turbolist/VirtualMemList.hpp

#ifndef VIRTUAL_MEM_LIST_H
#define VIRTUAL_MEM_LIST_H
#include "arena.h/arena.h"

#ifndef VML_NOINLINE
#define VML_NOINLINE __attribute__((noinline))
#endif /* VML_NOINLINE */
#ifndef VML_INLINE
#define VML_INLINE __attribute__((always_inline))
#endif /* VML_INLINE */

#ifndef VML_LIKELY
#define VML_LIKELY(x) __builtin_expect(!!(x), 1)
#endif /* VML_LIKELY */
#ifndef VML_UNLIKELY
#define VML_UNLIKELY(x) __builtin_expect(!!(x), 0)
#endif /* VML_UNLIKELY */

#ifndef VML_GROWTH_RATE
#define VML_GROWTH_RATE 2
#endif /* VML_GROWTH_RATE */

template<typename T>
class VirtualMemList {
	arena a;
	T *base;
	uint32_t end;

public:
	VML_INLINE VirtualMemList(uint32_t initial_size = 0) noexcept {
		a = newarena((ptrdiff_t)1 << 33);
		base = ((T*) aralloc(&a, sizeof(T), sizeof(T), 1)) + 1;
		end = initial_size;
	}

	VML_INLINE ~VirtualMemList() noexcept {
		// TODO: arena free currently not implemented
	}

	VML_INLINE T& operator[](uint32_t i) const noexcept {
		return base[i];
	}

	VML_INLINE void push_back(T elem) noexcept {
		// Smallest solution:
		// base[end++] = elem;

		// Non-working, but logically better solution:
		// T *value = (T*) aralloc(&a, sizeof(T), sizeof(T), 1);
		// *value = elem;

		// Longer solution (more correct - but I let it waste a bit of memory)
		T *value = (T*) aralloc(&a, sizeof(T), sizeof(T), 1);
		base[end++] = elem;
	}

	VML_INLINE void pop_back() noexcept {
		--end;
	}

	VML_INLINE uint32_t size() noexcept {
		return end;
	}
};

#endif // VIRTUAL_MEM_LIST_H