printing.hpp

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#ifndef NDNPH_CORE_PRINTING_HPP
#define NDNPH_CORE_PRINTING_HPP
 
#include "common.hpp"
 
#ifdef ARDUINO
#define NDNPH_PRINT_ARDUINO
#include <Print.h>
#include <Printable.h>
#else
#define NDNPH_PRINT_OSTREAM
#include <ostream>
#endif
 
namespace ndnph {
 
#if defined(ARDUINO_ARCH_ESP32)
 
// On ESP32, ::Printable type is not trivially destructible because it has a virtual destructor.
// Consequently, it cannot serve as a base class in a type that needs to be allocated from Region.
// This Printable class is a workaround that relies on implicit conversion to Esp32Printable.
class Printable {
private:
  class Esp32Printable : public ::Printable {
  public:
    Esp32Printable(const ndnph::Printable* obj)
      : m_obj(obj) {}
 
    size_t printTo(::Print& p) const final {
      return m_obj->printTo(p);
    }
 
  private:
    const ndnph::Printable* m_obj;
  };
 
public:
  operator Esp32Printable() const {
    return Esp32Printable(this);
  }
 
  virtual size_t printTo(::Print& p) const = 0;
};
 
#elif defined(ARDUINO)
 
using Printable = ::Printable;
 
#else
 
// In non-Arduino environment, declare Printable as an empty class, so that implementers
// do not have to ifdef away the inheritance. It's still necessary to surround printTo function
// with ifdef, because Arduino ::Print class is absent.
 
class Printable {
protected:
  ~Printable() = default;
};
 
#endif
 
} // namespace ndnph
 
#endif // NDNPH_CORE_PRINTING_HPP