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603 lines
14 KiB
C++
603 lines
14 KiB
C++
/*************************************************************************/
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/* hash_map.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) 2007-2020 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2020 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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#ifndef HASH_MAP_H
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#define HASH_MAP_H
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#include "core/error_macros.h"
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#include "core/hashfuncs.h"
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#include "core/list.h"
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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/ustring.h"
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/**
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* @class HashMap
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* @author Juan Linietsky <reduzio@gmail.com>
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*
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* Implementation of a standard Hashing HashMap, for quick lookups of Data associated with a Key.
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* The implementation provides hashers for the default types, if you need a special kind of hasher, provide
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* your own.
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* @param TKey Key, search is based on it, needs to be hasheable. It is unique in this container.
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* @param TData Data, data associated with the key
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* @param Hasher Hasher object, needs to provide a valid static hash function for TKey
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* @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.
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* @param MIN_HASH_TABLE_POWER Miminum size of the hash table, as a power of two. You rarely need to change this parameter.
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* @param RELATIONSHIP Relationship at which the hash table is resized. if amount of elements is RELATIONSHIP
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* times bigger than the hash table, table is resized to solve this condition. if RELATIONSHIP is zero, table is always MIN_HASH_TABLE_POWER.
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*
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*/
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template <class TKey, class TData, class Hasher = HashMapHasherDefault, class Comparator = HashMapComparatorDefault<TKey>, uint8_t MIN_HASH_TABLE_POWER = 3, uint8_t RELATIONSHIP = 8>
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class HashMap {
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public:
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struct Pair {
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TKey key;
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TData data;
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Pair() {}
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Pair(const TKey &p_key, const TData &p_data) :
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key(p_key),
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data(p_data) {
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}
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};
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struct Element {
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private:
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friend class HashMap;
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uint32_t hash;
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Element *next;
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Element() { next = 0; }
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Pair pair;
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public:
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const TKey &key() const {
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return pair.key;
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}
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TData &value() {
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return pair.data;
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}
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const TData &value() const {
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return pair.value();
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}
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};
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private:
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Element **hash_table;
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uint8_t hash_table_power;
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uint32_t elements;
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void make_hash_table() {
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ERR_FAIL_COND(hash_table);
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hash_table = memnew_arr(Element *, (1 << MIN_HASH_TABLE_POWER));
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hash_table_power = MIN_HASH_TABLE_POWER;
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elements = 0;
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for (int i = 0; i < (1 << MIN_HASH_TABLE_POWER); i++)
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hash_table[i] = 0;
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}
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void erase_hash_table() {
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ERR_FAIL_COND_MSG(elements, "Cannot erase hash table if there are still elements inside.");
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memdelete_arr(hash_table);
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hash_table = 0;
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hash_table_power = 0;
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elements = 0;
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}
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void check_hash_table() {
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int new_hash_table_power = -1;
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if ((int)elements > ((1 << hash_table_power) * RELATIONSHIP)) {
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/* rehash up */
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new_hash_table_power = hash_table_power + 1;
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while ((int)elements > ((1 << new_hash_table_power) * RELATIONSHIP)) {
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new_hash_table_power++;
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}
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} else if ((hash_table_power > (int)MIN_HASH_TABLE_POWER) && ((int)elements < ((1 << (hash_table_power - 1)) * RELATIONSHIP))) {
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/* rehash down */
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new_hash_table_power = hash_table_power - 1;
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while ((int)elements < ((1 << (new_hash_table_power - 1)) * RELATIONSHIP)) {
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new_hash_table_power--;
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}
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if (new_hash_table_power < (int)MIN_HASH_TABLE_POWER)
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new_hash_table_power = MIN_HASH_TABLE_POWER;
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}
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if (new_hash_table_power == -1)
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return;
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Element **new_hash_table = memnew_arr(Element *, ((uint64_t)1 << new_hash_table_power));
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ERR_FAIL_COND_MSG(!new_hash_table, "Out of memory.");
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for (int i = 0; i < (1 << new_hash_table_power); i++) {
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new_hash_table[i] = 0;
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}
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if (hash_table) {
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for (int i = 0; i < (1 << hash_table_power); i++) {
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while (hash_table[i]) {
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Element *se = hash_table[i];
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hash_table[i] = se->next;
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int new_pos = se->hash & ((1 << new_hash_table_power) - 1);
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se->next = new_hash_table[new_pos];
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new_hash_table[new_pos] = se;
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}
