;compile with "sc alsa.pcm_min.sc alsa.pcm_min.c && gcc -lasound alsa.pcm_min.c"

(includep "alsa/asoundlib.h")
(includep "inttypes.h")
(includep "stdio.h")
(define device-name uint8-t* "default")
(define output snd-output-t* 0)
(define-macro buffer-size (* 16 1024))
(define buffer[buffer-size] uint8-t)
(define channels uint32-t 1)
(define sample-rate uint32-t 48000)
(define latency uint32-t)

(define (main) void
  ;initialisation, concerning hardware capabilities
  (define s int32-t out snd-pcm-t*)
  (set s (snd-pcm-open (address-of out) device-name SND_PCM_STREAM_PLAYBACK 0))
  (if (< s 0) (begin (printf "Playback open error: %s\n" (snd_strerror s)) (exit EXIT_FAILURE)))
  (set s
    (snd-pcm-set-params out SND_PCM_FORMAT_U8
      SND_PCM_ACCESS_RW_INTERLEAVED channels sample-rate 0 latency))
  (if (< s 0) (begin (printf "Playback open error: %s\n" (snd-strerror s)) (exit EXIT_FAILURE)))
  ;sound data creation
  (define frames snd-pcm-sframes-t) (define index uint32-t 0)
  (while (< index buffer-size) (set (deref buffer index) (modulo index 5)) (set index (+ 1 index)))
  (set index 0)
  (while (< index 6) (set frames (snd-pcm-writei out buffer buffer-size))
    (if (< frames 0) (set s (snd-pcm-recover out frames 0)))
    (if (< s 0) (printf "snd_pcm_writei failed: %s\n" (snd-strerror s)))
    (if (and (> frames 0) (< frames buffer-size))
      (printf "short write (expected %li, wrote %li)\n" buffer-size frames))
    (set index (+ 1 index)))
  ;deinitialisation
  (snd-pcm-close out))