Add ability to match orphan audio devices - fixes #501

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

src/usb_libusb10.c

@@ -24,6 +24,7 @@
  * either License.
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -36,7 +37,6 @@
 	# define sleep(x) Sleep((x)*1000) 
 #endif 
 
-
 FN_INTERNAL int fnusb_num_devices(freenect_context *ctx)
 {
 	libusb_device **devs; // pointer to pointer of device, used to retrieve a list of devices
@@ -78,16 +78,59 @@ FN_INTERNAL int fnusb_is_pid_k4w_audio(int pid)
 	return (pid == PID_K4W_AUDIO || pid == PID_K4W_AUDIO_ALT_1 || pid == PID_K4W_AUDIO_ALT_2);
 }
 
-FN_INTERNAL libusb_device * fnusb_find_connected_audio_device(libusb_device * camera, libusb_device ** deviceList, int cnt)
+FN_INTERNAL libusb_device * fnusb_find_orphan_audio(libusb_device * camera, libusb_device ** deviceList, int count)
 {
-	if (cnt <= 0) return NULL;
+	if (count <= 0) return NULL;
 
-	int cameraBusNo = libusb_get_bus_number(camera);
+	const int cameraBusNo = libusb_get_bus_number(camera);
+	if (cameraBusNo < 0) return NULL;
+
+	const size_t max_busses = 4096;
+	assert(cameraBusNo <= max_busses);
+	int numAudioByBus[max_busses] = { 0 };
+	libusb_device* devicesByBus_Unique[max_busses] = { NULL };
+
+	int i = 0;
+	for (i = 0; i < count; i++)
+	{
+		struct libusb_device_descriptor desc;
+		int res = libusb_get_device_descriptor (deviceList[i], &desc);
+		if (res < 0)
+		{
+			continue;
+		}
+
+		if (desc.idVendor == VID_MICROSOFT)
+		{
+			// make sure its some type of Kinect audio device
+			if ((desc.idProduct == PID_NUI_AUDIO || fnusb_is_pid_k4w_audio(desc.idProduct)))
+			{
+				const int audioBusNo = libusb_get_bus_number(deviceList[i]);
+				if (audioBusNo == cameraBusNo)
+				{
+					if (++(numAudioByBus[cameraBusNo]) == 1) {
+						devicesByBus_Unique[cameraBusNo] = deviceList[i];
+					} else {
+						devicesByBus_Unique[cameraBusNo] = NULL; // no duplicates!
+					}
+				}
+			}
+		}
+	}
+
+	return devicesByBus_Unique[cameraBusNo];
+}
+
+FN_INTERNAL libusb_device * fnusb_find_connected_audio_device(libusb_device * camera, libusb_device ** deviceList, int count)
+{
+	if (count <= 0) return NULL;
+
+	const int cameraBusNo = libusb_get_bus_number(camera);
 	if (cameraBusNo < 0) return NULL;
 	libusb_device * cameraParent = libusb_get_parent(camera);
 
 	int i = 0;
-	for (i = 0; i < cnt; i++)
+	for (i = 0; i < count; i++)
 	{
 		struct libusb_device_descriptor desc;
 		int res = libusb_get_device_descriptor (deviceList[i], &desc);
@@ -101,12 +144,12 @@ FN_INTERNAL libusb_device * fnusb_find_connected_audio_device(libusb_device * ca
 			// make sure its some type of Kinect audio device
 			if ((desc.idProduct == PID_NUI_AUDIO || fnusb_is_pid_k4w_audio(desc.idProduct)))
 			{
-				int audioBusNo = libusb_get_bus_number(deviceList[i]);
+				const int audioBusNo = libusb_get_bus_number(deviceList[i]);
 				if (audioBusNo == cameraBusNo)
 				{
 					// we have a match!
 					// let's double check
-					libusb_device * audioParent = libusb_get_parent(deviceList[i]);
+					const libusb_device * audioParent = libusb_get_parent(deviceList[i]);
 					if (cameraParent == audioParent)
 					{
 						return deviceList[i];
@@ -116,7 +159,7 @@ FN_INTERNAL libusb_device * fnusb_find_connected_audio_device(libusb_device * ca
 		}
 	}
 
-	return NULL;
+	return fnusb_find_orphan_audio(camera, deviceList, count);
 }
 
 FN_INTERNAL int fnusb_list_device_attributes(freenect_context *ctx, struct freenect_device_attributes** attribute_list)