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}
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memdelete_arr(hash_table);
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}
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hash_table = new_hash_table;
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hash_table_power = new_hash_table_power;
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}
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/* I want to have only one function.. */
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_FORCE_INLINE_ const Element *get_element(const TKey &p_key) const {
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uint32_t hash = Hasher::hash(p_key);
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uint32_t index = hash & ((1 << hash_table_power) - 1);
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Element *e = hash_table[index];
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while (e) {
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/* checking hash first avoids comparing key, which may take longer */
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if (e->hash == hash && Comparator::compare(e->pair.key, p_key)) {
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/* the pair exists in this hashtable, so just update data */
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return e;
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}
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e = e->next;
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}
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return NULL;
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}
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Element *create_element(const TKey &p_key) {
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/* if element doesn't exist, create it */
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Element *e = memnew(Element);
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ERR_FAIL_COND_V_MSG(!e, NULL, "Out of memory.");
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uint32_t hash = Hasher::hash(p_key);
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uint32_t index = hash & ((1 << hash_table_power) - 1);
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e->next = hash_table[index];
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e->hash = hash;
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e->pair.key = p_key;
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e->pair.data = TData();
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hash_table[index] = e;
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elements++;
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return e;
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}
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void copy_from(const HashMap &p_t) {
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if (&p_t == this)
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return; /* much less bother with that */
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clear();
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if (!p_t.hash_table || p_t.hash_table_power == 0)
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return; /* not copying from empty table */
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hash_table = memnew_arr(Element *, (uint64_t)1 << p_t.hash_table_power);
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hash_table_power = p_t.hash_table_power;
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elements = p_t.elements;
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for (int i = 0; i < (1 << p_t.hash_table_power); i++) {
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hash_table[i] = NULL;
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const Element *e = p_t.hash_table[i];
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while (e) {
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Element *le = memnew(Element); /* local element */
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*le = *e; /* copy data */
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/* add to list and reassign pointers */
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le->next = hash_table[i];
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hash_table[i] = le;
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e = e->next;
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}
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}
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}
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public:
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Element *set(const TKey &p_key, const TData &p_data) {
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return set(Pair(p_key, p_data));
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}
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Element *set(const Pair &p_pair) {
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Element *e = NULL;
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if (!hash_table)
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make_hash_table(); // if no table, make one
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else
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e = const_cast<Element *>(get_element(p_pair.key));
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/* if we made it up to here, the pair doesn't exist, create and assign */
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if (!e) {
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e = create_element(p_pair.key);
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if (!e)
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return NULL;
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check_hash_table(); // perform mantenience routine
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}
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e->pair.data = p_pair.data;
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return e;
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}
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bool has(const TKey &p_key) const {
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return getptr(p_key) != NULL;
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}
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/**
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* Get a key from data, return a const reference.
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* WARNING: this doesn't check errors, use either getptr and check NULL, or check
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* first with has(key)
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*/
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const TData &get(const TKey &p_key) const {
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const TData *res = getptr(p_key);
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ERR_FAIL_COND_V(!res, *res);
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return *res;
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}
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TData &get(const TKey &p_key) {
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TData *res = getptr(p_key);
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ERR_FAIL_COND_V(!res, *res);
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return *res;
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}
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/**
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* Same as get, except it can return NULL when item was not found.
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* This is mainly used for speed purposes.
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*/
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_FORCE_INLINE_ TData *getptr(const TKey &p_key) {
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if (unlikely(!hash_table))
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return NULL;
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Element *e = const_cast<Element *>(get_element(p_key));
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if (e)
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return &e->pair.data;
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return NULL;
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}
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_FORCE_INLINE_ const TData *getptr(const TKey &p_key) const {
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if (unlikely(!hash_table))
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return NULL;
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const Element *e = const_cast<Element *>(get_element(p_key));
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if (e)
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return &e->pair.data;
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return NULL;
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}
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/**
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* Same as get, except it can return NULL when item was not found.
