typesetting/pitfall/fontkit/prep.rkt

#lang fontkit/racket
(require restructure)
(provide (all-defined-out))
#|
approximates
https://github.com/mbutterick/fontkit/blob/master/src/tables/prep.js
|#

(define-subclass Struct (Rprep))

(define prep (make-object Rprep
               (dictify
                'controlValueProgram (+Array uint8))))


(test-module
 (require racket/serialize)
 (define ip (open-input-file charter-path))
 (define dir (deserialize (read (open-input-file charter-directory-path))))
 (define offset (· dir tables prep offset))
 (define len (· dir tables prep length))
 (check-equal? offset 4512)
 (check-equal? len 78)
 (set-port-position! ip 0)
 (define table-bytes #"\270\0\0+\0\272\0\1\0\1\0\2+\1\272\0\2\0\1\0\2+\1\277\0\2\0C\0007\0+\0\37\0\23\0\0\0\b+\0\277\0\1\0\200\0i\0R\0;\0#\0\0\0\b+\0\272\0\3\0\5\0\a+\270\0\0 E}i\30D")
 (check-equal? table-bytes (peek-bytes len offset ip))
 (define ds (+DecodeStream (peek-bytes len offset ip)))
 (check-equal? (hash-ref (send prep decode ds) 'controlValueProgram) '(184
                                                                       0
                                                                       0
                                                                       43
                                                                       0
                                                                       186
                                                                       0
                                                                       1
                                                                       0
                                                                       1
                                                                       0
                                                                       2
                                                                       43
                                                                       1
                                                                       186
                                                                       0
                                                                       2
                                                                       0
                                                                       1
                                                                       0
                                                                       2
                                                                       43
                                                                       1
                                                                       191
                                                                       0
                                                                       2
                                                                       0
                                                                       67
                                                                       0
                                                                       55
                                                                       0
                                                                       43
                                                                       0
                                                                       31
                                                                       0
                                                                       19
                                                                       0
                                                                       0
                                                                       0
                                                                       8
                                                                       43
                                                                       0
                                                                       191
                                                                       0
                                                                       1
                                                                       0
                                                                       128
                                                                       0
                                                                       105
                                                                       0
                                                                       82
                                                                       0
                                                                       59
                                                                       0
                                                                       35
                                                                       0
                                                                       0
                                                                       0
                                                                       8
                                                                       43
                                                                       0
                                                                       186
                                                                       0
                                                                       3
                                                                       0
                                                                       5
                                                                       0
                                                                       7
                                                                       43
                                                                       184
                                                                       0
                                                                       0
                                                                       32
                                                                       69
                                                                       125
                                                                       105
                                                                       24
                                                                       68)))