yuzu-android/src/common/lru_cache.h
Morph 99ceb03a1c general: Convert source file copyright comments over to SPDX
This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.
2022-04-23 05:55:32 -04:00

140 lines
3.4 KiB
C++

// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <deque>
#include <memory>
#include <type_traits>
#include "common/common_types.h"
namespace Common {
template <class Traits>
class LeastRecentlyUsedCache {
using ObjectType = typename Traits::ObjectType;
using TickType = typename Traits::TickType;
struct Item {
ObjectType obj;
TickType tick;
Item* next{};
Item* prev{};
};
public:
LeastRecentlyUsedCache() : first_item{}, last_item{} {}
~LeastRecentlyUsedCache() = default;
size_t Insert(ObjectType obj, TickType tick) {
const auto new_id = Build();
auto& item = item_pool[new_id];
item.obj = obj;
item.tick = tick;
Attach(item);
return new_id;
}
void Touch(size_t id, TickType tick) {
auto& item = item_pool[id];
if (item.tick >= tick) {
return;
}
item.tick = tick;
if (&item == last_item) {
return;
}
Detach(item);
Attach(item);
}
void Free(size_t id) {
auto& item = item_pool[id];
Detach(item);
item.prev = nullptr;
item.next = nullptr;
free_items.push_back(id);
}
template <typename Func>
void ForEachItemBelow(TickType tick, Func&& func) {
static constexpr bool RETURNS_BOOL =
std::is_same_v<std::invoke_result<Func, ObjectType>, bool>;
Item* iterator = first_item;
while (iterator) {
if (static_cast<s64>(tick) - static_cast<s64>(iterator->tick) < 0) {
return;
}
Item* next = iterator->next;
if constexpr (RETURNS_BOOL) {
if (func(iterator->obj)) {
return;
}
} else {
func(iterator->obj);
}
iterator = next;
}
}
private:
size_t Build() {
if (free_items.empty()) {
const size_t item_id = item_pool.size();
auto& item = item_pool.emplace_back();
item.next = nullptr;
item.prev = nullptr;
return item_id;
}
const size_t item_id = free_items.front();
free_items.pop_front();
auto& item = item_pool[item_id];
item.next = nullptr;
item.prev = nullptr;
return item_id;
}
void Attach(Item& item) {
if (!first_item) {
first_item = &item;
}
if (!last_item) {
last_item = &item;
} else {
item.prev = last_item;
last_item->next = &item;
item.next = nullptr;
last_item = &item;
}
}
void Detach(Item& item) {
if (item.prev) {
item.prev->next = item.next;
}
if (item.next) {
item.next->prev = item.prev;
}
if (&item == first_item) {
first_item = item.next;
if (first_item) {
first_item->prev = nullptr;
}
}
if (&item == last_item) {
last_item = item.prev;
if (last_item) {
last_item->next = nullptr;
}
}
}
std::deque<Item> item_pool;
std::deque<size_t> free_items;
Item* first_item{};
Item* last_item{};
};
} // namespace Common