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(define-module (starlet midi-control base)
#:use-module (oop goops)
#:use-module (ice-9 atomic)
#:use-module (ice-9 threads)
#:use-module (ice-9 binary-ports)
#:use-module (srfi srfi-1)
#:export (start-midi-control
get-cc-value
scale-127-100
send-note-on
send-note-off
register-midi-note-callback!))
(define cc-arrays (make-atomic-box '()))
(define callback-list (make-atomic-box '()))
(define send-queue (make-atomic-box '()))
(define-class <midi-note-callback> (<object>)
(channel
#:init-keyword #:channel
#:getter get-channel)
(note-number
#:init-keyword #:note-number
#:getter get-note-number)
(callback
#:init-keyword #:func
#:getter get-callback-func))
(define* (register-midi-note-callback!
#:key (channel #f) (note-number 1) (func #f))
(let ((new-callback (make <midi-note-callback>
#:channel (if channel channel default-channel)
#:note-number note-number
#:func func)))
(atomic-box-set! callback-list
(cons new-callback
(atomic-box-ref callback-list)))
new-callback))
(define enqueue-midi-bytes!
(lambda bytes
(unless (eq? (atomic-box-compare-and-swap! send-queue '() bytes)
'())
(apply enqueue-midi-bytes! bytes))))
(define* (send-note-on note
#:key (channel #f))
(enqueue-midi-bytes! (+ #b10010000
(if channel channel default-channel))
note
127))
(define* (send-note-off note
#:key (channel #f))
(enqueue-midi-bytes! (+ #b10000000
(if channel channel default-channel))
note
0))
(define (all-notes-off! channel)
(let again ((l 0))
(enqueue-midi-bytes! (+ #b10000000 channel) l 0)
(unless (= l 127)
(again (+ l 1)))))
(define (ensure-cc-array channel)
(let ((old-list (atomic-box-ref cc-arrays)))
(unless (assq channel old-list)
(unless (eq?
old-list
(atomic-box-compare-and-swap! cc-arrays
old-list
(acons channel
(make-vector 128 #f)
old-list)))
;; CAS failed - try again
(ensure-cc-array channel)))))
(define (handle-cc-change! channel cc-number value)
(ensure-cc-array channel)
(vector-set! (assq-ref (atomic-box-ref cc-arrays) channel)
cc-number
value))
(define* (get-cc-value cc-number
#:key (channel #f))
(let ((cc-arrays (atomic-box-ref cc-arrays)))
(let ((ccs (assq-ref cc-arrays
(if channel channel default-channel))))
(if ccs
(vector-ref ccs cc-number)
0))))
(define (check-note-callbacks channel note-number)
(for-each (lambda (a) ((get-callback-func a)))
(filter (lambda (a)
(and (eq? note-number (get-note-number a))
(eq? channel (get-channel a))))
(atomic-box-ref callback-list))))
(define (scale-127-100 n)
(/ (* n 100) 127))
(define default-channel 0)
(define* (start-midi-control device-name
#:key (channel #f))
(when channel
(set! default-channel channel))
(let ((midi-port (open-file device-name "r+0b")))
;; Read thread
(begin-thread
(let again ()
(let* ((status-byte (get-u8 midi-port))
(channel (bit-extract status-byte 0 4))
(command (bit-extract status-byte 4 8)))
(case command
;; Note on
((9) (let* ((note (get-u8 midi-port))
(vel (get-u8 midi-port)))
(check-note-callbacks channel note)))
;; Control value
((11) (let* ((cc-number (get-u8 midi-port))
(value (get-u8 midi-port)))
(handle-cc-change! channel
cc-number
value))))
(yield)
(again))))
;; Write thread
(begin-thread
(let again ()
(let ((bytes-to-send (atomic-box-swap! send-queue '())))
(for-each (lambda (a)
(put-u8 midi-port a))
bytes-to-send)
(usleep 1000)
(again))))))
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