All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.kaka.util.LongMap Maven / Gradle / Ivy

/** *****************************************************************************
 * Copyright 2011 See AUTHORS file.
 *
 * Licensed 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 com.kaka.util;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * An unordered map that uses long keys. This implementation is a cuckoo hash
 * map using 3 hashes, random walking, and a small stash for problematic keys.
 * Null values are allowed. No allocation is done except when growing the table
 * size. 
*
* This map performs very fast get, containsKey, and remove (typically O(1), * worst case O(log(n))). Put may be a bit slower, depending on hash collisions. * Load factors greater than 0.91 greatly increase the chances the map will have * to rehash to the next higher POT size. * * @author Nathan Sweet */ public class LongMap implements Iterable>, Serializable { private static final int PRIME1 = 0xbe1f14b1; private static final int PRIME2 = 0xb4b82e39; private static final int PRIME3 = 0xced1c241; private static final int EMPTY = 0; int size; long[] keyTable; V[] valueTable; int capacity, stashSize; V zeroValue; boolean hasZeroValue; private float loadFactor; private int hashShift, mask, threshold; private int stashCapacity; private int pushIterations; private Entries entries1, entries2; private Values values1, values2; private Keys keys1, keys2; /** * Creates a new map with an initial capacity of 51 and a load factor of * 0.8. */ public LongMap() { this(51, 0.8f); } /** * Creates a new map with a load factor of 0.8. * * @param initialCapacity If not a power of two, it is increased to the next * nearest power of two. */ public LongMap(int initialCapacity) { this(initialCapacity, 0.8f); } /** * Creates a new map with the specified initial capacity and load factor. * This map will hold initialCapacity items before growing the backing * table. * * @param initialCapacity If not a power of two, it is increased to the next * nearest power of two. */ public LongMap(int initialCapacity, float loadFactor) { if (initialCapacity < 0) { throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity); } initialCapacity = MathUtils.nextPowerOfTwo((int) Math.ceil(initialCapacity / loadFactor)); if (initialCapacity > 1 << 30) { throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity); } capacity = initialCapacity; if (loadFactor <= 0) { throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor); } this.loadFactor = loadFactor; threshold = (int) (capacity * loadFactor); mask = capacity - 1; hashShift = 63 - Long.numberOfTrailingZeros(capacity); stashCapacity = Math.max(3, (int) Math.ceil(Math.log(capacity)) * 2); pushIterations = Math.max(Math.min(capacity, 8), (int) Math.sqrt(capacity) / 8); keyTable = new long[capacity + stashCapacity]; valueTable = (V[]) new Object[keyTable.length]; } /** * Creates a new map identical to the specified map. */ public LongMap(LongMap map) { this((int) Math.floor(map.capacity * map.loadFactor), map.loadFactor); stashSize = map.stashSize; System.arraycopy(map.keyTable, 0, keyTable, 0, map.keyTable.length); System.arraycopy(map.valueTable, 0, valueTable, 0, map.valueTable.length); size = map.size; zeroValue = map.zeroValue; hasZeroValue = map.hasZeroValue; } public V put(long key, V value) { if (key == 0) { V oldValue = zeroValue; zeroValue = value; if (!hasZeroValue) { hasZeroValue = true; size++; } return oldValue; } long[] keyTable = this.keyTable; // Check for existing keys. int index1 = (int) (key & mask); long key1 = keyTable[index1]; if (key1 == key) { V oldValue = valueTable[index1]; valueTable[index1] = value; return oldValue; } int index2 = hash2(key); long key2 = keyTable[index2]; if (key2 == key) { V oldValue = valueTable[index2]; valueTable[index2] = value; return oldValue; } int index3 = hash3(key); long key3 = keyTable[index3]; if (key3 == key) { V oldValue = valueTable[index3]; valueTable[index3] = value; return oldValue; } // Update key in the stash. for (int i = capacity, n = i + stashSize; i < n; i++) { if (keyTable[i] == key) { V oldValue = valueTable[i]; valueTable[i] = value; return oldValue; } } // Check for empty buckets. if (key1 == EMPTY) { keyTable[index1] = key; valueTable[index1] = value; if (size++ >= threshold) { resize(capacity << 1); } return null; } if (key2 == EMPTY) { keyTable[index2] = key; valueTable[index2] = value; if (size++ >= threshold) { resize(capacity << 1); } return null; } if (key3 == EMPTY) { keyTable[index3] = key; valueTable[index3] = value; if (size++ >= threshold) { resize(capacity << 1); } return null; } push(key, value, index1, key1, index2, key2, index3, key3); return null; } public void putAll(LongMap map) { for (Entry entry : map.entries()) { put(entry.key, entry.value); } } /** * Skips checks for existing keys. */ private void putResize(long key, V value) { if (key == 0) { zeroValue = value; hasZeroValue = true; return; } // Check for empty buckets. int index1 = (int) (key & mask); long key1 = keyTable[index1]; if (key1 == EMPTY) { keyTable[index1] = key; valueTable[index1] = value; if (size++ >= threshold) { resize(capacity << 1); } return; } int index2 = hash2(key); long key2 = keyTable[index2]; if (key2 == EMPTY) { keyTable[index2] = key; valueTable[index2] = value; if (size++ >= threshold) { resize(capacity << 1); } return; } int index3 = hash3(key); long key3 = keyTable[index3]; if (key3 == EMPTY) { keyTable[index3] = key; valueTable[index3] = value; if (size++ >= threshold) { resize(capacity << 1); } return; } push(key, value, index1, key1, index2, key2, index3, key3); } private void push(long insertKey, V insertValue, int index1, long key1, int index2, long key2, int index3, long key3) { long[] keyTable = this.keyTable; V[] valueTable = this.valueTable; int mask = this.mask; // Push keys until an empty bucket is found. long evictedKey; V evictedValue; int i = 0, pushIterations = this.pushIterations; do { // Replace the key and value for one of the hashes. switch (MathUtils.random(2)) { case 0: evictedKey = key1; evictedValue = valueTable[index1]; keyTable[index1] = insertKey; valueTable[index1] = insertValue; break; case 1: evictedKey = key2; evictedValue = valueTable[index2]; keyTable[index2] = insertKey; valueTable[index2] = insertValue; break; default: evictedKey = key3; evictedValue = valueTable[index3]; keyTable[index3] = insertKey; valueTable[index3] = insertValue; break; } // If the evicted key hashes to an empty bucket, put it there and stop. index1 = (int) (evictedKey & mask); key1 = keyTable[index1]; if (key1 == EMPTY) { keyTable[index1] = evictedKey; valueTable[index1] = evictedValue; if (size++ >= threshold) { resize(capacity << 1); } return; } index2 = hash2(evictedKey); key2 = keyTable[index2]; if (key2 == EMPTY) { keyTable[index2] = evictedKey; valueTable[index2] = evictedValue; if (size++ >= threshold) { resize(capacity << 1); } return; } index3 = hash3(evictedKey); key3 = keyTable[index3]; if (key3 == EMPTY) { keyTable[index3] = evictedKey; valueTable[index3] = evictedValue; if (size++ >= threshold) { resize(capacity << 1); } return; } if (++i == pushIterations) { break; } insertKey = evictedKey; insertValue = evictedValue; } while (true); putStash(evictedKey, evictedValue); } private void putStash(long key, V value) { if (stashSize == stashCapacity) { // Too many pushes occurred and the stash is full, increase the table size. resize(capacity << 1); put(key, value); return; } // Store key in the stash. int index = capacity + stashSize; keyTable[index] = key; valueTable[index] = value; stashSize++; size++; } public V get(long key) { if (key == 0) { if (!hasZeroValue) { return null; } return zeroValue; } int index = (int) (key & mask); if (keyTable[index] != key) { index = hash2(key); if (keyTable[index] != key) { index = hash3(key); if (keyTable[index] != key) { return getStash(key, null); } } } return valueTable[index]; } public V get(long key, V defaultValue) { if (key == 0) { if (!hasZeroValue) { return defaultValue; } return zeroValue; } int index = (int) (key & mask); if (keyTable[index] != key) { index = hash2(key); if (keyTable[index] != key) { index = hash3(key); if (keyTable[index] != key) { return getStash(key, defaultValue); } } } return valueTable[index]; } private V getStash(long key, V defaultValue) { long[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) { if (keyTable[i] == key) { return valueTable[i]; } } return defaultValue; } public V remove(long key) { if (key == 0) { if (!hasZeroValue) { return null; } V