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Repackaged the code from NetBeans
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common
* Development and Distribution License("CDDL") (collectively, the
* "License"). You may not use this file except in compliance with the
* License. You can obtain a copy of the License at
* http://www.netbeans.org/cddl-gplv2.html
* or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
* specific language governing permissions and limitations under the
* License. When distributing the software, include this License Header
* Notice in each file and include the License file at
* nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the
* License Header, with the fields enclosed by brackets [] replaced by
* your own identifying information:
* "Portions Copyrighted [year] [name of copyright owner]"
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* Contributor(s):
*
* The Original Software is NetBeans. The Initial Developer of the Original
* Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
* Microsystems, Inc. All Rights Reserved.
*
* If you wish your version of this file to be governed by only the CDDL
* or only the GPL Version 2, indicate your decision by adding
* "[Contributor] elects to include this software in this distribution
* under the [CDDL or GPL Version 2] license." If you do not indicate a
* single choice of license, a recipient has the option to distribute
* your version of this file under either the CDDL, the GPL Version 2 or
* to extend the choice of license to its licensees as provided above.
* However, if you add GPL Version 2 code and therefore, elected the GPL
* Version 2 license, then the option applies only if the new code is
* made subject to such option by the copyright holder.
*/
package com.cloudbees.diff;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
class HuntDiff {
private HuntDiff() {
}
/**
* @param lines1 array of lines from the first source
* @param lines2 array of lines from the second source
* @param ignoreWhitespace true to ignore leading and trailing whitespace when computing diff, false to also find differences in whitespace
* @return computed diff
*/
public static Diff diff(List lines1, List lines2, boolean ignoreWhitespace) {
int m = lines1.size();
int n = lines2.size();
List orig1=lines1, orig2=lines2;
if (ignoreWhitespace) {
lines1 = trimLines(lines1);
lines2 = trimLines(lines2);
}
Line[] l2s = new Line[n + 1];
// In l2s we have sorted lines of the second file <1, n>
for (int i = 1; i <= n; i++) {
l2s[i] = new Line(i, lines2.get(i - 1));
}
Arrays.sort(l2s, 1, n+1);
int[] equvalenceLines = new int[n+1];
boolean[] equivalence = new boolean[n+1];
for (int i = 1; i <= n; i++) {
Line l = l2s[i];
equvalenceLines[i] = l.lineNo;
equivalence[i] = (i == n) || !l.line.equals(l2s[i+1].line);//((Line) l2s.get(i)).line);
}
equvalenceLines[0] = 0;
equivalence[0] = true;
int[] equivalenceAssoc = new int[m + 1];
for (int i = 1; i <= m; i++) {
equivalenceAssoc[i] = findAssoc(lines1.get(i - 1), l2s, equivalence);
}
l2s = null;
Candidate[] K = new Candidate[Math.min(m, n) + 2];
K[0] = new Candidate(0, 0, null);
K[1] = new Candidate(m + 1, n + 1, null);
int k = 0;
for (int i = 1; i <= m; i++) {
if (equivalenceAssoc[i] != 0) {
k = merge(K, k, i, equvalenceLines, equivalence, equivalenceAssoc[i]);
}
}
int[] J = new int[m+2]; // Initialized with zeros
Candidate c = K[k];
while (c != null) {
J[c.a] = c.b;
c = c.c;
}
Diff differences = getDifferences(J, orig1, orig2);
cleanup(differences);
return differences;
}
private static List trimLines(List lines) {
List r = new ArrayList(lines.size());
for (String s : lines) {
r.add(s.trim());
}
return r;
}
private static int findAssoc(String line1, Line[] l2s, boolean[] equivalence) {
int idx = binarySearch(l2s, line1, 1, l2s.length - 1);
if (idx < 1) {
return 0;
} else {
int lastGoodIdx = 0;
for (; idx >= 1 && l2s[idx].line.equals(line1); idx--) {
if (equivalence[idx - 1]) {
lastGoodIdx = idx;
}
}
return lastGoodIdx;
}
}
