OpenShot Library | libopenshot 0.2.7
CacheMemory.h
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1/**
2 * @file
3 * @brief Header file for CacheMemory class
4 * @author Jonathan Thomas <jonathan@openshot.org>
5 *
6 * @ref License
7 */
8
9/* LICENSE
10 *
11 * Copyright (c) 2008-2019 OpenShot Studios, LLC
12 * <http://www.openshotstudios.com/>. This file is part of
13 * OpenShot Library (libopenshot), an open-source project dedicated to
14 * delivering high quality video editing and animation solutions to the
15 * world. For more information visit <http://www.openshot.org/>.
16 *
17 * OpenShot Library (libopenshot) is free software: you can redistribute it
18 * and/or modify it under the terms of the GNU Lesser General Public License
19 * as published by the Free Software Foundation, either version 3 of the
20 * License, or (at your option) any later version.
21 *
22 * OpenShot Library (libopenshot) is distributed in the hope that it will be
23 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU Lesser General Public License for more details.
26 *
27 * You should have received a copy of the GNU Lesser General Public License
28 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
29 */
30
31#ifndef OPENSHOT_CACHE_MEMORY_H
32#define OPENSHOT_CACHE_MEMORY_H
33
34#include <map>
35#include <deque>
36#include <memory>
37#include "CacheBase.h"
38#include "Frame.h"
39
40namespace openshot {
41
42 /**
43 * @brief This class is a memory-based cache manager for Frame objects.
44 *
45 * It is used by FileReaders (such as FFmpegReader) to cache recently accessed frames. Due to the
46 * high cost of decoding streams, once a frame is decoded, converted to RGB, and a Frame object is created,
47 * it critical to keep these Frames cached for performance reasons. However, the larger the cache, the more memory
48 * is required. You can set the max number of bytes to cache.
49 */
50 class CacheMemory : public CacheBase {
51 private:
52 std::map<int64_t, std::shared_ptr<openshot::Frame> > frames; ///< This map holds the frame number and Frame objects
53 std::deque<int64_t> frame_numbers; ///< This queue holds a sequential list of cached Frame numbers
54
55 bool needs_range_processing; ///< Something has changed, and the range data needs to be re-calculated
56 std::string json_ranges; ///< JSON ranges of frame numbers
57 std::vector<int64_t> ordered_frame_numbers; ///< Ordered list of frame numbers used by cache
58 std::map<int64_t, int64_t> frame_ranges; ///< This map holds the ranges of frames, useful for quickly displaying the contents of the cache
59 int64_t range_version; ///< The version of the JSON range data (incremented with each change)
60
61 /// Clean up cached frames that exceed the max number of bytes
62 void CleanUp();
63
64 /// Calculate ranges of frames
65 void CalculateRanges();
66
67 public:
68 /// Default constructor, no max bytes
70
71 /// @brief Constructor that sets the max bytes to cache
72 /// @param max_bytes The maximum bytes to allow in the cache. Once exceeded, the cache will purge the oldest frames.
73 CacheMemory(int64_t max_bytes);
74
75 // Default destructor
76 virtual ~CacheMemory();
77
78 /// @brief Add a Frame to the cache
79 /// @param frame The openshot::Frame object needing to be cached.
80 void Add(std::shared_ptr<openshot::Frame> frame);
81
82 /// Clear the cache of all frames
83 void Clear();
84
85 /// Count the frames in the queue
86 int64_t Count();
87
88 /// @brief Get a frame from the cache
89 /// @param frame_number The frame number of the cached frame
90 std::shared_ptr<openshot::Frame> GetFrame(int64_t frame_number);
91
92 /// Gets the maximum bytes value
93 int64_t GetBytes();
94
95 /// Get the smallest frame number
96 std::shared_ptr<openshot::Frame> GetSmallestFrame();
97
98 /// @brief Move frame to front of queue (so it lasts longer)
99 /// @param frame_number The frame number of the cached frame
100 void MoveToFront(int64_t frame_number);
101
102 /// @brief Remove a specific frame
103 /// @param frame_number The frame number of the cached frame
104 void Remove(int64_t frame_number);
105
106 /// @brief Remove a range of frames
107 /// @param start_frame_number The starting frame number of the cached frame
108 /// @param end_frame_number The ending frame number of the cached frame
109 void Remove(int64_t start_frame_number, int64_t end_frame_number);
110
111 // Get and Set JSON methods
112 std::string Json(); ///< Generate JSON string of this object
113 void SetJson(const std::string value); ///< Load JSON string into this object
114 Json::Value JsonValue(); ///< Generate Json::Value for this object
115 void SetJsonValue(const Json::Value root); ///< Load Json::Value into this object
116 };
117
118}
119
120#endif
Header file for CacheBase class.
Header file for Frame class.
All cache managers in libopenshot are based on this CacheBase class.
Definition: CacheBase.h:49
int64_t max_bytes
This is the max number of bytes to cache (0 = no limit)
Definition: CacheBase.h:52
This class is a memory-based cache manager for Frame objects.
Definition: CacheMemory.h:50
CacheMemory()
Default constructor, no max bytes.
Definition: CacheMemory.cpp:38
int64_t Count()
Count the frames in the queue.
void Add(std::shared_ptr< openshot::Frame > frame)
Add a Frame to the cache.
void SetJson(const std::string value)
Load JSON string into this object.
int64_t GetBytes()
Gets the maximum bytes value.
std::string Json()
Generate JSON string of this object.
std::shared_ptr< openshot::Frame > GetFrame(int64_t frame_number)
Get a frame from the cache.
void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
void MoveToFront(int64_t frame_number)
Move frame to front of queue (so it lasts longer)
void Remove(int64_t frame_number)
Remove a specific frame.
void Clear()
Clear the cache of all frames.
Json::Value JsonValue()
Generate Json::Value for this object.
std::shared_ptr< openshot::Frame > GetSmallestFrame()
Get the smallest frame number.
This namespace is the default namespace for all code in the openshot library.
Definition: Compressor.h:47