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#lang restructure/racket
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(require "number.rkt" (prefix-in utils- "utils.rkt") "stream.rkt")
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(provide (all-defined-out))
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#|
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approximates
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https://github.com/mbutterick/restructure/blob/master/src/String.coffee
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|#
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(define (byteLength val encoding)
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(define encoder
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(caseq encoding
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[(ascii utf8) string->bytes/utf-8]))
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(bytes-length (encoder val)))
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(define-subclass Streamcoder (StringT [length_ #f] [encoding_ 'ascii])
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(define/augment (decode stream [parent #f])
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(define length__
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(cond
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[length_ (utils-resolveLength length_ stream parent)]
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[else (send stream count-nonzero-chars)]))
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(define encoding__
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(cond
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[(procedure? encoding_) (or (encoding_ parent) 'ascii)]
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[else encoding_]))
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(define string (send stream readString length__ encoding__))
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(when (and (not length_) (< (send stream pos) (send stream length)))
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(send stream pos (add1 (send stream pos))))
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string)
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(define/augment (encode stream val [parent #f])
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(define encoding__
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(cond
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[(procedure? encoding_) (or (encoding_ (and parent (· parent val)) 'ascii))]
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[else encoding_]))
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(when (NumberT? length_)
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(send length_ encode stream (byteLength val encoding__)))
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(send stream writeString val encoding__)
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(when (not length_)
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(send stream writeUInt8 #x00)))
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(define/override (size [val #f] [parent #f])
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;; Use the defined value if no value was given
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(cond
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[(not val) (utils-resolveLength length_ #f parent)]
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[else
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(define encoding__
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(cond
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[(procedure? encoding_) (or (encoding_ (and parent (· parent val)) 'ascii))]
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[else encoding_]))
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(when (eq? encoding__ 'utf16be)
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(set! encoding__ 'utf16le))
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(define size (byteLength val encoding__))
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(when (NumberT? length_)
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(increment! size (send length_ size)))
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(when (not length_)
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(increment! size))
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size]))
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)
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(define-values (String? +String) (values StringT? +StringT))
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#;(test-module
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(require "stream.rkt")
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(define stream (+DecodeStream #"\2BCDEF"))
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(define S (+String uint8 'utf8))
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(check-equal? (send S decode stream) "BC")
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(define os (+EncodeStream))
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(send S encode os "Mike")
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(check-equal? (send os dump) #"\4Mike")
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(check-equal? (send (+String) size "foobar") 6)) |