| /* |
| * 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.analysis.charfilter; |
| |
| import java.io.Reader; |
| import java.util.Arrays; |
| import org.apache.lucene.analysis.CharFilter; |
| import org.apache.lucene.util.ArrayUtil; |
| |
| /** |
| * Base utility class for implementing a {@link CharFilter}. You subclass this, and then record |
| * mappings by calling {@link #addOffCorrectMap}, and then invoke the correct method to correct an |
| * offset. |
| */ |
| public abstract class BaseCharFilter extends CharFilter { |
| |
| private int offsets[]; |
| private int diffs[]; |
| private int size = 0; |
| |
| public BaseCharFilter(Reader in) { |
| super(in); |
| } |
| |
| /** Retrieve the corrected offset. */ |
| @Override |
| protected int correct(int currentOff) { |
| if (offsets == null) { |
| return currentOff; |
| } |
| |
| int index = Arrays.binarySearch(offsets, 0, size, currentOff); |
| if (index < -1) { |
| index = -2 - index; |
| } |
| |
| final int diff = index < 0 ? 0 : diffs[index]; |
| return currentOff + diff; |
| } |
| |
| protected int getLastCumulativeDiff() { |
| return offsets == null ? 0 : diffs[size - 1]; |
| } |
| |
| /** |
| * Adds an offset correction mapping at the given output stream offset. |
| * |
| * <p>Assumption: the offset given with each successive call to this method will not be smaller |
| * than the offset given at the previous invocation. |
| * |
| * @param off The output stream offset at which to apply the correction |
| * @param cumulativeDiff The input offset is given by adding this to the output offset |
| */ |
| protected 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); |
| } |
| |
| assert (size == 0 || off >= offsets[size - 1]) |
| : "Offset #" |
| + size |
| + "(" |
| + off |
| + ") is less than the last recorded offset " |
| + offsets[size - 1] |
| + "\n" |
| + Arrays.toString(offsets) |
| + "\n" |
| + Arrays.toString(diffs); |
| |
| if (size == 0 || off != offsets[size - 1]) { |
| offsets[size] = off; |
| diffs[size++] = cumulativeDiff; |
| } else { // Overwrite the diff at the last recorded offset |
| diffs[size - 1] = cumulativeDiff; |
| } |
| } |
| } |