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#ifndef ROCWMMA_GEMM_RESOURCE_HPP
#define ROCWMMA_GEMM_RESOURCE_HPP

#include <memory>
#include <tuple>

#include "hip_resource.hpp"
#include "singleton.hpp"

// GemmResource class is intended to manage a shared pool of resources for
// testing GEMM kernels on the GPU.
//
// It minimizes the memory handling overhead for launching thousands of GPU
// kernels by allowing re-use of existing memory allocations. Memory is only
// re-allocated as necessary to satisfy minimum size requirements.
//
// The interface indicates memory ownership by this class and shall only be
// used to access for read/write purposes.
//
// Currently uses HIP as the backend for device allocation.

namespace rocwmma
{

    template <typename InputT, typename OutputT>
    struct GemmResource : public HipResource, public LazySingleton<GemmResource<InputT, OutputT>>
    {
        // For static initialization
        friend std::unique_ptr<GemmResource<InputT, OutputT>>
            std::make_unique<GemmResource<InputT, OutputT>>();

        using Base = HipResource;

    public:
        template <typename DataT>
        using DevicePtrT = Base::template DevicePtrT<DataT>;

        template <typename DataT>
        using HostPtrT = Base::template HostPtrT<DataT>;

        // M, N, K
        using ProblemDims = std::tuple<int64_t, int64_t, int64_t>;

        // MatrixA, MatrixB, MatrixC, MatrixD (# of elements)
        using MatrixElements = std::tuple<int64_t, int64_t, int64_t, int64_t>;

        enum : uint32_t
        {
            // Matrix size indices
            MatrixA = 0,
            MatrixB = 1,
            MatrixC = 2,
            MatrixD = 3,

            // Problem size indices
            M = 0,
            N = 1,
            K = 2
        };

    private: // No public instantiation except make_unique.
             // No copy
        GemmResource();
        GemmResource(const GemmResource&)            = delete;
        GemmResource& operator=(const GemmResource&) = delete;

    public:
        GemmResource(GemmResource&&);
        ~GemmResource() = default;

        void copyHostToDeviceAll();
        void copyDeviceToHostAll();
        void resizeStorage(ProblemDims const& size);
        void resizeStorage(MatrixElements const& size);

        HostPtrT<InputT>&  hostA();
        HostPtrT<InputT>&  hostB();
        HostPtrT<OutputT>& hostC();
        HostPtrT<OutputT>& hostD();

        DevicePtrT<InputT>&  deviceA();
        DevicePtrT<InputT>&  deviceB();
        DevicePtrT<OutputT>& deviceC();
        DevicePtrT<OutputT>& deviceD();

        void reset() final;

    protected:
        DevicePtrT<InputT>  mDeviceA, mDeviceB;
        DevicePtrT<OutputT> mDeviceC, mDeviceD;
        HostPtrT<InputT>    mHostA, mHostB;
        HostPtrT<OutputT>   mHostC, mHostD;
        MatrixElements      mCurrentMatrixElements;
        MatrixElements      mCurrentAllocElements;
    };

} // namespace rocwmma

#endif // ROCWMMA_GEMM_RESOURCE_HPP