aokolnychyi commented on code in PR #11372: URL: https://github.com/apache/iceberg/pull/11372#discussion_r1813327452
########## core/src/main/java/org/apache/iceberg/deletes/RoaringPositionBitmap.java: ########## @@ -0,0 +1,309 @@ +/* + * 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.iceberg.deletes; + +import java.io.IOException; +import java.io.UncheckedIOException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import java.util.List; +import java.util.function.LongConsumer; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.roaringbitmap.RoaringBitmap; + +/** + * A bitmap that supports positive 64-bit positions, but is optimized for cases where most positions + * fit in 32 bits by using an array of 32-bit Roaring bitmaps. The bitmap array is grown as needed + * to accommodate the largest value. + * + * <p>Incoming 64-bit positions are divided into a 32-bit "key" using the most significant 4 bytes + * and a 32-bit position using the least significant 4 bytes. For each key in the set of positions, + * a 32-bit Roaring bitmap is maintained to store a set of 32-bit positions for that key. + * + * <p>To test whether a certain position is set, its most significant 4 bytes (the key) are used to + * find a 32-bit bitmap and the least significant 4 bytes are tested for inclusion in the bitmap. If + * a bitmap is not found for the key, then the position is not set. + * + * <p>Note that positions must be greater than or equal to 0 add less than {@link #MAX_POSITION}. + * This bitmap does not support positions larger than {@link #MAX_POSITION} as the bitmap array + * length is a signed 32-bit integer that must be greater than or equal to 0. + */ +class RoaringPositionBitmap { + + static final long MAX_POSITION = toPosition(Integer.MAX_VALUE - 1, Integer.MIN_VALUE); + private static final RoaringBitmap[] EMPTY_BITMAP_ARRAY = new RoaringBitmap[] {}; + private static final long BITMAP_COUNT_SIZE_BYTES = 8L; + private static final long BITMAP_KEY_SIZE_BYTES = 4L; + + private RoaringBitmap[] bitmaps; + + RoaringPositionBitmap() { + this.bitmaps = EMPTY_BITMAP_ARRAY; + } + + private RoaringPositionBitmap(RoaringBitmap[] bitmaps) { + this.bitmaps = bitmaps; + } + + /** + * Adds a position to the bitmap. + * + * @param pos the row position + */ + public void add(long pos) { + validatePosition(pos); + int high = highBytes(pos); + int low = lowBytes(pos); + allocateBitmapsIfNeeded(high + 1 /* required number of bitmaps */); + bitmaps[high].add(low); + } + + /** + * Adds a range of positions to the bitmap. + * + * @param posStartInclusive the start position of the range (inclusive) + * @param posEndExclusive the end position of the range (exclusive) + */ + public void addRange(long posStartInclusive, long posEndExclusive) { + for (long pos = posStartInclusive; pos < posEndExclusive; pos++) { + add(pos); + } + } + + /** + * Checks if the bitmap contains a position. + * + * @param pos the row position + * @return true if the position is in this bitmap, false otherwise + */ + public boolean contains(long pos) { + validatePosition(pos); + int high = highBytes(pos); + int low = lowBytes(pos); + return high < bitmaps.length && bitmaps[high].contains(low); + } + + /** + * Adds all positions from the other bitmap to this bitmap, modifying this bitmap in place. + * + * @param that the other bitmap + */ + public void or(RoaringPositionBitmap that) { + allocateBitmapsIfNeeded(that.bitmaps.length); + for (int index = 0; index < that.bitmaps.length; index++) { + bitmaps[index].or(that.bitmaps[index]); + } + } + + /** + * Indicates whether the bitmap is empty. + * + * @return true if the bitmap is empty, false otherwise + */ + public boolean isEmpty() { + return cardinality() == 0; + } + + /** + * Returns the number of positions in the bitmap. + * + * @return the number of set positions + */ + public long cardinality() { + long cardinality = 0L; + for (RoaringBitmap bitmap : bitmaps) { + cardinality += bitmap.getLongCardinality(); + } + return cardinality; + } + + /** + * Run-length compresses the bitmap if it is more space efficient. + * + * @return whether the bitmap was compressed + */ + public boolean runOptimize() { + boolean changed = false; + for (RoaringBitmap bitmap : bitmaps) { + changed |= bitmap.runOptimize(); + } + return changed; + } + + /** + * Iterates