/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.text.TextUtilities;

import dwtx.jface.text.IDocumentPartitioningListener; // packageimport
import dwtx.jface.text.DefaultTextHover; // packageimport
import dwtx.jface.text.AbstractInformationControl; // packageimport
import dwtx.jface.text.IInformationControlCreatorExtension; // packageimport
import dwtx.jface.text.AbstractInformationControlManager; // packageimport
import dwtx.jface.text.ITextViewerExtension2; // packageimport
import dwtx.jface.text.IDocumentPartitioner; // packageimport
import dwtx.jface.text.DefaultIndentLineAutoEditStrategy; // packageimport
import dwtx.jface.text.ITextSelection; // packageimport
import dwtx.jface.text.Document; // packageimport
import dwtx.jface.text.FindReplaceDocumentAdapterContentProposalProvider; // packageimport
import dwtx.jface.text.ITextListener; // packageimport
import dwtx.jface.text.BadPartitioningException; // packageimport
import dwtx.jface.text.ITextViewerExtension5; // packageimport
import dwtx.jface.text.IDocumentPartitionerExtension3; // packageimport
import dwtx.jface.text.IUndoManager; // packageimport
import dwtx.jface.text.ITextHoverExtension2; // packageimport
import dwtx.jface.text.IRepairableDocument; // packageimport
import dwtx.jface.text.IRewriteTarget; // packageimport
import dwtx.jface.text.DefaultPositionUpdater; // packageimport
import dwtx.jface.text.RewriteSessionEditProcessor; // packageimport
import dwtx.jface.text.TextViewerHoverManager; // packageimport
import dwtx.jface.text.DocumentRewriteSession; // packageimport
import dwtx.jface.text.TextViewer; // packageimport
import dwtx.jface.text.ITextViewerExtension8; // packageimport
import dwtx.jface.text.RegExMessages; // packageimport
import dwtx.jface.text.IDelayedInputChangeProvider; // packageimport
import dwtx.jface.text.ITextOperationTargetExtension; // packageimport
import dwtx.jface.text.IWidgetTokenOwner; // packageimport
import dwtx.jface.text.IViewportListener; // packageimport
import dwtx.jface.text.GapTextStore; // packageimport
import dwtx.jface.text.MarkSelection; // packageimport
import dwtx.jface.text.IDocumentPartitioningListenerExtension; // packageimport
import dwtx.jface.text.IDocumentAdapterExtension; // packageimport
import dwtx.jface.text.IInformationControlExtension; // packageimport
import dwtx.jface.text.IDocumentPartitioningListenerExtension2; // packageimport
import dwtx.jface.text.DefaultDocumentAdapter; // packageimport
import dwtx.jface.text.ITextViewerExtension3; // packageimport
import dwtx.jface.text.IInformationControlCreator; // packageimport
import dwtx.jface.text.TypedRegion; // packageimport
import dwtx.jface.text.ISynchronizable; // packageimport
import dwtx.jface.text.IMarkRegionTarget; // packageimport
import dwtx.jface.text.TextViewerUndoManager; // packageimport
import dwtx.jface.text.IRegion; // packageimport
import dwtx.jface.text.IInformationControlExtension2; // packageimport
import dwtx.jface.text.IDocumentExtension4; // packageimport
import dwtx.jface.text.IDocumentExtension2; // packageimport
import dwtx.jface.text.IDocumentPartitionerExtension2; // packageimport
import dwtx.jface.text.Assert; // packageimport
import dwtx.jface.text.DefaultInformationControl; // packageimport
import dwtx.jface.text.IWidgetTokenOwnerExtension; // packageimport
import dwtx.jface.text.DocumentClone; // packageimport
import dwtx.jface.text.DefaultUndoManager; // packageimport
import dwtx.jface.text.IFindReplaceTarget; // packageimport
import dwtx.jface.text.IAutoEditStrategy; // packageimport
import dwtx.jface.text.ILineTrackerExtension; // packageimport
import dwtx.jface.text.IUndoManagerExtension; // packageimport
import dwtx.jface.text.TextSelection; // packageimport
import dwtx.jface.text.DefaultAutoIndentStrategy; // packageimport
import dwtx.jface.text.IAutoIndentStrategy; // packageimport
import dwtx.jface.text.IPainter; // packageimport
import dwtx.jface.text.IInformationControl; // packageimport
import dwtx.jface.text.IInformationControlExtension3; // packageimport
import dwtx.jface.text.ITextViewerExtension6; // packageimport
import dwtx.jface.text.IInformationControlExtension4; // packageimport
import dwtx.jface.text.DefaultLineTracker; // packageimport
import dwtx.jface.text.IDocumentInformationMappingExtension; // packageimport
import dwtx.jface.text.IRepairableDocumentExtension; // packageimport
