Merge pull request #92554 from Nazarwadim/implement_a_hash_map

Implement array based hash map `AHashMap`

core/templates/a_hash_map.cpp

@@ -0,0 +1,39 @@
+/**************************************************************************/
+/*  a_hash_map.cpp                                                        */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#include "a_hash_map.h"
+#include "core/variant/variant.h"
+
+// Explicit instantiation.
+template class AHashMap<int, int>;
+template class AHashMap<String, int>;
+template class AHashMap<StringName, StringName>;
+template class AHashMap<StringName, Variant>;
+template class AHashMap<StringName, int>;

core/templates/a_hash_map.h

@@ -0,0 +1,732 @@
+/**************************************************************************/
+/*  a_hash_map.h                                                          */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef A_HASH_MAP_H
+#define A_HASH_MAP_H
+
+#include "core/templates/hash_map.h"
+
+struct HashMapData {
+	union {
+		struct
+		{
+			uint32_t hash;
+			uint32_t hash_to_key;
+		};
+		uint64_t data;
+	};
+};
+
+static_assert(sizeof(HashMapData) == 8);
+
+/**
+ * An array-based implementation of a hash map. It is very efficient in terms of performance and
+ * memory usage. Works like a dynamic array, adding elements to the end of the array, and
+ * allows you to access array elements by their index by using `get_by_index` method.
+ * Example:
+ * ```
+ *  AHashMap<int, Object *> map;
+ *
+ *  int get_object_id_by_number(int p_number) {
+ *		int id = map.get_index(p_number);
+ *		return id;
+ *  }
+ *
+ *  Object *get_object_by_id(int p_id) {
+ *		map.get_by_index(p_id).value;
+ *  }
+ * ```
+ * Still, don`t erase the elements because ID can break.
+ *
+ * When an element erase, its place is taken by the element from the end.
+ *
+ *        <-------------
+ *      |               |
+ *  6 8 X 9 32 -1 5 -10 7 X X X
+ *  6 8 7 9 32 -1 5 -10 X X X X
+ *
+ *
+ * Use RBMap if you need to iterate over sorted elements.
+ *
+ * Use HashMap if:
+ *   - You need to keep an iterator or const pointer to Key and you intend to add/remove elements in the meantime.
+ *   - You need to preserve the insertion order when using erase.
+ *
+ * It is recommended to use `HashMap` if `KeyValue` size is very large.
+ */
+template <typename TKey, typename TValue,
+		typename Hasher = HashMapHasherDefault,
+		typename Comparator = HashMapComparatorDefault<TKey>>
+class AHashMap {
+public:
+	// Must be a power of two.
+	static constexpr uint32_t INITIAL_CAPACITY = 16;
+	static constexpr uint32_t EMPTY_HASH = 0;
+	static_assert(EMPTY_HASH == 0, "EMPTY_HASH must always be 0 for the memcpy() optimization.");
+
+private:
+	typedef KeyValue<TKey, TValue> MapKeyValue;
+	MapKeyValue *elements = nullptr;
+	HashMapData *map_data = nullptr;
+
+	// Due to optimization, this is `capacity - 1`. Use + 1 to get normal capacity.
+	uint32_t capacity = 0;
+	uint32_t num_elements = 0;
+
+	uint32_t _hash(const TKey &p_key) const {
+		uint32_t hash = Hasher::hash(p_key);
+
+		if (unlikely(hash == EMPTY_HASH)) {
+			hash = EMPTY_HASH + 1;
+		}
+
+		return hash;
+	}
+
+	static _FORCE_INLINE_ uint32_t _get_resize_count(uint32_t p_capacity) {
+		return p_capacity ^ (p_capacity + 1) >> 2; // = get_capacity() * 0.75 - 1; Works only if p_capacity = 2^n - 1.
+	}
+
+	static _FORCE_INLINE_ uint32_t _get_probe_length(uint32_t p_pos, uint32_t p_hash, uint32_t p_local_capacity) {
+		const uint32_t original_pos = p_hash & p_local_capacity;
+		return (p_pos - original_pos + p_local_capacity + 1) & p_local_capacity;
+	}
+
+	bool _lookup_pos(const TKey &p_key, uint32_t &r_pos, uint32_t &r_hash_pos) const {
+		if (unlikely(elements == nullptr)) {
+			return false; // Failed lookups, no elements.
+		}
+		return _lookup_pos_with_hash(p_key, r_pos, r_hash_pos, _hash(p_key));
+	}
+
+	bool _lookup_pos_with_hash(const TKey &p_key, uint32_t &r_pos, uint32_t &r_hash_pos, uint32_t p_hash) const {
+		if (unlikely(elements == nullptr)) {
+			return false; // Failed lookups, no elements.
+		}
+
+		uint32_t pos = p_hash & capacity;
+		HashMapData data = map_data[pos];
+		if (data.hash == p_hash && Comparator::compare(elements[data.hash_to_key].key, p_key)) {
+			r_pos = data.hash_to_key;
+			r_hash_pos = pos;
+			return true;
+		}
+
+		if (data.data == EMPTY_HASH) {
+			return false;
+		}
+
+		// A collision occurred.
+		pos = (pos + 1) & capacity;
+		uint32_t distance = 1;
+		while (true) {
+			data = map_data[pos];
+			if (data.hash == p_hash && Comparator::compare(elements[data.hash_to_key].key, p_key)) {
+				r_pos = data.hash_to_key;
+				r_hash_pos = pos;
+				return true;
+			}
+
+			if (data.data == EMPTY_HASH) {
+				return false;
+			}
+
+			if (distance > _get_probe_length(pos, data.hash, capacity)) {
+				return false;
+			}
+
+			pos = (pos + 1) & capacity;
+			distance++;
+		}
+	}
+
+	uint32_t _insert_with_hash(uint32_t p_hash, uint32_t p_index) {
+		uint32_t pos = p_hash & capacity;
+
+		if (map_data[pos].data == EMPTY_HASH) {
+			uint64_t data = ((uint64_t)p_index << 32) | p_hash;
+			map_data[pos].data = data;
+			return pos;
+		}
+
+		uint32_t distance = 1;
+		pos = (pos + 1) & capacity;
+		HashMapData c_data;
+		c_data.hash = p_hash;
+		c_data.hash_to_key = p_index;
+
+		while (true) {
+			if (map_data[pos].data == EMPTY_HASH) {
+#ifdef DEV_ENABLED
+				if (unlikely(distance > 12)) {
+					WARN_PRINT("Excessive collision count (" +
+							itos(distance) + "), is the right hash function being used?");
+				}
+#endif
+				map_data[pos] = c_data;
+				return pos;
+			}
+
+			// Not an empty slot, let's check the probing length of the existing one.
+			uint32_t existing_probe_len = _get_probe_length(pos, map_data[pos].hash, capacity);
+			if (existing_probe_len < distance) {
+				SWAP(c_data, map_data[pos]);
+				distance = existing_probe_len;
+			}
+
+			pos = (pos + 1) & capacity;
+			distance++;
+		}
+	}
+
+	void _resize_and_rehash(uint32_t p_new_capacity) {
+		uint32_t real_old_capacity = capacity + 1;
+		// Capacity can't be 0 and must be 2^n - 1.
+		capacity = MAX(4u, p_new_capacity);
+		uint32_t real_capacity = next_power_of_2(capacity);
+		capacity = real_capacity - 1;
+
+		HashMapData *old_map_data = map_data;
+
+		map_data = reinterpret_cast<HashMapData *>(Memory::alloc_static(sizeof(HashMapData) * real_capacity));
+		elements = reinterpret_cast<MapKeyValue *>(Memory::realloc_static(elements, sizeof(MapKeyValue) * (_get_resize_count(capacity) + 1)));
+
+		memset(map_data, EMPTY_HASH, real_capacity * sizeof(HashMapData));
+
+		if (num_elements != 0) {
+			for (uint32_t i = 0; i < real_old_capacity; i++) {
+				HashMapData data = old_map_data[i];
+				if (data.data != EMPTY_HASH) {
+					_insert_with_hash(data.hash, data.hash_to_key);
+				}
+			}
+		}
+
+		Memory::free_static(old_map_data);
