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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.lucene.search.grouping;
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import java.util.Arrays;
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/** A native int set where one value is reserved to mean "EMPTY" */
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class SentinelIntSet {
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public final int emptyVal;
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public int rehashCount; // the count at which a rehash should be done
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public SentinelIntSet(int size, int emptyVal) {
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this.emptyVal = emptyVal;
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int tsize = Math.max(org.apache.lucene.util.BitUtil.nextHighestPowerOfTwo(size), 1);
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rehashCount = tsize - (tsize>>2);
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if (size >= rehashCount) { // should be able to hold "size" w/o rehashing
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rehashCount = tsize - (tsize>>2);
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keys = new int[tsize];
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Arrays.fill(keys, emptyVal);
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public int hash(int key) {
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public int size() { return count; }
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/** returns the slot for this key */
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public int getSlot(int key) {
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assert key != emptyVal;
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int s = h & (keys.length-1);
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if (keys[s] == key || keys[s]== emptyVal) return s;
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int increment = (h>>7)|1;
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s = (s + increment) & (keys.length-1);
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} while (keys[s] != key && keys[s] != emptyVal);
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/** returns the slot for this key, or -slot-1 if not found */
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public int find(int key) {
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assert key != emptyVal;
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int s = h & (keys.length-1);
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if (keys[s] == key) return s;
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if (keys[s] == emptyVal) return -s-1;
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int increment = (h>>7)|1;
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s = (s + increment) & (keys.length-1);
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if (keys[s] == key) return s;
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if (keys[s] == emptyVal) return -s-1;
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public boolean exists(int key) {
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return find(key) >= 0;
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public int put(int key) {
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if (count >= rehashCount) {
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public void rehash() {
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int newSize = keys.length << 1;
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int[] oldKeys = keys;
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keys = new int[newSize];
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if (emptyVal != 0) Arrays.fill(keys, emptyVal);
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for (int i=0; i<oldKeys.length; i++) {
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int key = oldKeys[i];
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if (key == emptyVal) continue;
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int newSlot = getSlot(key);
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rehashCount = newSize - (newSize>>2);