sonatype-lift[bot] commented on a change in pull request #453: URL: https://github.com/apache/lucene/pull/453#discussion_r761874066
########## File path: lucene/core/src/java/org/apache/lucene/util/packed/Packed64VHLongAndByte.java ########## @@ -0,0 +1,154 @@ +/* + * 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.packed; + +import org.apache.lucene.util.ArrayUtil; +import org.apache.lucene.util.BitUtil; +import org.apache.lucene.util.RamUsageEstimator; + +import java.util.Arrays; + +/** + * Space optimized random access capable array of values with a fixed number of bits/value. Values + * are packed contiguously. + * + * <p>The implementation strives to perform as fast as possible under the constraint of contiguous + * bits, by avoiding expensive operations. This comes at the cost of code clarity. + * + * <p>Technical details: This implementation is a refinement of a non-branching version. The + * non-branching get and set methods meant that 2 or 4 atomics in the underlying array were always + * accessed, even for the cases where only 1 or 2 were needed. Even with caching, this had a + * detrimental effect on performance. Related to this issue, the old implementation used lookup + * tables for shifts and masks, which also proved to be a bit slower than calculating the shifts and + * masks on the fly. See https://issues.apache.org/jira/browse/LUCENE-4062 for details. + */ +class Packed64VHLongAndByte extends PackedInts.MutableImpl { + static final int BLOCK_SIZE = 64; // 32 = int, 64 = long + static final int BYTE_BITS = 3; + static final int BYTE_BLOCK_SIZE = 8; + static final int BYTE_BLOCK_MOD_MASK = BYTE_BLOCK_SIZE - 1; // x % BYTE_BLOCK + + /** Values are stores contiguously in the blocks array. */ + private final byte[] blocks; + /** A right-aligned mask of width BitsPerValue used by {@link #get(int)}. */ + private final long maskRight; + /** Optimization: Saves one lookup in {@link #get(int)}. */ + private final int bpvMinusBlockSize; Review comment: *UnusedVariable:* The field 'bpvMinusBlockSize' is never read. [(details)](https://errorprone.info/bugpattern/UnusedVariable) (at-me [in a reply](https://help.sonatype.com/lift/talking-to-lift) with `help` or `ignore`) -- 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
