text: // Copyright (C) 2018-2019 Intel Corporation
  // SPDX-License-Identifier: Apache-2.0
  //
  
  #pragma once
  
  #include <description_buffer.hpp>
  #include "ie_built_in_impl.hpp"
  #include <ie_layers.h>
  #include <map>
  #include <memory>
  #include <string>
  #include <vector>
  #include <debug.h>
  #include <functional>
  
  namespace InferenceEngine {
  namespace ShapeInfer {
  
  /**
   *@brief Implementation of Shape inference for Reshape layer
   */
  class FlattenShapeProp : public BuiltInShapeInferImpl {
  public:
      explicit FlattenShapeProp(const std::string &type) : BuiltInShapeInferImpl(type) {}
  
      void inferShapesImpl(const std::vector<Blob::CPtr>& inBlobs,
                           const std::map<std::string, std::string>& params,
                           const std::map<std::string, Blob::Ptr>& blobs,
                           std::vector<SizeVector>& outShapes) override {
          LayerParams lp{};
          ReshapeLayer reshapeLayer(lp);
          reshapeLayer.params = params;
          reshapeLayer.type = _type;
          validate(&reshapeLayer, inBlobs, params, blobs);
  
          auto inputShape = inShapes[0];
          size_t inputShapeTotal = std::accumulate(inputShape.begin(), inputShape.end(), 1lu, std::multiplies<size_t>());
          SizeVector outShape;
  
          int numAxes = reshapeLayer.num_axes;
          int axis = reshapeLayer.axis;
          size_t notFlatten = 1;
          if (numAxes == -1 && axis == 0) {
              outShape = {inputShapeTotal};
          } else {
              if (axis > 0) {
                  for (int i = 0; i < axis; i++) {
                      notFlatten *= inputShape[i];
                      outShape.push_back(inputShape[i]);
                  }
              }
              outShape.push_back(1);
              if (numAxes > 0) {
                  for (int i = numAxes + 1; i < inputShape.size(); i++) {
                      notFlatten *= inputShape[i];
                      outShape.push_back(inputShape[i]);
                  }
              }
              outShape[axis] = inputShapeTotal / notFlatten;
          }
  
          outShapes.emplace_back(outShape);
      }
  };
  
  }  // namespace ShapeInfer
  }  // namespace InferenceEngine
  