+	}
+
+	int32_t _insert_element(const TKey &p_key, const TValue &p_value, uint32_t p_hash) {
+		if (unlikely(elements == nullptr)) {
+			// Allocate on demand to save memory.
+
+			uint32_t real_capacity = capacity + 1;
+			map_data = reinterpret_cast<HashMapData *>(Memory::alloc_static(sizeof(HashMapData) * real_capacity));
+			elements = reinterpret_cast<MapKeyValue *>(Memory::alloc_static(sizeof(MapKeyValue) * (_get_resize_count(capacity) + 1)));
+
+			memset(map_data, EMPTY_HASH, real_capacity * sizeof(HashMapData));
+		}
+
+		if (unlikely(num_elements > _get_resize_count(capacity))) {
+			_resize_and_rehash(capacity * 2);
+		}
+
+		memnew_placement(&elements[num_elements], MapKeyValue(p_key, p_value));
+
+		_insert_with_hash(p_hash, num_elements);
+		num_elements++;
+		return num_elements - 1;
+	}
+
+	void _init_from(const AHashMap &p_other) {
+		capacity = p_other.capacity;
+		uint32_t real_capacity = capacity + 1;
+		num_elements = p_other.num_elements;
+
+		if (p_other.num_elements == 0) {
+			return;
+		}
+
+		map_data = reinterpret_cast<HashMapData *>(Memory::alloc_static(sizeof(HashMapData) * real_capacity));
+		elements = reinterpret_cast<MapKeyValue *>(Memory::alloc_static(sizeof(MapKeyValue) * (_get_resize_count(capacity) + 1)));
+
+		if constexpr (std::is_trivially_copyable_v<TKey> && std::is_trivially_copyable_v<TValue>) {
+			void *destination = elements;
+			const void *source = p_other.elements;
+			memcpy(destination, source, sizeof(MapKeyValue) * num_elements);
+		} else {
+			for (uint32_t i = 0; i < num_elements; i++) {
+				memnew_placement(&elements[i], MapKeyValue(p_other.elements[i]));
+			}
+		}
+
+		memcpy(map_data, p_other.map_data, sizeof(HashMapData) * real_capacity);
+	}
+
+public:
+	/* Standard Godot Container API */
+
+	_FORCE_INLINE_ uint32_t get_capacity() const { return capacity + 1; }
+	_FORCE_INLINE_ uint32_t size() const { return num_elements; }
+
+	_FORCE_INLINE_ bool is_empty() const {
+		return num_elements == 0;
+	}
+
+	void clear() {
+		if (elements == nullptr || num_elements == 0) {
+			return;
+		}
+
+		memset(map_data, EMPTY_HASH, (capacity + 1) * sizeof(HashMapData));
+		if constexpr (!(std::is_trivially_destructible_v<TKey> && std::is_trivially_destructible_v<TValue>)) {
+			for (uint32_t i = 0; i < num_elements; i++) {
+				elements[i].key.~TKey();
+				elements[i].value.~TValue();
+			}
+		}
+
+		num_elements = 0;
+	}
+
+	TValue &get(const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t hash_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, hash_pos);
+		CRASH_COND_MSG(!exists, "AHashMap key not found.");
+		return elements[pos].value;
+	}
+
+	const TValue &get(const TKey &p_key) const {
+		uint32_t pos = 0;
+		uint32_t hash_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, hash_pos);
+		CRASH_COND_MSG(!exists, "AHashMap key not found.");
+		return elements[pos].value;
+	}
+
+	const TValue *getptr(const TKey &p_key) const {
+		uint32_t pos = 0;
+		uint32_t hash_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, hash_pos);
+
+		if (exists) {
+			return &elements[pos].value;
+		}
+		return nullptr;
+	}
+
+	TValue *getptr(const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t hash_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, hash_pos);
+
+		if (exists) {
+			return &elements[pos].value;
+		}
+		return nullptr;
+	}
+
+	bool has(const TKey &p_key) const {
+		uint32_t _pos = 0;
+		uint32_t h_pos = 0;
+		return _lookup_pos(p_key, _pos, h_pos);
+	}
+
+	bool erase(const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t element_pos = 0;
+		bool exists = _lookup_pos(p_key, element_pos, pos);
+
+		if (!exists) {
+			return false;
+		}
+
+		uint32_t next_pos = (pos + 1) & capacity;
+		while (map_data[next_pos].hash != EMPTY_HASH && _get_probe_length(next_pos, map_data[next_pos].hash, capacity) != 0) {
+			SWAP(map_data[next_pos], map_data[pos]);
+
+			pos = next_pos;
+			next_pos = (next_pos + 1) & capacity;
+		}
+
+		map_data[pos].data = EMPTY_HASH;
+		elements[element_pos].key.~TKey();
+		elements[element_pos].value.~TValue();
+		num_elements--;
+
+		if (element_pos < num_elements) {
+			void *destination = &elements[element_pos];
+			const void *source = &elements[num_elements];
+			memcpy(destination, source, sizeof(MapKeyValue));
+			uint32_t h_pos = 0;
+			_lookup_pos(elements[num_elements].key, pos, h_pos);
+			map_data[h_pos].hash_to_key = element_pos;
+		}
+
+		return true;
+	}
+
+	// Replace the key of an entry in-place, without invalidating iterators or changing the entries position during iteration.
+	// p_old_key must exist in the map and p_new_key must not, unless it is equal to p_old_key.
+	bool replace_key(const TKey &p_old_key, const TKey &p_new_key) {
+		if (p_old_key == p_new_key) {
+			return true;
+		}
+		uint32_t pos = 0;
+		uint32_t element_pos = 0;
+		ERR_FAIL_COND_V(_lookup_pos(p_new_key, element_pos, pos), false);
+		ERR_FAIL_COND_V(!_lookup_pos(p_old_key, element_pos, pos), false);
+		MapKeyValue &element = elements[element_pos];
+		const_cast<TKey &>(element.key) = p_new_key;
+
+		uint32_t next_pos = (pos + 1) & capacity;
+		while (map_data[next_pos].hash != EMPTY_HASH && _get_probe_length(next_pos, map_data[next_pos].hash, capacity) != 0) {
+			SWAP(map_data[next_pos], map_data[pos]);
+
+			pos = next_pos;
+			next_pos = (next_pos + 1) & capacity;
+		}
+
+		map_data[pos].data = EMPTY_HASH;
+
+		uint32_t hash = _hash(p_new_key);
+		_insert_with_hash(hash, element_pos);
+
+		return true;
+	}
+
+	// Reserves space for a number of elements, useful to avoid many resizes and rehashes.
+	// If adding a known (possibly large) number of elements at once, must be larger than old capacity.
+	void reserve(uint32_t p_new_capacity) {
+		ERR_FAIL_COND_MSG(p_new_capacity < get_capacity(), "It is impossible to reserve less capacity than is currently available.");
+		if (elements == nullptr) {
+			capacity = MAX(4u, p_new_capacity);
+			capacity = next_power_of_2(capacity) - 1;
+			return; // Unallocated yet.
+		}
+		_resize_and_rehash(p_new_capacity);
+	}
+
+	/** Iterator API **/
+
+	struct ConstIterator {
+		_FORCE_INLINE_ const MapKeyValue &operator*() const {
+			return *pair;
+		}
+		_FORCE_INLINE_ const MapKeyValue *operator->() const {
+			return pair;
+		}
+		_FORCE_INLINE_ ConstIterator &operator++() {
+			pair++;
+			return *this;
+		}
+
+		_FORCE_INLINE_ ConstIterator &operator--() {
+			pair--;
+			if (pair < begin) {
+				pair = end;
+			}
+			return *this;
+		}
+
+		_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return pair == b.pair; }
+		_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return pair != b.pair; }
+
+		_FORCE_INLINE_ explicit operator bool() const {
+			return pair != end;
+		}
+
+		_FORCE_INLINE_ ConstIterator(MapKeyValue *p_key, MapKeyValue *p_begin, MapKeyValue *p_end) {
+			pair = p_key;