oldValue = zeroValue; zeroValue = null; hasZeroValue = false; size--; return oldValue; } int index = (int) (key & mask); if (keyTable[index] == key) { keyTable[index] = EMPTY; V oldValue = valueTable[index]; valueTable[index] = null; size--; return oldValue; } index = hash2(key); if (keyTable[index] == key) { keyTable[index] = EMPTY; V oldValue = valueTable[index]; valueTable[index] = null; size--; return oldValue; } index = hash3(key); if (keyTable[index] == key) { keyTable[index] = EMPTY; V oldValue = valueTable[index]; valueTable[index] = null; size--; return oldValue; } return removeStash(key); } V removeStash(long key) { long[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) { if (keyTable[i] == key) { V oldValue = valueTable[i]; removeStashIndex(i); size--; return oldValue; } } return null; } void removeStashIndex(int index) { // If the removed location was not last, move the last tuple to the removed location. stashSize--; int lastIndex = capacity + stashSize; if (index < lastIndex) { keyTable[index] = keyTable[lastIndex]; valueTable[index] = valueTable[lastIndex]; valueTable[lastIndex] = null; } else { valueTable[index] = null; } } /** * Reduces the size of the backing arrays to be the specified capacity or * less. If the capacity is already less, nothing is done. If the map * contains more items than the specified capacity, the next highest power * of two capacity is used instead. */ public void shrink(int maximumCapacity) { if (maximumCapacity < 0) { throw new IllegalArgumentException("maximumCapacity must be >= 0: " + maximumCapacity); } if (size > maximumCapacity) { maximumCapacity = size; } if (capacity <= maximumCapacity) { return; } maximumCapacity = MathUtils.nextPowerOfTwo(maximumCapacity); resize(maximumCapacity); } /** * Clears the map and reduces the size of the backing arrays to be the * specified capacity if they are larger. */ public void clear(int maximumCapacity) { if (capacity <= maximumCapacity) { clear(); return; } zeroValue = null; hasZeroValue = false; size = 0; resize(maximumCapacity); } public void clear() { if (size == 0) { return; } long[] keyTable = this.keyTable; V[] valueTable = this.valueTable; for (int i = capacity + stashSize; i-- > 0;) { keyTable[i] = EMPTY; valueTable[i] = null; } size = 0; stashSize = 0; zeroValue = null; hasZeroValue = false; } /** * Returns true if the specified value is in the map. Note this traverses * the entire map and compares every value, which may be an expensive * operation. */ public boolean containsValue(Object value, boolean identity) { V[] valueTable = this.valueTable; if (value == null) { if (hasZeroValue && zeroValue == null) { return true; } long[] keyTable = this.keyTable; for (int i = capacity + stashSize; i-- > 0;) { if (keyTable[i] != EMPTY && valueTable[i] == null) { return true; } } } else if (identity) { if (value == zeroValue) { return true; } for (int i = capacity + stashSize; i-- > 0;) { if (valueTable[i] == value) { return true; } } } else { if (hasZeroValue && value.equals(zeroValue)) { return true; } for (int i = capacity + stashSize; i-- > 0;) { if (value.equals(valueTable[i])) { return true; } } } return false; } public boolean containsKey(long key) { if (key == 0) { return hasZeroValue; } int index = (int) (key & mask); if (keyTable[index] != key) { index = hash2(key); if (keyTable[index] != key) { index = hash3(key); if (keyTable[index] != key) { return containsKeyStash(key); } } } return true; } private boolean containsKeyStash(long key) { long[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) { if (keyTable[i] == key) { return true; } } return false; } /** * Returns the key for the specified value, or notFound if it is * not in the map. Note this traverses the entire map and compares every * value, which may be an expensive operation. * * @param identity If true, uses == to compare the specified value with * values in the map. If false, uses {@link #equals(Object)}. */ public long findKey(Object value, boolean identity, long notFound) { V[] valueTable = this.valueTable; if (value == null) { if (hasZeroValue && zeroValue == null) { return 0; } long[] keyTable = this.keyTable; for (int i = capacity + stashSize; i-- > 0;) { if (keyTable[i] != EMPTY && valueTable[i] == null) { return keyTable[i]; } } } else if (identity) { if (value == zeroValue) { return 0; } for (int i = capacity + stashSize; i-- > 0;) { if (valueTable[i] == value) { return keyTable[i]; } } } else { if (hasZeroValue && value.equals(zeroValue)) { return 0; } for (int i = capacity + stashSize; i-- > 0;) { if (value.equals(valueTable[i])) { return keyTable[i]; } } } return notFound; } /** * Increases the size of the backing array to accommodate the specified * number of additional items. Useful before adding many items to avoid * multiple backing array resizes. */ public void ensureCapacity(int additionalCapacity) { int sizeNeeded = size + additionalCapacity; if (sizeNeeded >= threshold) { resize(MathUtils.nextPowerOfTwo((int) Math.ceil(sizeNeeded / loadFactor))); } } private void resize(int newSize) { int oldEndIndex = capacity + stashSize; capacity = newSize; threshold = (int) (newSize * loadFactor); mask = newSize - 1; hashShift = 63 - Long.numberOfTrailingZeros(newSize); stashCapacity = Math.max(3, (int) Math.ceil(Math.log(newSize)) * 2); pushIterations = Math.max(Math.min(newSize, 8), (int) Math.sqrt(newSize) / 8); long[] oldKeyTable = keyTable; V[] oldValueTable = valueTable; keyTable = new long[newSize + stashCapacity]; valueTable = (V[]) new Object[newSize + stashCapacity]; int oldSize = size; size = hasZeroValue ? 1 : 0; stashSize = 0; if (oldSize > 0) { for (int i = 0; i < oldEndIndex; i++) { long key = oldKeyTable[i]; if (key != EMPTY) { putResize(key, oldValueTable[i]); } } } } private int hash2(long h) { h *= PRIME2; return (int) ((h ^ h >>> hashShift) & mask); } private int hash3(long h) { h *= PRIME3; return (int) ((h ^ h >>> hashShift) & mask); } public int hashCode() { int h = 0; if (hasZeroValue && zeroValue != null) { h += zeroValue.hashCode(); } long[] keyTable = this.keyTable; V[] valueTable = this.valueTable; for (int i = 0, n = capacity + stashSize; i < n; i++) { long key = keyTable[i]; if (key != EMPTY) { h += (int) (key ^ (key >>> 32)) * 31; V value = valueTable[i]; if (value != null) { h += value.hashCode(); } } } return h; } public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof LongMap)) { return false; } LongMap other = (LongMap) obj; if (other.size != size) { return false; } if (other.hasZeroValue != hasZeroValue) { return false; } if (hasZeroValue) { if (other.zeroValue == null) { if (zeroValue != null) { return false; } } else { if (!other.zeroValue.equals(zeroValue)) { return false; } } } long[] keyTable = this.keyTable; V[] valueTable = this.valueTable; for (int i = 0, n = capacity + stashSize; i < n; i++) { long key = keyTable[i]; if (key != EMPTY) { V value = valueTable[i]; if (value == null) { if (!other.containsKey(key) || other.get(key) != null) { return false; } } else { if (!value.equals(other.get(key))) { return false; } } } } return true; } public String toString() { if (size == 0) { return "[]"; } StringBuilder buffer = new StringBuilder(32); buffer.append('['); long[] keyTable = this.keyTable; V[] valueTable = this.valueTable; int i = keyTable.length; while (i-- > 0) { long key = keyTable[i]; if (key == EMPTY) { continue; } buffer.append(key); buffer.append('='); buffer.append(valueTable[i]); break; } while (i-- > 0) { long key = keyTable[i]; if (key == EMPTY) { continue; } buffer.append(", "); buffer.append(key); buffer.append('='); buffer.append(valueTable[i]); } buffer.append(']'); return buffer.toString(); } public int size() { return size; } public Iterator> iterator() { return entries(); } /** * Returns an iterator for the entries in the map. Remove is supported. Note * that the same iterator instance is returned each time this method is * called. Use the {@link Entries} constructor for nested or multithreaded * iteration. */ public Entries entries() { if (entries1 == null) { entries1 = new Entries(this); entries2 = new Entries(this); } if (!entries1.valid) { entries1.reset(); entries1.valid = true; entries2.valid = false; return entries1; } entries2.reset(); entries2.valid = true; entries1.valid = false; return entries2; } /** * Returns an iterator for the values in the map. Remove is supported. Note * that the same iterator instance is returned each time this method is * called. Use the {@link Entries} constructor for nested or multithreaded * iteration. */ public Values values() { if (values1 == null) { values1 = new Values(this); values2 = new Values(this); } if (!values1.valid) { values1.reset(); values1.valid = true; values2.valid = false; return values1; } values2.reset(); values2.valid = true; values1.valid = false; return values2; } /** * Returns an iterator for the keys in the map. Remove is supported. Note * that the same iterator instance is returned each time this method is * called. Use the {@link Entries} constructor for nested or multithreaded * iteration. */ public Keys keys() { if (keys1 == null) { keys1 = new Keys(this); keys2 = new Keys(this); } if (!keys1.valid) { keys1.reset(); keys1.valid = true; keys2.valid = false; return keys1; } keys2.reset(); keys2.valid = true; keys1.valid = false; return keys2; } static public class Entry { public long key; public V value; public String toString() { return key + "=" + value; } } static private class MapIterator { static final int INDEX_ILLEGAL = -2; static final int INDEX_ZERO = -1; public boolean hasNext; final LongMap map; int nextIndex, currentIndex; boolean valid = true; public MapIterator(LongMap map) { this.map = map; reset(); } public void reset() { currentIndex = INDEX_ILLEGAL; nextIndex = INDEX_ZERO; if (map.hasZeroValue) { hasNext = true; } else { findNextIndex(); } } void findNextIndex() { hasNext = false; long[] keyTable = map.keyTable; for (int n = map.capacity + map.stashSize; ++nextIndex < n;) { if (keyTable[nextIndex] != EMPTY) { hasNext = true; break; } } } public void remove() { if (currentIndex == INDEX_ZERO && map.hasZeroValue) { map.zeroValue = null; map.hasZeroValue = false; } else if (currentIndex < 0) { throw new IllegalStateException("next must be called before remove."); } else if (currentIndex >= map.capacity) { map.removeStashIndex(currentIndex); nextIndex = currentIndex - 1; findNextIndex(); } else { map.keyTable[currentIndex] = EMPTY; map.valueTable[currentIndex] = null; } currentIndex = INDEX_ILLEGAL; map.size--; } } static public class Entries extends MapIterator implements Iterable>, Iterator> { private Entry entry = new Entry(); public Entries(LongMap map) { super(map); } /** * Note the same entry instance is returned each time this method is * called. */ public Entry next() { if (!hasNext) { throw new NoSuchElementException(); } if (!valid) { throw new RuntimeException("#iterator() cannot be used nested."); } long[] keyTable = map.keyTable; if (nextIndex == INDEX_ZERO) { entry.key = 0; entry.value = map.zeroValue; } else { entry.key = keyTable[nextIndex]; entry.value = map.valueTable[nextIndex]; } currentIndex = nextIndex; findNextIndex(); return entry; } public boolean hasNext() { if (!valid) { throw new RuntimeException("#iterator() cannot be used nested."); } return hasNext; } public Iterator> iterator() { return this; } public void remove() { super.remove(); } } static public class Values extends MapIterator implements Iterable, Iterator { public Values(LongMap map) { super(map); } public boolean hasNext() { if (!valid) { throw new RuntimeException("#iterator() cannot be used nested."); } return hasNext; } public V next() { if (!hasNext) { throw new NoSuchElementException(); } if (!valid) { throw new RuntimeException("#iterator() cannot be used nested."); } V value; if (nextIndex == INDEX_ZERO) { value = map.zeroValue; } else { value = map.valueTable[nextIndex]; } currentIndex = nextIndex; findNextIndex(); return value; } public Iterator iterator() { return this; } /** * Returns a new array containing the remaining values. */ public ArrayList toArray() { ArrayList array = new ArrayList<>(map.size); while (hasNext) { array.add(next()); } return array; } public void remove() { super.remove(); } } static public class Keys extends MapIterator { public Keys(LongMap map) { super(map); } public long next() { if (!hasNext) { throw new NoSuchElementException(); } if (!valid) { throw new RuntimeException("#iterator() cannot be used nested."); } long key = nextIndex == INDEX_ZERO ? 0 : map.keyTable[nextIndex]; currentIndex = nextIndex; findNextIndex(); return key; } /** * Returns a new array containing the remaining values. */ public LongArray toArray() { LongArray array = new LongArray(true, map.size); while (hasNext) { array.add(next()); } return array; } } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy