X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/902ccab074b767f56385b36a6dc6161091527d4f..f2620548144b356661614eba36c9de12ef31395c:/lib/uaudio.h

diff --git a/lib/uaudio.h b/lib/uaudio.h
index 119d6b6..6592d53 100644
--- a/lib/uaudio.h
+++ b/lib/uaudio.h
@@ -34,6 +34,15 @@ extern size_t uaudio_sample_size;
  * @param max_samples How many samples to supply
  * @param userdata As passed to uaudio_open()
  * @return Number of samples filled
+ *
+ * This function should not block if possible (better to fill the buffer with
+ * 0s) and should definitely not block indefinitely.  This great caution with
+ * any locks or syscalls!  In particular avoid it taking a lock that may be
+ * held while any of the @ref uaudio members are called.
+ *
+ * If it's more convenient, it's OK to return less than the maximum number of
+ * samples (including 0) provided you expect to be called again for more
+ * samples immediately.
  */
 typedef size_t uaudio_callback(void *buffer,
                                size_t max_samples,
@@ -42,11 +51,33 @@ typedef size_t uaudio_callback(void *buffer,
 /** @brief Callback to play audio data
  * @param buffer Pointer to audio buffer
  * @param samples Number of samples to play
+ * @param flags Flags word
  * @return Number of samples played
  *
  * Used with uaudio_thread_start() etc.
+ *
+ * @p flags is a bitmap giving the current pause state and transitions:
+ * - @ref UAUDIO_PAUSE if this is the first call of a pause
+ * - @ref UAUDIO_RESUME if this is the first call of a resumse
+ * - @ref UAUDIO_PLAYING if this is outside a pause
+ * - @ref UAUDIO_PAUSED if this is in a pause
+ *
+ * During a pause, the sample data is guaranteed to be 0.
  */
-typedef size_t uaudio_playcallback(void *buffer, size_t samples);
+typedef size_t uaudio_playcallback(void *buffer, size_t samples,
+                                   unsigned flags);
+
+/** @brief Start of a pause */
+#define UAUDIO_PAUSE 0x0001
+
+/** @brief End of a pause */
+#define UAUDIO_RESUME 0x0002
+
+/** @brief Currently playing */
+#define UAUDIO_PLAYING 0x0004
+
+/** @brief Currently paused */
+#define UAUDIO_PAUSED 0x0008
 
 /** @brief Audio API definition */
 struct uaudio {
@@ -90,22 +121,53 @@ struct uaudio {
    */
   void (*deactivate)(void);
 
+  /** @brief Open mixer device */
+  void (*open_mixer)(void);
+
+  /** @brief Closer mixer device */
+  void (*close_mixer)(void);
+
+  /** @brief Get volume
+   * @param left Where to put the left-channel value
+   * @param right Where to put the right-channel value
+   *
+   * 0 is silent and 100 is maximum volume.
+   */
+  void (*get_volume)(int *left, int *right);
+
+  /** @brief Set volume
+   * @param left Pointer to left-channel value (updated)
+   * @param right Pointer to right-channel value (updated)
+   *
+   * The values are updated with those actually set by the underlying system
+   * call.
+   *
+   * 0 is silent and 100 is maximum volume.
+   */
+  void (*set_volume)(int *left, int *right);
+
+  /** @brief Set configuration */
+  void (*configure)(void);
+  
 };
 
 void uaudio_set_format(int rate, int channels, int samplesize, int signed_);
 void uaudio_set(const char *name, const char *value);
-char *uaudio_get(const char *name);
+char *uaudio_get(const char *name, const char *default_value);
 void uaudio_thread_start(uaudio_callback *callback,
 			 void *userdata,
 			 uaudio_playcallback *playcallback,
 			 size_t min,
-                         size_t max);
+                         size_t max,
+                         unsigned flags);
+
 void uaudio_thread_stop(void);
 void uaudio_thread_activate(void);
 void uaudio_thread_deactivate(void);
-void uaudio_schedule_synchronize(void);
-void uaudio_schedule_update(size_t written_samples);
+uint32_t uaudio_schedule_sync(void);
+void uaudio_schedule_sent(size_t nsamples_sent);
 void uaudio_schedule_init(void);
+const struct uaudio *uaudio_find(const char *name);
 
 extern uint64_t uaudio_schedule_timestamp;
 extern int uaudio_schedule_reactivated;
@@ -126,7 +188,7 @@ extern const struct uaudio uaudio_rtp;
 
 extern const struct uaudio uaudio_command;
 
-extern const struct uaudio *uaudio_apis[];
+extern const struct uaudio *const uaudio_apis[];
 
 #endif /* UAUDIO_H */