+			begin = p_begin;
+			end = p_end;
+		}
+		_FORCE_INLINE_ ConstIterator() {}
+		_FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) {
+			pair = p_it.pair;
+			begin = p_it.begin;
+			end = p_it.end;
+		}
+		_FORCE_INLINE_ void operator=(const ConstIterator &p_it) {
+			pair = p_it.pair;
+			begin = p_it.begin;
+			end = p_it.end;
+		}
+
+	private:
+		MapKeyValue *pair = nullptr;
+		MapKeyValue *begin = nullptr;
+		MapKeyValue *end = nullptr;
+	};
+
+	struct Iterator {
+		_FORCE_INLINE_ MapKeyValue &operator*() const {
+			return *pair;
+		}
+		_FORCE_INLINE_ MapKeyValue *operator->() const {
+			return pair;
+		}
+		_FORCE_INLINE_ Iterator &operator++() {
+			pair++;
+			return *this;
+		}
+		_FORCE_INLINE_ Iterator &operator--() {
+			pair--;
+			if (pair < begin) {
+				pair = end;
+			}
+			return *this;
+		}
+
+		_FORCE_INLINE_ bool operator==(const Iterator &b) const { return pair == b.pair; }
+		_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return pair != b.pair; }
+
+		_FORCE_INLINE_ explicit operator bool() const {
+			return pair != end;
+		}
+
+		_FORCE_INLINE_ Iterator(MapKeyValue *p_key, MapKeyValue *p_begin, MapKeyValue *p_end) {
+			pair = p_key;
+			begin = p_begin;
+			end = p_end;
+		}
+		_FORCE_INLINE_ Iterator() {}
+		_FORCE_INLINE_ Iterator(const Iterator &p_it) {
+			pair = p_it.pair;
+			begin = p_it.begin;
+			end = p_it.end;
+		}
+		_FORCE_INLINE_ void operator=(const Iterator &p_it) {
+			pair = p_it.pair;
+			begin = p_it.begin;
+			end = p_it.end;
+		}
+
+		operator ConstIterator() const {
+			return ConstIterator(pair, begin, end);
+		}
+
+	private:
+		MapKeyValue *pair = nullptr;
+		MapKeyValue *begin = nullptr;
+		MapKeyValue *end = nullptr;
+	};
+
+	_FORCE_INLINE_ Iterator begin() {
+		return Iterator(elements, elements, elements + num_elements);
+	}
+	_FORCE_INLINE_ Iterator end() {
+		return Iterator(elements + num_elements, elements, elements + num_elements);
+	}
+	_FORCE_INLINE_ Iterator last() {
+		if (unlikely(num_elements == 0)) {
+			return Iterator(nullptr, nullptr, nullptr);
+		}
+		return Iterator(elements + num_elements - 1, elements, elements + num_elements);
+	}
+
+	Iterator find(const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, h_pos);
+		if (!exists) {
+			return end();
+		}
+		return Iterator(elements + pos, elements, elements + num_elements);
+	}
+
+	void remove(const Iterator &p_iter) {
+		if (p_iter) {
+			erase(p_iter->key);
+		}
+	}
+
+	_FORCE_INLINE_ ConstIterator begin() const {
+		return ConstIterator(elements, elements, elements + num_elements);
+	}
+	_FORCE_INLINE_ ConstIterator end() const {
+		return ConstIterator(elements + num_elements, elements, elements + num_elements);
+	}
+	_FORCE_INLINE_ ConstIterator last() const {
+		if (unlikely(num_elements == 0)) {
+			return ConstIterator(nullptr, nullptr, nullptr);
+		}
+		return ConstIterator(elements + num_elements - 1, elements, elements + num_elements);
+	}
+
+	ConstIterator find(const TKey &p_key) const {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, h_pos);
+		if (!exists) {
+			return end();
+		}
+		return ConstIterator(elements + pos, elements, elements + num_elements);
+	}
+
+	/* Indexing */
+
+	const TValue &operator[](const TKey &p_key) const {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, h_pos);
+		CRASH_COND(!exists);
+		return elements[pos].value;
+	}
+
+	TValue &operator[](const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		uint32_t hash = _hash(p_key);
+		bool exists = _lookup_pos_with_hash(p_key, pos, h_pos, hash);
+
+		if (exists) {
+			return elements[pos].value;
+		} else {
+			pos = _insert_element(p_key, TValue(), hash);
+			return elements[pos].value;
+		}
+	}
+
+	/* Insert */
+
+	Iterator insert(const TKey &p_key, const TValue &p_value) {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		uint32_t hash = _hash(p_key);
+		bool exists = _lookup_pos_with_hash(p_key, pos, h_pos, hash);
+
+		if (!exists) {
+			pos = _insert_element(p_key, p_value, hash);
+		} else {
+			elements[pos].value = p_value;
+		}
+		return Iterator(elements + pos, elements, elements + num_elements);
+	}
+
+	// Inserts an element without checking if it already exists.
+	void insert_new(const TKey &p_key, const TValue &p_value) {
+		DEV_ASSERT(!has(p_key));
+		uint32_t hash = _hash(p_key);
+		_insert_element(p_key, p_value, hash);
+	}
+
+	/* Array methods. */
+
+	// Unsafe. Changing keys and going outside the bounds of an array can lead to undefined behavior.
+	KeyValue<TKey, TValue> *get_elements_ptr() {
+		return elements;
+	}
+
+	// Returns the element index. If not found, returns -1.
+	int get_index(const TKey &p_key) {
+		uint32_t pos = 0;
+		uint32_t h_pos = 0;
+		bool exists = _lookup_pos(p_key, pos, h_pos);
+		if (!exists) {
+			return -1;
+		}
+		return pos;
+	}
+
+	KeyValue<TKey, TValue> &get_by_index(uint32_t p_index) {
+		CRASH_BAD_UNSIGNED_INDEX(p_index, num_elements);
+		return elements[p_index];
+	}
+
+	bool erase_by_index(uint32_t p_index) {
+		if (p_index >= size()) {
+			return false;
+		}
+		return erase(elements[p_index].key);
+	}
+
+	/* Constructors */
+
+	AHashMap(const AHashMap &p_other) {
+		_init_from(p_other);
+	}
+
+	AHashMap(const HashMap<TKey, TValue> &p_other) {
+		reserve(p_other.size());
+		for (const KeyValue<TKey, TValue> &E : p_other) {
+			uint32_t hash = _hash(E.key);
+			_insert_element(E.key, E.value, hash);
+		}
+	}
+
+	void operator=(const AHashMap &p_other) {
+		if (this == &p_other) {
+			return; // Ignore self assignment.
+		}
+
+		reset();
+
+		_init_from(p_other);
+	}
+
+	void operator=(const HashMap<TKey, TValue> &p_other) {
+		reset();
+		if (p_other.size() > get_capacity()) {
+			reserve(p_other.size());
+		}
+		for (const KeyValue<TKey, TValue> &E : p_other) {
+			uint32_t hash = _hash(E.key);
+			_insert_element(E.key, E.value, hash);
+		}
+	}
+
+	AHashMap(uint32_t p_initial_capacity) {
+		// Capacity can't be 0 and must be 2^n - 1.
+		capacity = MAX(4u, p_initial_capacity);
+		capacity = next_power_of_2(capacity) - 1;
+	}
+	AHashMap() :
+			capacity(INITIAL_CAPACITY - 1) {
+	}
+
+	void reset() {
+		if (elements != nullptr) {
+			if constexpr (!(std::is_trivially_destructible_v<TKey> && std::is_trivially_destructible_v<TValue>)) {
+				for (uint32_t i = 0; i < num_elements; i++) {
+					elements[i].key.~TKey();
+					elements[i].value.~TValue();
+				}
+			}
+			Memory::free_static(elements);
+			Memory::free_static(map_data);
+			elements = nullptr;
+		}
+		capacity = INITIAL_CAPACITY - 1;
+		num_elements = 0;
+	}
+
+	~AHashMap() {
+		reset();
+	}
+};
+
+extern template class AHashMap<int, int>;
+extern template class AHashMap<String, int>;
+extern template class AHashMap<StringName, StringName>;
+extern template class AHashMap<StringName, Variant>;
+extern template class AHashMap<StringName, int>;
+
+#endif // A_HASH_MAP_H

