1 /*
2 * Copyright (C) 2011, Google Inc. and others
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Distribution License v. 1.0 which is available at
6 * https://www.eclipse.org/org/documents/edl-v10.php.
7 *
8 * SPDX-License-Identifier: BSD-3-Clause
9 */
10
11 package org.eclipse.jgit.blame;
12
13 /**
14 * Region of the result that still needs to be computed.
15 * <p>
16 * Regions are held in a singly-linked-list by {@link Candidate} using the
17 * {@link Candidate#regionList} field. The list is kept in sorted order by
18 * {@link #resultStart}.
19 */
20 class Region {
21 /** Next entry in the region linked list. */
22 Region next;
23
24 /** First position of this region in the result file blame is computing. */
25 int resultStart;
26
27 /** First position in the {@link Candidate} that owns this Region. */
28 int sourceStart;
29
30 /** Length of the region, always >= 1. */
31 int length;
32
33 Region(int rs, int ss, int len) {
34 resultStart = rs;
35 sourceStart = ss;
36 length = len;
37 }
38
39 /**
40 * Copy the entire result region, but at a new source position.
41 *
42 * @param newSource
43 * the new source position.
44 * @return the same result region, but offset for a new source.
45 */
46 Region copy(int newSource) {
47 return new Region(resultStart, newSource, length);
48 }
49
50 /**
51 * Split the region, assigning a new source position to the first half.
52 *
53 * @param newSource
54 * the new source position.
55 * @param newLen
56 * length of the new region.
57 * @return the first half of the region, at the new source.
58 */
59 Region splitFirst(int newSource, int newLen) {
60 return new Region(resultStart, newSource, newLen);
61 }
62
63 /**
64 * Edit this region to remove the first {@code d} elements.
65 *
66 * @param d
67 * number of elements to remove from the start of this region.
68 */
69 void slideAndShrink(int d) {
70 resultStart += d;
71 sourceStart += d;
72 length -= d;
73 }
74
75 Region deepCopy() {
76 Region head = new Region(resultStart, sourceStart, length);
77 Region tail = head;
78 for (Region n = next; n != null; n = n.next) {
79 Region q = new Region(n.resultStart, n.sourceStart, n.length);
80 tail.next = q;
81 tail = q;
82 }
83 return head;
84 }
85
86 /** {@inheritDoc} */
87 @Override
88 public String toString() {
89 StringBuilder buf = new StringBuilder();
90 Region r = this;
91 do {
92 if (r != this)
93 buf.append(',');
94 buf.append(r.resultStart);
95 buf.append('-');
96 buf.append(r.resultStart + r.length);
97 r = r.next;
98 } while (r != null);
99 return buf.toString();
100 }
101 }