import dwtx.jface.text.ITextHover; // packageimport
import dwtx.jface.text.FindReplaceDocumentAdapter; // packageimport
import dwtx.jface.text.ILineTracker; // packageimport
import dwtx.jface.text.Line; // packageimport
import dwtx.jface.text.ITextViewerExtension; // packageimport
import dwtx.jface.text.IDocumentAdapter; // packageimport
import dwtx.jface.text.TextEvent; // packageimport
import dwtx.jface.text.BadLocationException; // packageimport
import dwtx.jface.text.AbstractDocument; // packageimport
import dwtx.jface.text.AbstractLineTracker; // packageimport
import dwtx.jface.text.TreeLineTracker; // packageimport
import dwtx.jface.text.ITextPresentationListener; // packageimport
import dwtx.jface.text.Region; // packageimport
import dwtx.jface.text.ITextViewer; // packageimport
import dwtx.jface.text.IDocumentInformationMapping; // packageimport
import dwtx.jface.text.MarginPainter; // packageimport
import dwtx.jface.text.IPaintPositionManager; // packageimport
import dwtx.jface.text.TextPresentation; // packageimport
import dwtx.jface.text.IFindReplaceTargetExtension; // packageimport
import dwtx.jface.text.ISlaveDocumentManagerExtension; // packageimport
import dwtx.jface.text.ISelectionValidator; // packageimport
import dwtx.jface.text.IDocumentExtension; // packageimport
import dwtx.jface.text.PropagatingFontFieldEditor; // packageimport
import dwtx.jface.text.ConfigurableLineTracker; // packageimport
import dwtx.jface.text.SlaveDocumentEvent; // packageimport
import dwtx.jface.text.IDocumentListener; // packageimport
import dwtx.jface.text.PaintManager; // packageimport
import dwtx.jface.text.IFindReplaceTargetExtension3; // packageimport
import dwtx.jface.text.ITextDoubleClickStrategy; // packageimport
import dwtx.jface.text.IDocumentExtension3; // packageimport
import dwtx.jface.text.Position; // packageimport
import dwtx.jface.text.TextMessages; // packageimport
import dwtx.jface.text.CopyOnWriteTextStore; // packageimport
import dwtx.jface.text.WhitespaceCharacterPainter; // packageimport
import dwtx.jface.text.IPositionUpdater; // packageimport
import dwtx.jface.text.DefaultTextDoubleClickStrategy; // packageimport
import dwtx.jface.text.ListLineTracker; // packageimport
import dwtx.jface.text.ITextInputListener; // packageimport
import dwtx.jface.text.BadPositionCategoryException; // packageimport
import dwtx.jface.text.IWidgetTokenKeeperExtension; // packageimport
import dwtx.jface.text.IInputChangedListener; // packageimport
import dwtx.jface.text.ITextOperationTarget; // packageimport
import dwtx.jface.text.IDocumentInformationMappingExtension2; // packageimport
import dwtx.jface.text.ITextViewerExtension7; // packageimport
import dwtx.jface.text.IInformationControlExtension5; // packageimport
import dwtx.jface.text.IDocumentRewriteSessionListener; // packageimport
import dwtx.jface.text.JFaceTextUtil; // packageimport
import dwtx.jface.text.AbstractReusableInformationControlCreator; // packageimport
import dwtx.jface.text.TabsToSpacesConverter; // packageimport
import dwtx.jface.text.CursorLinePainter; // packageimport
import dwtx.jface.text.ITextHoverExtension; // packageimport
import dwtx.jface.text.IEventConsumer; // packageimport
import dwtx.jface.text.IDocument; // packageimport
import dwtx.jface.text.IWidgetTokenKeeper; // packageimport
import dwtx.jface.text.DocumentCommand; // packageimport
import dwtx.jface.text.TypedPosition; // packageimport
import dwtx.jface.text.IEditingSupportRegistry; // packageimport
import dwtx.jface.text.IDocumentPartitionerExtension; // packageimport
import dwtx.jface.text.AbstractHoverInformationControlManager; // packageimport
import dwtx.jface.text.IEditingSupport; // packageimport
import dwtx.jface.text.IMarkSelection; // packageimport
import dwtx.jface.text.ISlaveDocumentManager; // packageimport
import dwtx.jface.text.DocumentEvent; // packageimport
import dwtx.jface.text.DocumentPartitioningChangedEvent; // packageimport
import dwtx.jface.text.ITextStore; // packageimport
import dwtx.jface.text.JFaceTextMessages; // packageimport
import dwtx.jface.text.DocumentRewriteSessionEvent; // packageimport
import dwtx.jface.text.SequentialRewriteTextStore; // packageimport
import dwtx.jface.text.DocumentRewriteSessionType; // packageimport
import dwtx.jface.text.TextAttribute; // packageimport
import dwtx.jface.text.ITextViewerExtension4; // packageimport
import dwtx.jface.text.ITypedRegion; // packageimport


