serialization

[nadiap]

Hello again!
i am trying to store a struct into a file. The struct is:

struct single-event{
	eca event_name;
	vector<string>params;
	void WriteSingleEvent(ofstream& of);
	
};

where "eca" is an enum.

what i did in order to serialize this struct is :

template<typename T>
void Output(std::ofstream& o, T& t){
	o.write(reinterpret_cast<char*>(&t),sizeof(T));
}

void OutString(std::ofstream &o, const std::string &s)
{
	int size=s.size();
	Output<int>(o,size);
	o.write(s.c_str(),size);
}
void single-event::WriteSingleEvent(ofstream& o){
	of.write(reinterpret_cast<char*>(&event_name),sizeof(event_name));
	Output<long>(o,params.size());
	std::for_each(params.begin(),params.end(),std::bind1st(OutString,o)); 
}

now i really want your opinion. is this right?
thank you very much!:WAVE:

[Danny]

serializing a vector of strings requires that the strings in the vector be flatten into a sequence of char arrays, possible seprates by a certain token. Alternative you cna write the size of each string as the first word, and then read the same number of characters, in a loop. Remember: serialization has to be done with desrialization in mind so you have to devise a protocol that knows how the data are stored in the file.

[nadiap]

Danny thank you for your reply. Actually isn't this what i actually do?
I mean i do write the size of each string through

Output<long>(o,params.size());
std::for_each(params.begin(),params.end(),std::bind1st(OutString,o));//do i use the std::bind1st function right?

since the OutString function is:

void OutString(std::ofstream &o, const std::string &s)
{
	int size=s.size();
	Output<int>(o,size);//stores the size of each string
	o.write(s.c_str(),size);//stores the string itself
}

and the simple Output function:

template<typename T>
void Output(std::ofstream& o, T& t){
	o.write(reinterpret_cast<char*>(&t),sizeof(T));
}

[it career]

function pointer cannot be serialized.

[nadiap]

could you please be more certain?
what function pointer?
thank you.

[Danny]

No, that's not what your program does. You're (probably) trying to cast a whole string object and treat as if it were the char array that the string contains. Hint: you don't need reinterpret_cast or a template. Simple use write(str.c_str()).

[nadiap]

Danny thank you once again.
Would i ask so much if i told you to explain further?
i don't exactly understand what you suggest and why my code is wrong.
I am really stuck.
Thank you. Sorry for the insistence...

[Danny]

I discussed serialization of strings here:
http://www.devx.com/getHelpOn/LegacyLink/9487