core/templates/hashfuncs.h

@@ -393,6 +393,13 @@ struct HashMapHasherDefault {
 	}
 };
 
+struct HashHasher {
+	static _FORCE_INLINE_ uint32_t hash(const int32_t hash) { return hash; }
+	static _FORCE_INLINE_ uint32_t hash(const uint32_t hash) { return hash; }
+	static _FORCE_INLINE_ uint64_t hash(const int64_t hash) { return hash; }
+	static _FORCE_INLINE_ uint64_t hash(const uint64_t hash) { return hash; }
+};
+
 // TODO: Fold this into HashMapHasherDefault once C++20 concepts are allowed
 template <typename T>
 struct HashableHasher {

scene/3d/skeleton_3d.h

@@ -31,6 +31,7 @@
 #ifndef SKELETON_3D_H
 #define SKELETON_3D_H
 
+#include "core/templates/a_hash_map.h"
 #include "scene/3d/node_3d.h"
 #include "scene/resources/3d/skin.h"
 
@@ -159,7 +160,7 @@ private:
 	bool process_order_dirty = false;
 
 	Vector<int> parentless_bones;
-	HashMap<String, int> name_to_bone_index;
+	AHashMap<String, int> name_to_bone_index;
 
 	mutable StringName concatenated_bone_names = StringName();
 	void _update_bone_names() const;

scene/animation/animation_mixer.cpp

@@ -563,6 +563,7 @@ void AnimationMixer::_clear_caches() {
 		memdelete(K.value);
 	}
 	track_cache.clear();
+	animation_track_num_to_track_cashe.clear();
 	cache_valid = false;
 	capture_cache.clear();
 
@@ -922,6 +923,27 @@ bool AnimationMixer::_update_caches() {
 		idx++;
 	}
 
+	for (KeyValue<Animation::TypeHash, TrackCache *> &K : track_cache) {
+		K.value->blend_idx = track_map[K.value->path];
+	}
+
+	animation_track_num_to_track_cashe.clear();
+	LocalVector<TrackCache *> track_num_to_track_cashe;
+	for (const StringName &E : sname_list) {
+		Ref<Animation> anim = get_animation(E);
+		const Vector<Animation::Track *> tracks = anim->get_tracks();
+		track_num_to_track_cashe.resize(tracks.size());
+		for (int i = 0; i < tracks.size(); i++) {
+			TrackCache **track_ptr = track_cache.getptr(tracks[i]->thash);
+			if (track_ptr == nullptr) {
+				track_num_to_track_cashe[i] = nullptr;
+			} else {
+				track_num_to_track_cashe[i] = *track_ptr;
+			}
+		}
+		animation_track_num_to_track_cashe.insert(anim, track_num_to_track_cashe);
+	}
+
 	track_count = idx;
 
 	cache_valid = true;
@@ -946,7 +968,7 @@ void AnimationMixer::_process_animation(double p_delta, bool p_update_only) {
 	clear_animation_instances();
 }
 
-Variant AnimationMixer::_post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant p_value, ObjectID p_object_id, int p_object_sub_idx) {
+Variant AnimationMixer::_post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant &p_value, ObjectID p_object_id, int p_object_sub_idx) {
 #ifndef _3D_DISABLED
 	switch (p_anim->track_get_type(p_track)) {
 		case Animation::TYPE_POSITION_3D: {
@@ -1033,7 +1055,7 @@ void AnimationMixer::_blend_init() {
 	}
 }
 
-bool AnimationMixer::_blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) {
+bool AnimationMixer::_blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map) {
 	return true;
 }
 
