| /** |
| * 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.drill.exec.util; |
| |
| |
| import com.google.common.base.Preconditions; |
| |
| import java.util.Arrays; |
| |
| /** |
| * Simple Map type data structure for storing entries of (int -> int) mappings where the max key value is below 2^16 |
| * to avoid hashing keys and use direct array index reference for retrieving the values. Not thread-safe. Keys and |
| * values are expected to be >=0. |
| */ |
| public class ArrayWrappedIntIntMap { |
| private static final int MAX_KEY_VALUE = 1 << 16 - 1; |
| private static final int INITIAL_MAX_KEY_VALUE = 1 << 8 - 1; |
| private int[] values; |
| |
| public ArrayWrappedIntIntMap() { |
| values = new int[INITIAL_MAX_KEY_VALUE + 1]; |
| Arrays.fill(values, Integer.MIN_VALUE); |
| } |
| |
| public void put(final int key, final int value) { |
| Preconditions.checkArgument(key >= 0 && key <= MAX_KEY_VALUE, |
| String.format("Index should be in range [0, %d], given [%d].", MAX_KEY_VALUE, key)); |
| Preconditions.checkArgument(value >= 0, String.format("Value must be non-negative, given [%d]", value)); |
| |
| // resize the values array if the index falls beyond the current size of the array |
| if (values.length < key + 1) { |
| // Make the new size the next power of 2 number after the given index number |
| int newValuesLength = Integer.highestOneBit(key) * 2; |
| int[] newValues = Arrays.copyOf(values, newValuesLength); |
| Arrays.fill(newValues, values.length, newValues.length - 1, Integer.MIN_VALUE); |
| values = newValues; |
| } |
| |
| values[key] = value; |
| } |
| |
| /** |
| * Returns the value pointed by the given index. |
| * If the value is not set through put() it either returns Integer.MIN_VALUE or throws ArrayIndexOutOfBounds |
| * exception. Error checking is not done for faster retrieval. |
| */ |
| public int get(int key) { |
| return values[key]; |
| } |
| } |