static Arena *CreateArena(rawptr buffer, isize length)
{
	Arena *arena = (Arena *)buffer;
	buffer += ARENA_HEADER_SIZE;

	arena->buffer = buffer;
	arena->length = length;
	arena->pos = 0;

	return arena;
}

static rawptr ArenaAllocAlign(Arena *arena, isize size, isize align)
{
	rawptr ptr;

	uintptr curr_ptr = (uintptr)arena->buffer + (uintptr)arena->pos;
	uintptr offset = AlignPow2(curr_ptr, align);
	offset -= (uintptr)arena->buffer;

	if (offset+size <= arena->length)
	{
		ptr = &arena->buffer[offset];
		arena->pos = offset+size;
	}
	else
	{
		Printfln("Out of memory: %d", arena->init_line_no);
		Assert(0, "Memory Failure");
	}

	return ptr;
}

static rawptr ArenaAlloc(Arena *arena, isize size)
{
	return ArenaAllocAlign(arena, size, DEFAULT_ALIGNMENT);
}

static void ArenaFree(Arena *arena)
{
	arena->pos = 0;
}

static void ArenaFreeZeroed(Arena *arena)
{
	MemZero(arena->buffer, arena->pos);
	ArenaFree(arena);
}

static Arena * CreateArenaDebug(rawptr buffer, isize length, u32 init_line_no)
{
	Arena *arena = CreateArena(buffer, length);
	arena->init_line_no = init_line_no;
	return arena;
}