/*******************************************************************************
 * Copyright (c) 2000, 2006 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
 *******************************************************************************/
package org.eclipse.jface.text;

import org.eclipse.core.runtime.Assert;


/**
 * Standard implementation of a generic
 * {@link org.eclipse.jface.text.ILineTracker}.
 * <p>
 * The line tracker can be configured with the set of legal line delimiters.
 * Line delimiters are unconstrained. The line delimiters are used to compute
 * the tracker's line structure. In the case of overlapping line delimiters, the
 * longest line delimiter is given precedence of the shorter ones.
 * <p>
 * This class is not intended to be subclassed.
 * </p>
 */
public class ConfigurableLineTracker extends AbstractLineTracker {


	/** The strings which are considered being the line delimiter */
	private String[] fDelimiters;
	/** A predefined delimiter information which is always reused as return value */
	private DelimiterInfo fDelimiterInfo= new DelimiterInfo();


	/**
	 * Creates a standard line tracker for the given line delimiters.
	 *
	 * @param legalLineDelimiters the tracker's legal line delimiters,
	 *		may not be <code>null</code> and must be longer than 0
	 */
	public ConfigurableLineTracker(String[] legalLineDelimiters) {
		Assert.isTrue(legalLineDelimiters != null && legalLineDelimiters.length > 0);
		fDelimiters= TextUtilities.copy(legalLineDelimiters);
	}

	/*
	 * @see org.eclipse.jface.text.ILineTracker#getLegalLineDelimiters()
	 */
	public String[] getLegalLineDelimiters() {
		return TextUtilities.copy(fDelimiters);
	}

	/*
	 * @see org.eclipse.jface.text.AbstractLineTracker#nextDelimiterInfo(java.lang.String, int)
	 */
	protected DelimiterInfo nextDelimiterInfo(String text, int offset) {
		if (fDelimiters.length > 1) {
			int[] info= TextUtilities.indexOf(fDelimiters, text, offset);
			if (info[0] == -1)
				return null;
			fDelimiterInfo.delimiterIndex= info[0];
			fDelimiterInfo.delimiter= fDelimiters[info[1]];
		} else {
			int index= text.indexOf(fDelimiters[0], offset);
			if (index == -1)
				return null;
			fDelimiterInfo.delimiterIndex= index;
			fDelimiterInfo.delimiter= fDelimiters[0];
		}

		fDelimiterInfo.delimiterLength= fDelimiterInfo.delimiter.length();
		return fDelimiterInfo;
	}
}
