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Diffstat (limited to 'xmerge/java/org/openoffice/xmerge/merger/diff/IteratorLCSAlgorithm.java')
| -rw-r--r-- | xmerge/java/org/openoffice/xmerge/merger/diff/IteratorLCSAlgorithm.java | 236 |
1 files changed, 0 insertions, 236 deletions
diff --git a/xmerge/java/org/openoffice/xmerge/merger/diff/IteratorLCSAlgorithm.java b/xmerge/java/org/openoffice/xmerge/merger/diff/IteratorLCSAlgorithm.java deleted file mode 100644 index 7cc7c60b0439..000000000000 --- a/xmerge/java/org/openoffice/xmerge/merger/diff/IteratorLCSAlgorithm.java +++ /dev/null @@ -1,236 +0,0 @@ -/************************************************************************ - * - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * Copyright 2000, 2010 Oracle and/or its affiliates. - * - * OpenOffice.org - a multi-platform office productivity suite - * - * This file is part of OpenOffice.org. - * - * OpenOffice.org is free software: you can redistribute it and/or modify - * it under the terms of the GNU Lesser General Public License version 3 - * only, as published by the Free Software Foundation. - * - * OpenOffice.org is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU Lesser General Public License version 3 for more details - * (a copy is included in the LICENSE file that accompanied this code). - * - * You should have received a copy of the GNU Lesser General Public License - * version 3 along with OpenOffice.org. If not, see - * <http://www.openoffice.org/license.html> - * for a copy of the LGPLv3 License. - * - ************************************************************************/ - -package org.openoffice.xmerge.merger.diff; - -import java.util.Vector; -import org.openoffice.xmerge.merger.DiffAlgorithm; -import org.openoffice.xmerge.merger.Difference; -import org.openoffice.xmerge.merger.Iterator; -import org.openoffice.xmerge.util.Debug; - -/** - * This is one of the implementations of <code>DiffAlgorithm</code> interface. - * Using Longest Common Subsequence (LCS). The algorithm here is based - * on the book "Introduction to Algorithms" by Thomas H.Cormen, - * Charles E.Leiserson and Ronald L.Riverst (MIT Press 1990) page 314. - * - * @author smak - */ -public class IteratorLCSAlgorithm implements DiffAlgorithm { - - public Difference[] computeDiffs(Iterator orgSeq, Iterator modSeq) { - - int orgSeqlen = orgSeq.elementCount(); - int modSeqlen = modSeq.elementCount(); - - int[][] diffTable; - - // Diff table is used to keep track which element is the same or not - // in those 2 sequences - diffTable = createDiffTable(orgSeq, modSeq); - - // debug purpose... - if (Debug.isFlagSet(Debug.INFO)) { - printDiffTable(diffTable); - } - - Vector diffResult = new Vector(); - - generateResult(diffTable, orgSeqlen, modSeqlen, diffResult); - - Difference[] diffArray = new Difference[0]; - - // convert the vector to array, it has to do in here as - // generateResult is called recursively - if (diffResult.size() > 0) { - diffArray = new Difference[diffResult.size()]; - diffResult.copyInto(diffArray); - } - - diffTable = null; - diffResult = null; - - return diffArray; - } - - - /** - * Debug function used to print out the nicely formatted - * difference table. - * - * @param diffTable The difference table to display. - */ - private void printDiffTable(int[][] diffTable) { - - String tmpString = ""; - - for (int i = 0; i < diffTable.length; i++) { - for (int j = 0; j < diffTable[i].length; j++) { - tmpString = tmpString + " " + diffTable[i][j] + " "; - } - Debug.log(Debug.INFO, tmpString); - tmpString = ""; - } - } - - /** - * Create the difference table. - * The difference table is used internal to keep track what - * elements are common or different in the two sequences. - * - * @param orgSeq The original sequence to be used as a base. - * @param modSeq The modified sequence to compare. - * - * @return A difference table as a two-dimensional array of - * integers. - */ - private int[][] createDiffTable(Iterator orgSeq, Iterator modSeq) { - int orgSeqlen = orgSeq.elementCount() + 1; - int modSeqlen = modSeq.elementCount() + 1; - int[][] diffTable; - - // initialize the diffTable - diffTable = new int[orgSeqlen][]; - for (int i = 0; i < orgSeqlen; i++) { - diffTable[i] = new int[modSeqlen]; - } - - // compute the diff Table using LCS algorithm, refer to the book - // mentioned at the top of the program - - int i, j; - - Object orgSeqObject, modSeqObject; - - for (orgSeqObject = orgSeq.start(), i = 1; - orgSeqObject != null; - orgSeqObject = orgSeq.next(), i++) { - - for (modSeqObject = modSeq.start(), j = 1; - modSeqObject != null; - modSeqObject = modSeq.next(), j++) { - - if (orgSeq.equivalent(orgSeqObject, modSeqObject)) { - diffTable[i][j] = diffTable[i-1][j-1]+1; - } else { - if (diffTable[i-1][j] >= diffTable[i][j-1]) { - diffTable[i][j] = diffTable[i-1][j]; - } else { - diffTable[i][j] = diffTable[i][j-1]; - } - } - } - } - - return diffTable; - } - - - /** - * Generate the <code>Difference</code> object result vector. - * This method will be called recursively to backtrack the difference - * table to get the difference result (and also the LCS). - * - * @param diffTable The difference table containing the - * <code>Difference</code> result. - * @param i The nth element in original sequence to - * compare. This method is called recursively - * with i and j decreased until 0. - * @param j The nth element in modified sequence to - * compare. - * @param diffVector A vector to output the <code>Difference</code> - * result. Can not use a return variable as it - * is a recursive method. The vector will contain - * <code>Difference</code> objects with operation - * and positions fill in. - */ - private void generateResult(int[][] diffTable, - int i, int j, Vector diffVector) { - - // handle the first element - if (i == 0 && j == 0) { - return; - - } else if (j == 0) { - for (int cnt = 0; cnt < i; cnt++) { - Difference diff = - new Difference(Difference.DELETE, cnt, j); - diffVector.add(diff); - } - return; - - } else if (i == 0) { - for (int cnt = 0; cnt < j; cnt++) { - Difference diff = - new Difference(Difference.ADD, i, cnt); - diffVector.add(diff); - } - return; - } - - // for the detail of this algorithm, refer to the book mentioned on - // the top and page 317 and 318. - if ((diffTable[i-1][j-1] == diffTable[i][j] -1) && - (diffTable[i-1][j-1] == diffTable[i-1][j]) && - (diffTable[i-1][j-1] == diffTable[i][j-1])) { - - // the element of ith and jth in org and mod sequence is the same - generateResult(diffTable, i-1, j-1, diffVector); - } else { - if (diffTable[i-1][j] > diffTable[i][j-1]) { - - // recursively call first, then add the result so that - // the beginning of the diffs will be stored first - generateResult(diffTable, i-1, j, diffVector); - - Difference diff = - new Difference(Difference.DELETE, i-1, j); - diffVector.add(diff); - } else if (diffTable[i-1][j] < diffTable[i][j-1]) { - - // recursively call first, then add the result so that - // the beginning of the diffs will be stored first - generateResult(diffTable, i, j-1, diffVector); - - Difference diff = - new Difference(Difference.ADD, i, j-1); - diffVector.add(diff); - } else { // diffTable[i-1][j] == diffTable[i][j-1] - // recursively call first, then add the result so that - // the beginning of the diffs will be stored first - generateResult(diffTable, i-1, j-1, diffVector); - - Difference diff = - new Difference(Difference.CHANGE, i-1, j-1); - diffVector.add(diff); - - } - } - } -} - |