = UCK_SEMICOLON;
							nextChar = 0x3B;
						}

						if (ch == nextChar)
						{
							// This is doubled, copy it and skip the double.
							itemValue += ch;
							// Loop will add in charSize.
							itemEnd++;
						}
						else if (!isClosingingQuote(ch, openQuote, closeQuote))
						{
							// This is an undoubled, non-closing quote, copy it.
							itemValue += ch;
						}
						else
						{
							// This is an undoubled closing quote, skip it and
							// exit the loop.
							itemEnd++;
							break;
						}
					}
				}
			}

			// Add the separated item to the array. 
			// Keep a matching old value in case it had separators.
			int foundIndex = -1;
			for (int oldChild = 1; oldChild <= arrayNode.getChildrenLength(); oldChild++)
			{
				if (itemValue.equals(arrayNode.getChild(oldChild).getValue()))
				{
					foundIndex = oldChild;
					break;
				}
			}

			XMPNode newItem = null;
			if (foundIndex < 0)
			{
				newItem = new XMPNode(ARRAY_ITEM_NAME, itemValue, null);
				arrayNode.addChild(newItem);
			}			
		}
	}

	
	/**
	 * Utility to find or create the array used by <code>separateArrayItems()</code>.
	 * @param schemaNS a the namespace fo the array
	 * @param arrayName the name of the array 
	 * @param arrayOptions the options for the array if newly created
	 * @param xmp the xmp object
	 * @return Returns the array node.
	 * @throws XMPException Forwards exceptions
	 */
	private static XMPNode separateFindCreateArray(String schemaNS, String arrayName,
			PropertyOptions arrayOptions, XMPMetaImpl xmp) throws XMPException
	{
		arrayOptions = XMPNodeUtils.verifySetOptions(arrayOptions, null);
		if (!arrayOptions.isOnlyArrayOptions())
		{
			throw new XMPException("Options can only provide array form", XMPError.BADOPTIONS);
		}

		// Find the array node, make sure it is OK. Move the current children
		// aside, to be readded later if kept.
		XMPPath arrayPath = XMPPathParser.expandXPath(schemaNS, arrayName);
		XMPNode arrayNode = XMPNodeUtils.findNode(xmp.getRoot(), arrayPath, false, null);
		if (arrayNode != null)
		{
			// The array exists, make sure the form is compatible. Zero
			// arrayForm means take what exists.
			PropertyOptions arrayForm = arrayNode.getOptions();
			if (!arrayForm.isArray() || arrayForm.isArrayAlternate())
			{
				throw new XMPException("Named property must be non-alternate array", 
					XMPError.BADXPATH);
			}
			if (arrayOptions.equalArrayTypes(arrayForm))
			{
				throw new XMPException("Mismatch of specified and existing array form",
						XMPError.BADXPATH); // *** Right error?
			}
		}
		else
		{
			// The array does not exist, try to create it.
			// don't modify the options handed into the method
			arrayNode = XMPNodeUtils.findNode(xmp.getRoot(), arrayPath, true, arrayOptions
					.setArray(true));
			if (arrayNode == null)
			{
				throw new XMPException("Failed to create named array", XMPError.BADXPATH);
			}
		}
		return arrayNode;
	}


	/**
	 * @see XMPUtils#removeProperties(XMPMeta, String, String, boolean, boolean)
	 * 
	 * @param xmp
	 *            The XMP object containing the properties to be removed.
	 * 
	 * @param schemaNS
	 *            Optional schema namespace URI for the properties to be
	 *            removed.
	 * 
	 * @param propName
	 *            Optional path expression for the property to be removed.
	 * 
	 * @param doAllProperties
	 *            Option flag to control the deletion: do internal properties in
	 *            addition to external properties.
	 * @param includeAliases
	 *            Option flag to control the deletion: Include aliases in the
	 *            "named schema" case above.
	 * @throws XMPException If metadata processing fails
	 */
	public static void removeProperties(XMPMeta xmp, String schemaNS, String propName,
			boolean doAllProperties, boolean includeAliases) throws XMPException
	{
		ParameterAsserts.assertImplementation(xmp);
		XMPMetaImpl xmpImpl = (XMPMetaImpl) xmp;

		if (propName != null && propName.length() > 0)
		{
			// Remove just the one indicated property. This might be an alias,
			// the named schema might not actually exist. So don't lookup the
			// schema node.

