| /* |
| * 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.jackrabbit.oak.segment; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkElementIndex; |
| import static com.google.common.base.Preconditions.checkPositionIndexes; |
| import static com.google.common.collect.Lists.newArrayListWithCapacity; |
| import static java.util.Collections.emptyList; |
| import static java.util.Collections.singletonList; |
| |
| import java.util.List; |
| |
| /** |
| * A record of type "LIST". |
| */ |
| class ListRecord extends Record { |
| |
| static final int LEVEL_SIZE = 255; |
| |
| /** The maximum number of elements a list can contain */ |
| static final int MAX_ELEMENTS = LEVEL_SIZE * LEVEL_SIZE * LEVEL_SIZE; |
| |
| private final int size; |
| |
| private final int bucketSize; |
| |
| ListRecord(RecordId id, int size) { |
| super(id); |
| checkArgument(size >= 0, |
| "Negative list size: " + size); |
| checkArgument(size <= MAX_ELEMENTS, |
| "Too many elements in list: " + size); |
| this.size = size; |
| |
| int bs = 1; |
| while (bs * LEVEL_SIZE < size) { |
| bs *= LEVEL_SIZE; |
| } |
| this.bucketSize = bs; |
| } |
| |
| public int size() { |
| return size; |
| } |
| |
| public RecordId getEntry(int index) { |
| checkElementIndex(index, size); |
| if (size == 1) { |
| return getRecordId(); |
| } else { |
| int bucketIndex = index / bucketSize; |
| int bucketOffset = index % bucketSize; |
| Segment segment = getSegment(); |
| RecordId id = segment.readRecordId(getRecordNumber(), 0, bucketIndex); |
| ListRecord bucket = new ListRecord( |
| id, Math.min(bucketSize, size - bucketIndex * bucketSize)); |
| return bucket.getEntry(bucketOffset); |
| } |
| } |
| |
| public List<RecordId> getEntries() { |
| return getEntries(0, size); |
| } |
| |
| public List<RecordId> getEntries(int index, int count) { |
| if (index + count > size) { |
| count = size - index; |
| } |
| if (count == 0) { |
| return emptyList(); |
| } else if (count == 1) { |
| return singletonList(getEntry(index)); |
| } else { |
| List<RecordId> ids = newArrayListWithCapacity(count); |
| getEntries(index, count, ids); |
| return ids; |
| } |
| } |
| |
| private void getEntries(int index, int count, List<RecordId> ids) { |
| checkPositionIndexes(index, index + count, size); |
| Segment segment = getSegment(); |
| if (size == 1) { |
| ids.add(getRecordId()); |
| } else if (bucketSize == 1) { |
| for (int i = 0; i < count; i++) { |
| ids.add(segment.readRecordId(getRecordNumber(), 0, index + i)); |
| } |
| } else { |
| while (count > 0) { |
| int bucketIndex = index / bucketSize; |
| int bucketOffset = index % bucketSize; |
| RecordId id = segment.readRecordId(getRecordNumber(), 0, bucketIndex); |
| ListRecord bucket = new ListRecord( |
| id, Math.min(bucketSize, size - bucketIndex * bucketSize)); |
| int n = Math.min(bucket.size() - bucketOffset, count); |
| bucket.getEntries(bucketOffset, n, ids); |
| index += n; |
| count -= n; |
| } |
| } |
| } |
| |
| } |