text: /*
   * Copyright (c) 2016-2019 ARM Limited.
   *
   * SPDX-License-Identifier: MIT
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to
   * deal in the Software without restriction, including without limitation the
   * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   * sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  #include "arm_compute/core/CL/kernels/CLChannelExtractKernel.h"
  
  #include "arm_compute/core/CL/CLKernelLibrary.h"
  #include "arm_compute/core/CL/ICLMultiImage.h"
  #include "arm_compute/core/CL/ICLTensor.h"
  #include "arm_compute/core/CL/OpenCL.h"
  #include "arm_compute/core/Coordinates.h"
  #include "arm_compute/core/Error.h"
  #include "arm_compute/core/Helpers.h"
  #include "arm_compute/core/MultiImageInfo.h"
  #include "arm_compute/core/TensorInfo.h"
  #include "arm_compute/core/Types.h"
  #include "arm_compute/core/Utils.h"
  #include "arm_compute/core/Validate.h"
  #include "arm_compute/core/Window.h"
  
  #include <set>
  #include <string>
  
  using namespace arm_compute;
  
  CLChannelExtractKernel::CLChannelExtractKernel()
      : _input(nullptr), _output(nullptr), _num_elems_processed_per_iteration(8), _subsampling(1)
  {
  }
  
  void CLChannelExtractKernel::configure(const ICLTensor *input, Channel channel, ICLTensor *output)
  {
      ARM_COMPUTE_ERROR_ON_NULLPTR(input, output);
      ARM_COMPUTE_ERROR_ON(input == output);
  
      set_format_if_unknown(*output->info(), Format::U8);
  
      // Check if input tensor has a valid format
      ARM_COMPUTE_ERROR_ON_FORMAT_NOT_IN(input, Format::RGB888, Format::RGBA8888, Format::YUYV422, Format::UYVY422);
      ARM_COMPUTE_ERROR_ON_FORMAT_NOT_IN(output, Format::U8);
      ARM_COMPUTE_ERROR_ON_TENSOR_NOT_2D(output);
  
      // Check if channel is valid for given format
      const Format format = input->info()->format();
      ARM_COMPUTE_ERROR_ON_CHANNEL_NOT_IN_KNOWN_FORMAT(format, channel);
  
      // Half the processed elements for U,V channels due to sub-sampling of 2
      _subsampling = 1;
  
      if(format == Format::YUYV422 || format == Format::UYVY422)
      {
          // Check if the width of the tensor shape is even for formats with subsampled channels (UYVY422 and YUYV422)
          ARM_COMPUTE_ERROR_ON_TENSORS_NOT_EVEN(format, input);
  
          if(channel != Channel::Y)
          {
              _subsampling = 2;
          }
      }
  
      // Calculate output tensor shape using subsampling
      TensorShape output_shape = calculate_subsampled_shape(input->info()->tensor_shape(), format, channel);
      set_shape_if_empty(*output->info(), output_shape);
  
      ARM_COMPUTE_ERROR_ON_MISMATCHING_DIMENSIONS(output->info()->tensor_shape(), output_shape);
  
      _input  = input;
      _output = output;
  
      // Create kernel
      std::string           kernel_name = "channel_extract_" + string_from_format(format);
      std::set<std::string> build_opts  = { ("-DCHANNEL_" + string_from_channel(channel)) };
      _kernel                           = static_cast<cl::Kernel>(CLKernelLibrary::get().create_kernel(kernel_name, build_opts));
  
      // Configure window
      Window                 win = calculate_max_window(*input->info(), Steps(_num_elems_processed_per_iteration));
      AccessWindowHorizontal input_access(input->info(), 0, _num_elems_processed_per_iteration);
      AccessWindowRectangle  output_access(output->info(), 0, 0, _num_elems_processed_per_iteration, 1, 1.f / _subsampling, 1.f / _subsampling);
  
      update_window_and_padding(win, input_access, output_access);
  
