text: /*
   * Copyright (c) 2018-2021 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 "src/core/NEON/kernels/NEStackLayerKernel.h"
  
  #include "arm_compute/core/Error.h"
  #include "arm_compute/core/Helpers.h"
  #include "arm_compute/core/Helpers.h"
  #include "arm_compute/core/ITensor.h"
  #include "arm_compute/core/TensorInfo.h"
  #include "arm_compute/core/Utils.h"
  #include "arm_compute/core/Validate.h"
  #include "arm_compute/core/Window.h"
  #include "arm_compute/core/utils/misc/ShapeCalculator.h"
  #include "src/core/helpers/AutoConfiguration.h"
  #include "src/core/helpers/WindowHelpers.h"
  
  namespace arm_compute
  {
  using namespace arm_compute::misc::shape_calculator;
  
  namespace
  {
  Status validate_arguments(const ITensorInfo *input, unsigned int axis, unsigned int idx_input, unsigned int num_tensors, const ITensorInfo *output)
  {
      ARM_COMPUTE_RETURN_ERROR_ON_NULLPTR(input, output);
      // Note: ARM_COMPUTE_RETURN_ERROR_ON_CPU_F16_UNSUPPORTED(input) is not needed here as this kernel doesn't use CPU FP16 instructions.
      ARM_COMPUTE_RETURN_ERROR_ON(input->data_type() == DataType::UNKNOWN);
      ARM_COMPUTE_RETURN_ERROR_ON(idx_input >= num_tensors);
      ARM_COMPUTE_RETURN_ERROR_ON(axis > input->num_dimensions());
      ARM_COMPUTE_RETURN_ERROR_ON(input->num_dimensions() > 4);
  
      if(output->total_size() != 0)
      {
          ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DIMENSIONS(output->tensor_shape(), compute_stack_shape(*input, axis, num_tensors));
          ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(input, output);
          ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_QUANTIZATION_INFO(input, output);
      }
  
      return Status{};
  }
  
  std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, unsigned int axis, unsigned int num_tensors, ITensorInfo *output)
  {
      // Output auto inizialitation if not yet initialized
      auto_init_if_empty(*output, input->clone()->set_tensor_shape(compute_stack_shape(*input, axis, num_tensors)));
  
      // Configure kernel window
      Window win = calculate_max_window(*input);
  
      return std::make_pair(Status{}, win);
  }
  
  inline Coordinates shift_from_axis_and_replace_coordinate(const Coordinates &id, unsigned int axis, unsigned int idx_input)
  {
      constexpr int max_out_coord = 5; // Input shape is max a 4D shape, output is max 5D
      Coordinates   id_out        = id;
      for(unsigned int i = max_out_coord - 1; i > axis; --i)
      {
          id_out.set(i, id[i - 1]);
      }
      id_out.set(axis, idx_input);
      return id_out;
  }
  } // namespace
  
  NEStackLayerKernel::NEStackLayerKernel()
      : _input(nullptr), _output(nullptr), _axis(), _idx_input()
  {
  }
  
  void NEStackLayerKernel::configure(const ITensor *input, unsigned int axis, unsigned int idx_input, unsigned int num_tensors, ITensor *output)
  {
      ARM_COMPUTE_ERROR_ON_NULLPTR(input, output);
      ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(input->info(), axis, idx_input, num_tensors, output->info()));
  
      _input     = input;
      _output    = output;
      _axis      = axis;
      _idx_input = idx_input;
  
      // Configure kernel window
      auto win_config = validate_and_configure_window(input->info(), axis, num_tensors, output->info());
  
      ARM_COMPUTE_ERROR_THROW_ON(win_config.first);
      INEKernel::configure(win_config.second);
  }
  
  Status NEStackLayerKernel::validate(const ITensorInfo *input, unsigned int axis, unsigned int idx_input, unsigned int num_tensors, const ITensorInfo *output)
  {
      ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input, axis, idx_input, num_tensors, output));
      ARM_COMPUTE_RETURN_ON_ERROR(validate_and_configure_window(input->clone().get(), axis, num_tensors, output->clone().get()).first);
      return Status{};
  }
  
  void NEStackLayerKernel::run(const Window &window, const ThreadInfo &info)
  {
      ARM_COMPUTE_UNUSED(info);
      ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
      ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(INEKernel::window(), window);
  
      Window window_out;
      window_out.use_tensor_dimensions(_output->info()->tensor_shape());
  
      Iterator input(_input, window);
      Iterator output(_output, window_out);
  
      const int stride_x = _output->info()->strides_in_bytes()[0];
      const int stride_y = _output->info()->num_dimensions() >= 1 ? _output->info()->strides_in_bytes()[1] : 0;
      const int stride_z = _output->info()->num_dimensions() >= 2 ? _output->info()->strides_in_bytes()[2] : 0;
      const int stride_w = _output->info()->num_dimensions() >= 3 ? _output->info()->strides_in_bytes()[3] : 0;
      const int stride_k = _output->info()->num_dimensions() >= 4 ? _output->info()->strides_in_bytes()[4] : 0;
  
      execute_window_loop(window, [&](const Coordinates & id)
      {
          Coordinates id_out = shift_from_axis_and_replace_coordinate(id, _axis, _idx_input);
          const int   idx    = id_out[0] * stride_x + id_out[1] * stride_y + id_out[2] * stride_z + id_out[3] * stride_w + id_out[4] * stride_k;
          std::memcpy(output.ptr() + idx, input.ptr(), _input->info()->element_size());
      },
      input);
  }
  } // namespace arm_compute
  