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+/*************************************************************************/
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+/* hash_set.h */
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+/*************************************************************************/
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+/* This file is part of: */
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+/* GODOT ENGINE */
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+/* https://godotengine.org */
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+/*************************************************************************/
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+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
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+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
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+/* */
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+/* Permission is hereby granted, free of charge, to any person obtaining */
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+/* a copy of this software and associated documentation files (the */
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+/* "Software"), to deal in the Software without restriction, including */
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+/* without limitation the rights to use, copy, modify, merge, publish, */
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+/* distribute, sublicense, and/or sell copies of the Software, and to */
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+/* permit persons to whom the Software is furnished to do so, subject to */
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+/* the following conditions: */
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+/* */
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+/* The above copyright notice and this permission notice shall be */
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+/* included in all copies or substantial portions of the Software. */
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+/* */
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+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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+/*************************************************************************/
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+
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+#ifndef HASH_SET_H
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+#define HASH_SET_H
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+
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+#include "core/math/math_funcs.h"
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+#include "core/os/memory.h"
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+#include "core/templates/hash_map.h"
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+#include "core/templates/hashfuncs.h"
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+#include "core/templates/paged_allocator.h"
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+
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+/**
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+ * Implementation of Set using a bidi indexed hash map.
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+ * Use RBSet instead of this only if the following conditions are met:
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+ *
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+ * - You need to keep an iterator or const pointer to Key and you intend to add/remove elements in the meantime.
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+ * - Iteration order does matter (via operator<)
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+ *
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+ */
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+
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+template <class TKey,
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+ class Hasher = HashMapHasherDefault,
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+ class Comparator = HashMapComparatorDefault<TKey>>
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+class HashSet {
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+public:
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+ static constexpr uint32_t MIN_CAPACITY_INDEX = 2; // Use a prime.
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+ static constexpr float MAX_OCCUPANCY = 0.75;
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+ static constexpr uint32_t EMPTY_HASH = 0;
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+
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+private:
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+ TKey *keys = nullptr;
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+ uint32_t *hash_to_key = nullptr;
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+ uint32_t *key_to_hash = nullptr;
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+ uint32_t *hashes = nullptr;
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+
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+ uint32_t capacity_index = 0;
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+ uint32_t num_elements = 0;
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+
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+ _FORCE_INLINE_ uint32_t _hash(const TKey &p_key) const {
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+ uint32_t hash = Hasher::hash(p_key);
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+
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+ if (unlikely(hash == EMPTY_HASH)) {
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+ hash = EMPTY_HASH + 1;
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+ }
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+
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+ return hash;
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+ }
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+
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+ _FORCE_INLINE_ uint32_t _get_probe_length(uint32_t p_pos, uint32_t p_hash, uint32_t p_capacity) const {
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+ uint32_t original_pos = p_hash % p_capacity;
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+ return (p_pos - original_pos + p_capacity) % p_capacity;
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+ }
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+
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+ bool _lookup_pos(const TKey &p_key, uint32_t &r_pos) const {
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+ if (keys == nullptr) {
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+ return false; // Failed lookups, no elements
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+ }
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+
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+ uint32_t hash = _hash(p_key);
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+ uint32_t pos = hash % capacity;
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+ uint32_t distance = 0;
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+
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+ while (true) {
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+ if (hashes[pos] == EMPTY_HASH) {
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+ return false;
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+ }
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+
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+ if (distance > _get_probe_length(pos, hashes[pos], capacity)) {
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+ return false;
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+ }
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+
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+ if (hashes[pos] == hash && Comparator::compare(keys[hash_to_key[pos]], p_key)) {
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+ r_pos = hash_to_key[pos];
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+ return true;
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+ }
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+
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+ pos = (pos + 1) % capacity;
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+ distance++;
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+ }
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+ }
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+
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+ uint32_t _insert_with_hash(uint32_t p_hash, uint32_t p_index) {
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+ uint32_t hash = p_hash;
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+ uint32_t index = p_index;
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+ uint32_t distance = 0;
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+ uint32_t pos = hash % capacity;
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+
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+ while (true) {
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+ if (hashes[pos] == EMPTY_HASH) {
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+ hashes[pos] = hash;
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+ key_to_hash[index] = pos;
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+ hash_to_key[pos] = index;
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+ return pos;
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+ }
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+
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+ // Not an empty slot, let's check the probing length of the existing one.