import dwt.dwthelper.utils;

import dwtx.dwtxhelper.Collection;







import dwtx.core.runtime.Assert;


/**
 * A collection of text functions.
 * <p>
 * This class is neither intended to be instantiated nor subclassed.
 * </p>
 * @noinstantiate This class is not intended to be instantiated by clients.
 * @noextend This class is not intended to be subclassed by clients.
 */
public class TextUtilities {

    /**
     * Default line delimiters used by the text functions of this class.
     */
    public const static String[] DELIMITERS= [ "\n", "\r", "\r\n" ]; //$NON-NLS-3$ //$NON-NLS-2$ //$NON-NLS-1$

    /**
     * Default line delimiters used by these text functions.
     *
     * @deprecated use DELIMITERS instead
     */
    public const static String[] fgDelimiters= DELIMITERS;



    /**
     * Determines which one of default line delimiters appears first in the list. If none of them the
     * hint is returned.
     *
     * @param text the text to be checked
     * @param hint the line delimiter hint
     * @return the line delimiter
     */
    public static String determineLineDelimiter(String text, String hint) {
        try {
            int[] info= indexOf(DELIMITERS, text, 0);
            return DELIMITERS[info[1]];
        } catch (ArrayIndexOutOfBoundsException x) {
        }
        return hint;
    }

    /**
     * Returns the starting position and the index of the first matching search string
     * in the given text that is greater than the given offset. If more than one search
     * string matches with the same starting position then the longest one is returned.
     *
     * @param searchStrings the strings to search for
     * @param text the text to be searched
     * @param offset the offset at which to start the search
     * @return an <code>int[]</code> with two elements where the first is the starting offset, the second the index of the found
     *      search string in the given <code>searchStrings</code> array, returns <code>[-1, -1]</code> if no match exists
     */
    public static int[] indexOf(String[] searchStrings, String text, int offset) {

        int[] result= { -1, -1 };
        int zeroIndex= -1;

        for (int i= 0; i < searchStrings.length; i++) {

            int length= searchStrings[i].length();

