X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/f1199200e167a737a4676378da184387e543830c..05fcf7e2a79bebb978d4aeaef26b12f70c6826f8:/Demos/Host/LowLevel/MouseHostWithParser/HIDReport.c?ds=sidebyside

diff --git a/Demos/Host/LowLevel/MouseHostWithParser/HIDReport.c b/Demos/Host/LowLevel/MouseHostWithParser/HIDReport.c
index 4d895908e..faf8e98f4 100644
--- a/Demos/Host/LowLevel/MouseHostWithParser/HIDReport.c
+++ b/Demos/Host/LowLevel/MouseHostWithParser/HIDReport.c
@@ -69,3 +69,42 @@ uint8_t GetHIDReportData(void)
 	
 	return ParseSuccessful;
 }
+
+/** Callback for the HID Report Parser. This function is called each time the HID report parser is about to store
+ *  an IN, OUT or FEATURE item into the HIDReportInfo structure. To save on RAM, we are able to filter out items
+ *  we aren't interested in (preventing us from being able to extract them later on, but saving on the RAM they would
+ *  have occupied).
+ *
+ *  \param[in] CurrentItem  Pointer to the item the HID report parser is currently working with
+ *
+ *  \return Boolean true if the item should be stored into the HID report structure, false if it should be discarded
+ */
+bool CALLBACK_HIDParser_FilterHIDReportItem(HID_ReportItem_t* CurrentItem)
+{
+	bool IsMouse = false;
+
+	/* Iterate through the item's collection path, until either the root collection node or a collection with the
+	 * Mouse Usage is found - this prevents Joysticks, which use identical descriptors except for the Joystick usage
+	 * parent node, from being erroneously treated as a mouse
+	 */
+	for (HID_CollectionPath_t* CurrPath = CurrentItem->CollectionPath; CurrPath != NULL; CurrPath = CurrPath->Parent)
+	{
+		if ((CurrPath->Usage.Page  == USAGE_PAGE_GENERIC_DCTRL) &&
+		    (CurrPath->Usage.Usage == USAGE_MOUSE))
+		{
+			IsMouse = true;
+			break;
+		}
+	}
+
+	/* If a collection with the mouse usage was not found, indicate that we are not interested in this item */
+	if (!IsMouse)
+	  return false;
+  
+	/* Check the attributes of the current mouse item - see if we are interested in it or not;
+	 * only store BUTTON and GENERIC_DESKTOP_CONTROL items into the Processed HID Report
+	 * structure to save RAM and ignore the rest
+	 */
+	return ((CurrentItem->Attributes.Usage.Page == USAGE_PAGE_BUTTON) ||
+	        (CurrentItem->Attributes.Usage.Page == USAGE_PAGE_GENERIC_DCTRL));
+}