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+ uint32_t existing_probe_len = _get_probe_length(pos, hashes[pos], capacity);
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+ if (existing_probe_len < distance) {
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+ key_to_hash[index] = pos;
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+ SWAP(hash, hashes[pos]);
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+ SWAP(index, hash_to_key[pos]);
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+ distance = existing_probe_len;
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+ }
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+
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+ pos = (pos + 1) % capacity;
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+ distance++;
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+ }
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+ }
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+
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+ void _resize_and_rehash(uint32_t p_new_capacity_index) {
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+ // Capacity can't be 0.
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+ capacity_index = MAX((uint32_t)MIN_CAPACITY_INDEX, p_new_capacity_index);
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+
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+
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+ uint32_t *old_hashes = hashes;
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+ uint32_t *old_key_to_hash = key_to_hash;
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+
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+ hashes = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ keys = reinterpret_cast<TKey *>(Memory::realloc_static(keys, sizeof(TKey) * capacity));
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+ key_to_hash = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ hash_to_key = reinterpret_cast<uint32_t *>(Memory::realloc_static(hash_to_key, sizeof(uint32_t) * capacity));
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+
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+ for (uint32_t i = 0; i < capacity; i++) {
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+ hashes[i] = EMPTY_HASH;
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+ }
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+
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+ for (uint32_t i = 0; i < num_elements; i++) {
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+ uint32_t h = old_hashes[old_key_to_hash[i]];
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+ _insert_with_hash(h, i);
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+ }
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+
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+ Memory::free_static(old_hashes);
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+ Memory::free_static(old_key_to_hash);
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+ }
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+
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+ _FORCE_INLINE_ int32_t _insert(const TKey &p_key) {
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+ if (unlikely(keys == nullptr)) {
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+ // Allocate on demand to save memory.
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+
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+ hashes = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ keys = reinterpret_cast<TKey *>(Memory::alloc_static(sizeof(TKey) * capacity));
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+ key_to_hash = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ hash_to_key = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+
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+ for (uint32_t i = 0; i < capacity; i++) {
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+ hashes[i] = EMPTY_HASH;
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+ }
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+ }
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+
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+ uint32_t pos = 0;
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+ bool exists = _lookup_pos(p_key, pos);
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+
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+ if (exists) {
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+ return pos;
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+ } else {
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+ if (num_elements + 1 > MAX_OCCUPANCY * capacity) {
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+ ERR_FAIL_COND_V_MSG(capacity_index + 1 == HASH_TABLE_SIZE_MAX, -1, "Hash table maximum capacity reached, aborting insertion.");
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+ _resize_and_rehash(capacity_index + 1);
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+ }
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+
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+ uint32_t hash = _hash(p_key);
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+ memnew_placement(&keys[num_elements], TKey(p_key));
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+ _insert_with_hash(hash, num_elements);
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+ num_elements++;
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+ return num_elements - 1;
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+ }
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+ }
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+
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+ void _init_from(const HashSet &p_other) {
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+ capacity_index = p_other.capacity_index;
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+ num_elements = p_other.num_elements;
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+
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+ if (p_other.num_elements == 0) {
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+ return;
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+ }
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+
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+
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+ hashes = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ keys = reinterpret_cast<TKey *>(Memory::alloc_static(sizeof(TKey) * capacity));
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+ key_to_hash = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+ hash_to_key = reinterpret_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
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+
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+ for (uint32_t i = 0; i < num_elements; i++) {
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+ memnew_placement(&keys[i], TKey(p_other.keys[i]));
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+ key_to_hash[i] = p_other.key_to_hash[i];
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+ }
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+
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+ for (uint32_t i = 0; i < capacity; i++) {
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+ hashes[i] = p_other.hashes[i];
