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- /*
- Minetest
- Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
- #pragma once
- #include "../irrlichttypes.h"
- #include "../exceptions.h"
- #include "../threading/mutex_auto_lock.h"
- #include "../threading/semaphore.h"
- #include <list>
- #include <vector>
- #include <map>
- #include <set>
- #include <queue>
- /*
- Queue with unique values with fast checking of value existence
- */
- template<typename Value>
- class UniqueQueue
- {
- public:
- /*
- Does nothing if value is already queued.
- Return value:
- true: value added
- false: value already exists
- */
- bool push_back(const Value& value)
- {
- if (m_set.insert(value).second)
- {
- m_queue.push(value);
- return true;
- }
- return false;
- }
- void pop_front()
- {
- m_set.erase(m_queue.front());
- m_queue.pop();
- }
- const Value& front() const
- {
- return m_queue.front();
- }
- u32 size() const
- {
- return m_queue.size();
- }
- private:
- std::set<Value> m_set;
- std::queue<Value> m_queue;
- };
- template<typename Key, typename Value>
- class MutexedMap
- {
- public:
- MutexedMap() = default;
- void set(const Key &name, const Value &value)
- {
- MutexAutoLock lock(m_mutex);
- m_values[name] = value;
- }
- bool get(const Key &name, Value *result) const
- {
- MutexAutoLock lock(m_mutex);
- typename std::map<Key, Value>::const_iterator n =
- m_values.find(name);
- if (n == m_values.end())
- return false;
- if (result)
- *result = n->second;
- return true;
- }
- std::vector<Value> getValues() const
- {
- MutexAutoLock lock(m_mutex);
- std::vector<Value> result;
- for (typename std::map<Key, Value>::const_iterator
- it = m_values.begin();
- it != m_values.end(); ++it){
- result.push_back(it->second);
- }
- return result;
- }
- void clear() { m_values.clear(); }
- private:
- std::map<Key, Value> m_values;
- mutable std::mutex m_mutex;
- };
- // Thread-safe Double-ended queue
- template<typename T>
- class MutexedQueue
- {
- public:
- template<typename Key, typename U, typename Caller, typename CallerData>
- friend class RequestQueue;
- MutexedQueue() = default;
- bool empty() const
- {
- MutexAutoLock lock(m_mutex);
- return m_queue.empty();
- }
- void push_back(T t)
- {
- MutexAutoLock lock(m_mutex);
- m_queue.push_back(t);
- m_signal.post();
- }
- /* this version of pop_front returns a empty element of T on timeout.
- * Make sure default constructor of T creates a recognizable "empty" element
- */
- T pop_frontNoEx(u32 wait_time_max_ms)
- {
- if (m_signal.wait(wait_time_max_ms)) {
- MutexAutoLock lock(m_mutex);
- T t = m_queue.front();
- m_queue.pop_front();
- return t;
- }
- return T();
- }
- T pop_front(u32 wait_time_max_ms)
- {
- if (m_signal.wait(wait_time_max_ms)) {
- MutexAutoLock lock(m_mutex);
- T t = m_queue.front();
- m_queue.pop_front();
- return t;
- }
- throw ItemNotFoundException("MutexedQueue: queue is empty");
- }
- T pop_frontNoEx()
- {
- m_signal.wait();
- MutexAutoLock lock(m_mutex);
- T t = m_queue.front();
- m_queue.pop_front();
- return t;
- }
- T pop_back(u32 wait_time_max_ms=0)
- {
- if (m_signal.wait(wait_time_max_ms)) {
- MutexAutoLock lock(m_mutex);
- T t = m_queue.back();
- m_queue.pop_back();
- return t;
- }
- throw ItemNotFoundException("MutexedQueue: queue is empty");
- }
- /* this version of pop_back returns a empty element of T on timeout.
- * Make sure default constructor of T creates a recognizable "empty" element
- */
- T pop_backNoEx(u32 wait_time_max_ms)
- {
- if (m_signal.wait(wait_time_max_ms)) {
- MutexAutoLock lock(m_mutex);
- T t = m_queue.back();
- m_queue.pop_back();
- return t;
- }
- return T();
- }
- T pop_backNoEx()
- {
- m_signal.wait();
- MutexAutoLock lock(m_mutex);
- T t = m_queue.back();
- m_queue.pop_back();
- return t;
- }
- protected:
- std::mutex &getMutex() { return m_mutex; }
- std::deque<T> &getQueue() { return m_queue; }
- std::deque<T> m_queue;
- mutable std::mutex m_mutex;
- Semaphore m_signal;
- };
- template<typename K, typename V>
- class LRUCache
- {
- public:
- LRUCache(size_t limit, void (*cache_miss)(void *data, const K &key, V *dest),
- void *data)
- {
- m_limit = limit;
- m_cache_miss = cache_miss;
- m_cache_miss_data = data;
- }
- void setLimit(size_t limit)
- {
- m_limit = limit;
- invalidate();
- }
- void invalidate()
- {
- m_map.clear();
- m_queue.clear();
- }
- const V *lookupCache(K key)
- {
- typename cache_type::iterator it = m_map.find(key);
- V *ret;
- if (it != m_map.end()) {
- // found!
- cache_entry_t &entry = it->second;
- ret = &entry.second;
- // update the usage information
- m_queue.erase(entry.first);
- m_queue.push_front(key);
- entry.first = m_queue.begin();
- } else {
- // cache miss -- enter into cache
- cache_entry_t &entry =
- m_map[key];
- ret = &entry.second;
- m_cache_miss(m_cache_miss_data, key, &entry.second);
- // delete old entries
- if (m_queue.size() == m_limit) {
- const K &id = m_queue.back();
- m_map.erase(id);
- m_queue.pop_back();
- }
- m_queue.push_front(key);
- entry.first = m_queue.begin();
- }
- return ret;
- }
- private:
- void (*m_cache_miss)(void *data, const K &key, V *dest);
- void *m_cache_miss_data;
- size_t m_limit;
- typedef typename std::template pair<typename std::template list<K>::iterator, V> cache_entry_t;
- typedef std::template map<K, cache_entry_t> cache_type;
- cache_type m_map;
- // we can't use std::deque here, because its iterators get invalidated
- std::list<K> m_queue;
- };
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