racket backend for async ao

flac-decoder.rkt

@@ -50,6 +50,7 @@
         [(eq? e 'native-endian) (not (system-big-endian?))]
         [else (error (format "unknown endian value: ~a" e))]))
 
+  #|
   (define (flac-channels->interleaved-buffer buffer block-size channels bits endianness)
     (let* ([bytes   (quotient bits 8)]
            [little? (endian-little? endianness)]
@@ -78,6 +79,30 @@
             (set! out-pos (+ out-pos bytes)))))
 
       (list mem-out buf-size)))
+|#
+
+(define (flac-channels->interleaved-buffer buffer block-size channels bits endianness)
+  ;; buffer    = FLAC__int32 * const buffer[]
+  ;; block-size = samples per channel
+
+  (let* ([bytes    (quotient bits 8)]
+         [big?     (not (endian-little? endianness))]
+         [buf-size (* block-size channels bytes)]
+         [bs       (make-bytes buf-size)]
+         ;[out      (malloc buf-size 'atomic-interior)]
+         [out-pos  0])
+
+    (for ([k (in-range block-size)])
+      (for ([channel (in-range channels)])
+        (let* ([chan   (ptr-ref buffer _pointer channel)]
+               [sample (ptr-ref chan _int32 k)])
+          (integer->integer-bytes sample bytes #t big? bs out-pos)
+          (set! out-pos (+ out-pos bytes)))))
+
+    ;(memcpy out bs buf-size)
+    ;(list out buf-size)
+    (list bs buf-size)
+    ))
   
   (define (process-frame handle frame buffer)
     (let* ([h          (flac-ffi-frame-header frame)]