text: #ifndef CAFFE_DATA_LAYERS_HPP_
  #define CAFFE_DATA_LAYERS_HPP_
  
  #include <vector>
  
  #include "caffe/blob.hpp"
  #include "caffe/data_transformer.hpp"
  #include "caffe/internal_thread.hpp"
  #include "caffe/layer.hpp"
  #include "caffe/proto/caffe.pb.h"
  #include "caffe/util/blocking_queue.hpp"
  
  namespace caffe {
  
  /**
   * @brief Provides base for data layers that feed blobs to the Net.
   *
   * TODO(dox): thorough documentation for Forward and proto params.
   */
  template <typename Dtype>
  class BaseDataLayer : public Layer<Dtype> {
   public:
    explicit BaseDataLayer(const LayerParameter& param);
    // LayerSetUp: implements common data layer setup functionality, and calls
    // DataLayerSetUp to do special data layer setup for individual layer types.
    // This method may not be overridden except by the BasePrefetchingDataLayer.
    virtual void LayerSetUp(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
    virtual void DataLayerSetUp(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top) {}
    // Data layers have no bottoms, so reshaping is trivial.
    virtual void Reshape(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top) {}
  
    virtual void Backward_cpu(const vector<Blob<Dtype>*>& top,
        const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom) {}
    virtual void Backward_gpu(const vector<Blob<Dtype>*>& top,
        const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom) {}
  
   protected:
    TransformationParameter transform_param_;
    shared_ptr<DataTransformer<Dtype> > data_transformer_;
    bool output_labels_;
  };
  
  template <typename Dtype>
  class Batch {
   public:
    Blob<Dtype> data_, label_, dim_;    // Added for image_seg_data_layer.*
  };
  
  template <typename Dtype>
  class BasePrefetchingDataLayer :
      public BaseDataLayer<Dtype>, public InternalThread {
   public:
    explicit BasePrefetchingDataLayer(const LayerParameter& param);
    // LayerSetUp: implements common data layer setup functionality, and calls
    // DataLayerSetUp to do special data layer setup for individual layer types.
    // This method may not be overridden.
    void LayerSetUp(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
  
    virtual void Forward_cpu(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
    virtual void Forward_gpu(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
  
   protected:
    virtual void InternalThreadEntry();
    virtual void load_batch(Batch<Dtype>* batch) = 0;
  
    vector<shared_ptr<Batch<Dtype> > > prefetch_;
    BlockingQueue<Batch<Dtype>*> prefetch_free_;
    BlockingQueue<Batch<Dtype>*> prefetch_full_;
    Batch<Dtype>* prefetch_current_;
  
    Blob<Dtype> transformed_data_;
  };
  
  // For PSPNet's data layer: image_seg_data_layer.*
  template <typename Dtype>
  class ImageDimPrefetchingDataLayer : public BasePrefetchingDataLayer<Dtype> {
   public:
    explicit ImageDimPrefetchingDataLayer(const LayerParameter& param)
        : BasePrefetchingDataLayer<Dtype>(param) {}
    virtual ~ImageDimPrefetchingDataLayer() {}
    // LayerSetUp: implements common data layer setup functionality, and calls
    // DataLayerSetUp to do special data layer setup for individual layer types.
    // This method may not be overridden.
    void LayerSetUp(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
  
    virtual void Forward_cpu(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
    virtual void Forward_gpu(const vector<Blob<Dtype>*>& bottom,
        const vector<Blob<Dtype>*>& top);
  
    // The thread's function
    //virtual void InternalThreadEntry() {}
  
   protected:
    virtual void load_batch(Batch<Dtype>* batch) = 0;
  
    Blob<Dtype> prefetch_data_dim_;
    bool output_data_dim_;
  };
  
  }  // namespace caffe
  
  #endif  // CAFFE_DATA_LAYERS_HPP_
  