Re: Reducing the virtual function table size...

From:

Ian Collins <ian-news@hotmail.com>

Newsgroups:

comp.lang.c++

Date:

Tue, 17 Apr 2007 13:46:50 +1200

Message-ID:

<58in8aF2ghlicU26@mid.individual.net>

Chris Thomasson wrote:

Consider an an object that that can has 7 or 8 functions. If you create
an abstract base class for the "interface" of the object, well, that
means 7 or 8 pure virtual functions right? Well, IMHO, that's way too
much...

Why, is it causing you problems?

I was wondering if the following technique is "frowned" upon:

All you are doing is adding an extra layer of indirection in dispatch,
what do you hope to gain from this?

<pseudo-code>
_____________
typedef struct ... vztimespec_t;

class condmutex_base {
public:
enum wait_e {
WAITLOCK, TRYLOCK, WAITCOND
};

enum wake_e {
UNLOCK, SIGNAL, BROADCAST
};

protected:
condmutex_base() {}

public:
virtual ~condmutex_base() {}

private:
virtual bool wait(wait_e, vztimespec_t const*) = 0;
virtual bool wake(wake_e) = 0;

public:
inline void unlock() { wake(wake_e::UNLOCK); }

drop the inline.

inline void waitlock() { wait(wait_e::WAITLOCK, 0); }
inline void waitcond() { wait(wait_e::WAITCOND, 0); }
inline bool trylock() { return wait(wait_e::TRYLOCK, 0); }
inline bool signal() { return wake(wake_e::SIGNAL); }
inline bool broadcast() { return wake(wake_e::BROADCAST); }

inline bool timedwaitcond(vztimespec_t const *tspec) {
return wait(wait_e::WAITCOND, tspec);
}
};
_____________

I only have 2 virtual functions now, not counting dtor, ect... Well, 2
is better than 7, or 8?

Any thoughts?

:^)

--
Ian Collins.