text: /**
   * By downloading, copying, installing or using the software you agree to this license.
   * If you do not agree to this license, do not download, install,
   * copy or use the software.
   *
   *
   *                           License Agreement
   *                For Open Source Computer Vision Library
   *                        (3-clause BSD License)
   *
   * Copyright (C) 2000-2020, Intel Corporation, all rights reserved.
   * Copyright (C) 2009-2011, Willow Garage Inc., all rights reserved.
   * Copyright (C) 2009-2016, NVIDIA Corporation, all rights reserved.
   * Copyright (C) 2010-2013, Advanced Micro Devices, Inc., all rights reserved.
   * Copyright (C) 2015-2016, OpenCV Foundation, all rights reserved.
   * Copyright (C) 2015-2016, Itseez Inc., all rights reserved.
   * Copyright (C) 2019-2020, Xperience AI, all rights reserved.
   * Third party copyrights are property of their respective owners.
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   * are permitted provided that the following conditions are met:
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   *     this list of conditions and the following disclaimer.
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   *     this list of conditions and the following disclaimer in the documentation
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   *   * Neither the names of the copyright holders nor the names of the contributors
   *     may be used to endorse or promote products derived from this software
   *     without specific prior written permission.
   *
   * This software is provided by the copyright holders and contributors "as is" and
   * any express or implied warranties, including, but not limited to, the implied
   * warranties of merchantability and fitness for a particular purpose are disclaimed.
   * In no event shall copyright holders or contributors be liable for any direct,
   * indirect, incidental, special, exemplary, or consequential damages
   * (including, but not limited to, procurement of substitute goods or services;
   * loss of use, data, or profits; or business interruption) however caused
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   * the use of this software, even if advised of the possibility of such damage.
   *
   * ---------------------------------------------------------------------------
   * \file dnn/src/fallback/gaussian_blur/filter.h
   *
   * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
   *
   * Copyright (c) 2014-2020 Megvii Inc. All rights reserved.
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *
   * This file has been modified by Megvii ("Megvii Modifications").
   * All Megvii Modifications are Copyright (C) 2014-2019 Megvii Inc. All rights reserved.
   *
   * ---------------------------------------------------------------------------
   */
  #include "src/common/cv/filter.h"
  
  #include <cfloat>
  #include <cmath>
  #include <type_traits>
  
  namespace megdnn {
  namespace megcv {
  namespace gaussian_blur {
  
  using namespace filter_common;
  
  /*!
   * \brief get the row filter.
   * \tparam ST The src image type.
   * \tparam FT The inner buffer type, used to store the product of src and
   * filter.
   */
  template <typename ST, typename FT>
  static BaseRowFilter* getLinearRowFilter(Mat<FT>& kernel) {
      int ksize = kernel.cols();
      int anchor = ksize / 2;
  
      uchar* kernel_str = static_cast<uchar*>(kernel.raw_ptr());
  
      if (ksize <= 5) {
          if (std::is_same<ST, uchar>::value && std::is_same<FT, int>::value)
              return new SymmRowSmallFilter<ST, FT, SymmRowSmallNoVec>(
                      kernel, anchor, SymmRowSmallNoVec(kernel_str, ksize));
  
          if (std::is_same<ST, float>::value && std::is_same<FT, float>::value)
              return new SymmRowSmallFilter<ST, FT, SymmRowSmallNoVec>(
                      kernel, anchor, SymmRowSmallNoVec(kernel_str, ksize));
      }
  
      if (std::is_same<ST, uchar>::value && std::is_same<FT, int>::value)
          return new RowFilter<ST, FT, RowNoVec>(kernel, anchor,
                                                RowNoVec(kernel_str, ksize));
  
      if (std::is_same<ST, float>::value && std::is_same<FT, float>::value)
          return new RowFilter<ST, FT, RowNoVec>(kernel, anchor,
                                                RowNoVec(kernel_str, ksize));
  
      MegCVException(
              "Unsupported combination of source format and buffer format\n");
  }
  
  /*!
   * \brief get the column filter.
   * \tparam FT The inner buffer type, used to store the product of src and
   * filter.
   * \tparam DT The dst image type.
   */
  template <typename FT, typename DT>
  static BaseColumnFilter* getLinearColumnFilter(Mat<FT>& kernel, int bits) {
      int ksize = kernel.cols();
      int anchor = ksize / 2;
  
      uchar* kernel_str = static_cast<uchar*>(kernel.raw_ptr());
      if (ksize == 3) {
          if (std::is_same<DT, uchar>::value && std::is_same<FT, int>::value)
              return new SymmColumnSmallFilter<FixedPtCastEx<FT, DT>,
                                               SymmColumnSmallNoVec>(
                      kernel, anchor, FixedPtCastEx<FT, DT>(bits),
                      SymmColumnSmallNoVec(kernel_str, ksize, bits));
  
          if (std::is_same<DT, float>::value && std::is_same<FT, float>::value)
              return new SymmColumnSmallFilter<FixedPtCastEx<FT, DT>,
                                               SymmColumnSmallNoVec>(
                      kernel, anchor, FixedPtCastEx<FT, DT>(0),
                      SymmColumnSmallNoVec(kernel_str, ksize, 0));
      }
      if (std::is_same<DT, uchar>::value && std::is_same<FT, int>::value)
          return new SymmColumnFilter<FixedPtCastEx<FT, DT>, ColumnNoVec>(
                  kernel, anchor, FixedPtCastEx<FT, DT>(bits),
                  ColumnNoVec(kernel_str, ksize, bits));
  
      if (std::is_same<DT, float>::value && std::is_same<FT, float>::value)
          return new SymmColumnFilter<FixedPtCastEx<FT, DT>, ColumnNoVec>(
                  kernel, anchor, FixedPtCastEx<FT, DT>(),
                  ColumnNoVec(kernel_str, ksize, 0));
  
      MegCVException(
              "Unsupported combination of source format and buffer format\n");
  }
  
  }  // namespace gaussian_blur
  }  // namespace megcv
  }  // namespace megdnn
  
  // vim: syntax=cpp.doxygen
  