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+ hash_to_key[i] = p_other.hash_to_key[i];
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+ }
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+ }
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+
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+public:
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+ _FORCE_INLINE_ uint32_t get_capacity() const { return hash_table_size_primes[capacity_index]; }
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+ _FORCE_INLINE_ uint32_t size() const { return num_elements; }
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+
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+ /* Standard Godot Container API */
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+
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+ bool is_empty() const {
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+ return num_elements == 0;
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+ }
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+
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+ void clear() {
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+ if (keys == nullptr) {
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+ return;
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+ }
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+ for (uint32_t i = 0; i < capacity; i++) {
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+ hashes[i] = EMPTY_HASH;
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+ }
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+ for (uint32_t i = 0; i < num_elements; i++) {
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+ keys[i].~TKey();
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+ }
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+
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+ num_elements = 0;
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+ }
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+
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+ _FORCE_INLINE_ bool has(const TKey &p_key) const {
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+ uint32_t _pos = 0;
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+ return _lookup_pos(p_key, _pos);
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+ }
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+
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+ bool erase(const TKey &p_key) {
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+ uint32_t pos = 0;
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+ bool exists = _lookup_pos(p_key, pos);
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+
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+ if (!exists) {
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+ return false;
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+ }
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+
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+ uint32_t key_pos = pos;
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+ pos = key_to_hash[pos]; //make hash pos
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+
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+ uint32_t capacity = hash_table_size_primes[capacity_index];
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+ uint32_t next_pos = (pos + 1) % capacity;
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+ while (hashes[next_pos] != EMPTY_HASH && _get_probe_length(next_pos, hashes[next_pos], capacity) != 0) {
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+ uint32_t kpos = hash_to_key[pos];
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+ uint32_t kpos_next = hash_to_key[next_pos];
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+ SWAP(key_to_hash[kpos], key_to_hash[kpos_next]);
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+ SWAP(hashes[next_pos], hashes[pos]);
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+ SWAP(hash_to_key[next_pos], hash_to_key[pos]);
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+
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+ pos = next_pos;
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+ next_pos = (pos + 1) % capacity;
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+ }
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+
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+ hashes[pos] = EMPTY_HASH;
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+ keys[key_pos].~TKey();
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+ num_elements--;
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+ if (key_pos < num_elements) {
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+ // Not the last key, move the last one here to keep keys lineal
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+ memnew_placement(&keys[key_pos], TKey(keys[num_elements]));
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+ keys[num_elements].~TKey();
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+ key_to_hash[key_pos] = key_to_hash[num_elements];
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+ hash_to_key[key_to_hash[num_elements]] = key_pos;
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+ }
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+
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+ return true;
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+ }
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+
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+ // Reserves space for a number of elements, useful to avoid many resizes and rehashes.
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+ // If adding a known (possibly large) number of elements at once, must be larger than old capacity.
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+ void reserve(uint32_t p_new_capacity) {
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+ uint32_t new_index = capacity_index;
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+
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+ while (hash_table_size_primes[new_index] < p_new_capacity) {
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+ ERR_FAIL_COND_MSG(new_index + 1 == (uint32_t)HASH_TABLE_SIZE_MAX, nullptr);
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+ new_index++;
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+ }
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+
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+ if (new_index == capacity_index) {
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+ return;
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+ }
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+
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+ if (keys == nullptr) {
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+ capacity_index = new_index;
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+ return; // Unallocated yet.
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+ }
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+ _resize_and_rehash(new_index);
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+ }
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+
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+ /** Iterator API **/
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+
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+ struct Iterator {
