mirror of
https://github.com/godotengine/godot.git
synced 2024-12-09 10:09:20 +08:00
a7f49ac9a1
Happy new year to the wonderful Godot community! We're starting a new decade with a well-established, non-profit, free and open source game engine, and tons of further improvements in the pipeline from hundreds of contributors. Godot will keep getting better, and we're looking forward to all the games that the community will keep developing and releasing with it.
357 lines
9.1 KiB
C++
357 lines
9.1 KiB
C++
/*************************************************************************/
|
|
/* oa_hash_map.h */
|
|
/*************************************************************************/
|
|
/* This file is part of: */
|
|
/* GODOT ENGINE */
|
|
/* https://godotengine.org */
|
|
/*************************************************************************/
|
|
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
|
|
/* Copyright (c) 2014-2020 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 OA_HASH_MAP_H
|
|
#define OA_HASH_MAP_H
|
|
|
|
#include "core/hashfuncs.h"
|
|
#include "core/math/math_funcs.h"
|
|
#include "core/os/copymem.h"
|
|
#include "core/os/memory.h"
|
|
|
|
/**
|
|
* A HashMap implementation that uses open addressing with Robin Hood hashing.
|
|
* Robin Hood hashing swaps out entries that have a smaller probing distance
|
|
* than the to-be-inserted entry, that evens out the average probing distance
|
|
* and enables faster lookups. Backward shift deletion is employed to further
|
|
* improve the performance and to avoid infinite loops in rare cases.
|
|
*
|
|
* The entries are stored inplace, so huge keys or values might fill cache lines
|
|
* a lot faster.
|
|
*/
|
|
template <class TKey, class TValue,
|
|
class Hasher = HashMapHasherDefault,
|
|
class Comparator = HashMapComparatorDefault<TKey> >
|
|
class OAHashMap {
|
|
|
|
private:
|
|
TValue *values;
|
|
TKey *keys;
|
|
uint32_t *hashes;
|
|
|
|
uint32_t capacity;
|
|
|
|
uint32_t num_elements;
|
|
|
|
static const uint32_t EMPTY_HASH = 0;
|
|
|
|
_FORCE_INLINE_ uint32_t _hash(const TKey &p_key) const {
|
|
uint32_t hash = Hasher::hash(p_key);
|
|
|
|
if (hash == EMPTY_HASH) {
|
|
hash = EMPTY_HASH + 1;
|
|
}
|
|
|
|
return hash;
|
|
}
|
|
|
|
_FORCE_INLINE_ uint32_t _get_probe_length(uint32_t p_pos, uint32_t p_hash) const {
|
|
uint32_t original_pos = p_hash % capacity;
|
|
return (p_pos - original_pos + capacity) % capacity;
|
|
}
|
|
|
|
_FORCE_INLINE_ void _construct(uint32_t p_pos, uint32_t p_hash, const TKey &p_key, const TValue &p_value) {
|
|
memnew_placement(&keys[p_pos], TKey(p_key));
|
|
memnew_placement(&values[p_pos], TValue(p_value));
|
|
hashes[p_pos] = p_hash;
|
|
|
|
num_elements++;
|
|
}
|
|
|
|
bool _lookup_pos(const TKey &p_key, uint32_t &r_pos) const {
|
|
uint32_t hash = _hash(p_key);
|
|
uint32_t pos = hash % capacity;
|
|
uint32_t distance = 0;
|
|
|
|
while (42) {
|
|
if (hashes[pos] == EMPTY_HASH) {
|
|
return false;
|
|
}
|
|
|
|
