Add user-filtering to the HID report parser, so that the user code can decide which items are to be stored into the HID_ReportInfo_t structure and which should be discarded to save on RAM usage.

2 files changed, 49 insertions, 54 deletions

diff --git a/LUFA/Drivers/USB/Class/Host/HIDParser.c b/LUFA/Drivers/USB/Class/Host/HIDParser.c
index 241e17a05..accb8f36b 100644
--- a/LUFA/Drivers/USB/Class/Host/HIDParser.c
+++ b/LUFA/Drivers/USB/Class/Host/HIDParser.c
@@ -35,16 +35,14 @@
 

 uint8_t USB_ProcessHIDReport(const uint8_t* ReportData, uint16_t ReportSize, HID_ReportInfo_t* const ParserData)

 {

-	HID_StateTable_t  StateTable[HID_STATETABLE_STACK_DEPTH];

-	HID_StateTable_t* CurrStateTable          = &StateTable[0];

-	uint16_t          UsageStack[HID_USAGE_STACK_DEPTH];

-	uint8_t           UsageStackSize          = 0;

-	uint16_t          BitOffsetIn             = 0;

-	uint16_t          BitOffsetOut            = 0;

-#if defined(HID_ENABLE_FEATURE_PROCESSING)

-	uint16_t          BitOffsetFeature        = 0;

-#endif

+	HID_StateTable_t      StateTable[HID_STATETABLE_STACK_DEPTH];

+	HID_StateTable_t*     CurrStateTable          = &StateTable[0];

 	HID_CollectionPath_t* CurrCollectionPath  = NULL;

+	uint16_t              UsageStack[HID_USAGE_STACK_DEPTH];

+	uint8_t               UsageStackSize          = 0;

+	uint16_t              BitOffsetIn             = 0;

+	uint16_t              BitOffsetOut            = 0;

+	uint16_t              BitOffsetFeature        = 0;

 

 	ParserData->TotalReportItems     = 0;

 	ParserData->UsingMultipleReports = false;

@@ -131,10 +129,7 @@ uint8_t USB_ProcessHIDReport(const uint8_t* ReportData, uint16_t ReportSize, HID
 				ParserData->UsingMultipleReports = true;

 				BitOffsetIn      = 0;

 				BitOffsetOut     = 0;

-

-				#if defined(HID_ENABLE_FEATURE_PROCESSING)

 				BitOffsetFeature = 0;

-				#endif

 				break;

 			case (TYPE_LOCAL | TAG_LOCAL_USAGE):

 				if (UsageStackSize == HID_USAGE_STACK_DEPTH)

@@ -197,27 +192,22 @@ uint8_t USB_ProcessHIDReport(const uint8_t* ReportData, uint16_t ReportSize, HID
 				break;

 			case (TYPE_MAIN | TAG_MAIN_INPUT):

 			case (TYPE_MAIN | TAG_MAIN_OUTPUT):

-#if defined(HID_ENABLE_FEATURE_PROCESSING)

 			case (TYPE_MAIN | TAG_MAIN_FEATURE):

-#endif

 				for (uint8_t ReportItemNum = 0; ReportItemNum < CurrStateTable->ReportCount; ReportItemNum++)

 				{

-					HID_ReportItem_t* CurrReportItem = &ParserData->ReportItems[ParserData->TotalReportItems];

-				

-					if (ParserData->TotalReportItems == HID_MAX_REPORTITEMS)

-					  return HID_PARSE_InsufficientReportItems;

+					HID_ReportItem_t NewReportItem;

 				  

-					memcpy(&CurrReportItem->Attributes,

+					memcpy(&NewReportItem.Attributes,

 					       &CurrStateTable->Attributes,

 					       sizeof(HID_ReportItem_Attributes_t));

 

-					CurrReportItem->ItemFlags      = ReportItemData;

-					CurrReportItem->CollectionPath = CurrCollectionPath;

-					CurrReportItem->ReportID       = CurrStateTable->ReportID;

+					NewReportItem.ItemFlags      = ReportItemData;

+					NewReportItem.CollectionPath = CurrCollectionPath;

+					NewReportItem.ReportID       = CurrStateTable->ReportID;

 

 					if (UsageStackSize)

 					{

-						CurrReportItem->Attributes.Usage.Usage = UsageStack[0];

+						NewReportItem.Attributes.Usage.Usage = UsageStack[0];

 

 						for (uint8_t i = 0; i < UsageStackSize; i++)

 						  UsageStack[i] = UsageStack[i + 1];

@@ -226,42 +216,41 @@ uint8_t USB_ProcessHIDReport(const uint8_t* ReportData, uint16_t ReportSize, HID
 					}

 					else

 					{

-						CurrReportItem->Attributes.Usage.Usage = 0;

+						NewReportItem.Attributes.Usage.Usage = 0;

 					}

 											

 					switch (HIDReportItem & TAG_MASK)

 					{

 						case TAG_MAIN_INPUT:

-							CurrReportItem->ItemType  = REPORT_ITEM_TYPE_In;

-							CurrReportItem->BitOffset = BitOffsetIn;

+							NewReportItem.ItemType  = REPORT_ITEM_TYPE_In;

+							NewReportItem.BitOffset = BitOffsetIn;

 								

 							BitOffsetIn += CurrStateTable->Attributes.BitSize;

-							

 							break;

 						case TAG_MAIN_OUTPUT:

