bitfield tests pass

main
Matthew Butterick 6 years ago
parent 4e523ad74e
commit b5b5dff0cb

@ -7,45 +7,24 @@ approximates
https://github.com/mbutterick/restructure/blob/master/src/Bitfield.coffee
|#
#;(define/post-decode (xbitfield-decode xb [port-arg (current-input-port)] #:parent [parent #f])
(define port (->input-port port-arg))
(parameterize ([current-input-port port])
))
#;(define/pre-encode (xbitfield-encode xb flag-hash [port-arg (current-output-port)] #:parent [parent #f])
(define port (if (output-port? port-arg) port-arg (open-output-bytes)))
(parameterize ([current-output-port port])
(unless port-arg (get-output-bytes port))))
#;(define (xbitfield-size xb [val #f] #:parent [parent #f])
)
#;(struct xbitfield xbase (type flags) #:transparent
#:methods gen:xenomorphic
[(define decode xbitfield-decode)
(define xdecode xbitfield-decode)
(define encode xbitfield-encode)
(define size xbitfield-size)])
(define xbitfield%
(class xenobase%
(super-new)
(init-field type flags)
(define flag-hash (mhasheq))
(define/augment (xxdecode port parent)
(define flag-hash (mhasheq))
(define val (send type xxdecode port))
(for ([(flag i) (in-indexed flags)]
(for ([(flag idx) (in-indexed flags)]
#:when flag)
(hash-set! flag-hash flag (bitwise-bit-set? val i)))
(hash-set! flag-hash flag (bitwise-bit-set? val idx)))
flag-hash)
(define/augment (xxencode array port [parent #f])
(define bit-int (for/sum ([(flag i) (in-indexed flags)]
(define/augment (xxencode flag-hash port [parent #f])
(define bit-int (for/sum ([(flag idx) (in-indexed flags)]
#:when (and flag (dict-ref flag-hash flag #f)))
(arithmetic-shift 1 i)))
(arithmetic-shift 1 idx)))
(send type xxencode bit-int port))
(define/augment (xxsize [val #f] [parent #f])

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