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* This version is custom, will take a hash and a custom key (that should support operator==()
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*/
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template <class C>
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_FORCE_INLINE_ TData *custom_getptr(C p_custom_key, uint32_t p_custom_hash) {
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if (unlikely(!hash_table))
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return NULL;
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uint32_t hash = p_custom_hash;
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uint32_t index = hash & ((1 << hash_table_power) - 1);
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Element *e = hash_table[index];
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while (e) {
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/* checking hash first avoids comparing key, which may take longer */
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if (e->hash == hash && Comparator::compare(e->pair.key, p_custom_key)) {
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/* the pair exists in this hashtable, so just update data */
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return &e->pair.data;
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}
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e = e->next;
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}
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return NULL;
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}
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template <class C>
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_FORCE_INLINE_ const TData *custom_getptr(C p_custom_key, uint32_t p_custom_hash) const {
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if (unlikely(!hash_table))
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return NULL;
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uint32_t hash = p_custom_hash;
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uint32_t index = hash & ((1 << hash_table_power) - 1);
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const Element *e = hash_table[index];
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while (e) {
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/* checking hash first avoids comparing key, which may take longer */
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if (e->hash == hash && Comparator::compare(e->pair.key, p_custom_key)) {
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/* the pair exists in this hashtable, so just update data */
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return &e->pair.data;
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}
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e = e->next;
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}
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return NULL;
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}
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/**
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* Erase an item, return true if erasing was successful
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*/
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bool erase(const TKey &p_key) {
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if (unlikely(!hash_table))
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return false;
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uint32_t hash = Hasher::hash(p_key);
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uint32_t index = hash & ((1 << hash_table_power) - 1);
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Element *e = hash_table[index];
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Element *p = NULL;
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while (e) {
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/* checking hash first avoids comparing key, which may take longer */
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if (e->hash == hash && Comparator::compare(e->pair.key, p_key)) {
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if (p) {
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p->next = e->next;
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} else {
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//begin of list
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hash_table[index] = e->next;
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}
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memdelete(e);
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elements--;
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if (elements == 0)
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erase_hash_table();
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else
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check_hash_table();
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return true;
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}
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p = e;
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e = e->next;
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}
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return false;
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}
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inline const TData &operator[](const TKey &p_key) const { //constref
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return get(p_key);
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}
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inline TData &operator[](const TKey &p_key) { //assignment
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Element *e = NULL;
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if (!hash_table)
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make_hash_table(); // if no table, make one
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else
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e = const_cast<Element *>(get_element(p_key));
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/* if we made it up to here, the pair doesn't exist, create */
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if (!e) {
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e = create_element(p_key);
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CRASH_COND(!e);
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check_hash_table(); // perform mantenience routine
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}
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return e->pair.data;
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}
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/**
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* Get the next key to p_key, and the first key if p_key is null.
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* Returns a pointer to the next key if found, NULL otherwise.
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* Adding/Removing elements while iterating will, of course, have unexpected results, don't do it.
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*
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* Example:
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*
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* const TKey *k=NULL;
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*
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* while( (k=table.next(k)) ) {
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*
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* print( *k );
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* }
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*
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*/
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const TKey *next(const TKey *p_key) const {
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if (unlikely(!hash_table))
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return NULL;
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if (!p_key) { /* get the first key */
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for (int i = 0; i < (1 << hash_table_power); i++) {
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if (hash_table[i]) {
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return &hash_table[i]->pair.key;
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}
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}
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} else { /* get the next key */
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const Element *e = get_element(*p_key);
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ERR_FAIL_COND_V_MSG(!e, NULL, "Invalid key supplied.");
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if (e->next) {
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/* if there is a "next" in the list, return that */
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return &e->next->pair.key;
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} else {
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/* go to next elements */
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uint32_t index = e->hash & ((1 << hash_table_power) - 1);
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index++;
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for (int i = index; i < (1 << hash_table_power); i++) {
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if (hash_table[i]) {
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return &hash_table[i]->pair.key;
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}
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}
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}
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/* nothing found, was at end */
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}
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return NULL; /* nothing found */
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}
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inline unsigned int size() const {
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return elements;
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}
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inline bool empty() const {
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return elements == 0;
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}
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void clear() {
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/* clean up */
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if (hash_table) {
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for (int i = 0; i < (1 << hash_table_power); i++) {
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while (hash_table[i]) {
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Element *e = hash_table[i];
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hash_table[i] = e->next;
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memdelete(e);
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}
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}
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memdelete_arr(hash_table);
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}
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hash_table = 0;
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hash_table_power = 0;
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elements = 0;
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}
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void operator=(const HashMap &p_table) {
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copy_from(p_table);
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}
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HashMap() {
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hash_table = NULL;
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elements = 0;
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hash_table_power = 0;
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}
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void get_key_value_ptr_array(const Pair **p_pairs) const {
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if (unlikely(!hash_table))
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return;
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|
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
|