aokolnychyi commented on code in PR #11372: URL: https://github.com/apache/iceberg/pull/11372#discussion_r1812892153
########## 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() { Review Comment: I do like `compress`, I'll rename. -- This is an automated message from the Apache Git Service. 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