text: // Copyright (C) 2018-2019 Intel Corporation
  // SPDX-License-Identifier: Apache-2.0
  //
  
  /**
   * @brief A header file that provides a set of convenience utility functions and the main include file for all other .h files.
   * @file inference_engine.hpp
   */
  #pragma once
  
  #include <vector>
  #include <numeric>
  #include <algorithm>
  #include <memory>
  
  #include <ie_blob.h>
  #include <ie_api.h>
  #include <ie_error.hpp>
  #include <ie_layers.h>
  #include <ie_device.hpp>
  #include <ie_plugin_dispatcher.hpp>
  #include <ie_plugin_config.hpp>
  #include <ie_icnn_network.hpp>
  #include <ie_icnn_network_stats.hpp>
  #include <cpp/ie_cnn_net_reader.h>
  #include <cpp/ie_plugin_cpp.hpp>
  #include <cpp/ie_executable_network.hpp>
  #include <ie_version.hpp>
  
  namespace InferenceEngine {
  /**
   * @brief Gets the top n results from a tblob
   * @param n Top n count
   * @param input 1D tblob that contains probabilities
   * @param output Vector of indexes for the top n places
   */
  template<class T>
  inline void TopResults(unsigned int n, TBlob<T> &input, std::vector<unsigned> &output) {
      size_t input_rank = input.dims().size();
      if (!input_rank || !input.dims().at(input_rank - 1))
          THROW_IE_EXCEPTION << "Input blob has incorrect dimensions!";
      size_t batchSize = input.dims().at(input_rank - 1);
      std::vector<unsigned> indexes(input.size() / batchSize);
  
      n = static_cast<unsigned>(std::min<size_t>((size_t) n, input.size()));
  
      output.resize(n * batchSize);
  
      for (size_t i = 0; i < batchSize; i++) {
          size_t offset = i * (input.size() / batchSize);
          T *batchData = input.data();
          batchData += offset;
  
          std::iota(std::begin(indexes), std::end(indexes), 0);
          std::partial_sort(std::begin(indexes), std::begin(indexes) + n, std::end(indexes),
                            [&batchData](unsigned l, unsigned r) {
                                return batchData[l] > batchData[r];
                            });
          for (unsigned j = 0; j < n; j++) {
              output.at(i * n + j) = indexes.at(j);
          }
      }
  }
  
  #define TBLOB_TOP_RESULT(precision)\
      case InferenceEngine::Precision::precision  : {\
          using myBlobType = InferenceEngine::PrecisionTrait<Precision::precision>::value_type;\
          TBlob<myBlobType> &tblob = dynamic_cast<TBlob<myBlobType> &>(input);\
          TopResults(n, tblob, output);\
          break;\
      }
  
  /**
   * @brief Gets the top n results from a blob
   * @param n Top n count
   * @param input 1D blob that contains probabilities
   * @param output Vector of indexes for the top n places
   */
  inline void TopResults(unsigned int n, Blob &input, std::vector<unsigned> &output) {
      switch (input.precision()) {
          TBLOB_TOP_RESULT(FP32);
          TBLOB_TOP_RESULT(FP16);
          TBLOB_TOP_RESULT(Q78);
          TBLOB_TOP_RESULT(I16);
          TBLOB_TOP_RESULT(U8);
          TBLOB_TOP_RESULT(I8);
          TBLOB_TOP_RESULT(U16);
          TBLOB_TOP_RESULT(I32);
          default:
              THROW_IE_EXCEPTION << "cannot locate blob for precision: " << input.precision();
      }
  }
  
  #undef TBLOB_TOP_RESULT
  
  /**
   * @brief Copies a 8-bit RGB image to the blob.
   * Throws an exception in case of dimensions or input size mismatch
   * @tparam data_t Type of the target blob
   * @param RGB8 8-bit RGB image
   * @param RGB8_size Size of the image
   * @param blob Target blob to write image to
   */
  template<typename data_t>
  void copyFromRGB8(uint8_t *RGB8, size_t RGB8_size, InferenceEngine::TBlob<data_t> *blob) {
      if (4 != blob->dims().size())
          THROW_IE_EXCEPTION << "Cannot write data to input blob! Blob has incorrect dimensions size "
                             << blob->dims().size();
      size_t num_channels = blob->dims()[2];  // because RGB
      size_t num_images = blob->dims()[3];
      size_t w = blob->dims()[0];
      size_t h = blob->dims()[1];
      size_t nPixels = w * h;
  
      if (RGB8_size != w * h * num_channels * num_images)
          THROW_IE_EXCEPTION << "input pixels mismatch, expecting " << w * h * num_channels * num_images
                             << " bytes, got: " << RGB8_size;
  
      std::vector<data_t *> dataArray;
      for (unsigned int n = 0; n < num_images; n++) {
          for (unsigned int i = 0; i < num_channels; i++) {
              if (!n && !i && dataArray.empty()) {
                  dataArray.push_back(blob->data());
              } else {
                  dataArray.push_back(dataArray.at(n * num_channels + i - 1) + nPixels);
              }
          }
      }
      for (size_t n = 0; n < num_images; n++) {
          size_t n_num_channels = n * num_channels;
          size_t n_num_channels_nPixels = n_num_channels * nPixels;
          for (size_t i = 0; i < nPixels; i++) {
              size_t i_num_channels = i * num_channels + n_num_channels_nPixels;
              for (size_t j = 0; j < num_channels; j++) {
                  dataArray.at(n_num_channels + j)[i] = RGB8[i_num_channels + j];
              }
          }
      }
  }
  
  /**
   * @brief Splits the RGB channels to either I16 Blob or float blob.
   * The image buffer is assumed to be packed with no support for strides.
   * @param imgBufRGB8 Packed 24bit RGB image (3 bytes per pixel: R-G-B)
   * @param lengthbytesSize Size in bytes of the RGB image. It is equal to amount of pixels times 3 (number of channels)
   * @param input Blob to contain the split image (to 3 channels)
   */
  inline void ConvertImageToInput(unsigned char *imgBufRGB8, size_t lengthbytesSize, Blob &input) {
      TBlob<float> *float_input = dynamic_cast<TBlob<float> *>(&input);
      if (float_input != nullptr) copyFromRGB8(imgBufRGB8, lengthbytesSize, float_input);
  
      TBlob<short> *short_input = dynamic_cast<TBlob<short> *>(&input);
      if (short_input != nullptr) copyFromRGB8(imgBufRGB8, lengthbytesSize, short_input);
  
      TBlob<uint8_t> *byte_input = dynamic_cast<TBlob<uint8_t> *>(&input);
      if (byte_input != nullptr) copyFromRGB8(imgBufRGB8, lengthbytesSize, byte_input);
  }
  
  /**
   * @brief Copies data from a certain precision to float
   * @param dst Pointer to an output float buffer, must be allocated before the call
   * @param src Source blob to take data from
   */
  template<typename T>
  void copyToFloat(float *dst, const InferenceEngine::Blob *src) {
      if (!dst) {
          return;
      }
      const InferenceEngine::TBlob<T> *t_blob = dynamic_cast<const InferenceEngine::TBlob<T> *>(src);
      if (t_blob == nullptr) {
          THROW_IE_EXCEPTION << "input type is " << src->precision() << " but input is not " << typeid(T).name();
      }
  
      const T *srcPtr = t_blob->readOnly();
      if (srcPtr == nullptr) {
          THROW_IE_EXCEPTION << "Input data was not allocated.";
      }
      for (size_t i = 0; i < t_blob->size(); i++) dst[i] = srcPtr[i];
  }
  
  }  // namespace InferenceEngine
  