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47 lines
1.4 KiB
Racket
47 lines
1.4 KiB
Racket
#lang restructure/racket
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(require "number.rkt" (prefix-in utils- "utils.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/Buffer.coffee
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|#
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#|
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A Buffer is a container object for any data object that supports random access
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|#
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(define-subclass RestructureBase (Buffer [length_ #xffff])
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(define/override (decode stream [parent #f])
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(define length__ (utils-resolveLength length_ stream parent))
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(send stream readBuffer length__))
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(define/override (size [val #f] [parent #f])
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(when val (unless (bytes? val)
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(raise-argument-error 'Buffer:size "bytes" val)))
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(if val
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(bytes-length val)
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(utils-resolveLength length_ val parent)))
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(define/override (encode stream buf [parent #f])
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(unless (and (list? buf) (andmap byte? buf))
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(raise-argument-error 'Buffer:encode "list of bytes" buf))
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(when (NumberT? length_)
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(send length_ encode stream (length buf))
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(send stream writeBuffer buf))))
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(define-subclass Buffer (BufferT))
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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)) |