Tony-X commented on code in PR #12688: URL: https://github.com/apache/lucene/pull/12688#discussion_r1391564228
########## lucene/sandbox/src/java/org/apache/lucene/sandbox/codecs/lucene90/randomaccess/TermsIndexBuilder.java: ########## @@ -0,0 +1,70 @@ +/* + * 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 java.io.IOException; +import java.util.Arrays; +import org.apache.lucene.util.BytesRef; +import org.apache.lucene.util.IntsRefBuilder; +import org.apache.lucene.util.fst.FST; +import org.apache.lucene.util.fst.FSTCompiler; +import org.apache.lucene.util.fst.PositiveIntOutputs; +import org.apache.lucene.util.fst.Util; + +/** + * Builds a term index for a given field. Logically this is a map: term -> (type, ord) where the + * ordinals are scoped to type (not global). + */ +final class TermsIndexBuilder { + private static long MAX_ORD = (1L << 60) - 1; + + private final long[] countPerType = new long[TermType.NUM_TOTAL_TYPES]; + private final FSTCompiler<Long> fstCompiler = + new FSTCompiler<>(FST.INPUT_TYPE.BYTE1, PositiveIntOutputs.getSingleton()); + + TermsIndexBuilder() { + Arrays.fill(countPerType, -1); + } + + public void addTerm(BytesRef term, TermType termType) throws IOException { + IntsRefBuilder scratchInts = new IntsRefBuilder(); + long ord = ++countPerType[termType.getId()]; + fstCompiler.add(Util.toIntsRef(term, scratchInts), encode(ord, termType)); + } + + public TermsIndex build() throws IOException { + return new TermsIndex(fstCompiler.compile()); + } + + private long encode(long ord, TermType termType) { + // use a single long to encode `ord` and `termType` + // also consider the special value of `PositiveIntOutputs.NO_OUTPUT == 0` + // so it looks like this |... ord ...| termType| ... hasOutput ...| + // where termType takes 3 bit and hasOutput takes the lowest bit. The rest is taken by ord + if (ord < 0) { + throw new IllegalArgumentException("can't encode negative ord"); + } + if (ord > MAX_ORD) { + throw new IllegalArgumentException( + "Input ord is too large for TermType: " Review Comment: I see. That's a good point. I'll keep that in mind when implementing the main FieldsConsumer! -- 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