@@ -1084,26 +1106,30 @@ void AnimationMixer::_blend_calc_total_weight() {
 		real_t weight = ai.playback_info.weight;
 		const real_t *track_weights_ptr = ai.playback_info.track_weights.ptr();
 		int track_weights_count = ai.playback_info.track_weights.size();
-		static LocalVector<Animation::TypeHash> processed_hashes;
+		ERR_CONTINUE_EDMSG(!animation_track_num_to_track_cashe.has(a), "No animation in cache.");
+		LocalVector<TrackCache *> &track_num_to_track_cashe = animation_track_num_to_track_cashe[a];
+		thread_local HashSet<Animation::TypeHash, HashHasher> processed_hashes;
 		processed_hashes.clear();
 		const Vector<Animation::Track *> tracks = a->get_tracks();
-		for (const Animation::Track *animation_track : tracks) {
+		Animation::Track *const *tracks_ptr = tracks.ptr();
+		int count = tracks.size();
+		for (int i = 0; i < count; i++) {
+			Animation::Track *animation_track = tracks_ptr[i];
 			if (!animation_track->enabled) {
 				continue;
 			}
 			Animation::TypeHash thash = animation_track->thash;
-			TrackCache **track_ptr = track_cache.getptr(thash);
+			TrackCache *track = track_num_to_track_cashe[i];
-			if (track_ptr == nullptr || processed_hashes.has(thash)) {
+			if (track == nullptr || processed_hashes.has(thash)) {
 				// No path, but avoid error spamming.
 				// Or, there is the case different track type with same path; These can be distinguished by hash. So don't add the weight doubly.
 				continue;
 			}
-			TrackCache *track = *track_ptr;
+			int blend_idx = track->blend_idx;
-			int blend_idx = track_map[track->path];
 			ERR_CONTINUE(blend_idx < 0 || blend_idx >= track_count);
 			real_t blend = blend_idx < track_weights_count ? track_weights_ptr[blend_idx] * weight : weight;
 			track->total_weight += blend;
-			processed_hashes.push_back(thash);
+			processed_hashes.insert(thash);
 		}
 	}
 }
@@ -1130,6 +1156,8 @@ void AnimationMixer::_blend_process(double p_delta, bool p_update_only) {
 #ifndef _3D_DISABLED
 		bool calc_root = !seeked || is_external_seeking;
 #endif // _3D_DISABLED
+		ERR_CONTINUE_EDMSG(!animation_track_num_to_track_cashe.has(a), "No animation in cache.");
+		LocalVector<TrackCache *> &track_num_to_track_cashe = animation_track_num_to_track_cashe[a];
 		const Vector<Animation::Track *> tracks = a->get_tracks();
 		Animation::Track *const *tracks_ptr = tracks.ptr();
 		real_t a_length = a->get_length();
@@ -1139,15 +1167,11 @@ void AnimationMixer::_blend_process(double p_delta, bool p_update_only) {
 			if (!animation_track->enabled) {
 				continue;
 			}
-			Animation::TypeHash thash = animation_track->thash;
+			TrackCache *track = track_num_to_track_cashe[i];
-			TrackCache **track_ptr = track_cache.getptr(thash);
+			if (track == nullptr) {
-			if (track_ptr == nullptr) {
 				continue; // No path, but avoid error spamming.
 			}
-			TrackCache *track = *track_ptr;
+			int blend_idx = track->blend_idx;
-			int *blend_idx_ptr = track_map.getptr(track->path);
-			ERR_CONTINUE(blend_idx_ptr == nullptr);
-			int blend_idx = *blend_idx_ptr;
 			ERR_CONTINUE(blend_idx < 0 || blend_idx >= track_count);
 			real_t blend = blend_idx < track_weights_count ? track_weights_ptr[blend_idx] * weight : weight;
 			if (!deterministic) {
@@ -1581,7 +1605,7 @@ void AnimationMixer::_blend_process(double p_delta, bool p_update_only) {
 					track_info.loop = a->get_loop_mode() != Animation::LOOP_NONE;
 					track_info.backward = backward;
 					track_info.use_blend = a->audio_track_is_use_blend(i);
-					HashMap<int, PlayingAudioStreamInfo> &map = track_info.stream_info;
+					AHashMap<int, PlayingAudioStreamInfo> &map = track_info.stream_info;
 
 					// Main process to fire key is started from here.
 					if (p_update_only) {
@@ -1850,7 +1874,7 @@ void AnimationMixer::_blend_apply() {
 					PlayingAudioTrackInfo &track_info = L.value;
 					float db = Math::linear_to_db(track_info.use_blend ? track_info.volume : 1.0);
 					LocalVector<int> erase_streams;
-					HashMap<int, PlayingAudioStreamInfo> &map = track_info.stream_info;
+					AHashMap<int, PlayingAudioStreamInfo> &map = track_info.stream_info;
 					for (const KeyValue<int, PlayingAudioStreamInfo> &M : map) {
 						PlayingAudioStreamInfo pasi = M.value;
 
@@ -2134,7 +2158,7 @@ void AnimationMixer::restore(const Ref<AnimatedValuesBackup> &p_backup) {
 	ERR_FAIL_COND(p_backup.is_null());
 	track_cache = p_backup->get_data();
 	_blend_apply();
-	track_cache = HashMap<Animation::TypeHash, AnimationMixer::TrackCache *>();
+	track_cache = AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher>();
 	cache_valid = false;
 }
 
@@ -2370,7 +2394,7 @@ AnimationMixer::AnimationMixer() {
 AnimationMixer::~AnimationMixer() {
 }
 
-void AnimatedValuesBackup::set_data(const HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> p_data) {
+void AnimatedValuesBackup::set_data(const AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher> p_data) {
 	clear_data();
 
 	for (const KeyValue<Animation::TypeHash, AnimationMixer::TrackCache *> &E : p_data) {
@@ -2383,7 +2407,7 @@ void AnimatedValuesBackup::set_data(const HashMap<Animation::TypeHash, Animation
 	}
 }
 
-HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> AnimatedValuesBackup::get_data() const {
+AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher> AnimatedValuesBackup::get_data() const {
 	HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> ret;
 	for (const KeyValue<Animation::TypeHash, AnimationMixer::TrackCache *> &E : data) {
 		AnimationMixer::TrackCache *track = get_cache_copy(E.value);

scene/animation/animation_mixer.h

@@ -31,6 +31,7 @@
 #ifndef ANIMATION_MIXER_H
 #define ANIMATION_MIXER_H
 
+#include "core/templates/a_hash_map.h"
 #include "scene/animation/tween.h"
 #include "scene/main/node.h"
 #include "scene/resources/animation.h"
@@ -102,7 +103,7 @@ public:
 protected:
 	/* ---- Data lists ---- */
 	LocalVector<AnimationLibraryData> animation_libraries;
-	HashMap<StringName, AnimationData> animation_set; // HashMap<Library name + Animation name, AnimationData>
+	AHashMap<StringName, AnimationData> animation_set; // HashMap<Library name + Animation name, AnimationData>
 
 	TypedArray<StringName> _get_animation_library_list() const;
 	Vector<String> _get_animation_list() const {
@@ -148,6 +149,7 @@ protected:
 		uint64_t setup_pass = 0;
 		Animation::TrackType type = Animation::TrackType::TYPE_ANIMATION;
 		NodePath path;
+		int blend_idx = -1;
 		ObjectID object_id;
 		real_t total_weight = 0.0;
 
@@ -269,7 +271,7 @@ protected:
 