			if (schemaNS == null || schemaNS.length() == 0)
			{
				throw new XMPException("Property name requires schema namespace", 
					XMPError.BADPARAM);
			}

			XMPPath expPath = XMPPathParser.expandXPath(schemaNS, propName);

			XMPNode propNode = XMPNodeUtils.findNode(xmpImpl.getRoot(), expPath, false, null);
			if (propNode != null)
			{
				if (doAllProperties
						|| !Utils.isInternalProperty(expPath.getSegment(XMPPath.STEP_SCHEMA)
								.getName(), expPath.getSegment(XMPPath.STEP_ROOT_PROP).getName()))
				{
					XMPNode parent = propNode.getParent();
					parent.removeChild(propNode);
					if (parent.getOptions().isSchemaNode()  &&  !parent.hasChildren())
					{
						// remove empty schema node
						parent.getParent().removeChild(parent);
					}
						
				}
			}
		}
		else if (schemaNS != null && schemaNS.length() > 0)
		{

			// Remove all properties from the named schema. Optionally include
			// aliases, in which case
			// there might not be an actual schema node.

			// XMP_NodePtrPos schemaPos;
			XMPNode schemaNode = XMPNodeUtils.findSchemaNode(xmpImpl.getRoot(), schemaNS, false);
			if (schemaNode != null)
			{
				if (removeSchemaChildren(schemaNode, doAllProperties))
				{
					xmpImpl.getRoot().removeChild(schemaNode);
				}
			}

			if (includeAliases)
			{
				// We're removing the aliases also. Look them up by their
				// namespace prefix.
				// But that takes more code and the extra speed isn't worth it.
				// Lookup the XMP node
				// from the alias, to make sure the actual exists.

				XMPAliasInfo[] aliases = XMPMetaFactory.getSchemaRegistry().findAliases(schemaNS);
				for (int i = 0; i < aliases.length; i++)
				{
					XMPAliasInfo info = aliases[i];
					XMPPath path = XMPPathParser.expandXPath(info.getNamespace(), info
							.getPropName());
					XMPNode actualProp = XMPNodeUtils
							.findNode(xmpImpl.getRoot(), path, false, null);
					if (actualProp != null)
					{
						XMPNode parent = actualProp.getParent();
						parent.removeChild(actualProp);
					}
				}
			}
		}
		else
		{
			// Remove all appropriate properties from all schema. In this case
			// we don't have to be
			// concerned with aliases, they are handled implicitly from the
			// actual properties.
			for (Iterator it = xmpImpl.getRoot().iterateChildren(); it.hasNext();)
			{
				XMPNode schema = (XMPNode) it.next();
				if (removeSchemaChildren(schema, doAllProperties))
				{
					it.remove();
				}
			}
		}
	}


	/**
	 * @see XMPUtils#appendProperties(XMPMeta, XMPMeta, boolean, boolean)
	 * @param source The source XMP object.
	 * @param destination The destination XMP object.
	 * @param doAllProperties Do internal properties in addition to external properties.
	 * @param replaceOldValues Replace the values of existing properties.
	 * @param deleteEmptyValues Delete destination values if source property is empty. 
	 * @throws XMPException Forwards the Exceptions from the metadata processing
	 */
	public static void appendProperties(XMPMeta source, XMPMeta destination,
			boolean doAllProperties, boolean replaceOldValues, boolean deleteEmptyValues) 
		throws XMPException
	{
		ParameterAsserts.assertImplementation(source);
		ParameterAsserts.assertImplementation(destination);

