| /* |
| * 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 java.io.IOException; |
| |
| import org.apache.lucene.store.IndexInput; |
| |
| final class DirectPacked64SingleBlockReader extends PackedInts.ReaderImpl { |
| |
| private final IndexInput in; |
| private final int bitsPerValue; |
| private final long startPointer; |
| private final int valuesPerBlock; |
| private final long mask; |
| |
| DirectPacked64SingleBlockReader(int bitsPerValue, int valueCount, |
| IndexInput in) { |
| super(valueCount); |
| this.in = in; |
| this.bitsPerValue = bitsPerValue; |
| startPointer = in.getFilePointer(); |
| valuesPerBlock = 64 / bitsPerValue; |
| mask = ~(~0L << bitsPerValue); |
| } |
| |
| @Override |
| public long get(int index) { |
| final int blockOffset = index / valuesPerBlock; |
| final long skip = ((long) blockOffset) << 3; |
| try { |
| in.seek(startPointer + skip); |
| |
| long block = in.readLong(); |
| final int offsetInBlock = index % valuesPerBlock; |
| return (block >>> (offsetInBlock * bitsPerValue)) & mask; |
| } catch (IOException e) { |
| throw new IllegalStateException("failed", e); |
| } |
| } |
| |
| @Override |
| public long ramBytesUsed() { |
| return 0; |
| } |
| } |