 	// Audio track information for mixng and ending.
 	struct PlayingAudioTrackInfo {
-		HashMap<int, PlayingAudioStreamInfo> stream_info;
+		AHashMap<int, PlayingAudioStreamInfo> stream_info;
 		double length = 0.0;
 		double time = 0.0;
 		real_t volume = 0.0;
@@ -308,7 +310,8 @@ protected:
 	};
 
 	RootMotionCache root_motion_cache;
-	HashMap<Animation::TypeHash, TrackCache *> track_cache;
+	AHashMap<Animation::TypeHash, TrackCache *, HashHasher> track_cache;
+	AHashMap<Ref<Animation>, LocalVector<TrackCache *>> animation_track_num_to_track_cashe;
 	HashSet<TrackCache *> playing_caches;
 	Vector<Node *> playing_audio_stream_players;
 
@@ -324,7 +327,7 @@ protected:
 
 	/* ---- Blending processor ---- */
 	LocalVector<AnimationInstance> animation_instances;
-	HashMap<NodePath, int> track_map;
+	AHashMap<NodePath, int> track_map;
 	int track_count = 0;
 	bool deterministic = false;
 
@@ -359,12 +362,12 @@ protected:
 	virtual void _process_animation(double p_delta, bool p_update_only = false);
 
 	// For post process with retrieved key value during blending.
-	virtual Variant _post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant p_value, ObjectID p_object_id, int p_object_sub_idx = -1);
+	virtual Variant _post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant &p_value, ObjectID p_object_id, int p_object_sub_idx = -1);
 	Variant post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant p_value, ObjectID p_object_id, int p_object_sub_idx = -1);
 	GDVIRTUAL5RC(Variant, _post_process_key_value, Ref<Animation>, int, Variant, ObjectID, int);
 
 	void _blend_init();
-	virtual bool _blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map);
+	virtual bool _blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map);
 	virtual void _blend_capture(double p_delta);
 	void _blend_calc_total_weight(); // For undeterministic blending.
 	void _blend_process(double p_delta, bool p_update_only = false);
@@ -485,11 +488,11 @@ public:
 class AnimatedValuesBackup : public RefCounted {
 	GDCLASS(AnimatedValuesBackup, RefCounted);
 
-	HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> data;
+	AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher> data;
 
 public:
-	void set_data(const HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> p_data);
+	void set_data(const AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher> p_data);
-	HashMap<Animation::TypeHash, AnimationMixer::TrackCache *> get_data() const;
+	AHashMap<Animation::TypeHash, AnimationMixer::TrackCache *, HashHasher> get_data() const;
 	void clear_data();
 
 	AnimationMixer::TrackCache *get_cache_copy(AnimationMixer::TrackCache *p_cache) const;

scene/animation/animation_node_state_machine.cpp

@@ -1619,7 +1619,7 @@ AnimationNode::NodeTimeInfo AnimationNodeStateMachine::_process(const AnimationM
 		playback_new = playback_new->duplicate(); // Don't process original when testing.
 	}
 
-	return playback_new->process(node_state.base_path, this, p_playback_info, p_test_only);
+	return playback_new->process(node_state.get_base_path(), this, p_playback_info, p_test_only);
 }
 
 String AnimationNodeStateMachine::get_caption() const {

scene/animation/animation_player.cpp

@@ -133,7 +133,7 @@ void AnimationPlayer::_get_property_list(List<PropertyInfo> *p_list) const {
 	List<PropertyInfo> anim_names;
 
 	for (const KeyValue<StringName, AnimationData> &E : animation_set) {
-		HashMap<StringName, StringName>::ConstIterator F = animation_next_set.find(E.key);
+		AHashMap<StringName, StringName>::ConstIterator F = animation_next_set.find(E.key);
 		if (F && F->value != StringName()) {
 			anim_names.push_back(PropertyInfo(Variant::STRING, "next/" + String(E.key), PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
 		}
@@ -299,7 +299,7 @@ void AnimationPlayer::_blend_playback_data(double p_delta, bool p_started) {
 	}
 }
 
-bool AnimationPlayer::_blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) {
+bool AnimationPlayer::_blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map) {
 	if (!playback.current.from) {
 		_set_process(false);
 		return false;

scene/animation/animation_player.h

@@ -52,7 +52,7 @@ public:
 #endif // DISABLE_DEPRECATED
 
 private:
-	HashMap<StringName, StringName> animation_next_set; // For auto advance.
+	AHashMap<StringName, StringName> animation_next_set; // For auto advance.
 
 	float speed_scale = 1.0;
 	double default_blend_time = 0.0;
@@ -138,7 +138,7 @@ protected:
 	static void _bind_methods();
 
 	// Make animation instances.
-	virtual bool _blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) override;
+	virtual bool _blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map) override;
 	virtual void _blend_capture(double p_delta) override;
 	virtual void _blend_post_process() override;
 

scene/animation/animation_tree.cpp

@@ -75,20 +75,34 @@ void AnimationNode::set_parameter(const StringName &p_name, const Variant &p_val
 	if (process_state->is_testing) {
 		return;
 	}
+
+	const AHashMap<StringName, int>::Iterator it = property_cache.find(p_name);
+	if (it) {
+		process_state->tree->property_map.get_by_index(it->value).value.first = p_value;
+		return;
+	}
+
 	ERR_FAIL_COND(!process_state->tree->property_parent_map.has(node_state.base_path));
 	ERR_FAIL_COND(!process_state->tree->property_parent_map[node_state.base_path].has(p_name));
 	StringName path = process_state->tree->property_parent_map[node_state.base_path][p_name];
-
+	int idx = process_state->tree->property_map.get_index(path);
-	process_state->tree->property_map[path].first = p_value;
+	property_cache.insert_new(p_name, idx);
+	process_state->tree->property_map.get_by_index(idx).value.first = p_value;
 }
 
 Variant AnimationNode::get_parameter(const StringName &p_name) const {
 	ERR_FAIL_NULL_V(process_state, Variant());
+	const AHashMap<StringName, int>::ConstIterator it = property_cache.find(p_name);
+	if (it) {
+		return process_state->tree->property_map.get_by_index(it->value).value.first;
+	}
 	ERR_FAIL_COND_V(!process_state->tree->property_parent_map.has(node_state.base_path), Variant());
 	ERR_FAIL_COND_V(!process_state->tree->property_parent_map[node_state.base_path].has(p_name), Variant());
 
 	StringName path = process_state->tree->property_parent_map[node_state.base_path][p_name];
-	return process_state->tree->property_map[path].first;
+	int idx = process_state->tree->property_map.get_index(path);
+	property_cache.insert_new(p_name, idx);
+	return process_state->tree->property_map.get_by_index(idx).value.first;
 }
 
 void AnimationNode::set_node_time_info(const NodeTimeInfo &p_node_time_info) {
@@ -203,7 +217,7 @@ AnimationNode::NodeTimeInfo AnimationNode::_blend_node(Ref<AnimationNode> p_node
 		}
 
 		for (const KeyValue<NodePath, bool> &E : filter) {
-			const HashMap<NodePath, int> &map = *process_state->track_map;
+			const AHashMap<NodePath, int> &map = *process_state->track_map;
 			if (!map.has(E.key)) {
 				continue;
 			}
@@ -292,7 +306,7 @@ AnimationNode::NodeTimeInfo AnimationNode::_blend_node(Ref<AnimationNode> p_node
 
