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/******************************************************************************* * Copyright 2011 See AUTHORS file.//from w w w . ja va 2s . c o m * * 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.badlogic.gdx.utils; import java.util.Iterator; import java.util.NoSuchElementException; import com.badlogic.gdx.math.MathUtils; /** * 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. <br> * <br> * 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<V> { private static final int PRIME1 = 0xbe1f14b1; private static final int PRIME2 = 0xb4b82e39; private static final int PRIME3 = 0xced1c241; private static final int EMPTY = 0; public 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 entries; private Values values; private Keys keys; /** * Creates a new map with an initial capacity of 32 and a load factor of * 0.8. This map will hold 25 items before growing the backing table. */ public LongMap() { this(32, 0.8f); } /** * Creates a new map with a load factor of 0.8. This map will hold * initialCapacity * 0.8 items before growing the backing table. */ 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 * loadFactor items before growing the * backing table. */ public LongMap(int initialCapacity, float loadFactor) { if (initialCapacity < 0) throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity); if (capacity > 1 << 30) throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity); capacity = MathUtils.nextPowerOfTwo(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]; } 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<V> map) { for (Entry<V> 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) 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) 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; } public void clear() { 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 <tt>notFound</tt> 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 acommodate 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) (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]; size = hasZeroValue ? 1 : 0; stashSize = 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 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(); } /** * 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<V> entries() { if (entries == null) entries = new Entries(this); else entries.reset(); return entries; } /** * 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<V> values() { if (values == null) values = new Values(this); else values.reset(); return values; } /** * 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 (keys == null) keys = new Keys(this); else keys.reset(); return keys; } static public class Entry<V> { public long key; public V value; public String toString() { return key + "=" + value; } } static private class MapIterator<V> { static final int INDEX_ILLEGAL = -2; static final int INDEX_ZERO = -1; public boolean hasNext; final LongMap<V> map; int nextIndex, currentIndex; public MapIterator(LongMap<V> 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); } else { map.keyTable[currentIndex] = EMPTY; map.valueTable[currentIndex] = null; } currentIndex = INDEX_ILLEGAL; map.size--; } } static public class Entries<V> extends MapIterator<V> implements Iterable<Entry<V>>, Iterator<Entry<V>> { private Entry<V> entry = new Entry(); public Entries(LongMap map) { super(map); } /** * Note the same entry instance is returned each time this method is * called. */ public Entry<V> next() { if (!hasNext) throw new NoSuchElementException(); 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() { return hasNext; } public Iterator<Entry<V>> iterator() { return this; } } static public class Values<V> extends MapIterator<V> implements Iterable<V>, Iterator<V> { public Values(LongMap<V> map) { super(map); } public boolean hasNext() { return hasNext; } public V next() { V value; if (nextIndex == INDEX_ZERO) value = map.zeroValue; else value = map.valueTable[nextIndex]; currentIndex = nextIndex; findNextIndex(); return value; } public Iterator<V> iterator() { return this; } /** Returns a new array containing the remaining values. */ public Array<V> toArray() { Array array = new Array(true, map.size); while (hasNext) array.add(next()); return array; } } static public class Keys extends MapIterator { public Keys(LongMap map) { super(map); } public long next() { 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; } } }