		XMPMetaImpl src = (XMPMetaImpl) source;
		XMPMetaImpl dest = (XMPMetaImpl) destination;

		for (Iterator it = src.getRoot().iterateChildren(); it.hasNext();)
		{
			XMPNode sourceSchema = (XMPNode) it.next();
			
			// Make sure we have a destination schema node
			XMPNode destSchema = XMPNodeUtils.findSchemaNode(dest.getRoot(),
					sourceSchema.getName(), false);
			boolean createdSchema = false;
			if (destSchema == null)
			{
				destSchema = new XMPNode(sourceSchema.getName(), sourceSchema.getValue(),
						new PropertyOptions().setSchemaNode(true));
				dest.getRoot().addChild(destSchema);
				createdSchema = true;
			}

			// Process the source schema's children.			
			for (Iterator ic = sourceSchema.iterateChildren(); ic.hasNext();)
			{
				XMPNode sourceProp = (XMPNode) ic.next();
				if (doAllProperties
						|| !Utils.isInternalProperty(sourceSchema.getName(), sourceProp.getName()))
				{
					appendSubtree(
						dest, sourceProp, destSchema, replaceOldValues, deleteEmptyValues);
				}
			}

			if (!destSchema.hasChildren()  &&  (createdSchema  ||  deleteEmptyValues))
			{
				// Don't create an empty schema / remove empty schema.
				dest.getRoot().removeChild(destSchema);
			}
		}
	}


	/**
	 * Remove all schema children according to the flag
	 * <code>doAllProperties</code>. Empty schemas are automatically remove
	 * by <code>XMPNode</code>
	 * 
	 * @param schemaNode
	 *            a schema node
	 * @param doAllProperties
	 *            flag if all properties or only externals shall be removed.
	 * @return Returns true if the schema is empty after the operation.
	 */
	private static boolean removeSchemaChildren(XMPNode schemaNode, boolean doAllProperties)
	{
		for (Iterator it = schemaNode.iterateChildren(); it.hasNext();)
		{
			XMPNode currProp = (XMPNode) it.next();
			if (doAllProperties
					|| !Utils.isInternalProperty(schemaNode.getName(), currProp.getName()))
			{
				it.remove();
			}
		}
		
		return !schemaNode.hasChildren();
	}


	/**
	 * @see XMPUtilsImpl#appendProperties(XMPMeta, XMPMeta, boolean, boolean, boolean)
	 * @param destXMP The destination XMP object.
	 * @param sourceNode the source node
	 * @param destParent the parent of the destination node
	 * @param replaceOldValues Replace the values of existing properties.
	 * @param deleteEmptyValues flag if properties with empty values should be deleted 
	 * 		   in the destination object.
	 * @throws XMPException
	 */
	private static void appendSubtree(XMPMetaImpl destXMP, XMPNode sourceNode, XMPNode destParent,
			boolean replaceOldValues, boolean deleteEmptyValues) throws XMPException
	{
		XMPNode destNode = XMPNodeUtils.findChildNode(destParent, sourceNode.getName(), false);

		boolean valueIsEmpty = false;
		if (deleteEmptyValues)
		{
			valueIsEmpty = sourceNode.getOptions().isSimple() ?
				sourceNode.getValue() == null  ||  sourceNode.getValue().length() == 0 :
				!sourceNode.hasChildren();
		}
		
		if (deleteEmptyValues  &&  valueIsEmpty)
		{
			if (destNode != null)
			{
				destParent.removeChild(destNode);
			}
		} 
		else if (destNode == null)
		{
			// The one easy case, the destination does not exist.
			destParent.addChild((XMPNode) sourceNode.clone());
		}
		else if (replaceOldValues)
		{
			// The destination exists and should be replaced.
			destXMP.setNode(destNode, sourceNode.getValue(), sourceNode.getOptions(), true);
			destParent.removeChild(destNode);
			destNode = (XMPNode) sourceNode.clone();
			destParent.addChild(destNode);
		}
		else
		{
			// The destination exists and is not totally replaced. Structs and
			// arrays are merged.

