| /* |
| * 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.packed; |
| |
| |
| import static org.apache.lucene.util.packed.AbstractBlockPackedWriter.MAX_BLOCK_SIZE; |
| import static org.apache.lucene.util.packed.AbstractBlockPackedWriter.MIN_BLOCK_SIZE; |
| import static org.apache.lucene.util.packed.PackedInts.checkBlockSize; |
| import static org.apache.lucene.util.packed.PackedInts.numBlocks; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.util.Accountable; |
| import org.apache.lucene.util.LongValues; |
| import org.apache.lucene.util.RamUsageEstimator; |
| |
| /** |
| * Provides random access to a stream written with |
| * {@link MonotonicBlockPackedWriter}. |
| * @lucene.internal |
| */ |
| public class MonotonicBlockPackedReader extends LongValues implements Accountable { |
| |
| static long expected(long origin, float average, int index) { |
| return origin + (long) (average * (long) index); |
| } |
| |
| final int blockShift, blockMask; |
| final long valueCount; |
| final long[] minValues; |
| final float[] averages; |
| final PackedInts.Reader[] subReaders; |
| final long sumBPV; |
| |
| /** Sole constructor. */ |
| public static MonotonicBlockPackedReader of(IndexInput in, int packedIntsVersion, int blockSize, long valueCount, boolean direct) throws IOException { |
| return new MonotonicBlockPackedReader(in, packedIntsVersion, blockSize, valueCount, direct); |
| } |
| |
| private MonotonicBlockPackedReader(IndexInput in, int packedIntsVersion, int blockSize, long valueCount, boolean direct) throws IOException { |
| this.valueCount = valueCount; |
| blockShift = checkBlockSize(blockSize, MIN_BLOCK_SIZE, MAX_BLOCK_SIZE); |
| blockMask = blockSize - 1; |
| final int numBlocks = numBlocks(valueCount, blockSize); |
| minValues = new long[numBlocks]; |
| averages = new float[numBlocks]; |
| subReaders = new PackedInts.Reader[numBlocks]; |
| long sumBPV = 0; |
| for (int i = 0; i < numBlocks; ++i) { |
| minValues[i] = in.readZLong(); |
| averages[i] = Float.intBitsToFloat(in.readInt()); |
| final int bitsPerValue = in.readVInt(); |
| sumBPV += bitsPerValue; |
| if (bitsPerValue > 64) { |
| throw new IOException("Corrupted"); |
| } |
| if (bitsPerValue == 0) { |
| subReaders[i] = new PackedInts.NullReader(blockSize); |
| } else { |
| final int size = (int) Math.min(blockSize, valueCount - (long) i * blockSize); |
| if (direct) { |
| final long pointer = in.getFilePointer(); |
| subReaders[i] = PackedInts.getDirectReaderNoHeader(in, PackedInts.Format.PACKED, packedIntsVersion, size, bitsPerValue); |
| in.seek(pointer + PackedInts.Format.PACKED.byteCount(packedIntsVersion, size, bitsPerValue)); |
| } else { |
| subReaders[i] = PackedInts.getReaderNoHeader(in, PackedInts.Format.PACKED, packedIntsVersion, size, bitsPerValue); |
| } |
| } |
| } |
| this.sumBPV = sumBPV; |
| } |
| |
| @Override |
| public long get(long index) { |
| assert index >= 0 && index < valueCount; |
| final int block = (int) (index >>> blockShift); |
| final int idx = (int) (index & blockMask); |
| return expected(minValues[block], averages[block], idx) + subReaders[block].get(idx); |
| } |
| |
| /** Returns the number of values */ |
| public long size() { |
| return valueCount; |
| } |
| |
| @Override |
| public long ramBytesUsed() { |
| long sizeInBytes = 0; |
| sizeInBytes += RamUsageEstimator.sizeOf(minValues); |
| sizeInBytes += RamUsageEstimator.sizeOf(averages); |
| for(PackedInts.Reader reader: subReaders) { |
| sizeInBytes += reader.ramBytesUsed(); |
| } |
| return sizeInBytes; |
| } |
| |
| @Override |
| public String toString() { |
| long avgBPV = subReaders.length == 0 ? 0 : sumBPV / subReaders.length; |
| return getClass().getSimpleName() + "(blocksize=" + (1<<blockShift) + ",size=" + valueCount + ",avgBPV=" + avgBPV + ")"; |
| } |
| } |