001/*
002 * Sonar, open source software quality management tool.
003 * Copyright (C) 2008-2012 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * Sonar is free software; you can redistribute it and/or
007 * modify it under the terms of the GNU Lesser General Public
008 * License as published by the Free Software Foundation; either
009 * version 3 of the License, or (at your option) any later version.
010 *
011 * Sonar is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014 * Lesser General Public License for more details.
015 *
016 * You should have received a copy of the GNU Lesser General Public
017 * License along with Sonar; if not, write to the Free Software
018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019 */
020package org.sonar.plugins.core.timemachine;
021
022import org.sonar.plugins.core.timemachine.tracking.HashedSequence;
023import org.sonar.plugins.core.timemachine.tracking.HashedSequenceComparator;
024import org.sonar.plugins.core.timemachine.tracking.StringText;
025import org.sonar.plugins.core.timemachine.tracking.StringTextComparator;
026
027public class ViolationTrackingBlocksRecognizer {
028
029  private final HashedSequence<StringText> a;
030  private final HashedSequence<StringText> b;
031  private final HashedSequenceComparator<StringText> cmp;
032
033  public ViolationTrackingBlocksRecognizer(String referenceSource, String source) {
034    this(new StringText(referenceSource), new StringText(source), StringTextComparator.IGNORE_WHITESPACE);
035  }
036
037  private ViolationTrackingBlocksRecognizer(StringText a, StringText b, StringTextComparator cmp) {
038    this.a = HashedSequence.wrap(a, cmp);
039    this.b = HashedSequence.wrap(b, cmp);
040    this.cmp = new HashedSequenceComparator<StringText>(cmp);
041  }
042
043  public boolean isValidLineInReference(int line) {
044    return (0 <= line) && (line < a.length());
045  }
046
047  public boolean isValidLineInSource(int line) {
048    return (0 <= line) && (line < b.length());
049  }
050
051  /**
052   * @param startA number of line from first version of text (numbering starts from 0)
053   * @param startB number of line from second version of text (numbering starts from 0)
054   */
055  public int computeLengthOfMaximalBlock(int startA, int startB) {
056    if (!cmp.equals(a, startA, b, startB)) {
057      return 0;
058    }
059    int length = 0;
060    int ai = startA;
061    int bi = startB;
062    while (ai < a.length() && bi < b.length() && cmp.equals(a, ai, b, bi)) {
063      ai++;
064      bi++;
065      length++;
066    }
067    ai = startA;
068    bi = startB;
069    while (ai >= 0 && bi >= 0 && cmp.equals(a, ai, b, bi)) {
070      ai--;
071      bi--;
072      length++;
073    }
074    // Note that position (startA, startB) was counted twice
075    return length - 1;
076  }
077
078}