gortiz commented on code in PR #13304: URL: https://github.com/apache/pinot/pull/13304#discussion_r1650571343
########## pinot-segment-spi/src/main/java/org/apache/pinot/segment/spi/memory/CompoundDataBuffer.java: ########## @@ -0,0 +1,672 @@ +/** + * 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.pinot.segment.spi.memory; + +import java.io.File; +import java.io.IOException; +import java.nio.BufferUnderflowException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import java.util.ArrayList; +import java.util.List; +import org.roaringbitmap.buffer.ImmutableRoaringBitmap; + + +/** + * A {@link DataBuffer} that is composed of multiple {@link DataBuffer}s that define a single contiguous buffer. + * <p> + * While reads and writes can span multiple buffers, there may be a performance impact when doing so. + * Therefore it is recommended to try to wrap independent buffers. + * <p> + * Once this class is built, buffers cannot be added or removed. + */ +public class CompoundDataBuffer implements DataBuffer { + + private final DataBuffer[] _buffers; + private final long[] _bufferOffsets; + private int _lastBufferIndex = 0; + private final ByteOrder _order; + private final long _size; + private final boolean _owner; + + /** + * Creates a compound buffer from the given buffers. + * + * @param buffers The buffers that will be concatenated to form the compound buffer. + * @param order The byte order of the buffer. Buffers in the array that have a different byte order will be converted. + * @param owner Whether this buffer owns the underlying buffers. If true, the underlying buffers will be released when + * this buffer is closed. + */ + public CompoundDataBuffer(DataBuffer[] buffers, ByteOrder order, boolean owner) { + _owner = owner; + _buffers = buffers; + _bufferOffsets = new long[buffers.length]; + _order = order; + long offset = 0; + for (int i = 0; i < buffers.length; i++) { + if (buffers[i].size() == 0) { + throw new IllegalArgumentException("Buffer at index " + i + " is empty"); + } + if (buffers[i].order() != _order) { + buffers[i] = buffers[i].view(0, buffers[i].size(), _order); + } + } + for (int i = 0; i < buffers.length; i++) { + _bufferOffsets[i] = offset; + long size = buffers[i].size(); + offset += size; + } + _size = offset; + } + + public CompoundDataBuffer(ByteBuffer[] buffers, ByteOrder order, boolean owner) { + this(asDataBufferArray(buffers), order, owner); + } + + /** + * Creates a compound buffer from the given buffers. + * @param buffers The buffers that will be concatenated to form the compound buffer. + * @param order The byte order of the buffer. Buffers in the list that have a different byte order will be converted. + * @param owner Whether this buffer owns the underlying buffers. If true, the underlying buffers will be released when + * this buffer is closed. + */ + public CompoundDataBuffer(List<DataBuffer> buffers, ByteOrder order, boolean owner) { + this(buffers.toArray(new DataBuffer[0]), order, owner); + } + + private static DataBuffer[] asDataBufferArray(ByteBuffer[] buffers) { + DataBuffer[] result = new DataBuffer[buffers.length]; + for (int i = 0; i < buffers.length; i++) { + result[i] = PinotByteBuffer.wrap(buffers[i]); + } + return result; + } + + private int getBufferIndex(long offset) { + // this optimistically assumes that lookups are going to be in ascending order + // we don't care about concurrency here given that this is only used to speed up the lookup + int lastBufferIndex = _lastBufferIndex; + if (_bufferOffsets[lastBufferIndex] > offset) { + lastBufferIndex = 0; + } + + for (int i = lastBufferIndex; i < _bufferOffsets.length; i++) { + if (offset < _bufferOffsets[i]) { + int result = i - 1; + _lastBufferIndex = result; + return result; + } + } + return _bufferOffsets.length - 1; Review Comment: Yes, it makes sense. -- This is an automated message from the Apache Git Service. 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