/*************************************************************************/ /* hash_map.h */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* https://godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */ /* */ /* 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 HASH_MAP_H #define HASH_MAP_H #include "core/error_macros.h" #include "core/hashfuncs.h" #include "core/list.h" #include "core/math/math_funcs.h" #include "core/os/memory.h" #include "core/ustring.h" /** * @class HashMap * @author Juan Linietsky <reduzio@gmail.com> * * Implementation of a standard Hashing HashMap, for quick lookups of Data associated with a Key. * The implementation provides hashers for the default types, if you need a special kind of hasher, provide * your own. * @param TKey Key, search is based on it, needs to be hasheable. It is unique in this container. * @param TData Data, data associated with the key * @param Hasher Hasher object, needs to provide a valid static hash function for TKey * @param Comparator comparator object, needs to be able to safely compare two TKey values. It needs to ensure that x == x for any items inserted in the map. Bear in mind that nan != nan when implementing an equality check. * @param MIN_HASH_TABLE_POWER Miminum size of the hash table, as a power of two. You rarely need to change this parameter. * @param RELATIONSHIP Relationship at which the hash table is resized. if amount of elements is RELATIONSHIP * times bigger than the hash table, table is resized to solve this condition. if RELATIONSHIP is zero, table is always MIN_HASH_TABLE_POWER. * */ template <class TKey, class TData, class Hasher = HashMapHasherDefault, class Comparator = HashMapComparatorDefault<TKey>, uint8_t MIN_HASH_TABLE_POWER = 3, uint8_t RELATIONSHIP = 8> class HashMap { public: struct Pair { TKey key; TData data; Pair() {} Pair(const TKey &p_key, const TData &p_data) : key(p_key), data(p_data) { } }; struct Element { private: friend class HashMap; uint32_t hash; Element *next; Element() { next = 0; } Pair pair; public: const TKey &key() const { return pair.key; } TData &value() { return pair.data; } const TData &value() const { return pair.value(); } }; private: Element **hash_table; uint8_t hash_table_power; uint32_t elements; void make_hash_table() { ERR_FAIL_COND(hash_table); hash_table = memnew_arr(Element *, (1 << MIN_HASH_TABLE_POWER)); hash_table_power = MIN_HASH_TABLE_POWER; elements = 0; for (int i = 0; i < (1 << MIN_HASH_TABLE_POWER); i++) hash_table[i] = 0; } void erase_hash_table() { ERR_FAIL_COND(elements); memdelete_arr(hash_table); hash_table = 0; hash_table_power = 0; elements = 0; } void check_hash_table() { int new_hash_table_power = -1; if ((int)elements > ((1 << hash_table_power) * RELATIONSHIP)) { /* rehash up */ new_hash_table_power = hash_table_power + 1; while ((int)elements > ((1 << new_hash_table_power) * RELATIONSHIP)) { new_hash_table_power++; } } else if ((hash_table_power > (int)MIN_HASH_TABLE_POWER) && ((int)elements < ((1 << (hash_table_power - 1)) * RELATIONSHIP))) { /* rehash down */ new_hash_table_power = hash_table_power - 1; while ((int)elements < ((1 << (new_hash_table_power - 1)) * RELATIONSHIP)) { new_hash_table_power--; } if (new_hash_table_power < (int)MIN_HASH_TABLE_POWER) new_hash_table_power = MIN_HASH_TABLE_POWER; } if (new_hash_table_power == -1) return; Element **new_hash_table = memnew_arr(Element *, ((uint64_t)1 << new_hash_table_power)); if (!new_hash_table) { ERR_PRINT("Out of Memory"); return; } for (int i = 0; i < (1 << new_hash_table_power); i++) { new_hash_table[i] = 0; } for (int i = 0; i < (1 << hash_table_power); i++) { while (hash_table[i]) { Element *se = hash_table[i]; hash_table[i] = se->next; int new_pos = se->hash & ((1 << new_hash_table_power) - 1); se->next = new_hash_table[new_pos]; new_hash_table[new_pos] = se; } } if (hash_table) memdelete_arr(hash_table); hash_table = new_hash_table; hash_table_power = new_hash_table_power; } /* I want to have only one function.. */ _FORCE_INLINE_ const Element *get_element(const TKey &p_key) const { uint32_t hash = Hasher::hash(p_key); uint32_t index = hash & ((1 << hash_table_power) - 1); Element *e = hash_table[index]; while (e) { /* checking hash first avoids comparing key, which may take longer */ if (e->hash == hash && Comparator::compare(e->pair.key, p_key)) { /* the pair exists in this hashtable, so just update data */ return e; } e = e->next; } return NULL; } Element *create_element(const TKey &p_key) { /* if element doesn't exist, create it */ Element *e = memnew(Element); ERR_FAIL_COND_V(!e, NULL); /* out of memory */ uint32_t hash = Hasher::hash(p_key); uint32_t index = hash & ((1 << hash_table_power) - 1); e->next = hash_table[index]; e->hash = hash; e->pair.key = p_key; hash_table[index] = e; elements++; return e; } void copy_from(const HashMap &p_t) { if (&p_t == this) return; /* much less bother with that */ clear(); if (!p_t.hash_table || p_t.hash_table_power == 0) return; /* not copying from empty table */ hash_table = memnew_arr(Element *, (uint64_t)1 << p_t.hash_table_power); hash_table_power = p_t.hash_table_power; elements = p_t.elements; for (int i = 0; i < (1 << p_t.hash_table_power); i++) { hash_table[i] = NULL; const Element *e = p_t.hash_table[i]; while (e) { Element *le = memnew(Element); /* local element */ *le = *e; /* copy data */ /* add to list and reassign pointers */ le->next = hash_table[i]; hash_table[i] = le; e = e->next; } } } public: Element *set(const TKey &p_key, const TData &p_data) { return set(Pair(p_key, p_data)); } Element *set(const Pair &p_pair) { Element *e = NULL; if (!hash_table) make_hash_table(); // if no table, make one else e = const_cast<Element *>(get_element(p_pair.key)); /* if we made it up to here, the pair doesn't exist, create and assign */ if (!e) { e = create_element(p_pair.key); if (!e) return NULL; check_hash_table(); // perform mantenience routine } e->pair.data = p_pair.data; return e; } bool has(const TKey &p_key) const { return getptr(p_key) != NULL; } /** * Get a key from data, return a const reference. * WARNING: this doesn't check errors, use either getptr and check NULL, or check * first with has(key) */ const TData &get(const TKey &p_key) const { const TData *res = getptr(p_key); ERR_FAIL_COND_V(!res, *res); return *res; } TData &get(const TKey &p_key) { TData *res = getptr(p_key); ERR_FAIL_COND_V(!res, *res); return *res; } /** * Same as get, except it can return NULL when item was not found. * This is mainly used for speed purposes. */ _FORCE_INLINE_ TData *getptr(const TKey &p_key) { if (unlikely(!hash_table)) return NULL; Element *e = const_cast<Element *>(get_element(p_key)); if (e) return &e->pair.data; return NULL; } _FORCE_INLINE_ const TData *getptr(const TKey &p_key) const { if (unlikely(!hash_table)) return NULL; const Element *e = const_cast<Element *>(get_element(p_key)); if (e) return &e->pair.data; return NULL; } /** * Same as get, except it can return NULL when item was not found. * This version is custom, will take a hash and a custom key (that should support operator==() */ template <class C> _FORCE_INLINE_ TData *custom_getptr(C p_custom_key, uint32_t p_custom_hash) { if (unlikely(!hash_table)) return NULL; uint32_t hash = p_custom_hash; uint32_t index = hash & ((1 << hash_table_power) - 1); Element *e = hash_table[index]; while (e) { /* checking hash first avoids comparing key, which may take longer */ if (e->hash == hash && Comparator::compare(e->pair.key, p_custom_key)) { /* the pair exists in this hashtable, so just update data */ return &e->pair.data; } e = e->next; } return NULL; } template <class C> _FORCE_INLINE_ const TData *custom_getptr(C p_custom_key, uint32_t p_custom_hash) const { if (unlikely(!hash_table)) return NULL; uint32_t hash = p_custom_hash; uint32_t index = hash & ((1 << hash_table_power) - 1); const Element *e = hash_table[index]; while (e) { /* checking hash first avoids comparing key, which may take longer */ if (e->hash == hash && Comparator::compare(e->pair.key, p_custom_key)) { /* the pair exists in this hashtable, so just update data */ return &e->pair.data; } e = e->next; } return NULL; } /** * Erase an item, return true if erasing was successful */ bool erase(const TKey &p_key) { if (unlikely(!hash_table)) return false; uint32_t hash = Hasher::hash(p_key); uint32_t index = hash & ((1 << hash_table_power) - 1); Element *e = hash_table[index]; Element *p = NULL; while (e) { /* checking hash first avoids comparing key, which may take longer */ if (e->hash == hash && Comparator::compare(e->pair.key, p_key)) { if (p) { p->next = e->next; } else { //begin of list hash_table[index] = e->next; } memdelete(e); elements--; if (elements == 0) erase_hash_table(); else check_hash_table(); return true; } p = e; e = e->next; } return false; } inline const TData &operator[](const TKey &p_key) const { //constref return get(p_key); } inline TData &operator[](const TKey &p_key) { //assignment Element *e = NULL; if (!hash_table) make_hash_table(); // if no table, make one else e = const_cast<Element *>(get_element(p_key)); /* if we made it up to here, the pair doesn't exist, create */ if (!e) { e = create_element(p_key); CRASH_COND(!e); check_hash_table(); // perform mantenience routine } return e->pair.data; } /** * Get the next key to p_key, and the first key if p_key is null. * Returns a pointer to the next key if found, NULL otherwise. * Adding/Removing elements while iterating will, of course, have unexpected results, don't do it. * * Example: * * const TKey *k=NULL; * * while( (k=table.next(k)) ) { * * print( *k ); * } * */ const TKey *next(const TKey *p_key) const { if (unlikely(!hash_table)) return NULL; if (!p_key) { /* get the first key */ for (int i = 0; i < (1 << hash_table_power); i++) { if (hash_table[i]) { return &hash_table[i]->pair.key; } } } else { /* get the next key */ const Element *e = get_element(*p_key); ERR_FAIL_COND_V(!e, NULL); /* invalid key supplied */ if (e->next) { /* if there is a "next" in the list, return that */ return &e->next->pair.key; } else { /* go to next elements */ uint32_t index = e->hash & ((1 << hash_table_power) - 1); index++; for (int i = index; i < (1 << hash_table_power); i++) { if (hash_table[i]) { return &hash_table[i]->pair.key; } } } /* nothing found, was at end */ } return NULL; /* nothing found */ } inline unsigned int size() const { return elements; } inline bool empty() const { return elements == 0; } void clear() { /* clean up */ if (hash_table) { for (int i = 0; i < (1 << hash_table_power); i++) { while (hash_table[i]) { Element *e = hash_table[i]; hash_table[i] = e->next; memdelete(e); } } memdelete_arr(hash_table); } hash_table = 0; hash_table_power = 0; elements = 0; } void operator=(const HashMap &p_table) { copy_from(p_table); } HashMap() { hash_table = NULL; elements = 0; hash_table_power = 0; } void get_key_value_ptr_array(const Pair **p_pairs) const { if (unlikely(!hash_table)) return; for (int i = 0; i < (1 << hash_table_power); i++) { Element *e = hash_table[i]; while (e) { *p_pairs = &e->pair; p_pairs++; e = e->next; } } } void get_key_list(List<TKey> *p_keys) const { if (unlikely(!hash_table)) return; for (int i = 0; i < (1 << hash_table_power); i++) { Element *e = hash_table[i]; while (e) { p_keys->push_back(e->pair.key); e = e->next; } } } HashMap(const HashMap &p_table) { hash_table = NULL; elements = 0; hash_table_power = 0; copy_from(p_table); } ~HashMap() { clear(); } }; #endif