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/**
* @file
* @brief Header file for CacheMemory class
* @author Jonathan Thomas <jonathan@openshot.org>
*
* @section LICENSE
*
* Copyright (c) 2008-2014 OpenShot Studios, LLC
* <http://www.openshotstudios.com/>. This file is part of
* OpenShot Library (libopenshot), an open-source project dedicated to
* delivering high quality video editing and animation solutions to the
* world. For more information visit <http://www.openshot.org/>.
*
* OpenShot Library (libopenshot) 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 3 of the
* License, or (at your option) any later version.
*
* OpenShot Library (libopenshot) 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 OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef OPENSHOT_CACHE_MEMORY_H
#define OPENSHOT_CACHE_MEMORY_H
#include <map>
#include <deque>
#include <memory>
#include "CacheBase.h"
#include "Frame.h"
#include "Exceptions.h"
namespace openshot {
/**
* @brief This class is a memory-based cache manager for Frame objects.
*
* It is used by FileReaders (such as FFmpegReader) to cache recently accessed frames. Due to the
* high cost of decoding streams, once a frame is decoded, converted to RGB, and a Frame object is created,
* it critical to keep these Frames cached for performance reasons. However, the larger the cache, the more memory
* is required. You can set the max number of bytes to cache.
*/
class CacheMemory : public CacheBase {
private:
map<int64_t, std::shared_ptr<Frame> > frames; ///< This map holds the frame number and Frame objects
deque<int64_t> frame_numbers; ///< This queue holds a sequential list of cached Frame numbers
bool needs_range_processing; ///< Something has changed, and the range data needs to be re-calculated
string json_ranges; ///< JSON ranges of frame numbers
vector<int64_t> ordered_frame_numbers; ///< Ordered list of frame numbers used by cache
map<int64_t, int64_t> frame_ranges; ///< This map holds the ranges of frames, useful for quickly displaying the contents of the cache
int64_t range_version; ///< The version of the JSON range data (incremented with each change)
/// Clean up cached frames that exceed the max number of bytes
void CleanUp();
/// Calculate ranges of frames
void CalculateRanges();
public:
/// Default constructor, no max bytes
CacheMemory();
/// @brief Constructor that sets the max bytes to cache
/// @param max_bytes The maximum bytes to allow in the cache. Once exceeded, the cache will purge the oldest frames.
CacheMemory(int64_t max_bytes);
// Default destructor
~CacheMemory();
/// @brief Add a Frame to the cache
/// @param frame The openshot::Frame object needing to be cached.
void Add(std::shared_ptr<Frame> frame);
/// Clear the cache of all frames
void Clear();
/// Count the frames in the queue
int64_t Count();
/// @brief Get a frame from the cache
/// @param frame_number The frame number of the cached frame
std::shared_ptr<Frame> GetFrame(int64_t frame_number);
/// Gets the maximum bytes value
int64_t GetBytes();
/// Get the smallest frame number
std::shared_ptr<Frame> GetSmallestFrame();
/// @brief Move frame to front of queue (so it lasts longer)
/// @param frame_number The frame number of the cached frame
void MoveToFront(int64_t frame_number);
/// @brief Remove a specific frame
/// @param frame_number The frame number of the cached frame
void Remove(int64_t frame_number);
/// @brief Remove a range of frames
/// @param start_frame_number The starting frame number of the cached frame
/// @param end_frame_number The ending frame number of the cached frame
void Remove(int64_t start_frame_number, int64_t end_frame_number);
/// Get and Set JSON methods
string Json(); ///< Generate JSON string of this object
void SetJson(string value); ///< Load JSON string into this object
Json::Value JsonValue(); ///< Generate Json::JsonValue for this object
void SetJsonValue(Json::Value root); ///< Load Json::JsonValue into this object
};
}
#endif
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