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}
bslma::Allocator *allocator() const
// Return the allocator used by this object to supply memory.
{
return d_allocator_p;
}
// etc.
};
//..
// Next, we implement the constructors that allocate memory and construct a
// 'TYPE' object in the allocated memory. We perform the allocation using the
// 'allocate' method of 'bslma::Allocator' and the construction using the
// 'construct' method of 'ConstructionUtil' that provides the correct semantics
// for passing the allocator to the constructed object when appropriate:
//..
template <class TYPE>
MyContainer<TYPE>::MyContainer(bslma::Allocator *basicAllocator)
: d_allocator_p(bslma::Default::allocator(basicAllocator))
{
d_value_p = static_cast<TYPE *>(d_allocator_p->allocate(sizeof(TYPE)));
MyContainerProctor<TYPE> proctor(d_allocator_p, d_value_p);
// Call 'construct' with no constructor arguments (aside from the
// allocator).
bslma::ConstructionUtil::construct(d_value_p, d_allocator_p);
proctor.release();
}
template <class TYPE>
template <class OTHER>
MyContainer<TYPE>::MyContainer(
BSLS_COMPILERFEATURES_FORWARD_REF(OTHER) value,
bslma::Allocator *basicAllocator)
: d_allocator_p(bslma::Default::allocator(basicAllocator))
{
d_value_p = static_cast<TYPE *>(d_allocator_p->allocate(sizeof(TYPE)));
MyContainerProctor<TYPE> proctor(d_allocator_p, d_value_p);
// Call 'construct' by forwarding 'value'.
bslma::ConstructionUtil::construct(
d_value_p,
d_allocator_p,
BSLS_COMPILERFEATURES_FORWARD(OTHER, value));
proctor.release();
}
//..
// Then, we define the copy constructor for 'MyContainer'. Note that we don't
// propagate the allocator from the 'original' container, but use
// 'basicAllocator' instead:
//..
template <class TYPE>
MyContainer<TYPE>::MyContainer(const MyContainer& original,
bslma::Allocator *basicAllocator)
: d_allocator_p(bslma::Default::allocator(basicAllocator))
{
d_value_p = static_cast<TYPE *>(d_allocator_p->allocate(sizeof(TYPE)));
MyContainerProctor<TYPE> proctor(d_allocator_p, d_value_p);
// Call 'construct' so as to copy-construct the element contained by
// 'original'.
bslma::ConstructionUtil::construct(d_value_p,
d_allocator_p,
*original.d_value_p);
proctor.release();
}
//..
// Now, the destructor destroys the object and deallocates the memory used to
// hold the element using the allocator:
//..
template <class TYPE>
MyContainer<TYPE>::~MyContainer()
{
d_value_p->~TYPE();
d_allocator_p->deallocate(d_value_p);
}
//..
// Next, the assignment operator needs to assign the value without modifying
// the allocator.
//..
template <class TYPE>
MyContainer<TYPE>& MyContainer<TYPE>::operator=(const TYPE& rhs)
{
*d_value_p = rhs;
return *this;
}
template <class TYPE>
MyContainer<TYPE>& MyContainer<TYPE>::operator=(const MyContainer& rhs)
{
*d_value_p = *rhs.d_value_p;
return *this;
}
//..
// Finally, we perform a simple test of 'MyContainer', instantiating it with
// element type 'int':