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Fast, efficient Java serialization. This is the "main" kryo artifact, with a regular dependency on reflectasm.

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/* Copyright (c) 2008-2018, Nathan Sweet
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
 * conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided with the distribution.
 * - Neither the name of Esoteric Software nor the names of its contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */

package com.esotericsoftware.kryo.util;

/** An unordered map where identity comparison is used for keys and the values are ints. This implementation is a cuckoo hash map
 * using 3 hashes (if table size is less than 2^16) or 4 hashes (if table size is greater than or equal to 2^16), random walking,
 * and a small stash for problematic keys. Null keys are not 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 IdentityObjectIntMap { // primes for hash functions 2, 3, and 4 static private final int PRIME2 = 0xbe1f14b1; static private final int PRIME3 = 0xb4b82e39; static private final int PRIME4 = 0xced1c241; public int size; private K[] keyTable; private int[] valueTable; private int capacity, stashSize; private float loadFactor; private int hashShift, mask, threshold; private int stashCapacity; private int pushIterations; private boolean bigTable; /** 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 IdentityObjectIntMap () { 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 IdentityObjectIntMap (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 IdentityObjectIntMap (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 = ObjectMap.nextPowerOfTwo(initialCapacity); if (loadFactor <= 0) throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor); this.loadFactor = loadFactor; // big table is when capacity >= 2^16 bigTable = (capacity >>> 16) != 0 ? true : false; threshold = (int)(capacity * loadFactor); mask = capacity - 1; hashShift = 31 - Integer.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 = (K[])new Object[capacity + stashCapacity]; valueTable = new int[keyTable.length]; } public void put (K key, int value) { if (key == null) throw new IllegalArgumentException("key cannot be null."); K[] keyTable = this.keyTable; int mask = this.mask; // Check for existing keys. int hashCode = System.identityHashCode(key); int index1 = hashCode & mask; K key1 = keyTable[index1]; if (key == key1) { valueTable[index1] = value; return; } int index2 = hash2(hashCode); K key2 = keyTable[index2]; if (key == key2) { valueTable[index2] = value; return; } int index3 = hash3(hashCode); K key3 = keyTable[index3]; if (key == key3) { valueTable[index3] = value; return; } int index4 = -1; K key4 = null; if (bigTable) { index4 = hash4(hashCode); key4 = keyTable[index4]; if (key == key4) { valueTable[index4] = value; return; } } // Update key in the stash. for (int i = capacity, n = i + stashSize; i < n; i++) { if (keyTable[i] == key) { valueTable[i] = value; return; } } // Check for empty buckets. if (key1 == null) { keyTable[index1] = key; valueTable[index1] = value; if (size++ >= threshold) resize(capacity << 1); return; } if (key2 == null) { keyTable[index2] = key; valueTable[index2] = value; if (size++ >= threshold) resize(capacity << 1); return; } if (key3 == null) { keyTable[index3] = key; valueTable[index3] = value; if (size++ >= threshold) resize(capacity << 1); return; } if (bigTable && key4 == null) { keyTable[index4] = key; valueTable[index4] = value; if (size++ >= threshold) resize(capacity << 1); return; } push(key, value, index1, key1, index2, key2, index3, key3, index4, key4); } /** Skips checks for existing keys. */ private void putResize (K key, int value) { // Check for empty buckets. int hashCode = System.identityHashCode(key); int index1 = hashCode & mask; K key1 = keyTable[index1]; if (key1 == null) { keyTable[index1] = key; valueTable[index1] = value; if (size++ >= threshold) resize(capacity << 1); return; } int index2 = hash2(hashCode); K key2 = keyTable[index2]; if (key2 == null) { keyTable[index2] = key; valueTable[index2] = value; if (size++ >= threshold) resize(capacity << 1); return; } int index3 = hash3(hashCode); K key3 = keyTable[index3]; if (key3 == null) { keyTable[index3] = key; valueTable[index3] = value; if (size++ >= threshold) resize(capacity << 