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libao/libao-ffi.rkt

@@ -0,0 +1,68 @@
+#lang racket/base
+
+(require ffi/unsafe
+         ffi/unsafe/define
+         )
+
+(provide ;_libao_pointer
+         AO-FMT-LITTLE AO-FMT-BIG AO-FMT-NATIVE
+         ao_initialize
+         ao_default_driver_id
+         ao_driver_id
+         ao_open_live
+         ao_play
+         ao_close
+         ao_shutdown
+         ao_append_option
+         make-ao_sample_format
+         (all-from-out ffi/unsafe)
+         )
+
+(define-ffi-definer define-libao (ffi-lib "libao" '("3" "4" "5" #f)))
+
+
+(define _libao-pointer (_cpointer 'ao_device))
+(define-cstruct _ao_sample_format (
+                                   [bits _int]        ; bits per sample
+                                   [rate _int]        ; samples per second in a single channel
+                                   [channels _int]    ; number of audio channels
+                                   [byte_format _int] ; byte ordering in sample, see "constants" below
+                                   [matrix _pointer]  ; channel input matrix
+                                   ))
+
+(define-cstruct _ao_option (
+                            [key _pointer]
+                            [value _pointer]
+                            [next _pointer]   ; number of audio channels (list)
+                            ))
+
+(define AO-FMT-LITTLE  1)
+(define AO-FMT-BIG     2)
+(define AO-FMT-NATIVE  4)
+
+; void ao_initialize();
+(define-libao ao_initialize (_fun -> _void))
+
+; int ao_default_driver_id();
+(define-libao ao_default_driver_id (_fun -> _int))
+
+; ao_device* ao_open_live(int driver_id, ao_sample_format *format, ao_option *options);
+(define-libao ao_open_live (_fun _int _pointer _pointer -> _libao-pointer)) 
+
+; int ao_play(ao_device *device, char *output_samples, uint_32 num_bytes);
+(define-libao ao_play (_fun _libao-pointer _pointer _ulong -> _int))
+
+; int ao_close(ao_device *device);
+(define-libao ao_close (_fun _libao-pointer -> _int))
+
+; void ao_shutdown();
+(define-libao ao_shutdown (_fun -> _int))
+
+; int ao_append_option(ao_option **options, const char *key, const char *value);
+(define-libao ao_append_option (_fun _pointer _pointer _pointer -> _int))
+
+; int ao_driver_id(char *short_name);
+(define-libao ao_driver_id (_fun _pointer -> _int))
+
+
+

libao/libao.rkt

@@ -0,0 +1,62 @@
+#lang racket/base
+
+(require "libao-ffi.rkt")
+;(require finalizer)
+
+(provide ao-open-live
+         ao-play
+         ao-mk-format
+         ao-close
+         ao-default-driver-id
+         )
+
+(define currently-open   0)
+(define ao-device-handle 0)
+(define ao-devices (make-hash))
+
+(define (ao-mk-format bits rate channels byte-format . matrix)
+  (let ((bf (if (eq? byte-format 'little-endian)
+                AO-FMT-LITTLE
+                (if (eq? byte-format 'big-endian)
+                    AO-FMT-BIG
+                    AO-FMT-NATIVE))))
+    (let ((format (make-ao_sample_format bits rate channels bf #f)))
+      format)))
+
+(define (ao-default-driver-id)
+   (ao_default_driver_id))
+  
+
+(define (ao-open-live driver-id sample-format . options)
+  (when (= currently-open 0)
+    (ao_initialize))
+  (let ((ao-device (ao_open_live driver-id sample-format #f)))
+    (set! currently-open (+ currently-open 1))
+    (when (eq? ao-device _cpointer/null)
+      (set! currently-open (- currently-open 1))
+      (when (= currently-open 0)
+        (ao_shutdown)))
+    (if (eq? ao-device _cpointer/null)
+        #f
+        (begin
+          (set! ao-device-handle (+ ao-device-handle 1))
+          (hash-set! ao-devices ao-device-handle ao-device)
+          ao-device-handle))))
+
+(define (ao-close ao-handle)
+  (let ((ao-device (hash-ref ao-devices ao-handle #f)))
+    (when (eq? ao-device #f)
+        (error (format "Not a valid ao-handle ~a" ao-handle)))
+    (hash-remove! ao-devices ao-handle)
+    (let ((r (ao_close ao-device)))
+      (set! currently-open (- currently-open 1))
+      (when (= currently-open 0)
+        (ao_shutdown))
+      r)))
+
+(define (ao-play)
+  #t)
+
+
+
+