text: // Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #pragma once
  
  #include <NvInfer.h>
  #include <cuda_runtime_api.h>
  
  #include <atomic>
  #include <memory>
  #include <mutex>  // NOLINT
  #include <string>
  #include <unordered_map>
  #include <utility>
  #include <vector>
  
  #include "paddle/fluid/framework/tensor.h"
  #include "paddle/fluid/inference/tensorrt/engine.h"
  #include "paddle/fluid/platform/place.h"
  
  namespace paddle {
  namespace inference {
  namespace tensorrt {
  
  class TensorRTEngine;
  
  struct TRTInt8Calibrator : public nvinfer1::IInt8EntropyCalibrator2 {
   public:
    TRTInt8Calibrator(const std::unordered_map<std::string, size_t>& buffers,
                      int batch_size, std::string engine_name,
                      const platform::Place place);
  
    explicit TRTInt8Calibrator(const std::string& calibration_data);
    ~TRTInt8Calibrator();
  
    int getBatchSize() const TRT_NOEXCEPT override;
  
    bool getBatch(void* bindings[], const char* names[],
                  int num_bindings) TRT_NOEXCEPT override;
  
    bool setBatch(const std::unordered_map<std::string, void*>& data);
    void setDone();
    void waitAndSetDone();
  
    const void* readCalibrationCache(std::size_t& length) TRT_NOEXCEPT override;
    void writeCalibrationCache(const void* ptr,
                               std::size_t length) TRT_NOEXCEPT override;
    const std::string& getCalibrationTableAsString() {
      return calibration_table_;
    }
  
   private:
    const int batch_size_;
  
    bool calib_running_{true};
    bool data_is_set_{false};
    bool done_{false};
  
    std::mutex mut_;
    std::condition_variable cond_;
  
    std::unordered_map<std::string, std::pair<void*, size_t>> data_buffers_;
    std::vector<framework::Tensor> data_tensors_;
  
    std::string engine_name_;
    std::string calibration_table_;
  };
  
  class TRTCalibratorEngine {
   public:
    TRTCalibratorEngine() {}
    std::unique_ptr<TRTInt8Calibrator> calib_;
    std::unique_ptr<std::thread> thr_;
    std::unique_ptr<TensorRTEngine> engine_;
  };
  /*
   * Manager to control the TensorRT Int8 calibration creation and deltetion.
   */
  class TRTCalibratorEngineManager {
   public:
    bool Has() const { return res_.size() > 0; }
    bool Has(const std::string& name) const {
      if (res_.count(name) == 0) return false;
      return res_.at(name).get() != nullptr;
    }
  
    // Get Int8Calibrator via name
    TRTCalibratorEngine* Get(const std::string& name) const {
      return res_.at(name).get();
    }
  
    // Look up or create a calibrator.
    TRTCalibratorEngine* LookupOrCreate(const std::string& engine_name) {
      if (res_.count(engine_name) == 0) {
        auto* p = new TRTCalibratorEngine;
        res_[engine_name].reset(p);
      }
      return res_.at(engine_name).get();
    }
  
    // Create an Int8Calibrator
    TRTCalibratorEngine* Create(const std::string& engine_name) {
      auto* p = new TRTCalibratorEngine;
      res_[engine_name].reset(p);
      return p;
    }
  
    void DeleteALL() {
      for (auto& item : res_) {
        item.second.reset(nullptr);
      }
    }
  
   private:
    std::unordered_map<std::string, std::unique_ptr<TRTCalibratorEngine>> res_;
  };
  
  }  // namespace tensorrt
  }  // namespace inference
  }  // namespace paddle
  