easyice commented on code in PR #12782: URL: https://github.com/apache/lucene/pull/12782#discussion_r1388845597
########## lucene/core/src/java/org/apache/lucene/codecs/lucene99/GroupVintReader.java: ########## @@ -0,0 +1,176 @@ +/* + * 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.codecs.lucene99; + +import java.io.IOException; +import org.apache.lucene.store.IndexInput; +import org.apache.lucene.util.ArrayUtil; +import org.apache.lucene.util.BitUtil; + +/** + * Decode integers using group-varint. It will fully read the bytes for the block, to avoid repeated + * expensive bounds checking per readBytes. + */ +class GroupVintReader { + + private static final int[][] flagToLengths = { + {0, 0, 0, 0}, {0, 0, 0, 1}, {0, 0, 0, 2}, {0, 0, 0, 3}, + {0, 0, 1, 0}, {0, 0, 1, 1}, {0, 0, 1, 2}, {0, 0, 1, 3}, + {0, 0, 2, 0}, {0, 0, 2, 1}, {0, 0, 2, 2}, {0, 0, 2, 3}, + {0, 0, 3, 0}, {0, 0, 3, 1}, {0, 0, 3, 2}, {0, 0, 3, 3}, + {0, 1, 0, 0}, {0, 1, 0, 1}, {0, 1, 0, 2}, {0, 1, 0, 3}, + {0, 1, 1, 0}, {0, 1, 1, 1}, {0, 1, 1, 2}, {0, 1, 1, 3}, + {0, 1, 2, 0}, {0, 1, 2, 1}, {0, 1, 2, 2}, {0, 1, 2, 3}, + {0, 1, 3, 0}, {0, 1, 3, 1}, {0, 1, 3, 2}, {0, 1, 3, 3}, + {0, 2, 0, 0}, {0, 2, 0, 1}, {0, 2, 0, 2}, {0, 2, 0, 3}, + {0, 2, 1, 0}, {0, 2, 1, 1}, {0, 2, 1, 2}, {0, 2, 1, 3}, + {0, 2, 2, 0}, {0, 2, 2, 1}, {0, 2, 2, 2}, {0, 2, 2, 3}, + {0, 2, 3, 0}, {0, 2, 3, 1}, {0, 2, 3, 2}, {0, 2, 3, 3}, + {0, 3, 0, 0}, {0, 3, 0, 1}, {0, 3, 0, 2}, {0, 3, 0, 3}, + {0, 3, 1, 0}, {0, 3, 1, 1}, {0, 3, 1, 2}, {0, 3, 1, 3}, + {0, 3, 2, 0}, {0, 3, 2, 1}, {0, 3, 2, 2}, {0, 3, 2, 3}, + {0, 3, 3, 0}, {0, 3, 3, 1}, {0, 3, 3, 2}, {0, 3, 3, 3}, + {1, 0, 0, 0}, {1, 0, 0, 1}, {1, 0, 0, 2}, {1, 0, 0, 3}, + {1, 0, 1, 0}, {1, 0, 1, 1}, {1, 0, 1, 2}, {1, 0, 1, 3}, + {1, 0, 2, 0}, {1, 0, 2, 1}, {1, 0, 2, 2}, {1, 0, 2, 3}, + {1, 0, 3, 0}, {1, 0, 3, 1}, {1, 0, 3, 2}, {1, 0, 3, 3}, + {1, 1, 0, 0}, {1, 1, 0, 1}, {1, 1, 0, 2}, {1, 1, 0, 3}, + {1, 1, 1, 0}, {1, 1, 1, 1}, {1, 1, 1, 2}, {1, 1, 1, 3}, + {1, 1, 2, 0}, {1, 1, 2, 1}, {1, 1, 2, 2}, {1, 1, 2, 3}, + {1, 1, 3, 0}, {1, 1, 3, 1}, {1, 1, 3, 2}, {1, 1, 3, 3}, + {1, 2, 0, 0}, {1, 2, 0, 1}, {1, 2, 0, 2}, {1, 2, 0, 3}, + {1, 2, 1, 0}, {1, 2, 1, 1}, {1, 2, 1, 2}, {1, 2, 1, 3}, + {1, 2, 2, 0}, {1, 2, 2, 1}, {1, 2, 2, 2}, {1, 2, 2, 3}, + {1, 2, 3, 0}, {1, 2, 3, 1}, {1, 2, 3, 2}, {1, 2, 3, 3}, + {1, 3, 0, 0}, {1, 3, 0, 1}, {1, 3, 0, 2}, {1, 3, 0, 3}, + {1, 3, 1, 0}, {1, 3, 1, 1}, {1, 3, 1, 2}, {1, 3, 1, 3}, + {1, 3, 2, 0}, {1, 3, 2, 1}, {1, 3, 2, 2}, {1, 3, 2, 3}, + {1, 3, 3, 0}, {1, 3, 3, 1}, {1, 3, 3, 2}, {1, 3, 3, 3}, + {2, 0, 0, 0}, {2, 0, 0, 1}, {2, 0, 0, 2}, {2, 0, 0, 3}, + {2, 0, 1, 0}, {2, 0, 1, 1}, {2, 0, 1, 2}, {2, 0, 1, 3}, + {2, 0, 2, 0}, {2, 0, 2, 1}, {2, 0, 2, 2}, {2, 0, 2, 3}, + {2, 0, 3, 0}, {2, 0, 3, 1}, {2, 0, 3, 2}, {2, 0, 3, 3}, + {2, 1, 0, 0}, {2, 1, 0, 1}, {2, 1, 0, 2}, {2, 1, 0, 3}, + {2, 1, 1, 0}, {2, 1, 1, 1}, {2, 1, 1, 2}, {2, 1, 1, 