			PropertyOptions sourceForm = sourceNode.getOptions();
			PropertyOptions destForm = destNode.getOptions();
			if (sourceForm != destForm)
			{
				return;
			}
			if (sourceForm.isStruct())
			{
				// To merge a struct process the fields recursively. E.g. add simple missing fields.
				// The recursive call to AppendSubtree will handle deletion for fields with empty 
				// values.
				for (Iterator it = sourceNode.iterateChildren(); it.hasNext();)
				{
					XMPNode sourceField = (XMPNode) it.next();
					appendSubtree(destXMP, sourceField, destNode, 
						replaceOldValues, deleteEmptyValues);
					if (deleteEmptyValues  &&  !destNode.hasChildren())
					{
						destParent.removeChild(destNode);
					}
				}
			}
			else if (sourceForm.isArrayAltText())
			{
				// Merge AltText arrays by the "xml:lang" qualifiers. Make sure x-default is first. 
				// Make a special check for deletion of empty values. Meaningful in AltText arrays 
				// because the "xml:lang" qualifier provides unambiguous source/dest correspondence.
				for (Iterator it = sourceNode.iterateChildren(); it.hasNext();)
				{
					XMPNode sourceItem = (XMPNode) it.next();
					if (!sourceItem.hasQualifier()
							|| !XMPConst.XML_LANG.equals(sourceItem.getQualifier(1).getName()))
					{
						continue;
					}
					
					int destIndex = XMPNodeUtils.lookupLanguageItem(destNode, 
							sourceItem.getQualifier(1).getValue());
					if (deleteEmptyValues  &&  
							(sourceItem.getValue() == null  ||
							 sourceItem.getValue().length() == 0))
					{
						if (destIndex != -1)
						{
							destNode.removeChild(destIndex);
							if (!destNode.hasChildren())
							{
								destParent.removeChild(destNode);
							}
						}	
					}
					else if (destIndex == -1)
					{
						// Not replacing, keep the existing item.						
						if (!XMPConst.X_DEFAULT.equals(sourceItem.getQualifier(1).getValue())
								|| !destNode.hasChildren())
						{
							sourceItem.cloneSubtree(destNode);
						}
						else
						{
							XMPNode destItem = new XMPNode(
								sourceItem.getName(), 
								sourceItem.getValue(), 
								sourceItem.getOptions());
							sourceItem.cloneSubtree(destItem);
							destNode.addChild(1, destItem);
						}	
					}
				}				
			}
			else if (sourceForm.isArray())
			{
				// Merge other arrays by item values. Don't worry about order or duplicates. Source 
				// items with empty values do not cause deletion, that conflicts horribly with 
				// merging.

				for (Iterator is = sourceNode.iterateChildren(); is.hasNext();)
				{
					XMPNode sourceItem = (XMPNode) is.next();

					boolean match = false;
					for (Iterator id = destNode.iterateChildren(); id.hasNext();)
					{
						XMPNode destItem = (XMPNode) id.next();
						if (itemValuesMatch(sourceItem, destItem))
						{
							match = true;
						}
					}
					if (!match)
					{
						destNode = (XMPNode) sourceItem.clone();
						destParent.addChild(destNode);
					}
				}
			}
		}
	}


	/**
	 * Compares two nodes including its children and qualifier.
	 * @param leftNode an <code>XMPNode</code>
	 * @param rightNode an <code>XMPNode</code>
	 * @return Returns true if the nodes are equal, false otherwise.
	 * @throws XMPException Forwards exceptions to the calling method.
	 */
	private static boolean itemValuesMatch(XMPNode leftNode, XMPNode rightNode) throws XMPException
	{
		PropertyOptions leftForm = leftNode.getOptions();
		PropertyOptions rightForm = rightNode.getOptions();

		if (leftForm.equals(rightForm))
		{
			return false;
		}

		if (leftForm.getOptions() == 0)
		{
			// Simple nodes, check the values and xml:lang qualifiers.
			if (!leftNode.getValue().equals(rightNode.getValue()))
			{
				return false;
			}
			if (leftNode.getOptions().getHasLanguage() != rightNode.getOptions().getHasLanguage())
			{
				return false;
			}
			if (leftNode.getOptions().getHasLanguage()
					&& !leftNode.getQualifier(1).getValue().equals(
							rightNode.getQualifier(1).getValue()))
			{
				return false;
			}
		}
		else if (leftForm.isStruct())
		{
			// Struct nodes, see if all fields match, ignoring order.

