1 /*
2 * Copyright (C) 2010, 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.diff;
12
13 /**
14 * Wrap another comparator for use with
15 * {@link org.eclipse.jgit.diff.HashedSequence}.
16 * <p>
17 * This comparator acts as a proxy for the real comparator, evaluating the
18 * cached hash code before testing the underlying comparator's equality.
19 * Comparators of this type must be used with a
20 * {@link org.eclipse.jgit.diff.HashedSequence}.
21 * <p>
22 * To construct an instance of this type use
23 * {@link org.eclipse.jgit.diff.HashedSequencePair}.
24 *
25 * @param <S>
26 * the base sequence type.
27 */
28 public final class HashedSequenceComparator<S extends Sequence> extends
29 SequenceComparator<HashedSequence<S>> {
30 private final SequenceComparator<? super S> cmp;
31
32 HashedSequenceComparator(SequenceComparator<? super S> cmp) {
33 this.cmp = cmp;
34 }
35
36 /** {@inheritDoc} */
37 @Override
38 public boolean equals(HashedSequence<S> a, int ai, //
39 HashedSequence<S> b, int bi) {
40 return a.hashes[ai] == b.hashes[bi]
41 && cmp.equals(a.base, ai, b.base, bi);
42 }
43
44 /** {@inheritDoc} */
45 @Override
46 public int hash(HashedSequence<S> seq, int ptr) {
47 return seq.hashes[ptr];
48 }
49 }