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#pragma once

#ifndef OPENCV_CUDEV_GRID_REDUCE_TO_COLUMN_DETAIL_HPP
#define OPENCV_CUDEV_GRID_REDUCE_TO_COLUMN_DETAIL_HPP

#include "../../common.hpp"
#include "../../util/saturate_cast.hpp"
#include "../../block/reduce.hpp"

namespace cv { namespace cudev {

namespace grid_reduce_to_vec_detail
{
    template <int BLOCK_SIZE, typename work_type, typename work_elem_type, class Reductor, int cn> struct Reduce;

    template <int BLOCK_SIZE, typename work_type, typename work_elem_type, class Reductor> struct Reduce<BLOCK_SIZE, work_type, work_elem_type, Reductor, 1>
    {
        __device__ __forceinline__ static void call(work_elem_type smem[1][BLOCK_SIZE], work_type& myVal)
        {
            typename Reductor::template rebind<work_elem_type>::other op;
            blockReduce<BLOCK_SIZE>(smem[0], myVal, threadIdx.x, op);
        }
    };

    template <int BLOCK_SIZE, typename work_type, typename work_elem_type, class Reductor> struct Reduce<BLOCK_SIZE, work_type, work_elem_type, Reductor, 2>
    {
        __device__ __forceinline__ static void call(work_elem_type smem[2][BLOCK_SIZE], work_type& myVal)
        {
            typename Reductor::template rebind<work_elem_type>::other op;
            blockReduce<BLOCK_SIZE>(smem_tuple(smem[0], smem[1]), tie(myVal.x, myVal.y), threadIdx.x, make_tuple(op, op));
        }
    };

    template <int BLOCK_SIZE, typename work_type, typename work_elem_type, class Reductor> struct Reduce<BLOCK_SIZE, work_type, work_elem_type, Reductor, 3>
    {
        __device__ __forceinline__ static void call(work_elem_type smem[3][BLOCK_SIZE], work_type& myVal)
        {
            typename Reductor::template rebind<work_elem_type>::other op;
            blockReduce<BLOCK_SIZE>(smem_tuple(smem[0], smem[1], smem[2]), tie(myVal.x, myVal.y, myVal.z), threadIdx.x, make_tuple(op, op, op));
        }
    };

    template <int BLOCK_SIZE, typename work_type, typename work_elem_type, class Reductor> struct Reduce<BLOCK_SIZE, work_type, work_elem_type, Reductor, 4>
    {
        __device__ __forceinline__ static void call(work_elem_type smem[4][BLOCK_SIZE], work_type& myVal)
        {
            typename Reductor::template rebind<work_elem_type>::other op;
            blockReduce<BLOCK_SIZE>(smem_tuple(smem[0], smem[1], smem[2], smem[3]), tie(myVal.x, myVal.y, myVal.z, myVal.w), threadIdx.x, make_tuple(op, op, op, op));
        }
    };

    template <class Reductor, int BLOCK_SIZE, class SrcPtr, typename ResType, class MaskPtr>
    __global__ void reduceToColumn(const SrcPtr src, ResType* dst, const MaskPtr mask, const int cols)
    {
        typedef typename Reductor::work_type work_type;
        typedef typename VecTraits<work_type>::elem_type work_elem_type;
        const int cn = VecTraits<work_type>::cn;

        __shared__ work_elem_type smem[cn][BLOCK_SIZE];

        const int y = blockIdx.x;

        work_type myVal = Reductor::initialValue();

        Reductor op;

        for (int x = threadIdx.x; x < cols; x += BLOCK_SIZE)
        {
            if (mask(y, x))
            {
                myVal = op(myVal, saturate_cast<work_type>(src(y, x)));
            }
        }

        Reduce<BLOCK_SIZE, work_type, work_elem_type, Reductor, cn>::call(smem, myVal);

        if (threadIdx.x == 0)
            dst[y] = saturate_cast<ResType>(Reductor::result(myVal, cols));
    }

    template <class Reductor, class Policy, class SrcPtr, typename ResType, class MaskPtr>
    __host__ void reduceToColumn(const SrcPtr& src, ResType* dst, const MaskPtr& mask, int rows, int cols, cudaStream_t stream)
    {
        const int BLOCK_SIZE_X = Policy::block_size_x;
        const int BLOCK_SIZE_Y = Policy::block_size_y;

        const int BLOCK_SIZE = BLOCK_SIZE_X * BLOCK_SIZE_Y;

        const dim3 block(BLOCK_SIZE);
        const dim3 grid(rows);

        reduceToColumn<Reductor, BLOCK_SIZE><<<grid, block, 0, stream>>>(src, dst, mask, cols);
        CV_CUDEV_SAFE_CALL( cudaGetLastError() );

        if (stream == 0)
            CV_CUDEV_SAFE_CALL( cudaDeviceSynchronize() );

    }
}

}}

#endif