Add an iterator style mechanism for iterating through report IDs

lib_xua/src/core/buffer/ep/ep_buffer.xc

@@ -378,7 +378,7 @@ void XUA_Buffer_Ep(register chanend c_aud_out,
         while (!hidIsReportDescriptorPrepared())
             ;
 
-        /* Get data from the last report, which which we can prep XUD*/
+        /* Get the last report - we don't really care which it is, so long as there's some data we can grab. */
         int hidReportLength = (int) UserHIDGetData(hidGetReportIdLimit() - 1, g_hidData); 
 
         XUD_SetReady_In(ep_hid, g_hidData, hidReportLength);

lib_xua/src/hid/hid_report.c

@@ -254,6 +254,20 @@ unsigned hidIsReportIdInUse ( void ) {
     return 0;
 }
 
+unsigned hidGetNextValidReportId ( unsigned idPrev ) {
+    size_t retIndex = 0;
+
+    for( size_t idx = 0U; idx < HID_REPORT_COUNT; ++idx ) {
+        unsigned reportId = hidGetElementReportId( hidReports[ idx ]->location );
+        if( reportId == idPrev ) {
+            retIndex = (idx + 1) % HID_REPORT_COUNT;
+            break;
+        }
+    }
+
+    return hidGetElementReportId( hidReports[ retIndex ]->location );
+}
+
 #define HID_CONFIGURABLE_ELEMENT_COUNT ( sizeof hidConfigurableElements / sizeof ( USB_HID_Report_Element_t* ))
 unsigned hidGetReportItem(
     const unsigned id,
@@ -342,8 +356,8 @@ unsigned hidIsChangePending( const unsigned id )
 {
     unsigned retVal = 0U;
     for( size_t idx = 0U; idx < HID_REPORT_COUNT; ++idx) {
-        if( id == 0U ) {
-            retVal |= ( s_hidChangePending[ idx ] != 0U );
+        if( id == 0U && s_hidChangePending[ idx ] != 0U ) {
+            retVal = 1;
         } else if( id == hidGetElementReportId( hidReports[ idx ]->location )) {
             retVal  = ( s_hidChangePending[ idx ] != 0U );
             break;

lib_xua/src/hid/xua_hid_report.h

@@ -203,6 +203,17 @@ unsigned hidGetReportIdLimit ( void );
  */
 unsigned hidIsReportIdInUse ( void );
 
+/**
+ * @brief Get the next valid report ID - iterator style.
+ * 
+ * This function will loop around and start returning the first report ID again once it has
+ * returned all valid report IDs.
+ * 
+ * @param idPrev The previous returned id, or 0 if this is the first call
+ * @return unsigned The next valid report ID.
+ */
+unsigned hidGetNextValidReportId ( unsigned idPrev );
+
 /**
  * @brief Get a HID Report descriptor item
  *

tests/xua_unit_tests/src/test_multi_report/test_hid_multi_report.c

@@ -63,6 +63,22 @@ void test_reportid_in_use( void ) {
     TEST_ASSERT_EQUAL_UINT( 1, reportIdInUse );
 }
 
+void test_get_next_valid_report_id( void ) {
+    unsigned reportId = 0U;
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 1, reportIdInUse );
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 2, reportIdInUse );
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 3, reportIdInUse );
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 1, reportIdInUse );
+}
+
 // Basic report descriptor tests
 void test_unprepared_hidGetReportDescriptor( void )
 {

tests/xua_unit_tests/src/test_simple/test_hid.c

@@ -50,6 +50,16 @@ void test_reportid_in_use( void ) {
     TEST_ASSERT_EQUAL_UINT( 0, reportIdInUse );
 }
 
+void test_get_next_valid_report_id( void ) {
+    unsigned reportId = 0U;
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 0, reportIdInUse );
+
+    reportId = hidGetNextValidReportId(reportId);
+    TEST_ASSERT_EQUAL_UINT( 0, reportIdInUse );
+}
+
 // Basic report descriptor tests
 void test_unprepared_hidGetReportDescriptor( void )
 {