            if (length is 0) {
                zeroIndex= i;
                continue;
            }

            int index= text.indexOf(searchStrings[i], offset);
            if (index >= 0) {

                if (result[0] is -1) {
                    result[0]= index;
                    result[1]= i;
                } else if (index < result[0]) {
                    result[0]= index;
                    result[1]= i;
                } else if (index is result[0] && length > searchStrings[result[1]].length()) {
                    result[0]= index;
                    result[1]= i;
                }
            }
        }

        if (zeroIndex > -1 && result[0] is -1) {
            result[0]= 0;
            result[1]= zeroIndex;
        }

        return result;
    }

    /**
     * Returns the index of the longest search string with which the given text ends or
     * <code>-1</code> if none matches.
     *
     * @param searchStrings the strings to search for
     * @param text the text to search
     * @return the index in <code>searchStrings</code> of the longest string with which <code>text</code> ends or <code>-1</code>
     */
    public static int endsWith(String[] searchStrings, String text) {

        int index= -1;

        for (int i= 0; i < searchStrings.length; i++) {
            if (text.endsWith(searchStrings[i])) {
                if (index is -1 || searchStrings[i].length() > searchStrings[index].length())
                    index= i;
            }
        }

        return index;
    }

    /**
     * Returns the index of the longest search string with which the given text starts or <code>-1</code>
     * if none matches.
     *
     * @param searchStrings the strings to search for
     * @param text the text to search
     * @return the index in <code>searchStrings</code> of the longest string with which <code>text</code> starts or <code>-1</code>
     */
    public static int startsWith(String[] searchStrings, String text) {

        int index= -1;

        for (int i= 0; i < searchStrings.length; i++) {
            if (text.startsWith(searchStrings[i])) {
                if (index is -1 || searchStrings[i].length() > searchStrings[index].length())
                    index= i;
            }
        }

        return index;
    }

    /**
     * Returns the index of the first compare string that equals the given text or <code>-1</code>
     * if none is equal.
     *
     * @param compareStrings the strings to compare with
     * @param text the text to check
     * @return the index of the first equal compare string or <code>-1</code>
     */
    public static int equals(String[] compareStrings, String text) {
        for (int i= 0; i < compareStrings.length; i++) {
            if (text.equals(compareStrings[i]))
                return i;
        }
        return -1;
    }

    /**
     * Returns a document event which is an accumulation of a list of document events,
     * <code>null</code> if the list of documentEvents is empty.
     * The document of the document events are ignored.
     *
     * @param unprocessedDocument the document to which the document events would be applied
     * @param documentEvents the list of document events to merge
     * @return returns the merged document event
     * @throws BadLocationException might be thrown if document is not in the correct state with respect to document events
     */
    public static DocumentEvent mergeUnprocessedDocumentEvents(IDocument unprocessedDocument, List documentEvents)  {

        if (documentEvents.size() is 0)
            return null;

        final Iterator iterator= documentEvents.iterator();
        final DocumentEvent firstEvent= cast(DocumentEvent) iterator.next();

        // current merged event
        final IDocument document= unprocessedDocument;
        int offset= firstEvent.getOffset();
        int length= firstEvent.getLength();
        final StringBuffer text= new StringBuffer(firstEvent.getText() is null ? "" : firstEvent.getText()); //$NON-NLS-1$

        while (iterator.hasNext()) {

            final int delta= text.length() - length;

            final DocumentEvent event= cast(DocumentEvent) iterator.next();
            final int eventOffset= event.getOffset();
            final int eventLength= event.getLength();
            final String eventText= event.getText() is null ? "" : event.getText(); //$NON-NLS-1$

            // event is right from merged event
            if (eventOffset > offset + length + delta) {
                final String string= document.get(offset + length, (eventOffset - delta) - (offset + length));
                text.append(string);
                text.append(eventText);

                length= (eventOffset - delta) + eventLength - offset;