			if (leftNode.getChildrenLength() != rightNode.getChildrenLength())
			{
				return false;
			}

			for (Iterator it = leftNode.iterateChildren(); it.hasNext();)
			{
				XMPNode leftField = (XMPNode) it.next();
				XMPNode rightField = XMPNodeUtils.findChildNode(rightNode, leftField.getName(),
						false);
				if (rightField == null || !itemValuesMatch(leftField, rightField))
				{
					return false;
				}
			}
		}
		else
		{
			// Array nodes, see if the "leftNode" values are present in the
			// "rightNode", ignoring order, duplicates,
			// and extra values in the rightNode-> The rightNode is the
			// destination for AppendProperties.

			assert leftForm.isArray();

			for (Iterator il = leftNode.iterateChildren(); il.hasNext();)
			{
				XMPNode leftItem = (XMPNode) il.next();

				boolean match = false;
				for (Iterator ir = rightNode.iterateChildren(); ir.hasNext();)
				{
					XMPNode rightItem = (XMPNode) ir.next();
					if (itemValuesMatch(leftItem, rightItem))
					{
						match = true;
						break;
					}
				}
				if (!match)
				{
					return false;
				}
			}
		}
		return true; // All of the checks passed.
	}


	/**
	 * Make sure the separator is OK. It must be one semicolon surrounded by
	 * zero or more spaces. Any of the recognized semicolons or spaces are
	 * allowed.
	 * 
	 * @param separator
	 * @throws XMPException
	 */
	private static void checkSeparator(String separator) throws XMPException
	{
		boolean haveSemicolon = false;
		for (int i = 0; i < separator.length(); i++)
		{
			int charKind = classifyCharacter(separator.charAt(i));
			if (charKind == UCK_SEMICOLON)
			{
				if (haveSemicolon)
				{
					throw new XMPException("Separator can have only one semicolon", 
						XMPError.BADPARAM);
				}
				haveSemicolon = true;
			}
			else if (charKind != UCK_SPACE)
			{
				throw new XMPException("Separator can have only spaces and one semicolon",
						XMPError.BADPARAM);
			}
		}
		if (!haveSemicolon)
		{
			throw new XMPException("Separator must have one semicolon", XMPError.BADPARAM);
		}
	}


	/**
	 * Make sure the open and close quotes are a legitimate pair and return the
	 * correct closing quote or an exception.
	 * 
	 * @param quotes
	 *            opened and closing quote in a string
	 * @param openQuote
	 *            the open quote
	 * @return Returns a corresponding closing quote.
	 * @throws XMPException
	 */
	private static char checkQuotes(String quotes, char openQuote) throws XMPException
	{
		char closeQuote;

		int charKind = classifyCharacter(openQuote);
		if (charKind != UCK_QUOTE)
		{
			throw new XMPException("Invalid quoting character", XMPError.BADPARAM);
		}

		if (quotes.length() == 1)
		{
			closeQuote = openQuote;
		}
		else
		{
			closeQuote = quotes.charAt(1);
			charKind = classifyCharacter(closeQuote);
			if (charKind != UCK_QUOTE)
			{
				throw new XMPException("Invalid quoting character", XMPError.BADPARAM);
			}
		}

		if (closeQuote != getClosingQuote(openQuote))
		{
			throw new XMPException("Mismatched quote pair", XMPError.BADPARAM);
		}
		return closeQuote;
	}


