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#lang racket/base
( require racket/class racket/list xenomorph )
( provide CFFPointer )
#|
approximates
https://github.com/mbutterick/fontkit/blob/master/src/cff/CFFPointer.js
|#
( define CFFPointer
( class x:pointer%
( super-new )
( inherit-field offset-type )
( define ptr #false )
( define/override ( :decode stream parent operands )
( set! offset-type ( class xenobase%
( super-new )
( define/augment ( :decode . args ) ( first operands ) )
;; compute the size (so ctx.pointerSize is correct)
( define/augment ( :size . args ) 0 )
( define/augment ( :encode stream val ) ( set! ptr val ) ) ) )
( super :decode stream parent operands ) )
( define/override ( :encode stream value ctx )
( cond
[ ( not stream )
( send this :size value ctx )
( Ptr 0 ) ]
[ else
( super :encode stream value ctx )
( Ptr ptr ) ] ) ) ) )
( struct Ptr ( val [ forceLarge ] ) #:transparent #:mutable #:auto-value #true
;; use prop:procedure instead of JS `valueOf`
#:property prop:procedure ( λ ( ptr ) ( Ptr-val ptr ) ) )