text: // Copyright (c) Microsoft Corporation. All rights reserved.
  // Licensed under the MIT License.
  
  #include "core/providers/common.h"
  #include "core/providers/shared/utils/utils.h"
  #include "core/providers/coreml/builders/helper.h"
  #include "core/providers/coreml/builders/model_builder.h"
  #include "core/providers/coreml/builders/op_builder_factory.h"
  
  #include "base_op_builder.h"
  
  namespace onnxruntime {
  namespace coreml {
  
  class ConcatOpBuilder : public BaseOpBuilder {
    // Add operator related
   private:
    Status AddToModelBuilderImpl(ModelBuilder& model_builder, const Node& node,
                                 const logging::Logger& logger) const override ORT_MUST_USE_RESULT;
  
    // Operator support related
   private:
    bool IsOpSupportedImpl(const Node& node, const OpBuilderInputParams& input_params,
                           const logging::Logger& logger) const override;
  };
  
  // Add operator related
  
  Status ConcatOpBuilder::AddToModelBuilderImpl(ModelBuilder& model_builder,
                                                const Node& node,
                                                const logging::Logger& logger) const {
    std::unique_ptr<COREML_SPEC::NeuralNetworkLayer> layer = CreateNNLayer(model_builder, node);
  
    layer->mutable_concat()->set_sequenceconcat(false);
  
    for (const auto* input : node.InputDefs()) {
      LOGS(logger, VERBOSE) << "input name " << input->Name();
      *layer->mutable_input()->Add() = input->Name();
    }
  
    *layer->mutable_output()->Add() = node.OutputDefs()[0]->Name();
  
    model_builder.AddLayer(std::move(layer));
    return Status::OK();
  }
  
  // Operator support related
  bool ConcatOpBuilder::IsOpSupportedImpl(const Node& node, const OpBuilderInputParams& /* input_params */,
                                          const logging::Logger& logger) const {
    const auto& input_defs = node.InputDefs();
    if (input_defs.size() < 2) {
      LOGS(logger, VERBOSE) << "Concat only support 2+ inputs, actual number of inputs: " << input_defs.size();
      return false;
    }
  
    std::vector<int64_t> input_shape;
    if (!GetShape(*input_defs[0], input_shape, logger))
      return false;
  
    auto rank = input_shape.size();
    if (rank != 4) {
      // For some reason, the concat in CoreML running on 3d tensor will concat on wrong axis
      // Instead of concat on axis 0, it will concat on axis 1
      // Disable Concat support for 3d tensor for now
      // TODO, add ExpandDims and Squeeze, 3d -ExpandDims-> 4d -> Concat -Squeeze-> 3d
      LOGS(logger, VERBOSE) << "Concat only support 4d shape for now, input is "
                            << rank << "d shape";
      return false;
    }
  
    NodeAttrHelper helper(node);
    auto axis = static_cast<size_t>(HandleNegativeAxis(helper.Get("axis", 1), rank));
    if (rank != axis + 3) {
      LOGS(logger, VERBOSE) << "Concat only support axis to be -3, actual axis: " << axis
                            << ", actual rank: " << rank;
      return false;
    }
  
    return true;
  }
  
  void CreateConcatOpBuilder(const std::string& op_type, OpBuilderRegistrations& op_registrations) {
    op_registrations.builders.push_back(std::make_unique<ConcatOpBuilder>());
    op_registrations.op_builder_map.emplace(op_type, op_registrations.builders.back().get());
  }
  
  }  // namespace coreml
  }  // namespace onnxruntime
  