| /******************************************************************************* |
| * Copyright (c) 2000, 2005 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.jdt.internal.ui.compare; |
| |
| import org.eclipse.jface.util.Assert; |
| |
| import org.eclipse.jdt.core.ToolFactory; |
| import org.eclipse.jdt.core.compiler.*; |
| |
| import org.eclipse.compare.contentmergeviewer.ITokenComparator; |
| import org.eclipse.compare.rangedifferencer.IRangeComparator; |
| |
| |
| /** |
| * A comparator for Java tokens. |
| */ |
| public class JavaTokenComparator implements ITokenComparator { |
| |
| private String fText; |
| private boolean fShouldEscape= true; |
| private int fCount; |
| private int[] fStarts; |
| private int[] fLengths; |
| |
| /** |
| * Creates a TokenComparator for the given string. |
| */ |
| public JavaTokenComparator(String text, boolean shouldEscape) { |
| |
| Assert.isNotNull(text); |
| |
| fText= text; |
| fShouldEscape= shouldEscape; |
| |
| int length= fText.length(); |
| fStarts= new int[length]; |
| fLengths= new int[length]; |
| fCount= 0; |
| |
| IScanner scanner= ToolFactory.createScanner(true, true, false, false); // returns comments & whitespace |
| scanner.setSource(fText.toCharArray()); |
| try { |
| int endPos= 0; |
| while (scanner.getNextToken() != ITerminalSymbols.TokenNameEOF) { |
| int start= scanner.getCurrentTokenStartPosition(); |
| int end= scanner.getCurrentTokenEndPosition()+1; |
| fStarts[fCount]= start; |
| fLengths[fCount]= end - start; |
| endPos= end; |
| fCount++; |
| } |
| // workaround for #13907 |
| if (endPos < length) { |
| fStarts[fCount]= endPos; |
| fLengths[fCount]= length-endPos; |
| fCount++; |
| } |
| } catch (InvalidInputException ex) { |
| // NeedWork |
| } |
| } |
| |
| /** |
| * Returns the number of token in the string. |
| * |
| * @return number of token in the string |
| */ |
| public int getRangeCount() { |
| return fCount; |
| } |
| |
| /* (non Javadoc) |
| * see ITokenComparator.getTokenStart |
| */ |
| public int getTokenStart(int index) { |
| if (index >= 0 && index < fCount) |
| return fStarts[index]; |
| if (fCount > 0) |
| return fStarts[fCount-1] + fLengths[fCount-1]; |
| return 0; |
| } |
| |
| /* (non Javadoc) |
| * see ITokenComparator.getTokenLength |
| */ |
| public int getTokenLength(int index) { |
| if (index < fCount) |
| return fLengths[index]; |
| return 0; |
| } |
| |
| /** |
| * Returns <code>true</code> if a token given by the first index |
| * matches a token specified by the other <code>IRangeComparator</code> and index. |
| * |
| * @param thisIndex the number of the token within this range comparator |
| * @param other the range comparator to compare this with |
| * @param otherIndex the number of the token within the other comparator |
| * @return <code>true</code> if the token are equal |
| */ |
| public boolean rangesEqual(int thisIndex, IRangeComparator other, int otherIndex) { |
| if (other != null && getClass() == other.getClass()) { |
| JavaTokenComparator tc= (JavaTokenComparator) other; // safe cast |
| int thisLen= getTokenLength(thisIndex); |
| int otherLen= tc.getTokenLength(otherIndex); |
| if (thisLen == otherLen) |
| return fText.regionMatches(false, getTokenStart(thisIndex), tc.fText, tc.getTokenStart(otherIndex), thisLen); |
| } |
| return false; |
| } |
| |
| /** |
| * Aborts the comparison if the number of tokens is too large. |
| * |
| * @return <code>true</code> to abort a token comparison |
| */ |
| public boolean skipRangeComparison(int length, int max, IRangeComparator other) { |
| |
| if (!fShouldEscape) |
| return false; |
| |
| if (getRangeCount() < 50 || other.getRangeCount() < 50) |
| return false; |
| |
| if (max < 100) |
| return false; |
| |
| if (length < 100) |
| return false; |
| |
| if (max > 800) |
| return true; |
| |
| if (length < max / 4) |
| return false; |
| |
| return true; |
| } |
| } |