TheRock/rocm-libraries/projects/rocblas/clients/include/host_pinned_vector.hpp

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#pragma once

#include "pinned_memory_allocator.hpp"
#include <memory>

//!
//! @brief  Pseudo-vector subclass which uses host pinned memory.
//!         Delete this class once hipHostRegister has been proven equivalent and host_vector
//!         is extended to manage pinning/unpinning.
//!
template <typename T>
struct host_pinned_vector : std::vector<T, pinned_memory_allocator<T>>
{
    // Inherit constructors
    using std::vector<T, pinned_memory_allocator<T>>::vector;

    //!
    //! @brief Constructor.
    //!

    host_pinned_vector(size_t n, int64_t inc)
        : std::vector<T, pinned_memory_allocator<T>>(n * (inc ? inc : 1),
                                                     pinned_memory_allocator<T>())
        , m_n(n)
        , m_inc(inc ? inc : 1)
    {
    }

    //!
    //! @brief Decay into pointer wherever pointer is expected
    //!
    operator T*()
    {
        return this->data();
    }

    //!
    //! @brief Decay into constant pointer wherever constant pointer is expected
    //!
    operator const T*() const
    {
        return this->data();
    }

    //!
    //! @brief Transfer from a device vector.
    //! @param  that That device vector.
    //! @return the hip error.
    //!
    hipError_t transfer_from(const device_vector<T>& that)
    {
        return hipMemcpy(
            this->data(), (const T*)that, sizeof(T) * this->size(), hipMemcpyDeviceToHost);
    }

    //!
    //! @brief Returns the length of the vector.
    //!
    size_t n() const
    {
        return m_n;
    }

    //!
    //! @brief Returns the increment of the vector.
    //!
    int64_t inc() const
    {
        return m_inc;
    }

    //!
    //! @brief Check if memory exists.
    //! @return hipSuccess if memory exists, hipErrorOutOfMemory otherwise.
    //!
    hipError_t memcheck() const
    {
        return (nullptr != (const T*)this) ? hipSuccess : hipErrorOutOfMemory;
    }

private:
    size_t  m_n{};
    int64_t m_inc{};
};