1 /*
2 * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.diff;
45
46 /**
47 * A modified region detected between two versions of roughly the same content.
48 * <p>
49 * An edit covers the modified region only. It does not cover a common region.
50 * <p>
51 * Regions should be specified using 0 based notation, so add 1 to the start and
52 * end marks for line numbers in a file.
53 * <p>
54 * An edit where {@code beginA == endA && beginB < endB} is an insert edit, that
55 * is sequence B inserted the elements in region <code>[beginB, endB)</code> at
56 * <code>beginA</code>.
57 * <p>
58 * An edit where {@code beginA < endA && beginB == endB} is a delete edit, that
59 * is sequence B has removed the elements between <code>[beginA, endA)</code>.
60 * <p>
61 * An edit where {@code beginA < endA && beginB < endB} is a replace edit, that
62 * is sequence B has replaced the range of elements between
63 * <code>[beginA, endA)</code> with those found in <code>[beginB, endB)</code>.
64 */
65 public class Edit {
66 /** Type of edit */
67 public static enum Type {
68 /** Sequence B has inserted the region. */
69 INSERT,
70
71 /** Sequence B has removed the region. */
72 DELETE,
73
74 /** Sequence B has replaced the region with different content. */
75 REPLACE,
76
77 /** Sequence A and B have zero length, describing nothing. */
78 EMPTY;
79 }
80
81 int beginA;
82
83 int endA;
84
85 int beginB;
86
87 int endB;
88
89 /**
90 * Create a new empty edit.
91 *
92 * @param as
93 * beginA: start and end of region in sequence A; 0 based.
94 * @param bs
95 * beginB: start and end of region in sequence B; 0 based.
96 */
97 public Edit(final int as, final int bs) {
98 this(as, as, bs, bs);
99 }
100
101 /**
102 * Create a new edit.
103 *
104 * @param as
105 * beginA: start of region in sequence A; 0 based.
106 * @param ae
107 * endA: end of region in sequence A; must be >= as.
108 * @param bs
109 * beginB: start of region in sequence B; 0 based.
110 * @param be
111 * endB: end of region in sequence B; must be > = bs.
112 */
113 public Edit(final int as, final int ae, final int bs, final int be) {
114 beginA = as;
115 endA = ae;
116
117 beginB = bs;
118 endB = be;
119 }
120
121 /** @return the type of this region */
122 public final Type getType() {
123 if (beginA < endA) {
124 if (beginB < endB)
125 return Type.REPLACE;
126 else /* if (beginB == endB) */
127 return Type.DELETE;
128
129 } else /* if (beginA == endA) */{
130 if (beginB < endB)
131 return Type.INSERT;
132 else /* if (beginB == endB) */
133 return Type.EMPTY;
134 }
135 }
136
137 /** @return true if the edit is empty (lengths of both a and b is zero). */
138 public final boolean isEmpty() {
139 return beginA == endA && beginB == endB;
140 }
141
142 /** @return start point in sequence A. */
143 public final int getBeginA() {
144 return beginA;
145 }
146
147 /** @return end point in sequence A. */
148 public final int getEndA() {
149 return endA;
150 }
151
152 /** @return start point in sequence B. */
153 public final int getBeginB() {
154 return beginB;
155 }
156
157 /** @return end point in sequence B. */
158 public final int getEndB() {
159 return endB;
160 }
161
162 /** @return length of the region in A. */
163 public final int getLengthA() {
164 return endA - beginA;
165 }
166
167 /** @return length of the region in B. */
168 public final int getLengthB() {
169 return endB - beginB;
170 }
171
172 /**
173 * Construct a new edit representing the region before cut.
174 *
175 * @param cut
176 * the cut point. The beginning A and B points are used as the
177 * end points of the returned edit.
178 * @return an edit representing the slice of {@code this} edit that occurs
179 * before {@code cut} starts.
180 */
181 public final Edit before(Edit cut) {
182 return new Edit(beginA, cut.beginA, beginB, cut.beginB);
183 }
184
185 /**
186 * Construct a new edit representing the region after cut.
187 *
188 * @param cut
189 * the cut point. The ending A and B points are used as the
190 * starting points of the returned edit.
191 * @return an edit representing the slice of {@code this} edit that occurs
192 * after {@code cut} ends.
193 */
194 public final Edit after(Edit cut) {
195 return new Edit(cut.endA, endA, cut.endB, endB);
196 }
197
198 /** Increase {@link #getEndA()} by 1. */
199 public void extendA() {
200 endA++;
201 }
202
203 /** Increase {@link #getEndB()} by 1. */
204 public void extendB() {
205 endB++;
206 }
207
208 /** Swap A and B, so the edit goes the other direction. */
209 public void swap() {
210 final int sBegin = beginA;
211 final int sEnd = endA;
212
213 beginA = beginB;
214 endA = endB;
215
216 beginB = sBegin;
217 endB = sEnd;
218 }
219
220 @Override
221 public int hashCode() {
222 return beginA ^ endA;
223 }
224
225 @Override
226 public boolean equals(final Object o) {
227 if (o instanceof Edit) {
228 final Edit e = (Edit) o;
229 return this.beginA == e.beginA && this.endA == e.endA
230 && this.beginB == e.beginB && this.endB == e.endB;
231 }
232 return false;
233 }
234
235 @SuppressWarnings("nls")
236 @Override
237 public String toString() {
238 final Type t = getType();
239 return t + "(" + beginA + "-" + endA + "," + beginB + "-" + endB + ")";
240 }
241 }