circularbufferresidentobject.h

来自「C++封装的视频采集代码」· C头文件 代码 · 共 132 行

#ifndef CIRCULARBUFFERRESIDENTOBJECT_H
#define CIRCULARBUFFERRESIDENTOBJECT_H

#include "CircularBufferPosition.h"
#include "CircularBufferSpaceInfo.h"
#include "Misc/ObjectPool.h"
#include "Misc/PoolableObject.h"

namespace oxsemi
{
    namespace circular_buffer
    {
        class CircularBufferResidentObject : public PoolableObject
        {
        public:
            typedef unsigned long Id;

            class DecodeResult
            {
            public:
                DecodeResult(
                    bool successful,
                    unsigned long bytesConsumed);

                unsigned long GetBytesConsumed() const { return bytesConsumed_; }

                bool GetSuccessful() const { return successful_; }

            private:
                bool successful_;
                unsigned long bytesConsumed_;
            };

            class EncodeResult
            {
            public:
                EncodeResult(
                    bool successful,
                    bool skippedFirstSection,
                    unsigned long bytesConsumed);

                bool GetSkippedFirstSection() const { return skippedFirstSection_; }

                unsigned long GetBytesConsumed() const { return bytesConsumed_; }

                bool GetSuccessful() const { return successful_; }

            private:
                bool successful_;
                bool skippedFirstSection_;
                unsigned long bytesConsumed_;
            };

            /**
             * Make the association between the passed object and its in-buffer repre-
             * sentation
             *
             * @param writePositionInfo A const CircularBufferSpaceInfo& giving infor-
             *  mation on the write position of the CircularBuffer object into which
             *  this object is to be encoded
             * @return A EncodeResult indicating how much of the circular
             *  buffer to reserve for this object.
             */
            virtual EncodeResult AssociateWithBuffer(const CircularBufferSpaceInfo& writePositionInfo) = 0;

            /**
             * Store the completed object into the circular buffer and make it
             * available to the readers. Must store the object ID as the first
             * element written to buffer
             *
             * @return A EncodeResult indicating the how much of the circular
             *  buffer to commit to this object
             */
            virtual EncodeResult CommitToBuffer() const = 0;

            /**
             * Create an object from its in-buffer representation
             *
             * @param readPositionInfo A const CircularBufferSpaceInfo& giving infor-
             *  mation on the read position of the CircularBuffer object from which this
             *  object is to be decoded
             * @return A DecodeResult indicating the result of the decode operation
             */
            virtual DecodeResult DecodeFromBuffer(const CircularBufferSpaceInfo& readPositionInfo) = 0;

            virtual unsigned long GetEncodedSize() const = 0;

            const Id& GetId() const { return id_; }

            void SetId(const Id& id) { id_ = id; }

        protected:
            CircularBufferResidentObject();

        private:
            friend class CircularBuffer;

            Id id_;
            ObjectPool* pool_;
            CircularBufferPosition afterPosition_;

            CircularBufferResidentObject(const CircularBufferResidentObject&);

            CircularBufferResidentObject& operator=(const CircularBufferResidentObject&);

            const CircularBufferPosition& GetAfterPosition() const;

            ObjectPool* GetPool() const;

            void SetAfterPosition(const CircularBufferPosition& afterPosition);

            void SetPool(ObjectPool* pool);

            /**
             * The object should not write any data into it's buffer space within
             * the circular buffer, but should do any calculations required to
             * return an EncodeResult which contains the same data that it would
             * if a CommitToBuffer() call had been made. The object should also
             * update its internal record of how much circular buffer space it's
             * allocated to reflect the data returned in the EncodeResult
             *
             * @return A EncodeResult indicating the how much of the circular
             *  buffer is required by the trimmed object
             */
            virtual EncodeResult TrimBufferUsage() = 0;
        };
    }
}

#endif        //  #if !defined(__CIRCULARBUFFERRESIDENTOBJECT_H__)