            // event is left from merged event
            } else if (eventOffset + eventLength < offset) {
                final String string= document.get(eventOffset + eventLength, offset - (eventOffset + eventLength));
                text.insert(0, string);
                text.insert(0, eventText);

                length= offset + length - eventOffset;
                offset= eventOffset;

            // events overlap each other
            } else {
                final int start= Math.max(0, eventOffset - offset);
                final int end= Math.min(text.length(), eventLength + eventOffset - offset);
                text.replace(start, end, eventText);

                offset= Math.min(offset, eventOffset);
                final int totalDelta= delta + eventText.length() - eventLength;
                length= text.length() - totalDelta;
            }
        }

        return new DocumentEvent(document, offset, length, text.toString());
    }

    /**
     * Returns a document event which is an accumulation of a list of document events,
     * <code>null</code> if the list of document events is empty.
     * The document events being merged must all refer to the same document, to which
     * the document changes have been already applied.
     *
     * @param documentEvents the list of document events to merge
     * @return returns the merged document event
     * @throws BadLocationException might be thrown if document is not in the correct state with respect to document events
     */
    public static DocumentEvent mergeProcessedDocumentEvents(List documentEvents)  {

        if (documentEvents.size() is 0)
            return null;

        final ListIterator iterator= documentEvents.listIterator(documentEvents.size());
        final DocumentEvent firstEvent= cast(DocumentEvent) iterator.previous();

        // current merged event
        final IDocument document= firstEvent.getDocument();
        int offset= firstEvent.getOffset();
        int length= firstEvent.getLength();
        int textLength= firstEvent.getText() is null ? 0 : firstEvent.getText().length();

        while (iterator.hasPrevious()) {

            final int delta= length - textLength;

            final DocumentEvent event= cast(DocumentEvent) iterator.previous();
            final int eventOffset= event.getOffset();
            final int eventLength= event.getLength();
            final int eventTextLength= event.getText() is null ? 0 : event.getText().length();

            // event is right from merged event
            if (eventOffset > offset + textLength + delta) {
                length= (eventOffset - delta) - (offset + textLength) + length + eventLength;
                textLength= (eventOffset - delta) + eventTextLength - offset;

            // event is left from merged event
            } else if (eventOffset + eventTextLength < offset) {
                length= offset - (eventOffset + eventTextLength) + length + eventLength;
                textLength= offset + textLength - eventOffset;
                offset= eventOffset;

            // events overlap each other
            } else {
                final int start= Math.max(0, eventOffset - offset);
                final int end= Math.min(length, eventTextLength + eventOffset - offset);
                length += eventLength - (end - start);

                offset= Math.min(offset, eventOffset);
                final int totalDelta= delta + eventLength - eventTextLength;
                textLength= length - totalDelta;
            }
        }

        final String text= document.get(offset, textLength);
        return new DocumentEvent(document, offset, length, text);
    }

    /**
     * Removes all connected document partitioners from the given document and stores them
     * under their partitioning name in a map. This map is returned. After this method has been called
     * the given document is no longer connected to any document partitioner.
     *
     * @param document the document
     * @return the map containing the removed partitioners
     */
    public static Map removeDocumentPartitioners(IDocument document) {
        Map partitioners= new HashMap();
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            String[] partitionings= extension3.getPartitionings();
            for (int i= 0; i < partitionings.length; i++) {
                IDocumentPartitioner partitioner= extension3.getDocumentPartitioner(partitionings[i]);
                if (partitioner !is null) {
                    extension3.setDocumentPartitioner(partitionings[i], null);
                    partitioner.disconnect();
                    partitioners.put(partitionings[i], partitioner);
                }
            }
        } else {
            IDocumentPartitioner partitioner= document.getDocumentPartitioner();
            if (partitioner !is null) {
                document.setDocumentPartitioner(null);
                partitioner.disconnect();
                partitioners.put(IDocumentExtension3.DEFAULT_PARTITIONING, partitioner);
            }
        }
        return partitioners;
    }

