binary() generalization

[Igor Schein <igorschein@gmail.com>]

Hi,

I am looking for an efficient generalization of gp's binary() function.

digits(n,b)=local(m=n,L=List);while(m,v=divrem(m,b);listinsert(L,v[2],1);m=v[1]);

It's very inefficient compared to the native function:

? for(k=10^5,10^6,digits(k,2))

time = 18,749 ms.

? for(k=10^5,10^6,digits(k,10))

time = 6,401 ms.

? for(k=10^5,10^6,binary(k))

time = 236 ms.

Can I do better than that?

Thanks

Igor