allocator.h

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#ifndef VISTLE_UTIL_ALLOCATOR_H
#define VISTLE_UTIL_ALLOCATOR_H
 
#include <memory>
 
namespace vistle {
 
// Allocator adaptor that interposes construct() calls to
// convert value initialization into default initialization.
// from http://stackoverflow.com/a/21028912/273767
template<typename T, typename A = std::allocator<T>>
class default_init_allocator: public A {
    typedef std::allocator_traits<A> a_t;
 
public:
    template<typename U>
    struct rebind {
        using other = default_init_allocator<U, typename a_t::template rebind_alloc<U>>;
    };
 
    using A::A;
 
    template<typename U>
    void construct(U *ptr) noexcept(std::is_nothrow_default_constructible<U>::value)
    {
        ::new (static_cast<void *>(ptr)) U;
    }
    template<typename U, typename... Args>
    void construct(U *ptr, Args &&...args)
    {
        a_t::construct(static_cast<A &>(*this), ptr, std::forward<Args>(args)...);
    }
};
 
template<typename T>
using allocator = default_init_allocator<T>;
} // namespace vistle
#endif