| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.lucene.util; |
| |
| |
| /** {@link Sorter} implementation based on the merge-sort algorithm that merges |
| * in place (no extra memory will be allocated). Small arrays are sorted with |
| * insertion sort. |
| * @lucene.internal */ |
| public abstract class InPlaceMergeSorter extends Sorter { |
| |
| /** Create a new {@link InPlaceMergeSorter} */ |
| public InPlaceMergeSorter() {} |
| |
| @Override |
| public final void sort(int from, int to) { |
| checkRange(from, to); |
| mergeSort(from, to); |
| } |
| |
| void mergeSort(int from, int to) { |
| if (to - from < BINARY_SORT_THRESHOLD) { |
| binarySort(from, to); |
| } else { |
| final int mid = (from + to) >>> 1; |
| mergeSort(from, mid); |
| mergeSort(mid, to); |
| mergeInPlace(from, mid, to); |
| } |
| } |
| |
| } |