    /**
     * Connects the given document with all document partitioners stored in the given map under
     * their partitioning name. This method cleans the given map.
     *
     * @param document the document
     * @param partitioners the map containing the partitioners to be connected
     * @since 3.0
     */
    public static void addDocumentPartitioners(IDocument document, Map partitioners) {
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            Iterator e= partitioners.keySet().iterator();
            while (e.hasNext()) {
                String partitioning= cast(String) e.next();
                IDocumentPartitioner partitioner= cast(IDocumentPartitioner) partitioners.get(partitioning);
                partitioner.connect(document);
                extension3.setDocumentPartitioner(partitioning, partitioner);
            }
            partitioners.clear();
        } else {
            IDocumentPartitioner partitioner= cast(IDocumentPartitioner) partitioners.get(IDocumentExtension3.DEFAULT_PARTITIONING);
            partitioner.connect(document);
            document.setDocumentPartitioner(partitioner);
        }
    }

    /**
     * Returns the content type at the given offset of the given document.
     *
     * @param document the document
     * @param partitioning the partitioning to be used
     * @param offset the offset
     * @param preferOpenPartitions <code>true</code> if precedence should be
     *        given to a open partition ending at <code>offset</code> over a
     *        closed partition starting at <code>offset</code>
     * @return the content type at the given offset of the document
     * @throws BadLocationException if offset is invalid in the document
     * @since 3.0
     */
    public static String getContentType(IDocument document, String partitioning, int offset, bool preferOpenPartitions)  {
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            try {
                return extension3.getContentType(partitioning, offset, preferOpenPartitions);
            } catch (BadPartitioningException x) {
                return IDocument.DEFAULT_CONTENT_TYPE;
            }
        }

        return document.getContentType(offset);
    }

    /**
     * Returns the partition of the given offset of the given document.
     *
     * @param document the document
     * @param partitioning the partitioning to be used
     * @param offset the offset
     * @param preferOpenPartitions <code>true</code> if precedence should be
     *        given to a open partition ending at <code>offset</code> over a
     *        closed partition starting at <code>offset</code>
     * @return the content type at the given offset of this viewer's input
     *         document
     * @throws BadLocationException if offset is invalid in the given document
     * @since 3.0
     */
    public static ITypedRegion getPartition(IDocument document, String partitioning, int offset, bool preferOpenPartitions)  {
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            try {
                return extension3.getPartition(partitioning, offset, preferOpenPartitions);
            } catch (BadPartitioningException x) {
                return new TypedRegion(0, document.getLength(), IDocument.DEFAULT_CONTENT_TYPE);
            }
        }

        return document.getPartition(offset);
    }

    /**
     * Computes and returns the partitioning for the given region of the given
     * document for the given partitioning name.
     *
     * @param document the document
     * @param partitioning the partitioning name
     * @param offset the region offset
     * @param length the region length
     * @param includeZeroLengthPartitions whether to include zero-length partitions
     * @return the partitioning for the given region of the given document for
     *         the given partitioning name
     * @throws BadLocationException if the given region is invalid for the given
     *         document
     * @since 3.0
     */
    public static ITypedRegion[] computePartitioning(IDocument document, String partitioning, int offset, int length, bool includeZeroLengthPartitions)  {
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            try {
                return extension3.computePartitioning(partitioning, offset, length, includeZeroLengthPartitions);
            } catch (BadPartitioningException x) {
                return new ITypedRegion[0];
            }
        }

