Tony-X commented on code in PR #12688: URL: https://github.com/apache/lucene/pull/12688#discussion_r1381984403
########## lucene/sandbox/src/java/org/apache/lucene/sandbox/codecs/lucene90/randomaccess/TermStateCodecImpl.java: ########## @@ -0,0 +1,159 @@ +/* + * 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.sandbox.codecs.lucene90.randomaccess; + +import org.apache.lucene.codecs.lucene90.Lucene90PostingsFormat.IntBlockTermState; +import org.apache.lucene.sandbox.codecs.lucene90.randomaccess.bitpacking.BitPacker; +import org.apache.lucene.sandbox.codecs.lucene90.randomaccess.bitpacking.BitUnpacker; +import org.apache.lucene.store.ByteArrayDataInput; +import org.apache.lucene.store.ByteArrayDataOutput; +import org.apache.lucene.util.BytesRef; + +final class TermStateCodecImpl implements TermStateCodec { + private final TermStateCodecComponent[] components; + private final int metadataBytesLength; + + private static int getMetadataLength(TermStateCodecComponent component) { + // 1 byte for bitWidth; optionally 8 byte more for the reference value + return 1 + (component.isMonotonicallyIncreasing() ? 8 : 0); + } + + public TermStateCodecImpl(TermStateCodecComponent[] components) { + assert components.length > 0; + + this.components = components; + int metadataBytesLength = 0; + for (var component : components) { + metadataBytesLength += getMetadataLength(component); + } + this.metadataBytesLength = metadataBytesLength; + } + + @Override + public byte[] encodeBlock(IntBlockTermState[] inputs, BitPacker bitPacker) { + Metadata[] metadataPerComponent = getMetadataPerComponent(inputs); + byte[] metadataBytes = serializeMetadata(metadataPerComponent); + + // Encode inputs via the bitpacker + for (var termState : inputs) { + encodeOne(bitPacker, termState, metadataPerComponent); + } + + return metadataBytes; + } + + private Metadata[] getMetadataPerComponent(IntBlockTermState[] inputs) { + Metadata[] metadataPerComponent = new Metadata[components.length]; + for (int i = 0; i < components.length; i++) { + var component = components[i]; + byte bitWidth = TermStateCodecComponent.getBitWidth(inputs, component); + long referenceValue = + component.isMonotonicallyIncreasing() ? component.getTargetValue(inputs[0]) : 0L; + metadataPerComponent[i] = new Metadata(bitWidth, referenceValue); + } + return metadataPerComponent; + } + + private byte[] serializeMetadata(Metadata[] metadataPerComponent) { + byte[] metadataBytes = new byte[this.metadataBytesLength]; + ByteArrayDataOutput dataOut = new ByteArrayDataOutput(metadataBytes); + + for (int i = 0; i < components.length; i++) { + var metadata = metadataPerComponent[i]; + dataOut.writeByte(metadata.bitWidth); + if (components[i].isMonotonicallyIncreasing()) { + dataOut.writeLong(metadata.referenceValue); + } + } + return metadataBytes; + } + + private void encodeOne( Review Comment: Yes, since the common access pattern is to grab all interesting states for one term as oppose to "I want to get all posting start FP for many terms" -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
