/*******************************************************

* Copyright (c) 2020, ArrayFire

* All rights reserved.

*

* This file is distributed under 3-clause BSD license.

* The complete license agreement can be obtained at:

* http://arrayfire.com/licenses/BSD-3-Clause

********************************************************/

#pragma once

#include <Array.hpp>

#include <err_cuda.hpp>

#include <type_traits>

namespace arrayfire {

namespace cuda {

template<typename T>

class LookupTable1D {

public:

LookupTable1D() = delete;

LookupTable1D(const LookupTable1D& arg) = delete;

LookupTable1D(const LookupTable1D&& arg) = delete;

LookupTable1D& operator=(const LookupTable1D& arg) = delete;

LookupTable1D& operator=(const LookupTable1D&& arg) = delete;

LookupTable1D(const Array<T>& lutArray) : mTexture(0), mData(lutArray) {

cudaResourceDesc resDesc;

memset(&resDesc, 0, sizeof(resDesc));

cudaTextureDesc texDesc;

memset(&texDesc, 0, sizeof(texDesc));

resDesc.resType = cudaResourceTypeLinear;

resDesc.res.linear.devPtr = mData.get();

resDesc.res.linear.desc.x = sizeof(T) * 8;

resDesc.res.linear.sizeInBytes = mData.elements() * sizeof(T);

if (std::is_signed<T>::value)

resDesc.res.linear.desc.f = cudaChannelFormatKindSigned;

else if (std::is_unsigned<T>::value)

resDesc.res.linear.desc.f = cudaChannelFormatKindUnsigned;

else

resDesc.res.linear.desc.f = cudaChannelFormatKindFloat;

texDesc.readMode = cudaReadModeElementType;

CUDA_CHECK(

cudaCreateTextureObject(&mTexture, &resDesc, &texDesc, NULL));

}

~LookupTable1D() {

if (mTexture) { cudaDestroyTextureObject(mTexture); }

}

cudaTextureObject_t get() const noexcept { return mTexture; }

private:

// Keep a copy so that ref count doesn't go down to zero when

// original Array<T> goes out of scope before LookupTable1D object does.

Array<T> mData;

cudaTextureObject_t mTexture;

};

} // namespace cuda

} // namespace arrayfire