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/*** Copyright 2010 ***** S.A.R.L. ***
* File : utility.hpp
* Date : 08/01/2010
*** ***/
#ifndef UTILITY_HPP_INC_08_01_2010__252705754_
#define UTILITY_HPP_INC_08_01_2010__252705754_ 1
#include <boost/operators.hpp>
#include <boost/mpl/for_each.hpp>
#include <boost/mpl/range_c.hpp>
#include <boost/utility/in_place_factory.hpp>
#include <boost/static_assert.hpp>
#include <new>
#include <assert.h>
#define TOOLS_ASSERT_REL(x) do{assert(x);}while(0)
namespace tools
{
namespace mpl = boost::mpl;
template< typename T, size_t N >
struct MemoryBlock
{
T* addr_at(size_t pos) { TOOLS_ASSERT_REL(pos >= 0 && pos < N); return reinterpret_cast<T*>(block_) + pos; }
T const* addr_at(size_t pos) const { TOOLS_ASSERT_REL(pos >= 0 && pos < N); return reinterpret_cast<T*>(block_) + pos; }
template< size_t Pos >
T* addr_at() { BOOST_STATIC_ASSERT( Pos >= 0 && Pos < N ); return reinterpret_cast<T*>(block_) + Pos; }
template< size_t Pos >
T const* addr_at() const { BOOST_STATIC_ASSERT( Pos >= 0 && Pos < N ); return reinterpret_cast<T*>(block_) + Pos; }
private:
char block_[ sizeof(T) * N ];
};
template< typename T, size_t N >
class OnStackInitializableArray : boost::equality_comparable< OnStackInitializableArray<T,N> >
{
BOOST_STATIC_ASSERT(( N > 0 && "YOU CANNOT SPECIFY A NULL ARRAY" )); // concept check
typedef MemoryBlock< T, N > ArrayT;
typedef OnStackInitializableArray MyType;
public:
typedef T value_type;
typedef T* iterator;
typedef T const* const_iterator;
enum { static_size = N };
static size_t size() { return N; }
bool empty() const { return !IsInit(); }
//! default construction of all members, with compilation-time unrolled loop.
// warning: built-in compilator resource limit of template recursion. constated at 491 on gcc4.0.1
void Assign0()
{
if (init_)
Destruct();
mpl::for_each< mpl::range_c<size_t, 0, N> >( InPlaceConstructMetaFctor0(array_) );
init_ = true;
}
//! construction of all members calling a constructor taking one argument of type TypeOfConstructoArgument1 (type self deducted)
template< typename TypeOfConstructoArgument1 >
void Assign1(TypeOfConstructoArgument1 const& value)
{
if (init_)
Destruct();
mpl::for_each< mpl::range_c<size_t, 0, N> >( InPlaceConstructMetaFctor1<TypeOfConstructoArgument1>(array_, value) );
init_ = true;
}
//! boost in place factory version, if you want to use a constructor with more than one argument (up tp 10)
template< typename AutoDeducedFactoryT >
void AssignN(AutoDeducedFactoryT const& inPlaceFactory)
{
if (init_)
Destruct();
mpl::for_each< mpl::range_c<size_t, 0, N> >( InPlaceConstructMetaFctorN<AutoDeducedFactoryT>(array_, inPlaceFactory) );
init_ = true;
}
//! destruct contained objects and switch back to uninitialized state
void Destruct()
{
if (init_)
{
mpl::for_each< mpl::range_c<size_t, 0, N> >( DestructMetaFctor(array_) );
}
init_ = false;
}
bool IsInit() const { return init_; }
// access to members -- compile time index:
template< size_t Pos >
T& get() { AssertIsInit_(); return *array_.template addr_at<Pos>(); }
template< size_t Pos >
T const& get() const { AssertIsInit_(); return *array_.template addr_at<Pos>(); }
// access to members -- runtime index:
T& at(size_t i) { AssertIsInit_(); return *array_.template addr_at(i); }
T const& at(size_t i) const { AssertIsInit_(); return *array_.template addr_at(i); }
// by operator []:
T& operator [] (size_t i) { return at(i); }
T const& operator[] (size_t i) const { return at(i); }
T& front() { AssertIsInit_(); return get<0>(); }
T const& front() const { AssertIsInit_(); return get<0>(); }
T& back() { AssertIsInit_(); return get<N-1>(); }
T const& back() const { AssertIsInit_(); return get<N-1>(); }
// iteration
iterator begin() { AssertIsInit_(); return array_.template addr_at<0>(); }
const_iterator begin() const { AssertIsInit_(); return array_.template addr_at<0>(); }
iterator end() { return array_.template addr_at<N-1>() + 1; }
const_iterator end() const { return array_.template addr_at<N-1>() + 1; }
//
bool operator == (MyType const& rhs) const { /*todo*/ }
MyType& operator = (MyType const& rhs) { /*todo*/ }
// structors:
OnStackInitializableArray() : init_(false) {}
~OnStackInitializableArray() { Destruct(); }
private:
ArrayT array_;
bool init_;
void AssertIsInit_() { TOOLS_ASSERT_REL(IsInit() && "UN-INITIALIZED ACCESS ATTEMPT"); }
// == internal functors repository ==
// functor that will be passed to mpl::for_each
// it will construct-in-place with default constructor.
struct InPlaceConstructMetaFctor0
{
InPlaceConstructMetaFctor0(ArrayT& arrayref) : arrayref_(arrayref) {}
template< typename MplPlacedType > void operator () (MplPlacedType v)
{
new (arrayref_.template addr_at(v)) T(); // default
}
private:
ArrayT& arrayref_;
};
// version for one argument, and that will be all. newt arities of construction will use in place factories from boost.
template< typename CtorArg1 >
struct InPlaceConstructMetaFctor1
{
InPlaceConstructMetaFctor1(ArrayT& arrayref, CtorArg1 const& value) : arrayref_(arrayref), value_(value) {}
template< typename MplPlacedType > void operator () (MplPlacedType)
{
new (arrayref_.template addr_at<MplPlacedType::value>()) T(value_);
}
private:
ArrayT& arrayref_;
CtorArg1 const& value_;
};
// version for any other number of arguments, since they are embedded into the factory
template< typename FactoryT >
struct InPlaceConstructMetaFctorN
{
InPlaceConstructMetaFctorN(ArrayT& arrayref, FactoryT const& factory) : arrayref_(arrayref), factory_(factory) {}
template< typename MplPlacedType > void operator () (MplPlacedType)
{
factory_.template apply<T>(arrayref_.template addr_at<MplPlacedType::value>());
}
private:
ArrayT& arrayref_;
FactoryT const& factory_;
};
// when the class is destructed, we have to call the desctors on our objects if they are initialized.
struct DestructMetaFctor
{
DestructMetaFctor(ArrayT& arrayref) : arrayref_(arrayref) {}
template< typename MplPlacedType > void operator () (MplPlacedType)
{
arrayref_.template addr_at<MplPlacedType::value>()->~T(); // call destructor
}
private:
ArrayT& arrayref_;
};
};
}
#endif //UTILITY_HPP_INC_08_01_2010__252705754_ |
proposition: on stack initializable array
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