private static int binarySearch(Line[] L, String key, int low, int high) {
while (low <= high) {
int mid = (low + high) >> 1;
String midVal = L[mid].line;
int comparison = midVal.compareTo(key);
if (comparison < 0) {
low = mid + 1;
} else if (comparison > 0) {
high = mid - 1;
} else {
return mid;
}
}
return -(low + 1);
}
private static int binarySearch(Candidate[] K, int key, int low, int high) {
while (low <= high) {
int mid = (low + high) >> 1;
int midVal = K[mid].b;
if (midVal < key) {
low = mid + 1;
} else if (midVal > key) {
high = mid - 1;
} else {
return mid;
}
}
return -(low + 1);
}
private static int merge(Candidate[] K, int k, int i, int[] equvalenceLines,
boolean[] equivalence, int p) {
int r = 0;
Candidate c = K[0];
do {
int j = equvalenceLines[p];
int s = binarySearch(K, j, r, k);
if (s >= 0) {
// j was found in K[]
s = k + 1;
} else {
s = -s - 2;
if (s < r || s > k) s = k + 1;
}
if (s <= k) {
if (K[s+1].b > j) {
Candidate newc = new Candidate(i, j, K[s]);
K[r] = c;
r = s+1;
c = newc;
}
if (s == k) {
K[k+2] = K[k+1];
k++;
break;
}
}
if (equivalence[p]) {
break;
} else {
p++;
}
} while (true);
K[r] = c;
return k;
}
private static Diff getDifferences(int[] J, List lines1, List lines2) {
Diff differences = new Diff();
int n = lines1.size();
int m = lines2.size();
int start1 = 1;
int start2 = 1;
do {
while (start1 <= n && J[start1] == start2) {
start1++;
start2++;
}
if (start1 > n) break;
if (J[start1] < start2) { // There's something extra in the first file
int end1 = start1 + 1;
StringBuilder deletedText = new StringBuilder();
deletedText.append(lines1.get(start1-1)).append('\n');
while (end1 <= n && J[end1] < start2) {
String line = lines1.get(end1-1);
deletedText.append(line).append('\n');
end1++;
}
differences.add(new Difference(Difference.DELETE, start1, end1 - 1, start2 - 1, 0, deletedText.toString(), null));
start1 = end1;
} else { // There's something extra in the second file
int end2 = J[start1];
StringBuilder addedText = new StringBuilder();
for (int i = start2; i < end2; i++) {
String line = lines2.get(i-1);
addedText.append(line).append('\n');
}
differences.add(new Difference(Difference.ADD, (start1 - 1), 0, start2, (end2 - 1), null, addedText.toString()));
start2 = end2;
}
} while (start1 <= n);
if (start2 <= m) { // There's something extra at the end of the second file
int end2 = start2 + 1;
StringBuilder addedText = new StringBuilder();
addedText.append(lines2.get(start2-1)).append('\n');
while (end2 <= m) {
String line = lines2.get(end2-1);
addedText.append(line).append('\n');
end2++;
}
differences.add(new Difference(Difference.ADD, n, 0, start2, m, null, addedText.toString()));
}
return differences;
}
private static void cleanup(List diffs) {
Difference last = null;
for (int i = 0; i < diffs.size(); i++) {
Difference diff = diffs.get(i);
if (last != null) {
if (diff.getType() == Difference.ADD && last.getType() == Difference.DELETE ||
diff.getType() == Difference.DELETE && last.getType() == Difference.ADD) {
Difference add;
Difference del;
if (Difference.ADD == diff.getType()) {
add = diff;
del = last;
} else {
add = last;
del = diff;
}
int d1f1l1 = add.getFirstStart() - (del.getFirstEnd() - del.getFirstStart());
int d2f1l1 = del.getFirstStart();
if (d1f1l1 == d2f1l1) {
Difference newDiff = new Difference(Difference.CHANGE,
d1f1l1, del.getFirstEnd(), add.getSecondStart(), add.getSecondEnd(),
del.getFirstText(), add.getSecondText());
diffs.set(i - 1, newDiff);
diffs.remove(i);
i--;
diff = newDiff;
}
}
}
last = diff;
}
}
private static class Line implements Comparable {
public int lineNo;
public String line;
public int hash;
public Line(int lineNo, String line) {
this.lineNo = lineNo;
this.line = line;
this.hash = line.hashCode();
}
public int compareTo(Line that) {
return this.line.compareTo(that.line);
}
}
private static class Candidate {
private int a;
private int b;
private Candidate c;
public Candidate(int a, int b, Candidate c) {
this.a = a;
this.b = b;
this.c = c;
}
}
}
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