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#include "layers_common.hpp"

namespace cv
{
namespace dnn
{

namespace util
{

std::string makeName(const std::string& str1, const std::string& str2)
{
    return str1 + str2;
}

bool getParameter(const LayerParams &params, const std::string& nameBase, const std::string& nameAll,
                  int &parameterH, int &parameterW, bool hasDefault = false, const int& defaultValue = 0)
{
    std::string nameH = makeName(nameBase, std::string("_h"));
    std::string nameW = makeName(nameBase, std::string("_w"));
    std::string nameAll_ = nameAll;
    if(nameAll_ == "")
    {
        nameAll_ = nameBase;
    }

    if (params.has(nameH) && params.has(nameW))
    {
        parameterH = params.get<int>(nameH);
        parameterW = params.get<int>(nameW);
        return true;
    }
    else
    {
        if (params.has(nameAll_))
        {
            parameterH = parameterW = params.get<int>(nameAll_);
            return true;
        }
        else
        {
            if(hasDefault)
            {
                parameterH = parameterW = defaultValue;
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}

void getKernelSize(const LayerParams &params, int &kernelH, int &kernelW)
{
    if(!util::getParameter(params, "kernel", "kernel_size", kernelH, kernelW))
    {
        CV_Error(cv::Error::StsBadArg, "kernel_size (or kernel_h and kernel_w) not specified");
    }

    CV_Assert(kernelH > 0 && kernelW > 0);
}

void getStrideAndPadding(const LayerParams &params, int &padH, int &padW, int &strideH, int &strideW, cv::String& padMode)
{
    util::getParameter(params, "pad", "pad", padH, padW, true, 0);
    util::getParameter(params, "stride", "stride", strideH, strideW, true, 1);

    padMode = "";
    if (params.has("pad_mode"))
    {
        padMode = params.get<String>("pad_mode");
    }

    CV_Assert(padH >= 0 && padW >= 0 && strideH > 0 && strideW > 0);
}
}


void getPoolingKernelParams(const LayerParams &params, int &kernelH, int &kernelW, bool &globalPooling,
                            int &padH, int &padW, int &strideH, int &strideW, cv::String &padMode)
{
    util::getStrideAndPadding(params, padH, padW, strideH, strideW, padMode);

    globalPooling = params.has("global_pooling");

    if (globalPooling)
    {
        if(params.has("kernel_h") || params.has("kernel_w") || params.has("kernel_size"))
        {
            CV_Error(cv::Error::StsBadArg, "In global_pooling mode, kernel_size (or kernel_h and kernel_w) cannot be specified");
        }
        if(padH != 0 || padW != 0 || strideH != 1 || strideW != 1)
        {
            CV_Error(cv::Error::StsBadArg, "In global_pooling mode, pad_h and pad_w must be = 0, and stride_h and stride_w must be = 1");
        }
    }
    else
    {
        util::getKernelSize(params, kernelH, kernelW);
    }
}

void getConvolutionKernelParams(const LayerParams &params, int &kernelH, int &kernelW, int &padH, int &padW,
                                int &strideH, int &strideW, int &dilationH, int &dilationW, cv::String &padMode)
{
    util::getKernelSize(params, kernelH, kernelW);
    util::getStrideAndPadding(params, padH, padW, strideH, strideW, padMode);

    util::getParameter(params, "dilation", "dilation", dilationH, dilationW, true, 1);

    CV_Assert(dilationH > 0 && dilationW > 0);
}

// From TensorFlow code:
// Total padding on rows and cols is
// Pr = (R' - 1) * S + Kr - R
// Pc = (C' - 1) * S + Kc - C
// where (R', C') are output dimensions, (R, C) are input dimensions, S
// is stride, (Kr, Kc) are filter dimensions.
// We pad Pr/2 on the left and Pr - Pr/2 on the right, Pc/2 on the top
// and Pc - Pc/2 on the bottom.  When Pr or Pc is odd, this means
// we pad more on the right and bottom than on the top and left.
void getConvPoolOutParams(const Size& inp, const Size &kernel,
                          const Size &stride, const String &padMode,
                          Size& out)
{
    if (padMode == "VALID")
    {
        out.height = (inp.height - kernel.height + stride.height) / stride.height;
        out.width = (inp.width- kernel.width + stride.width) / stride.width;
    }
    else if (padMode == "SAME")
    {
        out.height = (inp.height - 1 + stride.height) / stride.height;
        out.width = (inp.width - 1 + stride.width) / stride.width;
    }
    else
    {
        CV_Error(Error::StsError, "Unsupported padding mode");
    }
}

void getConvPoolPaddings(const Size& inp, const Size& out,
                         const Size &kernel, const Size &stride,
                         const String &padMode, Size &pad)
{
    if (padMode == "VALID")
    {
        pad = cv::Size(0,0);
    }
    else if (padMode == "SAME")
    {
        int Ph = std::max(0, (out.height - 1) * stride.height + kernel.height - inp.height);
        int Pw = std::max(0, (out.width - 1) * stride.width + kernel.width - inp.width);
        // For odd values of total padding, add more padding at the 'right'
        // side of the given dimension.
        pad = cv::Size(Pw / 2, Ph / 2);
    }
}

}
}
