gplib/include/gp/allocator/aggregator.hpp

#pragma once

#include "gp/ring_list.hpp"
#include "gp/allocator/allocator.hpp"

#include <stddef.h>

namespace gp {
	class aggregator : public allocator {
		using local_container = ring_list<allocator, true>;

		local_container contents;
		local_container::explorer mark;

	public:
		/**
		* @brief Construct a new aggregator object from a bootstraping allocator
		* 
		* @tparam bootstrapper the type of allocator pushed in
		* @param allocator_v the allocator moved inside the new aggregator
		*/
		template<typename bootstrapper>
		aggregator(bootstrapper&& allocator_v)
		: contents{
			new(allocator_v.allocate(sizeof(local_container::node))) 
				local_container::node(
					new(allocator_v.allocate(sizeof(bootstrapper))) std::remove_reference_t<bootstrapper>(gp::forward<bootstrapper&&>(allocator_v))
				),
			*this
		}
		, mark{contents.explore()}
		{}

		/**
		 * @brief inserts a new allocator within the aggregator
		 * 
		 * @tparam s_allocator the type of newly inserted allocator
		 * @param value the inserted allocator
		 * @return true if the insertion was successful
		 * @return false if the insertion failed and the allocator is lost to the abyss of time
		 */
		template<typename s_allocator>
		bool insert(s_allocator&& value) {
			return contents.insert<
				std::remove_reference_t<
					s_allocator
				>
			>(gp::forward<s_allocator>(value));
		}

		virtual void* allocate(size_t sz) {
			auto cpy = mark;
			do{
				if(auto allocated = (*mark).allocate(sz))
				{
					return allocated;
				}
				++mark;
			}while(cpy != mark);
			return nullptr;
		}

		virtual bool deallocate(void* ptr) {
			auto cpy = mark;
			do{
				if((*cpy).deallocate(ptr))
				{
					return true;
				}
				--cpy;
			}while(cpy != mark);
			return false;
		}
		
		virtual bool try_reallocate(void* ptr, size_t sz) {
			auto cpy = mark;
			do{
				if((*cpy).try_reallocate(ptr, sz))
				{
					return true;
				}
				--cpy;
			}while(cpy != mark);
			return false;
		}
	};
}