over all positions in the bitmap. + * + * @param consumer a consumer for positions + */ + public void forEach(LongConsumer consumer) { + for (int index = 0; index < bitmaps.length; index++) { + forEach(bitmaps[index], index, consumer); + } + } + + /** + * Returns the number of bytes required to serialize the bitmap. + * + * @return the serialized size in bytes + */ + public long serializedSizeInBytes() { + long size = BITMAP_COUNT_SIZE_BYTES; + for (RoaringBitmap bitmap : bitmaps) { + size += BITMAP_KEY_SIZE_BYTES + bitmap.serializedSizeInBytes(); + } + return size; + } + + /** + * Serializes the bitmap using the portable serialization format described below. + * + * <ul> + * <li>The number of 32-bit Roaring bitmaps, serialized as 8 bytes + * <li>For each 32-bit Roaring bitmap, ordered by unsigned comparison of the 32-bit keys: + * <ul> + * <li>The key stored as 4 bytes + * <li>Serialized 32-bit Roaring bitmap using the standard format + * </ul> + * </ul> + * + * <p>Note the byte order of the buffer must be little-endian. + * + * @param buffer the buffer to write to + * @see <a href="https://github.com/RoaringBitmap/RoaringFormatSpe";>Roaring bitmap spec</a> + */ + public void serialize(ByteBuffer buffer) { + validateByteOrder(buffer); + buffer.putLong(bitmaps.length); + for (int index = 0; index < bitmaps.length; index++) { + buffer.putInt(index); + bitmaps[index].serialize(buffer); + } + } + + private void allocateBitmapsIfNeeded(int requiredLength) { + if (bitmaps.length < requiredLength) { + if (bitmaps.length == 0 && requiredLength == 1) { + this.bitmaps = new RoaringBitmap[] {new RoaringBitmap()}; + } else { + RoaringBitmap[] newBitmaps = new RoaringBitmap[requiredLength]; + System.arraycopy(bitmaps, 0, newBitmaps, 0, bitmaps.length); + for (int index = bitmaps.length; index < requiredLength; index++) { + newBitmaps[index] = new RoaringBitmap(); + } + this.bitmaps = newBitmaps; + } + } + } + + /** + * Deserializes a bitmap from a buffer, assuming the portable serialization format. + * + * @param buffer the buffer to read from + * @return a new bitmap instance with the deserialized data + */ + public static RoaringPositionBitmap deserialize(ByteBuffer buffer) { + validateByteOrder(buffer); + + // the bitmap array may be sparse with more elements than the number of read bitmaps + int remainingBitmapCount = readBitmapCount(buffer); + List<RoaringBitmap> bitmaps = Lists.newArrayListWithExpectedSize(remainingBitmapCount); + int lastKey = 0; + + while (remainingBitmapCount > 0) { + int key = readKey(buffer, lastKey); + + // fill gaps as the bitmap array may be sparse + while (lastKey < key) { + bitmaps.add(new RoaringBitmap()); + lastKey++; + } + + RoaringBitmap bitmap = readBitmap(buffer); + bitmaps.add(bitmap); + + lastKey++; + remainingBitmapCount--; + } + + return new RoaringPositionBitmap(bitmaps.toArray(EMPTY_BITMAP_ARRAY)); + } + + private static void validateByteOrder(ByteBuffer buffer) { + Preconditions.checkArgument( + buffer.order() == ByteOrder.LITTLE_ENDIAN, + "Roaring bitmap serialization requires little-endian byte order"); + } + + private static int readBitmapCount(ByteBuffer buffer) { + long bitmapCount = buffer.getLong(); + Preconditions.checkArgument( + bitmapCount >= 0 && bitmapCount <= Integer.MAX_VALUE, + "Invalid bitmap count: %s", + bitmapCount); + return (int) bitmapCount; + } + + private static int readKey(ByteBuffer buffer, int lastKey) { + int key = buffer.getInt(); + Preconditions.checkArgument(key >= 0, "Invalid unsigned key: %s", key); + Preconditions.checkArgument(key >= lastKey, "Keys must be sorted in ascending order"); + return key; + } + + private static RoaringBitmap readBitmap(ByteBuffer buffer) { + try { + RoaringBitmap bitmap = new RoaringBitmap(); + bitmap.deserialize(buffer); + buffer.position(buffer.position() + bitmap.serializedSizeInBytes()); + return bitmap; + } catch (IOException e) { + throw new UncheckedIOException(e); + } + } + + // extracts high 32 bits from a 64-bit position + private static int highBytes(long pos) { + return (int) (pos >> 32); + } + + // extracts low 32 bits from a 64-bit position + private static int lowBytes(long pos) { Review Comment: Renamed to `value`. -- This is an automated message from the Apache Git Service. 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