	/**
	 * Classifies the character into normal chars, spaces, semicola, quotes,
	 * control chars.
	 * 
	 * @param ch
	 *            a char
	 * @return Return the character kind.
	 */
	private static int classifyCharacter(char ch)
	{
		if (SPACES.indexOf(ch) >= 0 || (0x2000 <= ch && ch <= 0x200B))
		{
			return UCK_SPACE;
		}
		else if (COMMAS.indexOf(ch) >= 0)
		{
			return UCK_COMMA;
		}
		else if (SEMICOLA.indexOf(ch) >= 0)
		{
			return UCK_SEMICOLON;
		}
		else if (QUOTES.indexOf(ch) >= 0 || (0x3008 <= ch && ch <= 0x300F)
				|| (0x2018 <= ch && ch <= 0x201F))
		{
			return UCK_QUOTE;
		}
		else if (ch < 0x0020 || CONTROLS.indexOf(ch) >= 0)
		{
			return UCK_CONTROL;
		}
		else
		{
			// Assume typical case.
			return UCK_NORMAL;
		}
	}


	/**
	 * @param openQuote
	 *            the open quote char
	 * @return Returns the matching closing quote for an open quote.
	 */
	private static char getClosingQuote(char openQuote)
	{
		switch (openQuote)
		{
		case 0x0022:
			return 0x0022; // ! U+0022 is both opening and closing.
		case 0x005B:
			return 0x005D;
		case 0x00AB:
			return 0x00BB; // ! U+00AB and U+00BB are reversible.
		case 0x00BB:
			return 0x00AB;
		case 0x2015:
			return 0x2015; // ! U+2015 is both opening and closing.
		case 0x2018:
			return 0x2019;
		case 0x201A:
			return 0x201B;
		case 0x201C:
			return 0x201D;
		case 0x201E:
			return 0x201F;
		case 0x2039:
			return 0x203A; // ! U+2039 and U+203A are reversible.
		case 0x203A:
			return 0x2039;
		case 0x3008:
			return 0x3009;
		case 0x300A:
			return 0x300B;
		case 0x300C:
			return 0x300D;
		case 0x300E:
			return 0x300F;
		case 0x301D:
			return 0x301F; // ! U+301E also closes U+301D.
		default:
			return 0;
		}
	}


	/**
	 * Add quotes to the item.
	 * 
	 * @param item
	 *            the array item
	 * @param openQuote
	 *            the open quote character
	 * @param closeQuote
	 *            the closing quote character
	 * @param allowCommas
	 *            flag if commas are allowed
	 * @return Returns the value in quotes.
	 */
	private static String applyQuotes(String item, char openQuote, char closeQuote,
			boolean allowCommas)
	{
		if (item == null)
		{
			item = "";
		}
		
		boolean prevSpace = false;
		int charOffset;
		int charKind;

		// See if there are any separators in the value. Stop at the first
		// occurrance. This is a bit
		// tricky in order to make typical typing work conveniently. The purpose
		// of applying quotes
		// is to preserve the values when splitting them back apart. That is
		// CatenateContainerItems
		// and SeparateContainerItems must round trip properly. For the most
		// part we only look for
		// separators here. Internal quotes, as in -- Irving "Bud" Jones --
		// won't cause problems in
		// the separation. An initial quote will though, it will make the value
		// look quoted.

		int i;
		for (i = 0; i < item.length(); i++)
		{
			char ch = item.charAt(i);
			charKind = classifyCharacter(ch);
			if (i == 0 && charKind == UCK_QUOTE)
			{
				break;
			}

			if (charKind == UCK_SPACE)
			{
				// Multiple spaces are a separator.
				if (prevSpace)
				{
					break;
				}
				prevSpace = true;
			}
			else
			{
				prevSpace = false;
				if ((charKind == UCK_SEMICOLON || charKind == UCK_CONTROL)
						|| (charKind == UCK_COMMA && !allowCommas))
				{
					break;
				}
			}
		}


		if (i < item.length())
		{
			// Create a quoted copy, doubling any internal quotes that match the
			// outer ones. Internal quotes did not stop the "needs quoting"
			// search, but they do need
			// doubling. So we have to rescan the front of the string for
			// quotes. Handle the special
			// case of U+301D being closed by either U+301E or U+301F.