      ValidRegion input_valid_region = input->info()->valid_region();
      output_access.set_valid_region(win, ValidRegion(input_valid_region.anchor, output->info()->tensor_shape()));
  
      ICLKernel::configure_internal(win);
  }
  
  void CLChannelExtractKernel::configure(const ICLMultiImage *input, Channel channel, ICLImage *output)
  {
      ARM_COMPUTE_ERROR_ON_NULLPTR(input, output);
      ARM_COMPUTE_ERROR_ON_TENSOR_NOT_2D(output);
  
      set_format_if_unknown(*output->info(), Format::U8);
  
      // Check if channel is valid for given format
      const Format format = input->info()->format();
      ARM_COMPUTE_ERROR_ON_CHANNEL_NOT_IN_KNOWN_FORMAT(format, channel);
  
      // Get input plane from the given channel
      const ICLImage *input_plane = input->cl_plane(plane_idx_from_channel(format, channel));
      ARM_COMPUTE_ERROR_ON_NULLPTR(input_plane);
  
      if(Channel::Y == channel && format != Format::YUV444)
      {
          // Check if the width of the tensor shape is even for formats with subsampled channels (UYVY422 and YUYV422)
          ARM_COMPUTE_ERROR_ON_TENSORS_NOT_EVEN(format, input_plane);
      }
  
      // Calculate 2x2 subsampled tensor shape
      TensorShape output_shape = calculate_subsampled_shape(input->cl_plane(0)->info()->tensor_shape(), format, channel);
      set_shape_if_empty(*output->info(), output_shape);
  
      ARM_COMPUTE_ERROR_ON_MISMATCHING_DIMENSIONS(output_shape, output->info()->tensor_shape());
  
      // Check if input tensor has a valid format
      ARM_COMPUTE_ERROR_ON_FORMAT_NOT_IN(input, Format::NV12, Format::NV21, Format::IYUV, Format::YUV444);
      ARM_COMPUTE_ERROR_ON_FORMAT_NOT_IN(output, Format::U8);
  
      _output      = output;
      _input       = input_plane;
      _subsampling = 1;
  
      // Create kernel
      std::string           kernel_name;
      std::set<std::string> build_opts;
      if(Channel::Y == channel || Format::IYUV == format || Format::YUV444 == format)
      {
          kernel_name = "copy_plane";
      }
      else
      {
          kernel_name = "channel_extract_" + string_from_format(format);
          build_opts.insert(("-DCHANNEL_" + string_from_channel(channel)));
      }
      _kernel = static_cast<cl::Kernel>(CLKernelLibrary::get().create_kernel(kernel_name, build_opts));
  
      // Configure window
      Window                 win = calculate_max_window(*input_plane->info(), Steps(_num_elems_processed_per_iteration));
      AccessWindowHorizontal input_access(input_plane->info(), 0, _num_elems_processed_per_iteration);
      AccessWindowHorizontal output_access(output->info(), 0, _num_elems_processed_per_iteration);
  
      update_window_and_padding(win, input_access, output_access);
  
      output_access.set_valid_region(win, input_plane->info()->valid_region());
  
      ICLKernel::configure_internal(win);
  }
  
  void CLChannelExtractKernel::run(const Window &window, cl::CommandQueue &queue)
  {
      ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
      ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(ICLKernel::window(), window);
  
      Window slice = window.first_slice_window_2D();
  
      do
      {
          Window win_sub(slice);
          win_sub.set(Window::DimX, Window::Dimension(win_sub.x().start() / _subsampling, win_sub.x().end() / _subsampling, win_sub.x().step() / _subsampling));
          win_sub.set(Window::DimY, Window::Dimension(win_sub.y().start() / _subsampling, win_sub.y().end() / _subsampling, 1));
  
          unsigned int idx = 0;
          add_2D_tensor_argument(idx, _input, slice);
          add_2D_tensor_argument(idx, _output, win_sub);
          enqueue(queue, *this, slice, lws_hint());
      }
      while(window.slide_window_slice_2D(slice));
  }
  