-							CurrReportItem->ItemType  = REPORT_ITEM_TYPE_Out;

-							CurrReportItem->BitOffset = BitOffsetOut;

+							NewReportItem.ItemType  = REPORT_ITEM_TYPE_Out;

+							NewReportItem.BitOffset = BitOffsetOut;

 								

 							BitOffsetOut += CurrStateTable->Attributes.BitSize;

-							

 							break;

-#if defined(HID_ENABLE_FEATURE_PROCESSING)

 						case TAG_MAIN_FEATURE:

-							CurrReportItem->ItemType  = REPORT_ITEM_TYPE_Feature;						

-							CurrReportItem->BitOffset = BitOffsetFeature;

+							NewReportItem.ItemType  = REPORT_ITEM_TYPE_Feature;						

+							NewReportItem.BitOffset = BitOffsetFeature;

 								

-							BitOffsetFeature += CurrStateTable->Attributes.BitSize;		

-

+							BitOffsetFeature += CurrStateTable->Attributes.BitSize;

 							break;

-#endif

 					}

+

+					if (!(ReportItemData & IOF_CONSTANT) && CALLBACK_HIDParser_FilterHIDReportItem(&CurrStateTable->Attributes))

+					{					

+						if (ParserData->TotalReportItems == HID_MAX_REPORTITEMS)

+						  return HID_PARSE_InsufficientReportItems;

 					

-#if defined(HID_INCLUDE_CONSTANT_DATA_ITEMS)

-					ParserData->TotalReportItems++;

-#else

-					if (!(ReportItemData & IOF_CONSTANT))

-					  ParserData->TotalReportItems++;

-#endif

+						memcpy(&ParserData->ReportItems[ParserData->TotalReportItems],

+						       &NewReportItem, sizeof(HID_ReportItem_t));

+					

+						ParserData->TotalReportItems++;

+					}

 				}

 				

 				UsageStackSize = 0;

diff --git a/LUFA/Drivers/USB/Class/Host/HIDParser.h b/LUFA/Drivers/USB/Class/Host/HIDParser.h
index ec7ff53be..8d3fbf212 100644
--- a/LUFA/Drivers/USB/Class/Host/HIDParser.h
+++ b/LUFA/Drivers/USB/Class/Host/HIDParser.h
@@ -46,16 +46,11 @@
  *  Functions, macros, variables, enums and types related to the parsing of HID class device report descriptors.

  *

  *  The processed HID report is presented back to the user application as a flat structure containing each report

- *  item's IN, OUT and FEATURE (if desired) items along with each item's attributes.

+ *  item's IN, OUT and FEATURE items along with each item's attributes.

  *

  *  This library portion also allows for easy setting and retrieval of data from a HID report, including devices

  *  with multiple reports on the one HID interface.

  *

- *  By default, FEATURE reports and IN/OUT reports with constant data are ignored in the HID report when processed

- *  to save on memory. This can be overridden by defining the HID_ENABLE_FEATURE_PROCESSING or

- *  HID_INCLUDE_CONSTANT_DATA_ITEMS tokens in the user project makefile, passing them to the compiler via the -D

- *  switch.

- *

  *  @{

  */

 

@@ -108,13 +103,13 @@
 		#endif

 		

 		#if !defined(HID_MAX_REPORTITEMS) || defined(__DOXYGEN__)

-			/** Constant indicating the maximum number of report items (IN, OUT or FEATURE if enabled) that can be

-			 *  processed in the report item descriptor. A large value allows for more report items to be

-			 *  processed, but consumes more memory. By default this is set to 30 items, but this can be

-			 *  overridden by defining HID_MAX_REPORTITEMS to another value in the user project makefile, passing

-			 *  the define to the compiler using the -D compiler switch.

+			/** Constant indicating the maximum number of report items (IN, OUT or FEATURE) that can be processed 

+			 *  in the report item descriptor and stored in the user HID Report Info structure. A large value allows

+			 *  for more report items to be stored, but consumes more memory. By default this is set to 20 items, 

+			 *  but this can be overridden by defining HID_MAX_REPORTITEMS to another value in the user project

+			 *  makefile, passing the define to the compiler using the -D compiler switch.

 			 */

-			#define HID_MAX_REPORTITEMS           30

+			#define HID_MAX_REPORTITEMS           20

 		#endif

 

 	/* Public Interface - May be used in end-application: */

@@ -250,6 +245,17 @@
 			 */

 			void USB_SetHIDReportItemInfo(uint8_t* ReportData, const HID_ReportItem_t* ReportItem)

 			                              ATTR_NON_NULL_PTR_ARG(1, 2);

+										  

+			/** Callback routine for the HID Report Parser. This callback <b>must</b> be implemented by the user code when

+			 *  the parser is used, to determine what report IN, OUT and FEATURE item's information is stored into the user

+			 *  HID_ReportInfo_t structure. This can be used to filter only those items the application will be using, so that

+			 *  no RAM is wasted storing the attributes for report items which will never be referenced by the application.

+			 *

+			 *  \param CurrentItemAttributes  Pointer to the current report item attributes for user checking

+			 *

+			 *  \return Boolean true if the item should be stored into the HID_ReportInfo_t structure, false if it should be ignored

+			 */

+			bool CALLBACK_HIDParser_FilterHIDReportItem(HID_ReportItem_Attributes_t* CurrentItemAttributes);

 

 	/* Private Interface - For use in library only: */

 	#if !defined(__DOXYGEN__)