        return document.computePartitioning(offset, length);
    }

    /**
     * Computes and returns the partition managing position categories for the
     * given document or <code>null</code> if this was impossible.
     *
     * @param document the document
     * @return the partition managing position categories or <code>null</code>
     * @since 3.0
     */
    public static String[] computePartitionManagingCategories(IDocument document) {
        if (cast(IDocumentExtension3)document ) {
            IDocumentExtension3 extension3= cast(IDocumentExtension3) document;
            String[] partitionings= extension3.getPartitionings();
            if (partitionings !is null) {
                Set categories= new HashSet();
                for (int i= 0; i < partitionings.length; i++) {
                    IDocumentPartitioner p= extension3.getDocumentPartitioner(partitionings[i]);
                    if (cast(IDocumentPartitionerExtension2)p ) {
                        IDocumentPartitionerExtension2 extension2= cast(IDocumentPartitionerExtension2) p;
                        String[] c= extension2.getManagingPositionCategories();
                        if (c !is null) {
                            for (int j= 0; j < c.length; j++)
                                categories.add(c[j]);
                        }
                    }
                }
                String[] result= new String[categories.size()];
                categories.toArray(result);
                return result;
            }
        }
        return null;
    }

    /**
     * Returns the default line delimiter for the given document. This is either the delimiter of the first line, or the platform line delimiter if it is
     * a legal line delimiter or the first one of the legal line delimiters. The default line delimiter should be used when performing document
     * manipulations that span multiple lines.
     *
     * @param document the document
     * @return the document's default line delimiter
     * @since 3.0
     */
    public static String getDefaultLineDelimiter(IDocument document) {

        if (cast(IDocumentExtension4)document )
            return (cast(IDocumentExtension4)document).getDefaultLineDelimiter();

        String lineDelimiter= null;

        try {
            lineDelimiter= document.getLineDelimiter(0);
        } catch (BadLocationException x) {
        }

        if (lineDelimiter !is null)
            return lineDelimiter;

        String sysLineDelimiter= System.getProperty("line.separator"); //$NON-NLS-1$
        String[] delimiters= document.getLegalLineDelimiters();
        Assert.isTrue(delimiters.length > 0);
        for (int i= 0; i < delimiters.length; i++) {
            if (delimiters[i].equals(sysLineDelimiter)) {
                lineDelimiter= sysLineDelimiter;
                break;
            }
        }

        if (lineDelimiter is null)
            lineDelimiter= delimiters[0];

        return lineDelimiter;
    }

    /**
     * Returns <code>true</code> if the two regions overlap. Returns <code>false</code> if one of the
     * arguments is <code>null</code>.
     *
     * @param left the left region
     * @param right the right region
     * @return <code>true</code> if the two regions overlap, <code>false</code> otherwise
     * @since 3.0
     */
    public static bool overlaps(IRegion left, IRegion right) {

        if (left is null || right is null)
            return false;

        int rightEnd= right.getOffset() + right.getLength();
        int leftEnd= left.getOffset()+ left.getLength();

        if (right.getLength() > 0) {
            if (left.getLength() > 0)
                return left.getOffset() < rightEnd && right.getOffset() < leftEnd;
            return  right.getOffset() <= left.getOffset() && left.getOffset() < rightEnd;
        }

        if (left.getLength() > 0)
            return left.getOffset() <= right.getOffset() && right.getOffset() < leftEnd;

        return left.getOffset() is right.getOffset();
    }

    /**
     * Returns a copy of the given string array.
     *
     * @param array the string array to be copied
     * @return a copy of the given string array or <code>null</code> when <code>array</code> is <code>null</code>
     * @since 3.1
     */
    public static String[] copy(String[] array) {
        if (array !is null) {
            String[] copy= new String[array.length];
            System.arraycopy(array, 0, copy, 0, array.length);
            return copy;
        }
        return null;
    }

    /**
     * Returns a copy of the given integer array.
     *
     * @param array the integer array to be copied
     * @return a copy of the given integer array or <code>null</code> when <code>array</code> is <code>null</code>
     * @since 3.1
     */
    public static int[] copy(int[] array) {
        if (array !is null) {
            int[] copy= new int[array.length];
            System.arraycopy(array, 0, copy, 0, array.length);
            return copy;
        }
        return null;
    }
}