t_count
return (l_index * v_count + v_index) * t_count + s_base;
if (s_index % t_count != 0)
if (in[1] < t_base || in[1] >= t_base + t_count)
enum { n_count = v_count * t_count};
v = v_base + (s_index % n_count) / t_count;
t = t_base + s_index % t_count;