/*
* Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.diff;
/**
* A modified region detected between two versions of roughly the same content.
* <p>
* An edit covers the modified region only. It does not cover a common region.
* <p>
* Regions should be specified using 0 based notation, so add 1 to the start and
* end marks for line numbers in a file.
* <p>
* An edit where {@code beginA == endA && beginB < endB} is an insert edit, that
* is sequence B inserted the elements in region <code>[beginB, endB)</code> at
* <code>beginA</code>.
* <p>
* An edit where {@code beginA < endA && beginB == endB} is a delete edit, that
* is sequence B has removed the elements between <code>[beginA, endA)</code>.
* <p>
* An edit where {@code beginA < endA && beginB < endB} is a replace edit, that
* is sequence B has replaced the range of elements between
* <code>[beginA, endA)</code> with those found in <code>[beginB, endB)</code>.
*/
public class Edit {
/** Type of edit */
public static enum Type {
/** Sequence B has inserted the region. */
INSERT,
/** Sequence B has removed the region. */
DELETE,
/** Sequence B has replaced the region with different content. */
REPLACE,
/** Sequence A and B have zero length, describing nothing. */
EMPTY;
}
int beginA;
int endA;
int beginB;
int endB;
/**
* Create a new empty edit.
*
* @param as
* beginA: start and end of region in sequence A; 0 based.
* @param bs
* beginB: start and end of region in sequence B; 0 based.
*/
public Edit(final int as, final int bs) {
this(as, as, bs, bs);
}
/**
* Create a new edit.
*
* @param as
* beginA: start of region in sequence A; 0 based.
* @param ae
* endA: end of region in sequence A; must be >= as.
* @param bs
* beginB: start of region in sequence B; 0 based.
* @param be
* endB: end of region in sequence B; must be > = bs.
*/
public Edit(final int as, final int ae, final int bs, final int be) {
beginA = as;
endA = ae;
beginB = bs;
endB = be;
}
/** @return the type of this region */
public final Type getType() {
if (beginA < endA) {
if (beginB < endB)
return Type.REPLACE;
else /* if (beginB == endB) */
return Type.DELETE;
} else /* if (beginA == endA) */{
if (beginB < endB)
return Type.INSERT;
else /* if (beginB == endB) */
return Type.EMPTY;
}
}
/** @return true if the edit is empty (lengths of both a and b is zero). */
public final boolean isEmpty() {
return beginA == endA && beginB == endB;
}
/** @return start point in sequence A. */
public final int getBeginA() {
return beginA;
}
/** @return end point in sequence A. */
public final int getEndA() {
return endA;
}
/** @return start point in sequence B. */
public final int getBeginB() {
return beginB;
}
/** @return end point in sequence B. */
public final int getEndB() {
return endB;
}
/** @return length of the region in A. */
public final int getLengthA() {
return endA - beginA;
}
/** @return length of the region in B. */
public final int getLengthB() {
return endB - beginB;
}
/**
* Construct a new edit representing the region before cut.
*
* @param cut
* the cut point. The beginning A and B points are used as the
* end points of the returned edit.
* @return an edit representing the slice of {@code this} edit that occurs
* before {@code cut} starts.
*/
public final Edit before(Edit cut) {
return new Edit(beginA, cut.beginA, beginB, cut.beginB);
}
/**
* Construct a new edit representing the region after cut.
*
* @param cut
* the cut point. The ending A and B points are used as the
* starting points of the returned edit.
* @return an edit representing the slice of {@code this} edit that occurs
* after {@code cut} ends.
*/
public final Edit after(Edit cut) {
return new Edit(cut.endA, endA, cut.endB, endB);
}
/** Increase {@link #getEndA()} by 1. */
public void extendA() {
endA++;
}
/** Increase {@link #getEndB()} by 1. */
public void extendB() {
endB++;
}
/** Swap A and B, so the edit goes the other direction. */
public void swap() {
final int sBegin = beginA;
final int sEnd = endA;
beginA = beginB;
endA = endB;
beginB = sBegin;
endB = sEnd;
}
@Override
public int hashCode() {
return beginA ^ endA;
}
@Override
public boolean equals(final Object o) {
if (o instanceof Edit) {
final Edit e = (Edit) o;
return this.beginA == e.beginA && this.endA == e.endA
&& this.beginB == e.beginB && this.endB == e.endB;
}
return false;
}
@SuppressWarnings("nls")
@Override
public String toString() {
final Type t = getType();
return t + "(" + beginA + "-" + endA + "," + beginB + "-" + endB + ")";
}
}