Logger.h

[詳解]

#ifndef LOGGER_H
#define LOGGER_H
#include <cstdio>
#include <cstdarg>
#include <cassert>
#include <type_traits>

namespace LogFile {
  class TemporaryObject {
   private:
    FILE* fp;
    bool isHead;

   public:
    TemporaryObject(FILE* fp_);
    ~TemporaryObject();
    void putDelimiter();

    template <typename T,
              typename std::enable_if<std::is_integral<T>::value, std::nullptr_t>::type = nullptr>
    TemporaryObject& operator<<(T intValue)
    {
      putDelimiter();
      fprintf(fp, "%d", intValue);
      return *this;
    }

    template <typename T,
              typename std::enable_if<std::is_floating_point<T>::value, std::nullptr_t>::type
              = nullptr>
    TemporaryObject& operator<<(T floatingPointValue)
    {
      putDelimiter();
      fprintf(fp, "%f", floatingPointValue);
      return *this;
    }

    template <typename T,
              typename std::enable_if<std::is_same<T, const char*>::value>::type* = nullptr>
    TemporaryObject& operator<<(T stringLiteral)
    {
      putDelimiter();
      fprintf(fp, "%s", stringLiteral);
      return *this;
    }
  };
}  // namespace LogFile

class Logger {
 private:
  FILE* fp;

 public:
  Logger(const char* fileName = "log.csv", const char* mode = "w");

  ~Logger();

  void write(const char* format, ...);

  template <typename T>
  LogFile::TemporaryObject operator<<(T data)
  {
    LogFile::TemporaryObject object(fp);
    object << data;
    return object;
  }
};

#endif