- (and (<= min i) (< i (+ min (ash 1 shift)))
- (let ((i (- i min)))
- (let lp ((node root) (shift shift))
- (and node
- (if (= shift *branch-bits*)
- (vector-ref node (logand i *branch-mask*))
- (let* ((shift (- shift *branch-bits*))
- (idx (logand (ash i (- shift))
- *branch-mask*)))
- (lp (vector-ref node idx) shift))))))))))
+ (if (zero? shift)
+ (and (= i min) root)
+ (and (<= min i) (< i (+ min (ash 1 shift)))
+ (let ((i (- i min)))
+ (let lp ((node root) (shift shift))
+ (and node
+ (if (= shift *branch-bits*)
+ (vector-ref node (logand i *branch-mask*))
+ (let* ((shift (- shift *branch-bits*))
+ (idx (logand (ash i (- shift))
+ *branch-mask*)))
+ (lp (vector-ref node idx) shift)))))))))))