def clamp
import bend-collections@1.0.0.0/src/crypto/poly1305/poly1305.bend as Poly1305import Base
29def clamp(r: List<&2, U32>, +i: Nat) -> List<&2, U32>:
30 match r:
31 case Nil{}: Nil{}
32 case b <> rest: U32.and(b, clamp_mask(i)) <> clamp(rest, 1n+i)