LineCommentEndOffsets.java

/*******************************************************************************
 * Copyright (c) 2009 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
 *     Zend Technologies
 *******************************************************************************/
package org2.eclipse.php.internal.core.ast.rewrite;

import java.util.Arrays;
import java.util.List;

import org2.eclipse.php.internal.core.ast.nodes.Comment;
@SuppressWarnings("rawtypes")
public class LineCommentEndOffsets {

	private static final int[] EMPTY_INT_ARRAY = {};
	private int[] offsets;
	private final List commentList;

	public LineCommentEndOffsets(List commentList) {
		this.commentList = commentList;
		this.offsets = null; // create on demand
	}

	private int[] getOffsets() {
		if (this.offsets == null) {
			if (this.commentList != null) {
				int nComments = this.commentList.size();
				// count the number of line comments
				int count = 0;
				for (int i = 0; i < nComments; i++) {
					Object curr = this.commentList.get(i);
					if (isLineComment(curr)) {
						count++;
					}
				}
				// fill the offset table
				this.offsets = new int[count];
				for (int i = 0, k = 0; i < nComments; i++) {
					Object curr = this.commentList.get(i);
					if (isLineComment(curr)) {
						Comment comment = (Comment) curr;
						this.offsets[k++] = comment.getStart()
								+ comment.getLength();
					}
				}
			} else {
				this.offsets = EMPTY_INT_ARRAY;
			}
		}
		return this.offsets;
	}

	private boolean isLineComment(Object curr) {
		return curr instanceof Comment
				&& ((Comment) curr).getCommentType() == Comment.TYPE_SINGLE_LINE;
	}

	public boolean isEndOfLineComment(int offset) {
		return offset >= 0 && Arrays.binarySearch(getOffsets(), offset) >= 0;
	}

	public boolean isEndOfLineComment(int offset, char[] content) {
		if (offset < 0
				|| (offset < content.length && !IndentManipulation
						.isLineDelimiterChar(content[offset]))) {
			return false;
		}
		return Arrays.binarySearch(getOffsets(), offset) >= 0;
	}

	public boolean remove(int offset) {
		int[] offsetArray = getOffsets(); // returns the shared array
		int index = Arrays.binarySearch(offsetArray, offset);
		if (index >= 0) {
			if (index > 0) {
				// shift from the beginning and insert -1 (smallest number) at
				// the beginning
				// 1, 2, 3, x, 4, 5 -> -1, 1, 2, 3, 4, 5
				System.arraycopy(offsetArray, 0, offsetArray, 1, index);
			}
			offsetArray[0] = -1;
			return true;
		}
		return false;
	}

}