racket/collects/tests/gracket/jpeg-stress.rkt

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1.1 KiB
Racket

#lang racket/base
(require racket/class
racket/draw
racket/file)
;; Check memory-management in the JPEG library by reading and writing
;; in many threads at the same time.
(define ts
(for/list ([i (in-range 40)])
(thread
(lambda()
(for ([i (in-range 10)])
(define bm (read-bitmap (collection-file-path "plt.jpg" "icons")))
(define t (make-temporary-file))
(send bm save-file t 'jpeg)
(define bm2 (read-bitmap t))
(define w (send bm get-width))
(define h (send bm get-width))
(define s1 (make-bytes (* w h 4)))
(define s2 (make-bytes (* w h 4)))
(send bm get-argb-pixels 0 0 w h s1)
(send bm2 get-argb-pixels 0 0 w h s2)
;; JPEG is lossy, so use a fuzzy compare:
(define diff (for/sum ([b1 (in-bytes s1)]
[b2 (in-bytes s2)])
(- b2 b1)))
(unless ((abs diff) . < . (* w h 1))
(error 'jpeg-stree "mismatch ~s ~s ~e" w h diff))
(delete-file t))))))
(for ([t (in-list ts)]) (sync t))