#!r6rs
(library (rsc3 supercollider sndfile)
(export write-snd-file au-f32)
(import (rnrs)
	(rsc3 collection list)
	(rsc3 collection tree)
	(rsc3 osc encode)
	(rsc3 u8 encode))

(define au-magic #x2e736e64)

(define au-unspecified 0)
(define au-mulaw8      1)
(define au-linear8     2)
(define au-linear16    3)
(define au-linear24    4)
(define au-linear32    5)
(define au-float       6)
(define au-double      7)

(define (au-size-of e)
  (cond ((= e au-unspecified) (error 'au-size-of "unspecified encoding"))
	((= e au-mulaw8)      1)
	((= e au-linear8)     1)
	((= e au-linear16)    2)
	((= e au-linear24)    3)
	((= e au-linear32)    4)
	((= e au-float)       4)
	((= e au-double)      8)
	(else                 (error "au-size-of: illegal encoding"))))

(define (au-mk-hdr nf enc sr nc)
  (let ((nb (* nf nc (au-size-of enc))))
    (append-map encode-i32 (list au-magic 28 nb enc sr nc 0))))

(define au-f32 (list au-float  encode-f32))
(define au-f64 (list au-double encode-f64))

(define (write-snd-file e sr nc fn d)
  (let ((enc   (car e))
	(encdr (cadr e))
	(nf    (/ (length d) nc)))
    (with-output-to-file fn
      (lambda ()
	(for-each put-u8 (au-mk-hdr nf enc sr nc))
	(for-each put-u8 (append-map encdr d))))))

)