Added templated class LRUCache for Least-Recently-Used Caching

2026-05-08 04:20:14 -05:00 · 2016-04-15 18:05:11 -04:00
parent 527f83aacd
commit fafe4819e2
5 changed files with 217 additions and 1 deletions
@@ -43,6 +43,7 @@ set(HEADER_FILES

 	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/chunknode.h
 	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/latlon.h
+	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/lrucache.h

 )

@@ -62,6 +63,7 @@ set(SOURCE_FILES
 	
 	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/chunknode.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/latlon.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/datastructures/lrucache.inl
   
 )
 source_group("Source Files" FILES ${SOURCE_FILES})
@@ -0,0 +1,70 @@
+/*****************************************************************************************
+ *                                                                                       *
+ * OpenSpace                                                                             *
+ *                                                                                       *
+ * Copyright (c) 2014-2016                                                               *
+ *                                                                                       *
+ * 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 __LRU_CACHE_H__
+#define __LRU_CACHE_H__
+
+#include <glm/glm.hpp>
+#include <memory>
+#include <ostream>
+#include <unordered_map>
+#include <list>
+
+
+
+namespace openspace {
+
+	// Templated class implementing a Least-Recently-Used Cache
+	template<typename KeyType, typename ValueType>
+	class LRUCache {
+	public:
+		LRUCache(size_t size);
+		~LRUCache();
+
+
+		void put(const KeyType& key, const ValueType& value);
+		bool exist(const KeyType& key) const;
+		ValueType get(const KeyType& key);
+
+
+	private:
+		void clean();
+
+
+	// Member varialbes
+	private:
+		
+		std::list<std::pair<KeyType, ValueType>> _itemList;
+		std::unordered_map<KeyType, decltype(_itemList.begin())> _itemMap;
+		size_t _cacheSize;
+
+	};
+
+
+} // namespace openspace
+
+
+#include <modules/globebrowsing/datastructures/lrucache.inl>
+
+#endif // __LRU_CACHE_H__
@@ -0,0 +1,91 @@
+/*****************************************************************************************
+ *                                                                                       *
+ * OpenSpace                                                                             *
+ *                                                                                       *
+ * Copyright (c) 2014-2016                                                               *
+ *                                                                                       *
+ * 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.                                         *
+ ****************************************************************************************/
+
+#include <ghoul/misc/assert.h>
+//#include <modules/globebrowsing/datastructures/lrucache.h>
+
+
+namespace openspace {
+
+	
+	template<typename KeyType, typename ValueType>
+	LRUCache<KeyType, ValueType>::LRUCache(size_t size)
+		: _cacheSize(size) { }
+
+	template<typename KeyType, typename ValueType>
+	LRUCache<KeyType, ValueType>::~LRUCache() {	}
+
+
+	//////////////////////////////
+	//		PUBLIC INTERFACE	//
+	//////////////////////////////
+
+	template<typename KeyType, typename ValueType>
+	void LRUCache<KeyType, ValueType>::put(const KeyType& key, const ValueType& value)
+	{
+		auto it = _itemMap.find(key);
+		if (it != _itemMap.end()) {
+			_itemList.erase(it->second);
+			_itemMap.erase(it);
+		}
+		_itemList.push_front(std::make_pair(key, value));
+		_itemMap.insert(std::make_pair(key, _itemList.begin()));
+		clean();
+	}
+
+
+	template<typename KeyType, typename ValueType>
+	bool LRUCache<KeyType, ValueType>::exist(const KeyType& key) const
+	{
+		return _itemMap.count(key) > 0;
+	}
+
+
+	template<typename KeyType, typename ValueType>
+	ValueType LRUCache<KeyType, ValueType>::get(const KeyType& key)
+	{
+		ghoul_assert(exist(key), "Key " << key << " must exists");
+		auto it = _itemMap.find(key);
+		// Move list iterator pointing to value
+		_itemList.splice(_itemList.begin(), _itemList, it->second);
+		return it->second->second;
+	}
+
+
+
+	//////////////////////////////
+	//		PRIVATE HELPERS		//
+	//////////////////////////////
+	template<typename KeyType, typename ValueType>
+	void LRUCache<KeyType, ValueType>::clean()
+	{
+		while (_itemMap.size() > _cacheSize) {
+			auto last_it = _itemList.end(); last_it--;
+			_itemMap.erase(last_it->first);
+			_itemList.pop_back();
+		}
+	}
+
+
+} // namespace openspace