| using Lucene.Net.Diagnostics; |
| using Lucene.Net.Support; |
| using Lucene.Net.Util; |
| using System.Diagnostics; |
| using System.IO; |
| |
| namespace Lucene.Net.Analysis.CharFilters |
| { |
| /* |
| * 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> |
| /// Base utility class for implementing a <see cref="CharFilter"/>. |
| /// You subclass this, and then record mappings by calling |
| /// <see cref="AddOffCorrectMap"/>, and then invoke the correct |
| /// method to correct an offset. |
| /// </summary> |
| public abstract class BaseCharFilter : CharFilter |
| { |
| |
| private int[] offsets; |
| private int[] diffs; |
| private int size = 0; |
| |
| public BaseCharFilter(TextReader @in) |
| : base(@in) |
| { |
| } |
| |
| /// <summary> |
| /// Retrieve the corrected offset. </summary> |
| protected override int Correct(int currentOff) |
| { |
| if (offsets == null || currentOff < offsets[0]) |
| { |
| return currentOff; |
| } |
| |
| int hi = size - 1; |
| if (currentOff >= offsets[hi]) |
| { |
| return currentOff + diffs[hi]; |
| } |
| |
| int lo = 0; |
| int mid = -1; |
| |
| while (hi >= lo) |
| { |
| mid = (int)((uint)(lo + hi) >> 1); |
| if (currentOff < offsets[mid]) |
| { |
| hi = mid - 1; |
| } |
| else if (currentOff > offsets[mid]) |
| { |
| lo = mid + 1; |
| } |
| else |
| { |
| return currentOff + diffs[mid]; |
| } |
| } |
| |
| if (currentOff < offsets[mid]) |
| { |
| return mid == 0 ? currentOff : currentOff + diffs[mid - 1]; |
| } |
| else |
| { |
| return currentOff + diffs[mid]; |
| } |
| } |
| |
| protected virtual int LastCumulativeDiff => offsets == null ? 0 : diffs[size - 1]; |
| |
| /// <summary> |
| /// <para> |
| /// Adds an offset correction mapping at the given output stream offset. |
| /// </para> |
| /// <para> |
| /// Assumption: the offset given with each successive call to this method |
| /// will not be smaller than the offset given at the previous invocation. |
| /// </para> |
| /// </summary> |
| /// <param name="off"> The output stream offset at which to apply the correction </param> |
| /// <param name="cumulativeDiff"> The input offset is given by adding this |
| /// to the output offset </param> |
| protected virtual void AddOffCorrectMap(int off, int cumulativeDiff) |
| { |
| if (offsets == null) |
| { |
| offsets = new int[64]; |
| diffs = new int[64]; |
| } |
| else if (size == offsets.Length) |
| { |
| offsets = ArrayUtil.Grow(offsets); |
| diffs = ArrayUtil.Grow(diffs); |
| } |
| |
| int offset = offsets[(size == 0) ? 0 : size - 1]; |
| if (Debugging.AssertsEnabled) Debugging.Assert(size == 0 || off >= offset, "Offset #{0}({1}) is less than the last recorded offset {2}\n{3}\n{4}", size, off, offset, offsets, diffs); |
| |
| if (size == 0 || off != offsets[size - 1]) |
| { |
| offsets[size] = off; |
| diffs[size++] = cumulativeDiff; |
| } // Overwrite the diff at the last recorded offset |
| else |
| { |
| diffs[size - 1] = cumulativeDiff; |
| } |
| } |
| } |
| } |