C++Talk.NET

Sarir Khamsi · Guest

I'm working on a data store to hold any type of object. It is based
slightly on boost::any, but I found that class to be too cumbersome to
use. Briefly, the more elements I add to the store, it appears to
increase the compile time quadratically.

The data store class looks like:

class Store {
public:
typedef std::map<const char *, Any*> Data;
// members

private:
Data data_; // this is where all the data is
};

The class Any looks like:

class Any {
public:
template<typename T>
Any(const T &value) :
pHeld_(new Holder<T>(value)) { }

private:
HolderBase *pHeld_;
};

(HolderBase is not a class template.) The class Holder looks like:

template<typename T>
class Holder : public HolderBase
{
public:
Holder(const T &value) :
HolderBase(),
value_(value) { }

// yes, it's public
typename Types<T>::value_type value_;
};

Types is a type generator:

template<typename T> struct Types { typedef T value_type; };

When I try and add more elements to the map data_ member in Store's ctor
with:

Store::Store() :
data_()
{
data_["vel"] = new Any(double(5.9));
data_["mode"] = new Any(int(73));
data_["finishedBIT"] = new Any(bool(false));
// add more elements here
}

I'm fine until I get to larger numbers of elements. It seems like the
more elements I add, the longer it takes to compile...a lot
longer...not what I would have expected. This is using gcc 3.3.1 on
Win2k, SP3.

My questions are:

1) Is there a way to find out where the compiler spending most of its
time?
2) I tried to explicitly instantiate some templates, such as
template Any::Any(const int&);
template Any::Any(const unsigned int&);
template Any::Any(const double&);
but that didn't help. Is there something else I can do as far as
explicit instantiation is concerned to speed up the compile?
3) What's wrong with this code?
4) Is my code possessed by some satanic entity?

Thanks.

Sarir

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David Abrahams · Guest

Sarir Khamsi <sarir_a_khamsi (AT) raytheon (DOT) com> writes:

Sarir Khamsi · Guest

David Abrahams <dave (AT) boost-consulting (DOT) com> writes: