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34 lines
834 B
Racket
34 lines
834 B
Racket
#lang restructure/racket
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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/Pointer.coffee
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|#
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(define-subclass RestructureBase (Pointer offsetType type [options (mhash)])
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(define/override (decode stream ctx)
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(report (file-position (· stream _port)))
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(define offset (send offsetType decode stream ctx))
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(define ptr offset)
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(report* offset ptr)
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(cond
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[type (define orig-pos (send stream pos))
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(send stream pos ptr)
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(define val (send type decode stream ctx))
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(send stream pos orig-pos)
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(report* options)
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val]
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[else ptr]))
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(define/override (encode stream val)
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(error 'Pointer-encode-not-done))
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(define/override (size val)
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(error 'Pointer-size-not-done))
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) |