if (distance > _get_probe_length(pos, hashes[pos])) {
|
|
return false;
|
|
}
|
|
|
|
if (hashes[pos] == hash && Comparator::compare(keys[pos], p_key)) {
|
|
r_pos = pos;
|
|
return true;
|
|
}
|
|
|
|
pos = (pos + 1) % capacity;
|
|
distance++;
|
|
}
|
|
}
|
|
|
|
void _insert_with_hash(uint32_t p_hash, const TKey &p_key, const TValue &p_value) {
|
|
|
|
uint32_t hash = p_hash;
|
|
uint32_t distance = 0;
|
|
uint32_t pos = hash % capacity;
|
|
|
|
TKey key = p_key;
|
|
TValue value = p_value;
|
|
|
|
while (42) {
|
|
if (hashes[pos] == EMPTY_HASH) {
|
|
_construct(pos, hash, key, value);
|
|
|
|
return;
|
|
}
|
|
|
|
// not an empty slot, let's check the probing length of the existing one
|
|
uint32_t existing_probe_len = _get_probe_length(pos, hashes[pos]);
|
|
if (existing_probe_len < distance) {
|
|
SWAP(hash, hashes[pos]);
|
|
SWAP(key, keys[pos]);
|
|
SWAP(value, values[pos]);
|
|
distance = existing_probe_len;
|
|
}
|
|
|
|
pos = (pos + 1) % capacity;
|
|
distance++;
|
|
}
|
|
}
|
|
|
|
void _resize_and_rehash(uint32_t p_new_capacity) {
|
|
|
|
uint32_t old_capacity = capacity;
|
|
capacity = p_new_capacity;
|
|
|
|
TKey *old_keys = keys;
|
|
TValue *old_values = values;
|
|
uint32_t *old_hashes = hashes;
|
|
|
|
num_elements = 0;
|
|
keys = memnew_arr(TKey, capacity);
|
|
values = memnew_arr(TValue, capacity);
|
|
hashes = memnew_arr(uint32_t, capacity);
|
|
|
|
for (uint32_t i = 0; i < capacity; i++) {
|
|
hashes[i] = 0;
|
|
}
|
|
|
|
for (uint32_t i = 0; i < old_capacity; i++) {
|
|
if (old_hashes[i] == EMPTY_HASH) {
|
|
continue;
|
|
}
|
|
|
|
_insert_with_hash(old_hashes[i], old_keys[i], old_values[i]);
|
|
}
|
|
|
|
memdelete_arr(old_keys);
|
|
memdelete_arr(old_values);
|
|
memdelete_arr(old_hashes);
|
|
}
|
|
|
|
void _resize_and_rehash() {
|
|
_resize_and_rehash(capacity * 2);
|
|
}
|
|
|
|
public:
|
|
_FORCE_INLINE_ uint32_t get_capacity() const { return capacity; }
|
|
_FORCE_INLINE_ uint32_t get_num_elements() const { return num_elements; }
|
|
|
|
bool empty() const {
|
|
return num_elements == 0;
|
|
}
|
|
|
|
void clear() {
|
|
|
|
for (uint32_t i = 0; i < capacity; i++) {
|
|
|
|
if (hashes[i] == EMPTY_HASH) {
|
|
continue;
|
|
}
|
|
|
|
hashes[i] = EMPTY_HASH;
|
|
values[i].~TValue();
|
|
keys[i].~TKey();
|
|
}
|
|
|
|
num_elements = 0;
|
|
}
|
|
|
|
void insert(const TKey &p_key, const TValue &p_value) {
|
|
|
|
if (num_elements + 1 > 0.9 * capacity) {
|
|
_resize_and_rehash();
|
|
}
|
|
|
|
uint32_t hash = _hash(p_key);
|
|
|
|
_insert_with_hash(hash, p_key, p_value);
|
|
}
|
|
|
|
void set(const TKey &p_key, const TValue &p_data) {
|
|
uint32_t pos = 0;
|
|
bool exists = _lookup_pos(p_key, pos);
|
|
|
|
if (exists) {
|
|
values[pos].~TValue();
|
|
memnew_placement(&values[pos], TValue(p_data));
|
|
} else {
|
|
insert(p_key, p_data);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* returns true if the value was found, false otherwise.
|
|
*
|
|
* if r_data is not NULL then the value will be written to the object
|
|
* it points to.
