6.3.90.900
Ring Buffers
| (require data/ring-buffer) | package: ring-buffer |
This package defines an imperative, overwritting ring buffer that holds a finite number of elements and may be used as a sequence.
procedure
(ring-buffer? v) → boolean?
v : any/c
Determines if v is a ring buffer.
procedure
(empty-ring-buffer max) → ring-buffer?
max : exact-nonnegative-integer?
Constructs an empty ring buffer that may hold max elements.
procedure
rb : ring-buffer?
Returns the length of rb.
procedure
(ring-buffer-push! rb v) → void
rb : ring-buffer? v : (and/c any/c (not/c false/c))
Pushes v on to the end of rb, potentially pushing the first element of rb off.
Examples:
(define rb (empty-ring-buffer 3))
> (ring-buffer-push! rb 1)
> (ring-buffer-push! rb 2)
> (ring-buffer-push! rb 3)
> (for/list ([v rb]) v) '(1 2 3)
> (ring-buffer-push! rb 4)
> (for/list ([v rb]) v) '(2 3 4)
procedure
(ring-buffer-ref rb i) → (or/c any/c false/c)
rb : ring-buffer? i : exact-nonnegative-integer?
Returns the value in the ith position of rb.
This interacts with ring-buffer-push!.
Examples:
(define rb (empty-ring-buffer 3))
> (ring-buffer-push! rb 1)
> (ring-buffer-push! rb 2)
> (ring-buffer-push! rb 3)
> (for/list ([v rb]) v) '(1 2 3)
> (ring-buffer-ref rb 1) 2
> (ring-buffer-push! rb 4)
> (ring-buffer-ref rb 1) 3
procedure
(ring-buffer-set! rb i v) → void
rb : ring-buffer? i : exact-nonnegative-integer? v : (and/c any/c (not/c false/c))
Sets the value in the ith position of rb to v
This interacts with ring-buffer-push!.