easyice commented on code in PR #12841: URL: https://github.com/apache/lucene/pull/12841#discussion_r1415479977
########## lucene/core/src/java/org/apache/lucene/store/DataOutput.java: ########## @@ -324,4 +326,42 @@ public void writeSetOfStrings(Set<String> set) throws IOException { writeString(value); } } + + /** + * Encode integers using group-varint. It uses {@link DataOutput#writeVInt VInt} to encode tail + * values that are not enough for a group. we need a long[] because this is what postings are + * using, all longs are actually required to be integers. + * + * @param values the values to write + * @param limit the number of values to write. + */ + public void writeGroupVInts(long[] values, int limit) throws IOException { Review Comment: okay! ########## lucene/core/src/java/org/apache/lucene/store/ByteBuffersDataInput.java: ########## @@ -212,6 +213,46 @@ public long readLong() throws IOException { } } + @Override + public void readGroupVInts(long[] dst, int limit) throws IOException { + int i; + for (i = 0; i <= limit - 4; i += 4) { + readGroupVInt(dst, i); + } + for (; i < limit; ++i) { + dst[i] = readVInt(); + } + } + + private void readGroupVInt(long[] dst, int offset) throws IOException { + ByteBuffer block = blocks[blockIndex(pos)]; + int blockOffset = blockOffset(pos); + if (block.limit() - blockOffset < GroupVIntUtil.MAX_LENGTH_PER_GROUP) { + GroupVIntUtil.fallbackReadGroupVInt(this, dst, offset); + return; + } + + final int flag = readByte() & 0xFF; + + final int n1Minus1 = flag >> 6; + final int n2Minus1 = (flag >> 4) & 0x03; + final int n3Minus1 = (flag >> 2) & 0x03; + final int n4Minus1 = flag & 0x03; + + blockOffset = blockOffset(pos); Review Comment: +1, i did the similar change in `BufferedIndexInput#readGroupVInt` ########## lucene/core/src/java/org/apache/lucene/store/DataOutput.java: ########## @@ -29,6 +30,7 @@ * internal state like file position). */ public abstract class DataOutput { + private BytesRefBuilder groupVIntBytes = new BytesRefBuilder(); Review Comment: +1, I will pay more attention to this issue. ########## lucene/core/src/java21/org/apache/lucene/store/MemorySegmentIndexInput.java: ########## @@ -303,6 +304,48 @@ public byte readByte(long pos) throws IOException { } } + @Override + public void readGroupVInts(long[] dst, int limit) throws IOException { + int i; + for (i = 0; i <= limit - 4; i += 4) { + readGroupVInt(dst, i); + } + for (; i < limit; ++i) { + dst[i] = readVInt(); + } + } + + private void readGroupVInt(long[] dst, int offset) throws IOException { + if (curSegment.byteSize() - curPosition < GroupVIntUtil.MAX_LENGTH_PER_GROUP) { + GroupVIntUtil.fallbackReadGroupVInt(this, dst, offset); + return; + } + + try { + final int flag = readByte() & 0xFF; Review Comment: +1 ########## lucene/core/src/java21/org/apache/lucene/store/MemorySegmentIndexInput.java: ########## @@ -303,6 +304,48 @@ public byte readByte(long pos) throws IOException { } } + @Override + public void readGroupVInts(long[] dst, int limit) throws IOException { + int i; + for (i = 0; i <= limit - 4; i += 4) { + readGroupVInt(dst, i); + } + for (; i < limit; ++i) { + dst[i] = readVInt(); + } + } + + private void readGroupVInt(long[] dst, int offset) throws IOException { + if (curSegment.byteSize() - curPosition < GroupVIntUtil.MAX_LENGTH_PER_GROUP) { + GroupVIntUtil.fallbackReadGroupVInt(this, dst, offset); + return; + } + Review Comment: done, i wonder what the impact on JVM if the variable maybe updated? Thanks! ########## lucene/test-framework/src/java/org/apache/lucene/tests/store/BaseDirectoryTestCase.java: ########## @@ -1438,4 +1440,68 @@ public void testListAllIsSorted() throws IOException { assertArrayEquals(expected, actual); } } + + public void testDataTypes() throws IOException { + final long[] values = new long[] {43, 12345, 123456, 1234567890}; + try (Directory dir = getDirectory(createTempDir("testDataTypes"))) { + IndexOutput out = dir.createOutput("test", IOContext.DEFAULT); + out.writeByte((byte) 43); + out.writeShort((short) 12345); + out.writeInt(1234567890); + out.writeGroupVInts(values, 4); + out.writeLong(1234567890123456789L); + out.close(); + + long[] restored = new long[4]; + IndexInput in = dir.openInput("test", IOContext.DEFAULT); + assertEquals(43, in.readByte()); + assertEquals(12345, in.readShort()); + assertEquals(1234567890, in.readInt()); + in.readGroupVInts(restored, 4); + assertArrayEquals(values, restored); + assertEquals(1234567890123456789L, in.readLong()); + in.close(); + } + } + + public void testGroupVInt() throws IOException { + try (Directory dir = getDirectory(createTempDir("testGroupVInt"))) { + // test fallbackReadGroupVInt + doTestGroupVInt(dir, 5, 1, 6, 8); + + // test large data to covers multiple blocks in ByteBuffersDataInput Review Comment: Thank you @jpountz , i added a separate test to `BaseChunkedDirectoryTestCase` to make sure use multi blocks, this will both cover `MMapDirectory` and `ByteBuffersDataInput` ########## lucene/core/src/java/org/apache/lucene/util/GroupVIntUtil.java: ########## @@ -0,0 +1,65 @@ +/* + * 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; + +import java.io.IOException; +import org.apache.lucene.store.DataInput; + +/** + * This class contains utility methods and constants for group varint + * + * @lucene.internal + */ +public final class GroupVIntUtil { + // the maximum length of a single group-varint is 4 integers + 1 byte flag. + public static final int MAX_LENGTH_PER_GROUP = 17; + public static final int[] GROUP_VINT_MASKS = new int[] {0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF}; + + /** + * Read single group varint. we need a long[] because this is what postings are using. + * + * @param dst the array to read ints into. + * @param offset the offset in the array to start storing ints. + */ + public static void fallbackReadGroupVInt(DataInput in, long[] dst, int offset) Review Comment: +1 -- This is an automated message from the Apache Git Service. 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