| /* |
| * 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.druid.query.groupby.epinephelinae; |
| |
| import javax.annotation.Nullable; |
| import java.nio.ByteBuffer; |
| |
| public class Groupers |
| { |
| private Groupers() |
| { |
| // No instantiation |
| } |
| |
| private static final AggregateResult DICTIONARY_FULL_ZERO_COUNT = AggregateResult.partial( |
| 0, |
| "Not enough dictionary space to execute this query. Try increasing " |
| + "druid.query.groupBy.maxMergingDictionarySize or enable disk spilling by setting " |
| + "druid.query.groupBy.maxOnDiskStorage to a positive number." |
| ); |
| |
| private static final AggregateResult HASH_TABLE_FULL_ZERO_COUNT = AggregateResult.partial( |
| 0, |
| "Not enough aggregation buffer space to execute this query. Try increasing " |
| + "druid.processing.buffer.sizeBytes or enable disk spilling by setting " |
| + "druid.query.groupBy.maxOnDiskStorage to a positive number." |
| ); |
| |
| private static final int USED_FLAG_MASK = 0x7fffffff; |
| |
| private static final int C1 = 0xcc9e2d51; |
| private static final int C2 = 0x1b873593; |
| |
| /** |
| * This method was rewritten in Java from an intermediate step of the Murmur hash function in |
| * https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp, which contained the |
| * following header: |
| * |
| * MurmurHash3 was written by Austin Appleby, and is placed in the public domain. The author |
| * hereby disclaims copyright to this source code. |
| */ |
| public static int smear(int hashCode) |
| { |
| return C2 * Integer.rotateLeft(hashCode * C1, 15); |
| } |
| |
| public static AggregateResult dictionaryFull(final int count) |
| { |
| if (count == 0) { |
| return DICTIONARY_FULL_ZERO_COUNT; |
| } else { |
| return AggregateResult.partial(count, DICTIONARY_FULL_ZERO_COUNT.getReason()); |
| } |
| } |
| |
| public static AggregateResult hashTableFull(final int count) |
| { |
| if (count == 0) { |
| return HASH_TABLE_FULL_ZERO_COUNT; |
| } else { |
| return AggregateResult.partial(count, HASH_TABLE_FULL_ZERO_COUNT.getReason()); |
| } |
| } |
| |
| public static int hashObject(final Object obj) |
| { |
| // Mask off the high bit so we can use that to determine if a bucket is used or not. |
| // Also apply the "smear" function, to improve distribution. |
| return smear(obj.hashCode()) & USED_FLAG_MASK; |
| } |
| |
| static int getUsedFlag(int keyHash) |
| { |
| return keyHash | 0x80000000; |
| } |
| |
| public static ByteBuffer getSlice(ByteBuffer buffer, int sliceSize, int i) |
| { |
| final ByteBuffer slice = buffer.duplicate(); |
| slice.position(sliceSize * i); |
| slice.limit(slice.position() + sliceSize); |
| return slice.slice(); |
| } |
| |
| /** |
| * Write ints from "start" to "end" into "scratch", if start != 0. Otherwise, return null. |
| */ |
| @Nullable |
| public static int[] writeAggregationRows(final int[] scratch, final int start, final int end) |
| { |
| if (start == 0) { |
| return null; |
| } else { |
| final int numRows = end - start; |
| for (int i = 0; i < numRows; i++) { |
| scratch[i] = start + i; |
| } |
| |
| return scratch; |
| } |
| } |
| } |