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#include "../precomp.hpp"
#include "layers_common.hpp"

namespace cv
{
namespace dnn
{

class CropLayerImpl : public CropLayer
{
public:
    CropLayerImpl(const LayerParams& params)
    {
        setParamsFrom(params);
        startAxis = params.get<int>("axis", 2);
        const DictValue *paramOffset = params.ptr("offset");

        if (paramOffset)
        {
            for (int i = 0; i < paramOffset->size(); i++)
                offset.push_back(paramOffset->get<int>(i));
        }
    }

    bool getMemoryShapes(const std::vector<MatShape> &inputs,
                         const int requiredOutputs,
                         std::vector<MatShape> &outputs,
                         std::vector<MatShape> &internals) const
    {
        CV_Assert(inputs.size() == 2);

        MatShape dstShape = inputs[0];
        int start = clamp(startAxis, dstShape);
        for (int i = start; i < dstShape.size(); i++)
        {
            dstShape[i] = inputs[1][i];
        }

        outputs.resize(1, dstShape);

        return false;
    }

    void finalize(const std::vector<Mat *> &inputs, std::vector<Mat> &outputs)
    {
        CV_Assert(2 == inputs.size());

        const Mat &inpBlob = *inputs[0];
        const Mat &inpSzBlob = *inputs[1];

        int dims = inpBlob.dims;
        int start_axis = clamp(startAxis, dims);

        std::vector<int> offset_final(dims, 0);
        if (offset.size() == 1)
        {
            for (int i = start_axis; i < dims; i++)
                offset_final[i] = offset[0];
        }
        else if (offset.size() > 1)
        {
            if ((int)offset.size() != dims - start_axis)
                CV_Error(Error::StsBadArg, "number of offset values specified must be "
                                           "equal to the number of dimensions following axis.");

            for (int i = start_axis; i < dims; i++)
                offset_final[i] = offset[i - start_axis];
        }

        crop_ranges.resize(dims, Range::all());
        for (int i = 0; i < dims; i++)
        {
            if( i < start_axis )
                continue;

            if (!offset.empty()) //normal case
            {
                if (offset_final[i] < 0 || offset_final[i] + inpSzBlob.size[i] > inpBlob.size[i])
                    CV_Error(Error::StsBadArg, "invalid crop parameters");

                crop_ranges[i] = Range(offset_final[i], offset_final[i] + inpSzBlob.size[i]);
            }
            else //detect offset automatically so that cropped image is center of original one
            {
                if (inpSzBlob.size[i] > inpBlob.size[i])
                    CV_Error(Error::StsBadArg, "invalid output blob size");

                int cur_crop = (inpBlob.size[i] - inpSzBlob.size[i]) / 2;
                crop_ranges[i] = Range(cur_crop, cur_crop + inpSzBlob.size[i]);
            }
        }
    }

    void forward(std::vector<Mat *> &inputs, std::vector<Mat> &outputs, std::vector<Mat> &internals)
    {
        CV_TRACE_FUNCTION();
        CV_TRACE_ARG_VALUE(name, "name", name.c_str());

        Mat &input = *inputs[0];
        Mat &output = outputs[0];

        input(&crop_ranges[0]).copyTo(output);
    }

    std::vector<Range> crop_ranges;
};


Ptr<CropLayer> CropLayer::create(const LayerParams& params)
{
    return Ptr<CropLayer>(new CropLayerImpl(params));
}

}
}