			StringBuffer newItem = new StringBuffer(item.length() + 2);
			int splitPoint;
			for (splitPoint = 0; splitPoint <= i; splitPoint++)
			{
				if (classifyCharacter(item.charAt(i)) == UCK_QUOTE)
				{
					break;
				}
			}

			// Copy the leading "normal" portion.
			newItem.append(openQuote).append(item.substring(0, splitPoint));

			for (charOffset = splitPoint; charOffset < item.length(); charOffset++)
			{
				newItem.append(item.charAt(charOffset));
				if (classifyCharacter(item.charAt(charOffset)) == UCK_QUOTE
						&& isSurroundingQuote(item.charAt(charOffset), openQuote, closeQuote))
				{
					newItem.append(item.charAt(charOffset));
				}
			}

			newItem.append(closeQuote);

			item = newItem.toString();
		}

		return item;
	}


	/**
	 * @param ch a character
	 * @param openQuote the opening quote char
	 * @param closeQuote the closing quote char 
	 * @return Return it the character is a surrounding quote.
	 */
	private static boolean isSurroundingQuote(char ch, char openQuote, char closeQuote)
	{
		return ch == openQuote || isClosingingQuote(ch, openQuote, closeQuote);
	}


	/**
	 * @param ch a character
	 * @param openQuote the opening quote char
	 * @param closeQuote the closing quote char 
	 * @return Returns true if the character is a closing quote.
	 */
	private static boolean isClosingingQuote(char ch, char openQuote, char closeQuote)
	{
		return ch == closeQuote || (openQuote == 0x301D && ch == 0x301E || ch == 0x301F);
	}
	
	
	
	/**
	 * U+0022 ASCII space<br>
	 * U+3000, ideographic space<br>
	 * U+303F, ideographic half fill space<br>
	 * U+2000..U+200B, en quad through zero width space
	 */
	private static final String SPACES = "\u0020\u3000\u303F";
	/**
	 * U+002C, ASCII comma<br>
	 * U+FF0C, full width comma<br>
	 * U+FF64, half width ideographic comma<br>
	 * U+FE50, small comma<br>
	 * U+FE51, small ideographic comma<br>
	 * U+3001, ideographic comma<br>
	 * U+060C, Arabic comma<br>
	 * U+055D, Armenian comma
	 */
	private static final String COMMAS = "\u002C\uFF0C\uFF64\uFE50\uFE51\u3001\u060C\u055D";
	/**
	 * U+003B, ASCII semicolon<br>
	 * U+FF1B, full width semicolon<br>
	 * U+FE54, small semicolon<br>
	 * U+061B, Arabic semicolon<br>
	 * U+037E, Greek "semicolon" (really a question mark)
	 */
	private static final String SEMICOLA = "\u003B\uFF1B\uFE54\u061B\u037E";
	/**
	 * U+0022 ASCII quote<br>
	 * ASCII '[' (0x5B) and ']' (0x5D) are used as quotes in Chinese and
	 * Korean.<br>
	 * U+00AB and U+00BB, guillemet quotes<br>
	 * U+3008..U+300F, various quotes.<br>
	 * U+301D..U+301F, double prime quotes.<br>
	 * U+2015, dash quote.<br>
	 * U+2018..U+201F, various quotes.<br>
	 * U+2039 and U+203A, guillemet quotes.
	 */
	private static final String QUOTES = 
		"\"\u005B\u005D\u00AB\u00BB\u301D\u301E\u301F\u2015\u2039\u203A";
	/**
	 * U+0000..U+001F ASCII controls<br>
	 * U+2028, line separator.<br>
	 * U+2029, paragraph separator.
	 */
	private static final String CONTROLS = "\u2028\u2029";	
}