implement freenect_get_device_serial()

Signed-off-by: Benn Snyder <benn.snyder@gmail.com>

Author: piedar

include/libfreenect.h

@@ -355,6 +355,15 @@ FREENECTAPI int freenect_open_device(freenect_context *ctx, freenect_device **de
  */
 FREENECTAPI int freenect_open_device_by_camera_serial(freenect_context *ctx, freenect_device **dev, const char* camera_serial);
 
+/**
+ * Gets a serial number for the device.
+ * The caller must free() the serial after use.
+ *
+ * @param dev
+ * @return an appropriate serial number, or NULL if none was found.
+ */
+FREENECTAPI char* freenect_get_device_serial(freenect_device* dev);
+
 /**
  * Closes a device that is currently open
  *

src/core.c

@@ -202,6 +202,19 @@ FREENECTAPI int freenect_open_device_by_camera_serial(freenect_context *ctx, fre
 	return -1;
 }
 
+FREENECTAPI char* freenect_get_device_serial(freenect_device* dev)
+{
+	if (dev == NULL) return NULL;
+
+	char* camera_serial = fnusb_get_serial(&dev->usb_cam);
+	if (camera_serial) return camera_serial;
+
+	char* audio_serial = fnusb_get_serial(&dev->usb_audio);
+	if (audio_serial) return audio_serial;
+
+	return NULL;
+}
+
 FREENECTAPI int freenect_close_device(freenect_device *dev)
 {
 	freenect_context *ctx = dev->parent;