|
|
*/
|
|
bool lookup(const TKey &p_key, TValue &r_data) const {
|
|
uint32_t pos = 0;
|
|
bool exists = _lookup_pos(p_key, pos);
|
|
|
|
if (exists) {
|
|
r_data.~TValue();
|
|
memnew_placement(&r_data, TValue(values[pos]));
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
_FORCE_INLINE_ bool has(const TKey &p_key) const {
|
|
uint32_t _pos = 0;
|
|
return _lookup_pos(p_key, _pos);
|
|
}
|
|
|
|
void remove(const TKey &p_key) {
|
|
uint32_t pos = 0;
|
|
bool exists = _lookup_pos(p_key, pos);
|
|
|
|
if (!exists) {
|
|
return;
|
|
}
|
|
|
|
uint32_t next_pos = (pos + 1) % capacity;
|
|
while (hashes[next_pos] != EMPTY_HASH &&
|
|
_get_probe_length(next_pos, hashes[next_pos]) != 0) {
|
|
SWAP(hashes[next_pos], hashes[pos]);
|
|
SWAP(keys[next_pos], keys[pos]);
|
|
SWAP(values[next_pos], values[pos]);
|
|
pos = next_pos;
|
|
next_pos = (pos + 1) % capacity;
|
|
}
|
|
|
|
hashes[pos] = EMPTY_HASH;
|
|
values[pos].~TValue();
|
|
keys[pos].~TKey();
|
|
|
|
num_elements--;
|
|
}
|
|
|
|
/**
|
|
* 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(p_new_capacity < capacity);
|
|
_resize_and_rehash(p_new_capacity);
|
|
}
|
|
|
|
struct Iterator {
|
|
bool valid;
|
|
|
|
const TKey *key;
|
|
const TValue *value;
|
|
|
|
private:
|
|
uint32_t pos;
|
|
friend class OAHashMap;
|
|
};
|
|
|
|
Iterator iter() const {
|
|
Iterator it;
|
|
|
|
it.valid = true;
|
|
it.pos = 0;
|
|
|
|
return next_iter(it);
|
|
}
|
|
|
|
Iterator next_iter(const Iterator &p_iter) const {
|
|
|
|
if (!p_iter.valid) {
|
|
return p_iter;
|
|
}
|
|
|
|
Iterator it;
|
|
it.valid = false;
|
|
it.pos = p_iter.pos;
|
|
it.key = NULL;
|
|
it.value = NULL;
|
|
|
|
for (uint32_t i = it.pos; i < capacity; i++) {
|
|
it.pos = i + 1;
|
|
|
|
if (hashes[i] == EMPTY_HASH) {
|
|
continue;
|
|
}
|
|
|
|
it.valid = true;
|
|
it.key = &keys[i];
|
|
it.value = &values[i];
|
|
return it;
|
|
}
|
|
|
|
return it;
|
|
}
|
|
|
|
OAHashMap(const OAHashMap &) = delete; // Delete the copy constructor so we don't get unexpected copies and dangling pointers.
|
|
OAHashMap &operator=(const OAHashMap &) = delete; // Same for assignment operator.
|
|
|
|
OAHashMap(uint32_t p_initial_capacity = 64) {
|
|
|
|
capacity = p_initial_capacity;
|
|
num_elements = 0;
|
|
|
|
keys = memnew_arr(TKey, p_initial_capacity);
|
|
values = memnew_arr(TValue, p_initial_capacity);
|
|
hashes = memnew_arr(uint32_t, p_initial_capacity);
|
|
|
|
for (uint32_t i = 0; i < p_initial_capacity; i++) {
|
|
hashes[i] = EMPTY_HASH;
|
|
}
|
|
}
|
|
|
|
~OAHashMap() {
|
|
|
|
memdelete_arr(keys);
|
|
memdelete_arr(values);
|
|
memdelete_arr(hashes);
|
|
}
|
|
};
|
|
|
|
#endif
|