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#include "test_precomp.hpp"

#ifdef HAVE_CUDA

namespace
{
    struct GreedyLabeling
    {
        struct dot
        {
            int x;
            int y;

            static dot make(int i, int j)
            {
                dot d; d.x = i; d.y = j;
                return d;
            }
        };

        struct InInterval
        {
            InInterval(const int& _lo, const int& _hi) : lo(-_lo), hi(_hi) {};
            const int lo, hi;

            bool operator() (const unsigned char a, const unsigned char b) const
            {
                int d = a - b;
                return lo <= d && d <= hi;
            }
        };

        GreedyLabeling(cv::Mat img)
        : image(img), _labels(image.size(), CV_32SC1, cv::Scalar::all(-1)) {}

        void operator() (cv::Mat labels) const
        {
            InInterval inInt(0, 2);
            dot* stack = new dot[image.cols * image.rows];

            int cc = -1;

            int* dist_labels = (int*)labels.data;
            int pitch = (int) labels.step1();

            unsigned char* source = (unsigned char*)image.data;
            int width = image.cols;
            int height = image.rows;
            int step1 = (int)image.step1();

            for (int j = 0; j < image.rows; ++j)
                for (int i = 0; i < image.cols; ++i)
                {
                    if (dist_labels[j * pitch + i] != -1) continue;

                    dot* top = stack;
                    dot p = dot::make(i, j);
                    cc++;

                    dist_labels[j * pitch + i] = cc;

                    while (top >= stack)
                    {
                        int*  dl = &dist_labels[p.y * pitch + p.x];
                        unsigned char* sp = &source[p.y * step1 + p.x];

                        dl[0] = cc;

                        //right
                        if( p.x < (width - 1) && dl[ +1] == -1 && inInt(sp[0], sp[+1]))
                            *top++ = dot::make(p.x + 1, p.y);

                        //left
                        if( p.x > 0 && dl[-1] == -1 && inInt(sp[0], sp[-1]))
                            *top++ = dot::make(p.x - 1, p.y);

                        //bottom
                        if( p.y < (height - 1) && dl[+pitch] == -1 && inInt(sp[0], sp[+step1]))
                            *top++ = dot::make(p.x, p.y + 1);

                        //top
                        if( p.y > 0 && dl[-pitch] == -1 && inInt(sp[0], sp[-step1]))
                            *top++ = dot::make(p.x, p.y - 1);

                        p = *--top;
                    }
                }
            delete[] stack;
        }

        void checkCorrectness(cv::Mat gpu)
        {
            cv::Mat diff = gpu - _labels;

            int outliers = 0;
            for (int j = 0; j < image.rows; ++j)
                for (int i = 0; i < image.cols - 1; ++i)
                {
                    if ( (_labels.at<int>(j,i) == gpu.at<int>(j,i + 1)) && (diff.at<int>(j, i) != diff.at<int>(j,i + 1)))
                    {
                        outliers++;
                    }
                }
            ASSERT_TRUE(outliers < gpu.cols + gpu.rows);
        }

        cv::Mat image;
        cv::Mat _labels;
    };
}

struct Labeling : testing::TestWithParam<cv::gpu::DeviceInfo>
{
    cv::gpu::DeviceInfo devInfo;

    virtual void SetUp()
    {
        devInfo = GetParam();
        cv::gpu::setDevice(devInfo.deviceID());
    }

    cv::Mat loat_image()
    {
        return cv::imread(std::string( cvtest::TS::ptr()->get_data_path() ) + "labeling/label.png");
    }
};

GPU_TEST_P(Labeling, ConnectedComponents)
{
    cv::Mat image;
    cvtColor(loat_image(), image, CV_BGR2GRAY);

    cv::threshold(image, image, 150, 255, CV_THRESH_BINARY);

    ASSERT_TRUE(image.type() == CV_8UC1);

    GreedyLabeling host(image);
    host(host._labels);

    cv::gpu::GpuMat mask;
    mask.create(image.rows, image.cols, CV_8UC1);

    cv::gpu::GpuMat components;
    components.create(image.rows, image.cols, CV_32SC1);

    cv::gpu::connectivityMask(cv::gpu::GpuMat(image), mask, cv::Scalar::all(0), cv::Scalar::all(2));

    ASSERT_NO_THROW(cv::gpu::labelComponents(mask, components));

    host.checkCorrectness(cv::Mat(components));
}

INSTANTIATE_TEST_CASE_P(GPU_ConnectedComponents, Labeling, ALL_DEVICES);

#endif // HAVE_CUDA