3}, + {2, 1, 2, 0}, {2, 1, 2, 1}, {2, 1, 2, 2}, {2, 1, 2, 3}, + {2, 1, 3, 0}, {2, 1, 3, 1}, {2, 1, 3, 2}, {2, 1, 3, 3}, + {2, 2, 0, 0}, {2, 2, 0, 1}, {2, 2, 0, 2}, {2, 2, 0, 3}, + {2, 2, 1, 0}, {2, 2, 1, 1}, {2, 2, 1, 2}, {2, 2, 1, 3}, + {2, 2, 2, 0}, {2, 2, 2, 1}, {2, 2, 2, 2}, {2, 2, 2, 3}, + {2, 2, 3, 0}, {2, 2, 3, 1}, {2, 2, 3, 2}, {2, 2, 3, 3}, + {2, 3, 0, 0}, {2, 3, 0, 1}, {2, 3, 0, 2}, {2, 3, 0, 3}, + {2, 3, 1, 0}, {2, 3, 1, 1}, {2, 3, 1, 2}, {2, 3, 1, 3}, + {2, 3, 2, 0}, {2, 3, 2, 1}, {2, 3, 2, 2}, {2, 3, 2, 3}, + {2, 3, 3, 0}, {2, 3, 3, 1}, {2, 3, 3, 2}, {2, 3, 3, 3}, + {3, 0, 0, 0}, {3, 0, 0, 1}, {3, 0, 0, 2}, {3, 0, 0, 3}, + {3, 0, 1, 0}, {3, 0, 1, 1}, {3, 0, 1, 2}, {3, 0, 1, 3}, + {3, 0, 2, 0}, {3, 0, 2, 1}, {3, 0, 2, 2}, {3, 0, 2, 3}, + {3, 0, 3, 0}, {3, 0, 3, 1}, {3, 0, 3, 2}, {3, 0, 3, 3}, + {3, 1, 0, 0}, {3, 1, 0, 1}, {3, 1, 0, 2}, {3, 1, 0, 3}, + {3, 1, 1, 0}, {3, 1, 1, 1}, {3, 1, 1, 2}, {3, 1, 1, 3}, + {3, 1, 2, 0}, {3, 1, 2, 1}, {3, 1, 2, 2}, {3, 1, 2, 3}, + {3, 1, 3, 0}, {3, 1, 3, 1}, {3, 1, 3, 2}, {3, 1, 3, 3}, + {3, 2, 0, 0}, {3, 2, 0, 1}, {3, 2, 0, 2}, {3, 2, 0, 3}, + {3, 2, 1, 0}, {3, 2, 1, 1}, {3, 2, 1, 2}, {3, 2, 1, 3}, + {3, 2, 2, 0}, {3, 2, 2, 1}, {3, 2, 2, 2}, {3, 2, 2, 3}, + {3, 2, 3, 0}, {3, 2, 3, 1}, {3, 2, 3, 2}, {3, 2, 3, 3}, + {3, 3, 0, 0}, {3, 3, 0, 1}, {3, 3, 0, 2}, {3, 3, 0, 3}, + {3, 3, 1, 0}, {3, 3, 1, 1}, {3, 3, 1, 2}, {3, 3, 1, 3}, + {3, 3, 2, 0}, {3, 3, 2, 1}, {3, 3, 2, 2}, {3, 3, 2, 3}, + {3, 3, 3, 0}, {3, 3, 3, 1}, {3, 3, 3, 2}, {3, 3, 3, 3} + }; + + IndexInput in; + private static final int[] MASKS = {0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF}; + + // buffer for all groups + private int offset = 0; + private byte[] bytes = new byte[16]; + + private byte numGroup = 0; + private int[] groupLengths = null; + + // the next int will be read in the single group. in the range [0-3]. + private int posInGroup = 0; + + public GroupVintReader() {} + + /** Called when decode a new block. */ + public void reset(IndexInput indexInput, int num) throws IOException { + this.in = indexInput; + offset = 0; + posInGroup = 0; + + if (num > 0) { + int len = in.readVInt(); + if (len > 0) { + numGroup = in.readByte(); + // + 3 bytes to avoid BitUtil.VH_LE_INT.get out of array bounds when reading the last value + bytes = ArrayUtil.growNoCopy(bytes, len + 3); + in.readBytes(bytes, 0, len); + } + } + } + + private void readVInts(long[] docs, int off, int limit) throws IOException { + for (int i = off; i < limit; i++) { + docs[i] = in.readVInt(); + } + } + + /** only readValues or nextInt can be called after reset */ + public void readValues(long[] docs, int limit) throws IOException { + if (numGroup == 0) { + readVInts(docs, 0, limit); + return; + } + int groupValues = limit / 4 * 4; Review Comment: nice idea :) -- This is an automated message from the Apache Git Service. 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