FrameCollection.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_MEDIA_FRAME_COLLECTION_H
#define META_OCEAN_MEDIA_FRAME_COLLECTION_H
 
#include "ocean/media/Media.h"
 
#include "ocean/base/Frame.h"
#include "ocean/base/RingMap.h"
#include "ocean/base/Timestamp.h"
 
#include "ocean/math/AnyCamera.h"
 
namespace Ocean
{
 
namespace Media
{
 
/**
 * This class implements a simple buffer holding several frames combined with their timestamps and optional camera calibrations.
 * @ingroup media
 */
class OCEAN_MEDIA_EXPORT FrameCollection
{
    protected:
 
        /**
         * Definition of a pair combining a frame with a camera profile.
         */
        using FrameCameraPair = std::pair<FrameRef, SharedAnyCamera>;
 
        /**
         * Definition of a ring map mapping timestamps to frame pairs.
         */
        using RingMap = RingMapT<Timestamp, FrameCameraPair, true /*thread-safe*/, true /*ordered keys*/>;
 
    public:
 
        /**
         * Creates an empty frame collection able to hold one frame.
         */
        FrameCollection() = default;
 
        /**
         * Move constructor.
         * @param frameCollection Frame collection to move
         */
        FrameCollection(FrameCollection&& frameCollection) = default;
 
        /**
         * Copy constructor.
         * @param frameCollection Frame collection to copy
         */
        FrameCollection(const FrameCollection& frameCollection) = default;
 
        /**
         * Creates a new frame collection.
         * @param capacity Number of maximal frames this object can store [1, infinity)
         */
        explicit FrameCollection(const size_t capacity);
 
        /**
         * Destructs a frame collection.
         */
        ~FrameCollection();
 
        /**
         * Returns the capacity of this frame collection object.
         * @return The frame collection object's capacity, with range [0, infinity)
         */
        inline size_t capacity() const;
 
        /**
         * Returns the most recent frame.
         * @param anyCamera Optional resulting camera if known; nullptr if not of interest
         * @return Most recent frame
         */
        FrameRef recent(SharedAnyCamera* anyCamera = nullptr) const;
 
        /**
         * Returns the frame with a specific timestamp.
         * If no frame with the given timestamp exists, the most recent frame will be returned.
         * @param timestamp The timestamp of the frame to return
         * @param anyCamera Optional resulting camera if known; nullptr if not of interest
         * @return Frame with the specific timestamp
         */
        FrameRef get(const Timestamp timestamp, SharedAnyCamera* anyCamera = nullptr) const;
 
        /**
         * Returns whether a frame with specific timestamp is currently stored inside the frame collection.
         * @param timestamp The timestamp to be checked
         * @return True, if so
         */
        bool has(const Timestamp timestamp) const;
 
        /**
         * Sets a new frame and overwrites the oldest frame.
         * @param frame The frame to set, a copy will be created
         * @param anyCamera Optional camera profile associated with the given frame, nullptr if unknown
         * @return Reference to the stored frame, if succeeded
         */
        FrameRef set(const Frame& frame, SharedAnyCamera anyCamera = nullptr);
 
        /**
         * Sets a new frame and overwrites the oldest frame.
         * @param frame The frame to set
         * @param anyCamera Optional camera profile associated with the given frame, nullptr if unknown
         * @return Reference to the stored frame, if succeeded
         */
        FrameRef set(Frame&& frame, SharedAnyCamera anyCamera = nullptr);
 
        /**
         * Sets or changes the capacity of this frame collection.
         * In case the capacity is reduced, the oldest frames will be removed
         * @param capacity The capacity to set, with range [1, infinity)
         * @return True, if succeeded
         */
        bool setCapacity(const size_t capacity);
 
        /**
         * Returns whether the frame collection is empty.
         * @return True, if so
         */
        inline bool isNull() const;
 
        /**
         * Removes all frames from this frame collection.
         * The capacity will be kept.
         */
        void clear();
 
        /**
         * Returns whether the frame collection is not empty.
         * @return True, if so
         */
        explicit inline operator bool() const;
 
        /**
         * Default move operator.
         * @param frameCollection Frame collection to move
         */
        FrameCollection& operator=(FrameCollection&& frameCollection) = default;
 
        /**
         * Default assign operator.
         * @param frameCollection Frame collection to assign
         */
        FrameCollection& operator=(const FrameCollection& frameCollection) = default;
 
    protected:
 
        /// The ring map mapping timestamps to frame/camera pairs.
        RingMap ringMap_ = RingMap(1);
};
 
inline size_t FrameCollection::capacity() const
{
    return ringMap_.capacity();
}
 
inline bool FrameCollection::isNull() const
{
    return ringMap_.isEmpty();
}
 
inline FrameCollection::operator bool() const
{
    return !ringMap_.isEmpty();
}
 
}
 
}
 
#endif // META_OCEAN_MEDIA_FRAME_COLLECTION_H