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+ _FORCE_INLINE_ const TKey &operator*() const {
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+ return keys[index];
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+ }
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+ _FORCE_INLINE_ const TKey *operator->() const {
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+ return &keys[index];
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+ }
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+ _FORCE_INLINE_ Iterator &operator++() {
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+ index++;
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+ if (index >= (int32_t)num_keys) {
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+ index = -1;
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+ keys = nullptr;
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+ num_keys = 0;
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+ }
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+ return *this;
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+ }
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+ _FORCE_INLINE_ Iterator &operator--() {
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+ index--;
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+ if (index < 0) {
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+ index = -1;
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+ keys = nullptr;
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+ num_keys = 0;
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+ }
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+ return *this;
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+ }
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+
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+ _FORCE_INLINE_ bool operator==(const Iterator &b) const { return keys == b.keys && index == b.index; }
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+ _FORCE_INLINE_ bool operator!=(const Iterator &b) const { return keys != b.keys || index != b.index; }
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+
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+ _FORCE_INLINE_ explicit operator bool() const {
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+ return keys != nullptr;
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+ }
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+
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+ _FORCE_INLINE_ Iterator(const TKey *p_keys, uint32_t p_num_keys, int32_t p_index = -1) {
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+ keys = p_keys;
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+ num_keys = p_num_keys;
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+ index = p_index;
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+ }
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+ _FORCE_INLINE_ Iterator() {}
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+ _FORCE_INLINE_ Iterator(const Iterator &p_it) {
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+ keys = p_it.keys;
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+ num_keys = p_it.num_keys;
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+ index = p_it.index;
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+ }
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+ _FORCE_INLINE_ void operator=(const Iterator &p_it) {
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+ keys = p_it.keys;
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+ num_keys = p_it.num_keys;
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+ index = p_it.index;
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+ }
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+
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+ private:
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+ const TKey *keys = nullptr;
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+ uint32_t num_keys = 0;
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+ int32_t index = -1;
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+ };
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+
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+ _FORCE_INLINE_ Iterator begin() const {
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+ return num_elements ? Iterator(keys, num_elements, 0) : Iterator();
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+ }
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+ _FORCE_INLINE_ Iterator end() const {
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+ return Iterator();
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+ }
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+ _FORCE_INLINE_ Iterator last() const {
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+ if (num_elements == 0) {
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+ return Iterator();
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+ }
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+ return Iterator(keys, num_elements, num_elements - 1);
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+ }
|
|
|
+
|
|
|
+ _FORCE_INLINE_ Iterator find(const TKey &p_key) const {
|
|
|
+ uint32_t pos = 0;
|
|
|
+ bool exists = _lookup_pos(p_key, pos);
|
|
|
+ if (!exists) {
|
|
|
+ return end();
|
|
|
+ }
|
|
|
+ return Iterator(keys, num_elements, pos);
|
|
|
+ }
|
|
|
+
|
|
|
+ _FORCE_INLINE_ void remove(const Iterator &p_iter) {
|
|
|
+ if (p_iter) {
|
|
|
+ erase(*p_iter);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Insert */
|
|
|
+
|
|
|
+ Iterator insert(const TKey &p_key) {
|
|
|
+ uint32_t pos = _insert(p_key);
|
|
|
+ return Iterator(keys, num_elements, pos);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Constructors */
|
|
|
+
|
|
|
+ HashSet(const HashSet &p_other) {
|
|
|
+ _init_from(p_other);
|
|
|
+ }
|
|
|
+
|
|
|
+ void operator=(const HashSet &p_other) {
|
|
|
+ if (this == &p_other) {
|
|
|
+ return; // Ignore self assignment.
|
|
|
+ }
|
|
|
+
|
|
|
+ clear();
|
|
|
+
|
|
|
+ if (keys != nullptr) {
|
|
|
+ Memory::free_static(keys);
|
|
|
+ Memory::free_static(key_to_hash);
|
|
|
+ Memory::free_static(hash_to_key);
|
|
|
+ Memory::free_static(hashes);
|
|
|
+ keys = nullptr;
|
|
|
+ hashes = nullptr;
|
|
|
+ hash_to_key = nullptr;
|
|
|
+ key_to_hash = nullptr;
|
|
|
+ }
|
|
|
+
|
|
|
+ _init_from(p_other);
|
|
|
+ }
|
|
|
+
|
|
|
+ HashSet(uint32_t p_initial_capacity) {
|
|
|
+ // Capacity can't be 0.
|
|
|
+ capacity_index = 0;
|
|
|
+ reserve(p_initial_capacity);
|
|
|
+ }
|
|
|
+ HashSet() {
|
|
|
+ capacity_index = MIN_CAPACITY_INDEX;
|
|
|
+ }
|
|
|
+
|
|
|
+ void reset() {
|
|
|
+ clear();
|
|
|
+
|
|
|
+ if (keys != nullptr) {
|
|
|
+ Memory::free_static(keys);
|
|
|
+ Memory::free_static(key_to_hash);
|
|
|
+ Memory::free_static(hash_to_key);
|
|
|
+ Memory::free_static(hashes);
|
|
|
+ keys = nullptr;
|
|
|
+ hashes = nullptr;
|
|
|
+ hash_to_key = nullptr;
|
|
|
+ key_to_hash = nullptr;
|
|
|
+ }
|
|
|
+ capacity_index = MIN_CAPACITY_INDEX;
|
|
|
+ }
|
|
|
+
|
|
|
+ ~HashSet() {
|
|
|
+ clear();
|
|
|
+
|
|
|
+ if (keys != nullptr) {
|
|
|
+ Memory::free_static(keys);
|
|
|
+ Memory::free_static(key_to_hash);
|
|
|
+ Memory::free_static(hash_to_key);
|
|
|
+ Memory::free_static(hashes);
|
|
|
+ }
|
|
|
+ }
|
|
|
+};
|
|
|
+
|
|
|
+#endif // HASH_SET_H
|