370 lines
9.5 KiB
C++
370 lines
9.5 KiB
C++
/*************************************************************************/
|
|
/* oa_hash_map.h */
|
|
/*************************************************************************/
|
|
/* This file is part of: */
|
|
/* GODOT ENGINE */
|
|
/* https://godotengine.org */
|
|
/*************************************************************************/
|
|
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
|
|
/* Copyright (c) 2014-2021 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/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.
|
|
*
|
|
* Only used keys and values are constructed. For free positions there's space
|
|
* in the arrays for each, but that memory is kept uninitialized.
|
|
*/
|
|
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 = static_cast<TKey *>(Memory::alloc_static(sizeof(TKey) * capacity));
|
|
values = static_cast<TValue *>(Memory::alloc_static(sizeof(TValue) * capacity));
|
|
hashes = static_cast<uint32_t *>(Memory::alloc_static(sizeof(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]);
|
|
|
|
old_keys[i].~TKey();
|
|
old_values[i].~TValue();
|
|
}
|
|
|
|
Memory::free_static(old_keys);
|
|
Memory::free_static(old_values);
|
|
Memory::free_static(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] = 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 = 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;
|
|
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 = static_cast<TKey *>(Memory::alloc_static(sizeof(TKey) * capacity));
|
|
values = static_cast<TValue *>(Memory::alloc_static(sizeof(TValue) * capacity));
|
|
hashes = static_cast<uint32_t *>(Memory::alloc_static(sizeof(uint32_t) * capacity));
|
|
|
|
for (uint32_t i = 0; i < p_initial_capacity; i++) {
|
|
hashes[i] = EMPTY_HASH;
|
|
}
|
|
}
|
|
|
|
~OAHashMap() {
|
|
|
|
for (uint32_t i = 0; i < capacity; i++) {
|
|
|
|
if (hashes[i] == EMPTY_HASH) {
|
|
continue;
|
|
}
|
|
|
|
values[i].~TValue();
|
|
keys[i].~TKey();
|
|
}
|
|
|
|
Memory::free_static(keys);
|
|
Memory::free_static(values);
|
|
Memory::free_static(hashes);
|
|
}
|
|
};
|
|
|
|
#endif
|