GnuDiffAlgorithm (SourceJammer library API)

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JLibDiff
Class GnuDiffAlgorithm

java.lang.Object
  |
  +--JLibDiff.GnuDiffAlgorithm

All Implemented Interfaces:: DiffAlgorithm, DiffMaker

public class GnuDiffAlgorithm
extends java.lang.Object
implements DiffAlgorithm, DiffMaker

Title: $FileName: GnuDiffAlgorithm.java$

Version:

$VerNum: 1$

Author:

$AuthorName: Rob MacGrogan$

$Description: GNU diff algorithm.$
$KeyWordsOff: $

This class implements GNU diff and is adapted and copied (where possible) from Java implementation of this program created by Stuart D Gathman.

The code has been significantly modified by Robert MacGrogan to fit into SourceJammer and use the JLibDiff objects.

Please note that this module is released under the GNU Public License only. If the version of SourceJammer you are using contains this module it is released as GPL and can only be re-distributed as GPL.

Original file header and copyright information follows:

A class to compare vectors of objects. The result of comparison is a list of change objects which form an edit script. The objects compared are traditionally lines of text from two files. Comparison options such as "ignore whitespace" are implemented by modifying the equals and hashcode methods for the objects compared.

The basic algorithm is described in:
"An O(ND) Difference Algorithm and its Variations", Eugene Myers, Algorithmica Vol. 1 No. 2, 1986, p 251.

This class outputs different results from GNU diff 1.15 on some inputs. Our results are actually better (smaller change list, smaller total size of changes), but it would be nice to know why. Perhaps there is a memory overwrite bug in GNU diff 1.15., Stuart D. Gathman, translated from GNU diff 1.15 Copyright (C) 2000 Business Management Systems, Inc.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

Field Summary

private int[] bdiag


private int bdiagoff


private int cost


private int equivMax


private int[] fdiag


private int fdiagoff


private FileData[] fileInfo


boolean heuristic


private boolean noDiscards


private int[] xvec


private int[] yvec


Constructor Summary

GnuDiffAlgorithm()


Method Summary

private java.util.Vector buildChangeList(java.lang.String[] A, java.lang.String[] B)


private void compareseq(int xoff, int xlim, int yoff, int ylim)


private int diag(int xoff, int xlim, int yoff, int ylim)


private void discardConfusingLines()


int getEquivMax()
          Returns the equivMax.

private java.lang.Object[] getLines(int firstLine, int numLines, java.lang.Object[] parent)


void incrimentEquivMax()


boolean isNoDiscards()
          Returns the noDiscards.

java.util.Vector makeDiff(java.lang.String[] A, java.lang.String[] B)


void setEol(java.lang.String s)


private void shiftBoundaries()


Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

equivMax

private int equivMax

noDiscards

private boolean noDiscards

fileInfo

private FileData[] fileInfo

xvec

private int[] xvec

yvec

private int[] yvec

fdiag

private int[] fdiag

bdiag

private int[] bdiag

fdiagoff

private int fdiagoff

bdiagoff

private int bdiagoff

cost

private int cost

heuristic

public boolean heuristic

Constructor Detail