123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121 |
- /*
- * Copyright (C) 2010, Google Inc.
- * 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;
-
- /**
- * Wraps two {@link org.eclipse.jgit.diff.Sequence} instances to cache their
- * element hash codes.
- * <p>
- * This pair wraps two sequences that contain cached hash codes for the input
- * sequences.
- *
- * @param <S>
- * the base sequence type.
- */
- public class HashedSequencePair<S extends Sequence> {
- private final SequenceComparator<? super S> cmp;
-
- private final S baseA;
-
- private final S baseB;
-
- private HashedSequence<S> cachedA;
-
- private HashedSequence<S> cachedB;
-
- /**
- * Construct a pair to provide fast hash codes.
- *
- * @param cmp
- * the base comparator for the sequence elements.
- * @param a
- * the A sequence.
- * @param b
- * the B sequence.
- */
- public HashedSequencePair(SequenceComparator<? super S> cmp, S a, S b) {
- this.cmp = cmp;
- this.baseA = a;
- this.baseB = b;
- }
-
- /**
- * Get comparator
- *
- * @return obtain a comparator that uses the cached hash codes
- */
- public HashedSequenceComparator<S> getComparator() {
- return new HashedSequenceComparator<>(cmp);
- }
-
- /**
- * Get A
- *
- * @return wrapper around A that includes cached hash codes
- */
- public HashedSequence<S> getA() {
- if (cachedA == null)
- cachedA = wrap(baseA);
- return cachedA;
- }
-
- /**
- * Get B
- *
- * @return wrapper around B that includes cached hash codes
- */
- public HashedSequence<S> getB() {
- if (cachedB == null)
- cachedB = wrap(baseB);
- return cachedB;
- }
-
- private HashedSequence<S> wrap(S base) {
- final int end = base.size();
- final int[] hashes = new int[end];
- for (int ptr = 0; ptr < end; ptr++)
- hashes[ptr] = cmp.hash(base, ptr);
- return new HashedSequence<>(base, hashes);
- }
- }
|