| using J2N.Numerics; |
| using System.Collections.Generic; |
| |
| namespace Lucene.Net.Index |
| { |
| /* |
| * 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. |
| */ |
| |
| /// <summary> |
| /// Common util methods for dealing with <see cref="IndexReader"/>s and <see cref="IndexReaderContext"/>s. |
| /// <para/> |
| /// @lucene.internal |
| /// </summary> |
| public sealed class ReaderUtil |
| { |
| private ReaderUtil() // no instance |
| { |
| } |
| |
| /// <summary> |
| /// Walks up the reader tree and return the given context's top level reader |
| /// context, or in other words the reader tree's root context. |
| /// </summary> |
| public static IndexReaderContext GetTopLevelContext(IndexReaderContext context) |
| { |
| while (context.Parent != null) |
| { |
| context = context.Parent; |
| } |
| return context; |
| } |
| |
| /// <summary> |
| /// Returns index of the searcher/reader for document <c>n</c> in the |
| /// array used to construct this searcher/reader. |
| /// </summary> |
| public static int SubIndex(int n, int[] docStarts) // find |
| { |
| // searcher/reader for doc n: |
| int size = docStarts.Length; |
| int lo = 0; // search starts array |
| int hi = size - 1; // for first element less than n, return its index |
| while (hi >= lo) |
| { |
| int mid = (lo + hi).TripleShift(1); |
| int midValue = docStarts[mid]; |
| if (n < midValue) |
| { |
| hi = mid - 1; |
| } |
| else if (n > midValue) |
| { |
| lo = mid + 1; |
| } |
| else // found a match |
| { |
| while (mid + 1 < size && docStarts[mid + 1] == midValue) |
| { |
| mid++; // scan to last match |
| } |
| return mid; |
| } |
| } |
| return hi; |
| } |
| |
| /// <summary> |
| /// Returns index of the searcher/reader for document <c>n</c> in the |
| /// array used to construct this searcher/reader. |
| /// </summary> |
| public static int SubIndex(int n, IList<AtomicReaderContext> leaves) // find |
| { |
| // searcher/reader for doc n: |
| int size = leaves.Count; |
| int lo = 0; // search starts array |
| int hi = size - 1; // for first element less than n, return its index |
| while (hi >= lo) |
| { |
| int mid = (lo + hi).TripleShift(1); |
| int midValue = leaves[mid].DocBase; |
| if (n < midValue) |
| { |
| hi = mid - 1; |
| } |
| else if (n > midValue) |
| { |
| lo = mid + 1; |
| } |
| else // found a match |
| { |
| while (mid + 1 < size && leaves[mid + 1].DocBase == midValue) |
| { |
| mid++; // scan to last match |
| } |
| return mid; |
| } |
| } |
| return hi; |
| } |
| } |
| } |