 	// This process, which depends on p_sync is needed to process sync correctly in the case of
 	// that a synced AnimationNodeSync exists under the un-synced AnimationNodeSync.
-	p_node->node_state.base_path = new_path;
+	p_node->set_node_state_base_path(new_path);
 	p_node->node_state.parent = new_parent;
 	if (!p_playback_info.seeked && !p_sync && !any_valid) {
 		p_playback_info.delta = 0.0;
@@ -603,7 +617,7 @@ Ref<AnimationRootNode> AnimationTree::get_root_animation_node() const {
 	return root_animation_node;
 }
 
-bool AnimationTree::_blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) {
+bool AnimationTree::_blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map) {
 	_update_properties(); // If properties need updating, update them.
 
 	if (!root_animation_node.is_valid()) {
@@ -627,7 +641,7 @@ bool AnimationTree::_blend_pre_process(double p_delta, int p_track_count, const
 		for (int i = 0; i < p_track_count; i++) {
 			src_blendsw[i] = 1.0; // By default all go to 1 for the root input.
 		}
-		root_animation_node->node_state.base_path = SNAME(Animation::PARAMETERS_BASE_PATH.ascii().get_data());
+		root_animation_node->set_node_state_base_path(SNAME(Animation::PARAMETERS_BASE_PATH.ascii().get_data()));
 		root_animation_node->node_state.parent = nullptr;
 	}
 
@@ -732,7 +746,7 @@ void AnimationTree::_animation_node_removed(const ObjectID &p_oid, const StringN
 void AnimationTree::_update_properties_for_node(const String &p_base_path, Ref<AnimationNode> p_node) {
 	ERR_FAIL_COND(p_node.is_null());
 	if (!property_parent_map.has(p_base_path)) {
-		property_parent_map[p_base_path] = HashMap<StringName, StringName>();
+		property_parent_map[p_base_path] = AHashMap<StringName, StringName>();
 	}
 	if (!property_reference_map.has(p_node->get_instance_id())) {
 		property_reference_map[p_node->get_instance_id()] = p_base_path;
@@ -767,7 +781,7 @@ void AnimationTree::_update_properties_for_node(const String &p_base_path, Ref<A
 		pinfo.name = p_base_path + key;
 		properties.push_back(pinfo);
 	}
-
+	p_node->make_cache_dirty();
 	List<AnimationNode::ChildNode> children;
 	p_node->get_child_nodes(&children);
 

scene/animation/animation_tree.h

@@ -60,7 +60,7 @@ public:
 
 	bool closable = false;
 	Vector<Input> inputs;
-	HashMap<NodePath, bool> filter;
+	AHashMap<NodePath, bool> filter;
 	bool filter_enabled = false;
 
 	// To propagate information from upstream for use in estimation of playback progress.
@@ -97,22 +97,57 @@ public:
 
 	// Temporary state for blending process which needs to be stored in each AnimationNodes.
 	struct NodeState {
+		friend AnimationNode;
+
+	private:
 		StringName base_path;
+
+	public:
 		AnimationNode *parent = nullptr;
 		Vector<StringName> connections;
 		Vector<real_t> track_weights;
+
+		const StringName get_base_path() const {
+			return base_path;
+		}
+
 	} node_state;
 
 	// Temporary state for blending process which needs to be started in the AnimationTree, pass through the AnimationNodes, and then return to the AnimationTree.
 	struct ProcessState {
 		AnimationTree *tree = nullptr;
-		const HashMap<NodePath, int> *track_map; // TODO: Is there a better way to manage filter/tracks?
+		const AHashMap<NodePath, int> *track_map; // TODO: Is there a better way to manage filter/tracks?
 		bool is_testing = false;
 		bool valid = false;
 		String invalid_reasons;
 		uint64_t last_pass = 0;
 	} *process_state = nullptr;
 
+private:
+	mutable AHashMap<StringName, int> property_cache;
+
+public:
+	void set_node_state_base_path(const StringName p_base_path) {
+		if (p_base_path != node_state.base_path) {
+			node_state.base_path = p_base_path;
+			make_cache_dirty();
+		}
+	}
+
+	void set_node_state_base_path(const String p_base_path) {
+		if (p_base_path != node_state.base_path) {
+			node_state.base_path = p_base_path;
+			make_cache_dirty();
+		}
+	}
+
+	const StringName get_node_state_base_path() const {
+		return node_state.get_base_path();
+	}
+
+	void make_cache_dirty() {
+		property_cache.clear();
+	}
 	Array _get_filters() const;
 	void _set_filters(const Array &p_filters);
 	friend class AnimationNodeBlendTree;
@@ -250,9 +285,9 @@ private:
 	friend class AnimationNode;
 
 	List<PropertyInfo> properties;
-	HashMap<StringName, HashMap<StringName, StringName>> property_parent_map;
+	AHashMap<StringName, AHashMap<StringName, StringName>> property_parent_map;
-	HashMap<ObjectID, StringName> property_reference_map;
+	AHashMap<ObjectID, StringName> property_reference_map;
-	HashMap<StringName, Pair<Variant, bool>> property_map; // Property value and read-only flag.
+	AHashMap<StringName, Pair<Variant, bool>> property_map; // Property value and read-only flag.
 
 	bool properties_dirty = true;
 
@@ -286,7 +321,7 @@ private:
 	virtual void _set_active(bool p_active) override;
 
 	// Make animation instances.
-	virtual bool _blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) override;
+	virtual bool _blend_pre_process(double p_delta, int p_track_count, const AHashMap<NodePath, int> &p_track_map) override;
 
 #ifndef DISABLE_DEPRECATED
 	void _set_process_callback_bind_compat_80813(AnimationProcessCallback p_mode);

