C++ Serialization

For various reasons I would like to be able to serialize some C++ classes that contain various arrays and other objects. In fact what I'm trying to do is to save state, contained in some nested classes and restart my program so that I can do some debugging.

My question is, is there an automated technique or perhaps some cut and paste boilerplate code or templates for achieving serialization and deserialization in C++? Do I have to write my own for every class?

Some languages provide some automation for this task.

There's no automatic method for doing this, but generally, you can do this:

Code:

---

class subclass
{
private:
    int x;
    int y;
    ...
    friend ostream &operator<<(ostream &os, const subclass &sub);
    friend istream &operator>>(ostream &is, subclass &sub);
};

ostream &operator<<(ostream &os, const subclass &sub)
{
    os << sub.x << " " << sub.y << endl;
    return os;
}

istream &operator>>(istream &is, subclass &sub)
{
  is >> sub.x >> sub.y;
  return is;
}

class mainclass
{
private:
  subclass arr[10];
  std::string s;

  friend ostream& operator<<(ostream &os, const mainclass &m);
  friend istream& operator>>(istream &os, mainclass &m);
}

friend ostream& operator<<(ostream &os, const mainclass &m)
{
    for(i = 0; i < 10; i++)
      os << arr[i];
    os << string;
}

friend istream& operator>>(istream &os, mainclass &m)
{
    for(i = 0; i < 10; i++)
      os >> arr[i];
    getline(os, string);
}

---

So, you let each subclass output itself, making the overall serialization simpler.

--
Mats

OK I understand and it makes sense. I'm curious though, when you output a numeric array via the stream operators << , are they saved as text or binary by default?

Quote:

---

Originally Posted by SevenThunders

OK I understand and it makes sense. I'm curious though, when you output a numeric array via the stream operators << , are they saved as text or binary by default?

---

Text, since << and >> are text extraction/insertion operators.


You may want to look into Boost's serialization facilities. They use the same operator for serialization and deserialization ('&') which means you don't have to write two functions which look identical to each other except for the '<<' vs '>>'

Boost.Serialization provides many other advantages over plain iostream overloading, like the ability to resolve circular and multiple references, polymorphic pointers, support for versioning and support for multiple serialization formats.