uschindler commented on a change in pull request #2176: URL: https://github.com/apache/lucene-solr/pull/2176#discussion_r552031972
########## File path: lucene/core/src/java/org/apache/lucene/store/MemorySegmentIndexInput.java ########## @@ -0,0 +1,524 @@ +/* + * 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.store; + +import java.io.EOFException; +import java.io.IOException; +import java.lang.invoke.VarHandle; +import java.nio.ByteOrder; +import java.util.Arrays; +import java.util.Objects; + +import org.apache.lucene.util.IOUtils; + +import jdk.incubator.foreign.MemoryHandles; +import jdk.incubator.foreign.MemorySegment; + +/** + * Base IndexInput implementation that uses an array of MemorySegments to represent a file. + * + * <p>For efficiency, this class requires that the segment size are a power-of-two + * (<code>chunkSizePower</code>). + */ +public abstract class MemorySegmentIndexInput extends IndexInput implements RandomAccessInput { + // We pass 1L as alignment, because currently Lucene file formats are heavy unaligned: :( + static final VarHandle VH_getByte = MemoryHandles.varHandle(byte.class, 1L, ByteOrder.BIG_ENDIAN).withInvokeExactBehavior(); + static final VarHandle VH_getShort = MemoryHandles.varHandle(short.class, 1L, ByteOrder.BIG_ENDIAN).withInvokeExactBehavior(); Review comment: Thanks for review! In fact that's wanted, because Lucene Apis read any type always from a file offset. The alignment of 1L is wanted because currently we have ints/longs/floats anywhere in files (see PR description). ---------------------------------------------------------------- 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. 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