tests/core/templates/test_a_hash_map.h

@@ -0,0 +1,295 @@
+/**************************************************************************/
+/*  test_a_hash_map.h                                                     */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef TEST_A_HASH_MAP_H
+#define TEST_A_HASH_MAP_H
+
+#include "core/templates/a_hash_map.h"
+
+#include "tests/test_macros.h"
+
+namespace TestAHashMap {
+
+TEST_CASE("[AHashMap] Insert element") {
+	AHashMap<int, int> map;
+	AHashMap<int, int>::Iterator e = map.insert(42, 84);
+
+	CHECK(e);
+	CHECK(e->key == 42);
+	CHECK(e->value == 84);
+	CHECK(map[42] == 84);
+	CHECK(map.has(42));
+	CHECK(map.find(42));
+}
+
+TEST_CASE("[AHashMap] Overwrite element") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(42, 1234);
+
+	CHECK(map[42] == 1234);
+}
+
+TEST_CASE("[AHashMap] Erase via element") {
+	AHashMap<int, int> map;
+	AHashMap<int, int>::Iterator e = map.insert(42, 84);
+	map.remove(e);
+	CHECK(!map.has(42));
+	CHECK(!map.find(42));
+}
+
+TEST_CASE("[AHashMap] Erase via key") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.erase(42);
+	CHECK(!map.has(42));
+	CHECK(!map.find(42));
+}
+
+TEST_CASE("[AHashMap] Size") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 84);
+	map.insert(123, 84);
+	map.insert(0, 84);
+	map.insert(123485, 84);
+
+	CHECK(map.size() == 4);
+}
+
+TEST_CASE("[AHashMap] Iteration") {
+	AHashMap<int, int> map;
+
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+	map.insert(123485, 1238888);
+	map.insert(123, 111111);
+
+	Vector<Pair<int, int>> expected;
+	expected.push_back(Pair<int, int>(42, 84));
+	expected.push_back(Pair<int, int>(123, 111111));
+	expected.push_back(Pair<int, int>(0, 12934));
+	expected.push_back(Pair<int, int>(123485, 1238888));
+
+	int idx = 0;
+	for (const KeyValue<int, int> &E : map) {
+		CHECK(expected[idx] == Pair<int, int>(E.key, E.value));
+		idx++;
+	}
+
+	idx--;
+	for (AHashMap<int, int>::Iterator it = map.last(); it; --it) {
+		CHECK(expected[idx] == Pair<int, int>(it->key, it->value));
+		idx--;
+	}
+}
+
+TEST_CASE("[AHashMap] Const iteration") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+	map.insert(123485, 1238888);
+	map.insert(123, 111111);
+
+	const AHashMap<int, int> const_map = map;
+
+	Vector<Pair<int, int>> expected;
+	expected.push_back(Pair<int, int>(42, 84));
+	expected.push_back(Pair<int, int>(123, 111111));
+	expected.push_back(Pair<int, int>(0, 12934));
+	expected.push_back(Pair<int, int>(123485, 1238888));
+	expected.push_back(Pair<int, int>(123, 111111));
+
+	int idx = 0;
+	for (const KeyValue<int, int> &E : const_map) {
+		CHECK(expected[idx] == Pair<int, int>(E.key, E.value));
+		idx++;
+	}
+
+	idx--;
+	for (AHashMap<int, int>::ConstIterator it = const_map.last(); it; --it) {
+		CHECK(expected[idx] == Pair<int, int>(it->key, it->value));
+		idx--;
+	}
+}
+
+TEST_CASE("[AHashMap] Replace key") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(0, 12934);
+	CHECK(map.replace_key(0, 1));
+	CHECK(map.has(1));
+	CHECK(map[1] == 12934);
+}
+
+TEST_CASE("[AHashMap] Clear") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+
+	map.clear();
+	CHECK(!map.has(42));
+	CHECK(map.size() == 0);
+	CHECK(map.is_empty());
+}
+
+TEST_CASE("[AHashMap] Get") {
+	AHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+
+	CHECK(map.get(123) == 12385);
+	map.get(123) = 10;
+	CHECK(map.get(123) == 10);
+
+	CHECK(*map.getptr(0) == 12934);
+	*map.getptr(0) = 1;
+	CHECK(*map.getptr(0) == 1);
+
+	CHECK(map.get(42) == 84);
+	CHECK(map.getptr(-10) == nullptr);
+}
+
+TEST_CASE("[AHashMap] Insert, iterate and remove many elements") {
+	const int elem_max = 1234;
+	AHashMap<int, int> map;
+	for (int i = 0; i < elem_max; i++) {
+		map.insert(i, i);
+	}
+
+	//insert order should have been kept
+	int idx = 0;
+	for (auto &K : map) {
+		CHECK(idx == K.key);
+		CHECK(idx == K.value);
+		CHECK(map.has(idx));
+		idx++;
+	}
+
+	Vector<int> elems_still_valid;
+
+	for (int i = 0; i < elem_max; i++) {
+		if ((i % 5) == 0) {
+			map.erase(i);
+		} else {
+			elems_still_valid.push_back(i);
+		}
+	}
+
+	CHECK(elems_still_valid.size() == map.size());
+
+	for (int i = 0; i < elems_still_valid.size(); i++) {
+		CHECK(map.has(elems_still_valid[i]));
+	}
+}
+
+TEST_CASE("[AHashMap] Insert, iterate and remove many strings") {
+	const int elem_max = 432;
+	AHashMap<String, String> map;
+	for (int i = 0; i < elem_max; i++) {
+		map.insert(itos(i), itos(i));
+	}
+
+	//insert order should have been kept
+	int idx = 0;
+	for (auto &K : map) {
+		CHECK(itos(idx) == K.key);
+		CHECK(itos(idx) == K.value);
+		CHECK(map.has(itos(idx)));
+		idx++;
+	}
+
+	Vector<String> elems_still_valid;
+
+	for (int i = 0; i < elem_max; i++) {
+		if ((i % 5) == 0) {
+			map.erase(itos(i));
+		} else {
+			elems_still_valid.push_back(itos(i));
+		}
+	}
+
+	CHECK(elems_still_valid.size() == map.size());
+
+	for (int i = 0; i < elems_still_valid.size(); i++) {
+		CHECK(map.has(elems_still_valid[i]));
+	}
+
+	elems_still_valid.clear();
+}
+
+TEST_CASE("[AHashMap] Copy constructor") {
+	AHashMap<int, int> map0;
+	const uint32_t count = 5;
+	for (uint32_t i = 0; i < count; i++) {
+		map0.insert(i, i);
+	}
+	AHashMap<int, int> map1(map0);
+	CHECK(map0.size() == map1.size());
+	CHECK(map0.get_capacity() == map1.get_capacity());
+	CHECK(*map0.getptr(0) == *map1.getptr(0));
+}
+
+TEST_CASE("[AHashMap] Operator =") {
+	AHashMap<int, int> map0;
+	AHashMap<int, int> map1;
+	const uint32_t count = 5;
+	map1.insert(1234, 1234);
+	for (uint32_t i = 0; i < count; i++) {
+		map0.insert(i, i);
+	}
+	map1 = map0;
+	CHECK(map0.size() == map1.size());
+	CHECK(map0.get_capacity() == map1.get_capacity());
+	CHECK(*map0.getptr(0) == *map1.getptr(0));
+}
+
+TEST_CASE("[AHashMap] Array methods") {
+	AHashMap<int, int> map;
+	for (int i = 0; i < 100; i++) {
+		map.insert(100 - i, i);
+	}
+	for (int i = 0; i < 100; i++) {
+		CHECK(map.get_by_index(i).value == i);
+	}
+	int index = map.get_index(1);
+	CHECK(map.get_by_index(index).value == 99);
+	CHECK(map.erase_by_index(index));
+	CHECK(!map.erase_by_index(index));
+	CHECK(map.get_index(1) == -1);
+}
+
+} // namespace TestAHashMap
+
+#endif // TEST_A_HASH_MAP_H

tests/test_main.cpp

@@ -86,6 +86,7 @@
 #include "tests/core/string/test_string.h"
 #include "tests/core/string/test_translation.h"
 #include "tests/core/string/test_translation_server.h"
+#include "tests/core/templates/test_a_hash_map.h"
 #include "tests/core/templates/test_command_queue.h"
 #include "tests/core/templates/test_hash_map.h"
 #include "tests/core/templates/test_hash_set.h"