[latency api] Add the new latency api.

This commit adds

jack_port_set_latency_range()
jack_port_get_latency_range()
jack_set_latency_callback()

It also extends jack_port_set_latency() to set the playback or capture
latency range of the port.

git-svn-id: svn+ssh://jackaudio.org/trunk/jack@4098 0c269be4-1314-0410-8aa9-9f06e86f4224

4 files changed, 81 insertions, 1 deletions

diff --git a/jack/internal.h b/jack/internal.h
index c6107c8..c2009e7 100644
--- a/jack/internal.h
+++ b/jack/internal.h
@@ -219,7 +219,8 @@ typedef enum  {
   StopFreewheel,
   ClientRegistered,
   ClientUnregistered,
-  SaveSession
+  SaveSession,
+  LatencyCallback
 } JackEventType;
 
 typedef struct {
@@ -298,6 +299,7 @@ typedef volatile struct {
     volatile uint8_t	client_register_cbset;
     volatile uint8_t	thread_cb_cbset;
     volatile uint8_t	session_cbset;
+    volatile uint8_t	latency_cbset;
 
 } POST_PACKED_STRUCTURE jack_client_control_t;
 
diff --git a/jack/jack.h b/jack/jack.h
index c80f879..f634a8b 100644
--- a/jack/jack.h
+++ b/jack/jack.h
@@ -406,6 +406,16 @@ int jack_set_graph_order_callback (jack_client_t *,
  */
 int jack_set_xrun_callback (jack_client_t *,
 			    JackXRunCallback xrun_callback, void *arg) JACK_OPTIONAL_WEAK_EXPORT;
+
+/**
+ * Tell the JACK server to call @a latency_callback whenever the
+ * port latencies need to be recalculated.
+ *
+ * @return 0 on success, otherwise a non-zero error code
+ */
+int jack_set_latency_callback (jack_client_t *,
+				   JackLatencyCallback latency_callback,
+				   void *) JACK_WEAK_EXPORT;
 /*@}*/
 
 /**
@@ -691,6 +701,18 @@ jack_nframes_t jack_port_get_total_latency (jack_client_t *,
 void jack_port_set_latency (jack_port_t *, jack_nframes_t) JACK_OPTIONAL_WEAK_EXPORT;
 	
 /**
+ * get the new latency, either capture latency or playback latency.
+ * this is normally used in the LatencyCallback.
+ * and therefor safe to execute from callbacks.
+ */
+void jack_port_get_latency_range (jack_port_t *port, jack_latency_callback_mode_t mode, jack_latency_range_t *range) JACK_WEAK_EXPORT;
+
+/**
+ * set the new latency, either capture latency or playback latency.
+ */
+void jack_port_set_latency_range (jack_port_t *port, jack_latency_callback_mode_t mode, jack_latency_range_t *range) JACK_WEAK_EXPORT;
+
+/**
  * Request a complete recomputation of a port's total latency. This
  * can be called by a client that has just changed the internal
  * latency of its port using  jack_port_set_latency
diff --git a/jack/port.h b/jack/port.h
index 796a19a..4447f74 100644
--- a/jack/port.h
+++ b/jack/port.h
@@ -121,6 +121,8 @@ typedef struct _jack_port_shared {
 
     volatile jack_nframes_t  latency;
     volatile jack_nframes_t  total_latency;
+    volatile jack_latency_range_t  playback_latency;
+    volatile jack_latency_range_t  capture_latency;
     volatile uint8_t	     monitor_requests;
 
     char		     has_mixdown; /* port has a mixdown function */
diff --git a/jack/types.h b/jack/types.h
index 91d2523..859d693 100644
--- a/jack/types.h
+++ b/jack/types.h
@@ -220,6 +220,60 @@ enum JackStatus {
 typedef enum JackStatus jack_status_t;
 
 /**
+ *  @ref jack_latency_callback_mode_t
+ */
+enum JackLatencyCallbackMode {
+
+     /**
+      * Latency Callback for Capture Latency.
+      * Input Ports have their latency value setup.
+      * In the Callback the client needs to set the latency of the output ports
+      */
+     JackCaptureLatency,
+
+     /**
+      * Latency Callback for Playback Latency.
+      * Output Ports have their latency value setup.
+      * In the Callback the client needs to set the latency of the input ports
+      */
+     JackPlaybackLatency
+
+};
+
+/**
+ *  Type of Latency Callback (Capture or Playback)
+ */
+typedef enum JackLatencyCallbackMode jack_latency_callback_mode_t;
+
+/**
+ * Prototype for the client supplied function that is called 
+ * by the engine when port latencies need to be recalculated
+ *
+ * @param mode playback or capture latency
+ * @param arg pointer to a client supplied data
+ *
+ * @return zero on success, non-zero on error
+ */ 
+typedef int  (*JackLatencyCallback)(jack_latency_callback_mode_t mode, void *arg);
+
+/**
+ * the new latency API operates on Ranges.
+ */
+struct _jack_latency_range
+{
+    /**
+     * minimum latency
+     */
+    jack_nframes_t min;
+    /**
+     * maximum latency
+     */
+    jack_nframes_t max;
+};
+
+typedef struct _jack_latency_range jack_latency_range_t;
+
+/**
  * Prototype for the client supplied function that is called 
  * by the engine anytime there is work to be done.
  *