1); return; } int index4 = -1; K key4 = null; if (bigTable) { index4 = hash4(hashCode); key4 = keyTable[index4]; if (key4 == null) { keyTable[index4] = key; valueTable[index4] = value; if (size++ >= threshold) resize(capacity << 1); return; } } push(key, value, index1, key1, index2, key2, index3, key3, index4, key4); } private void push (K insertKey, int insertValue, int index1, K key1, int index2, K key2, int index3, K key3, int index4, K key4) { K[] keyTable = this.keyTable; int[] valueTable = this.valueTable; int mask = this.mask; boolean bigTable = this.bigTable; // Push keys until an empty bucket is found. K evictedKey; int evictedValue; int i = 0, pushIterations = this.pushIterations; int n = bigTable ? 4 : 3; do { // Replace the key and value for one of the hashes. switch (ObjectMap.random.nextInt(n)) { 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; case 2: evictedKey = key3; evictedValue = valueTable[index3]; keyTable[index3] = insertKey; valueTable[index3] = insertValue; break; default: evictedKey = key4; evictedValue = valueTable[index4]; keyTable[index4] = insertKey; valueTable[index4] = insertValue; break; } // If the evicted key hashes to an empty bucket, put it there and stop. int hashCode = System.identityHashCode(evictedKey); index1 = hashCode & mask; key1 = keyTable[index1]; if (key1 == null) { keyTable[index1] = evictedKey; valueTable[index1] = evictedValue; if (size++ >= threshold) resize(capacity << 1); return; } index2 = hash2(hashCode); key2 = keyTable[index2]; if (key2 == null) { keyTable[index2] = evictedKey; valueTable[index2] = evictedValue; if (size++ >= threshold) resize(capacity << 1); return; } index3 = hash3(hashCode); key3 = keyTable[index3]; if (key3 == null) { keyTable[index3] = evictedKey; valueTable[index3] = evictedValue; if (size++ >= threshold) resize(capacity << 1); return; } if (bigTable) { index4 = hash4(hashCode); key4 = keyTable[index4]; if (key4 == null) { keyTable[index4] = evictedKey; valueTable[index4] = evictedValue; if (size++ >= threshold) resize(capacity << 1); return; } } if (++i == pushIterations) break; insertKey = evictedKey; insertValue = evictedValue; } while (true); putStash(evictedKey, evictedValue); } private void putStash (K key, int value) { if (stashSize == stashCapacity) { // Too many pushes occurred and the stash is full, increase the table size. resize(capacity << 1); putResize(key, value); return; } // Store key in the stash. int index = capacity + stashSize; keyTable[index] = key; valueTable[index] = value; stashSize++; size++; } /** @param defaultValue Returned if the key was not associated with a value. */ public int get (K key, int defaultValue) { int hashCode = System.identityHashCode(key); int index = hashCode & mask; if (key != keyTable[index]) { index = hash2(hashCode); if (key != keyTable[index]) { index = hash3(hashCode); if (key != keyTable[index]) { if (bigTable) { index = hash4(hashCode); if (key != keyTable[index]) return getStash(key, defaultValue); } else { return getStash(key, defaultValue); } } } } return valueTable[index]; } private int getStash (K key, int defaultValue) { K[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) if (key == keyTable[i]) return valueTable[i]; return defaultValue; } /** Returns the key's current value and increments the stored value. If the key is not in the map, defaultValue + increment is * put into the map. */ public int getAndIncrement (K key, int defaultValue, int increment) { int hashCode = System.identityHashCode(key); int index = hashCode & mask; if (key != keyTable[index]) { index = hash2(hashCode); if (key != keyTable[index]) { index = hash3(hashCode); if (key != keyTable[index]) { if (bigTable) { index = hash4(hashCode); if (key != keyTable[index]) return getAndIncrementStash(key, defaultValue, increment); } else { return getAndIncrementStash(key, defaultValue, increment); } } } } int value = valueTable[index]; valueTable[index] = value + increment; return value; } private int getAndIncrementStash (K key, int defaultValue, int increment) { K[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) if (key == keyTable[i]) { int value = valueTable[i]; valueTable[i] = value + increment; return value; } put(key, defaultValue + increment); return defaultValue; } public int remove (K key, int defaultValue) { int hashCode = System.identityHashCode(key); int index = hashCode & mask; if (key == keyTable[index]) { keyTable[index] = null; int oldValue = valueTable[index]; size--; return oldValue; } index = hash2(hashCode); if (key == keyTable[index]) { keyTable[index] = null; int oldValue = valueTable[index]; size--; return oldValue; } index = hash3(hashCode); if (key == keyTable[index]) { keyTable[index] = null; int oldValue = valueTable[index]; size--; return oldValue; } if (bigTable) { index = hash4(hashCode); if (key == keyTable[index]) { keyTable[index] = null; int oldValue = valueTable[index]; size--; return oldValue; } } return removeStash(key, defaultValue); } int removeStash (K key, int defaultValue) { K[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) { if (key == keyTable[i]) { int oldValue = valueTable[i]; removeStashIndex(i); size--; return oldValue; } } return defaultValue; } 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]; keyTable[lastIndex] = 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, nothing is done. */ 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 = ObjectMap.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; } size = 0; resize(maximumCapacity); } public void clear () { if (size == 0) return; K[] keyTable = this.keyTable; for (int i = capacity + stashSize; i-- > 0;) keyTable[i] = null; size = 0; stashSize = 0; } /** 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 (int value) { K[] keyTable = this.keyTable; int[] valueTable = this.valueTable; for (int i = capacity + stashSize; i-- > 0;) if (keyTable[i] != null && valueTable[i] == value) return true; return false; } public boolean containsKey (K key) { int hashCode = System.identityHashCode(key); int index = hashCode & mask; if (key != keyTable[index]) { index = hash2(hashCode); if (key != keyTable[index]) { index = hash3(hashCode); if (key != keyTable[index]) { if (bigTable) { index = hash4(hashCode); if (key != keyTable[index]) return containsKeyStash(key); } else { return containsKeyStash(key); } } } } return true; } private boolean containsKeyStash (K key) { K[] keyTable = this.keyTable; for (int i = capacity, n = i + stashSize; i < n; i++) if (key == keyTable[i]) return true; return false; } /** Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares * every value, which may be an expensive operation. */ public K findKey (int value) { K[] keyTable = this.keyTable; int[] valueTable = this.valueTable; for (int i = capacity + stashSize; i-- > 0;) if (keyTable[i] != null && valueTable[i] == value) return keyTable[i]; return null; } /** 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) { if (additionalCapacity < 0) throw new IllegalArgumentException("additionalCapacity must be >= 0: " + additionalCapacity); int sizeNeeded = size + additionalCapacity; if (sizeNeeded >= threshold) resize(ObjectMap.nextPowerOfTwo((int)(sizeNeeded / loadFactor))); } private void resize (int newSize) { int oldEndIndex = capacity + stashSize; capacity = newSize; threshold = (int)(newSize * loadFactor); mask = newSize - 1; hashShift = 31 - Integer.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); // big table is when capacity >= 2^16 bigTable = (capacity >>> 16) != 0 ? true : false; K[] oldKeyTable = keyTable; int[] oldValueTable = valueTable; keyTable = (K[])new Object[newSize + stashCapacity]; valueTable = new int[newSize + stashCapacity]; int oldSize = size; size = 0; stashSize = 0; if (oldSize > 0) { for (int i = 0; i < oldEndIndex; i++) { K key = oldKeyTable[i]; if (key != null) putResize(key, oldValueTable[i]); } } } private int hash2 (int h) { h *= PRIME2; return (h ^ h >>> hashShift) & mask; } private int hash3 (int h) { h *= PRIME3; return (h ^ h >>> hashShift) & mask; } private int hash4 (int h) { h *= PRIME4; return (h ^ h >>> hashShift) & mask; } public String toString () { if (size == 0) return "{}"; StringBuilder buffer = new StringBuilder(32); buffer.append('{'); K[] keyTable = this.keyTable; int[] valueTable = this.valueTable; int i = keyTable.length; while (i-- > 0) { K key = keyTable[i]; if (key == null) continue; buffer.append(key); buffer.append('='); buffer.append(valueTable[i]); break; } while (i-- > 0) { K key = keyTable[i]; if (key == null) continue; buffer.append(", "); buffer.append(key); buffer.append('='); buffer.append(valueTable[i]); } buffer.append('}'); return buffer.toString(); } }




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