rngxx/include/mem.h

#pragma once

#include <new>
#include <utility>

#include "common.h"

namespace mem
{	template<typename T>
	struct aligned_ptr;
	template<>
	struct aligned_ptr<void>;
	using aligned_ptr_util = aligned_ptr<void>;
	template<>
	struct aligned_ptr<void> final
	{
		template<typename T>
		static inline T* alloc(T&& value) 
		{
			u8* ptr = reinterpret_cast<u8*>(_alloc(alignof(T), sizeof(T)));
			new(ptr) T(std::move(value));
			return reinterpret_cast<T*>(ptr);
		}
		template<typename T>
		static inline T* alloc()
		{
			return alloc(T());
		}
		template<typename T, typename... Args>
		static inline T* make(Args&&... init) { return alloc(T(std::forward<Args>(init)...)); }

		template<typename T>
		static inline void dealloc(T* ptr) { ptr->~T(); _dealloc(reinterpret_cast<void*>(ptr)); }
	private:
		static void* _alloc(usize align, usize size);
		static void  _dealloc(void* ptr);
		constexpr inline ~aligned_ptr(){}
	};
	template<typename T>
	struct aligned_ptr final
	{
		inline explicit aligned_ptr(T* raw) : ptr(raw){}

		inline aligned_ptr(aligned_ptr<T>&& move) : ptr(move.ptr) { *const_cast<T**>(&move.ptr) = nullptr; }

		inline aligned_ptr(T&& box) : aligned_ptr(aligned_ptr_util::alloc(std::move(box))){}
		inline aligned_ptr() : aligned_ptr(T()){}

		inline ~aligned_ptr() { if(ptr) aligned_ptr<void>::dealloc<T>(ptr); } 

		inline aligned_ptr<T> clone() const { return aligned_ptr(*this); }

		inline const T  & get() const { if(ptr) return *ptr; else throw "TODO: moved"; }
		inline T	& get()	    { if(ptr) return *ptr; else throw "TODO: moved"; }

		inline const T	* get_ptr() const { if(ptr) return ptr; else throw "TODO: moved"; }
		inline T	* get_ptr()       { if(ptr) return ptr; else throw "TODO: moved"; }

		inline const T  * operator->() const { return get_ptr(); }
		inline T	* operator->()       { return get_ptr(); }

		inline const T  & operator*() const { return get(); }
		inline T	& operator*()	    { return get(); }

		inline operator const T*() const { return get_ptr(); }
		inline operator       T*()	 { return get_ptr(); }

		inline aligned_ptr<T>& operator=(aligned_ptr<T>&& other)
		{
			if(ptr) aligned_ptr<void>::dealloc<T>(ptr);
			*const_cast<T**>(&ptr) = other.ptr;
			*const_cast<T**>(&other.ptr) = nullptr;

			return *this;
		}
	private:
		inline aligned_ptr<T>& operator=(const aligned_ptr<T>& other)
		{
			return (*this = other.clone());
		}
		inline aligned_ptr(const aligned_ptr<T>& copy) : ptr(aligned_ptr<void>::make<T>(copy.get())){}
		T* const ptr;
	};

	template<typename T, typename... Args>
	inline aligned_ptr<T> make_aligned(Args&&... init) { return aligned_ptr<T >(aligned_ptr_util::template make<T>(std::forward<Args>(init)...)); }
}