Added facility to refer to base class object model

2 files changed, 71 insertions, 29 deletions

diff --git a/src/ObjectModel/ObjectModel.cpp b/src/ObjectModel/ObjectModel.cpp
index 14d6487c..6c4dd0e5 100644
--- a/src/ObjectModel/ObjectModel.cpp
+++ b/src/ObjectModel/ObjectModel.cpp
@@ -288,32 +288,43 @@ void ObjectModel::ReportAsJson(OutputBuffer* buf, ObjectExplorationContext& cont
 	if (context.IncreaseDepth())
 	{
 		bool added = false;
-		const uint8_t *descriptor;
-		const ObjectModelTableEntry *tbl = GetObjectModelTable(descriptor);
-		if (tableNumber < descriptor[0])
+		const ObjectModelClassDescriptor * classDescriptor = GetObjectModelClassDescriptor();
+
+		if ((tableNumber & 0x80) != 0)								// if we want the parent class table
 		{
-			size_t numEntries = descriptor[tableNumber + 1];
-			while (tableNumber != 0)
-			{
-				--tableNumber;
-				tbl += descriptor[tableNumber + 1];
-			}
+			classDescriptor = classDescriptor->parent;
+			tableNumber &= 0x7F;
+		}
 
-			while (numEntries != 0)
+		if (classDescriptor != nullptr)
+		{
+			const uint8_t * const descriptor = classDescriptor->omd;
+			if (tableNumber < descriptor[0])
 			{
-				if (tbl->Matches(filter, context))
+				const ObjectModelTableEntry *tbl = classDescriptor->omt;
+				size_t numEntries = descriptor[tableNumber + 1];
+				while (tableNumber != 0)
 				{
-					if (tbl->ReportAsJson(buf, context, this, filter, !added))
+					--tableNumber;
+					tbl += descriptor[tableNumber + 1];
+				}
+
+				while (numEntries != 0)
+				{
+					if (tbl->Matches(filter, context))
 					{
-						added = true;
+						if (tbl->ReportAsJson(buf, context, this, filter, !added))
+						{
+							added = true;
+						}
 					}
+					--numEntries;
+					++tbl;
+				}
+				if (added && *filter == 0)
+				{
+					buf->cat('}');
 				}
-				--numEntries;
-				++tbl;
-			}
-			if (added && *filter == 0)
-			{
-				buf->cat('}');
 			}
 		}
 		if (!added)
@@ -647,13 +658,24 @@ void ObjectModel::ReportArrayAsJson(OutputBuffer *buf, ObjectExplorationContext&
 // Find the requested entry
 const ObjectModelTableEntry* ObjectModel::FindObjectModelTableEntry(uint8_t tableNumber, const char* idString) const noexcept
 {
-	const uint8_t *descriptor;
-	const ObjectModelTableEntry *tbl = GetObjectModelTable(descriptor);
+	const ObjectModelClassDescriptor * classDescriptor = GetObjectModelClassDescriptor();
+	if ((tableNumber & 0x80) != 0)								// if we want the parent class table
+	{
+		classDescriptor = classDescriptor->parent;
+		if (classDescriptor == nullptr)
+		{
+			return nullptr;										// no parent
+		}
+		tableNumber &= 0x7F;
+	}
+
+	const uint8_t * const descriptor = classDescriptor->omd;
 	if (tableNumber >= descriptor[0])
 	{
 		return nullptr;
 	}
 
+	const ObjectModelTableEntry *tbl = classDescriptor->omt;
 	const size_t numEntries = descriptor[tableNumber + 1];
 	while (tableNumber != 0)
 	{
diff --git a/src/ObjectModel/ObjectModel.h b/src/ObjectModel/ObjectModel.h
index f6a3c2be..b67617f7 100644
--- a/src/ObjectModel/ObjectModel.h
+++ b/src/ObjectModel/ObjectModel.h
@@ -27,7 +27,7 @@ enum class TypeCode : uint8_t
 	Char,
 	Uint32,
 	Int32,
-	Uint64,
+	Uint64,			// only 56 bits actually available
 	Float,
 	Bitmap16,
 	Bitmap32,
@@ -211,6 +211,8 @@ public:
 	ExpressionValue (*GetElement)(const ObjectModel*, ObjectExplorationContext&) noexcept;
 };
 
+struct ObjectModelClassDescriptor;
+
 // Class from which other classes that represent part of the object model are derived
 class ObjectModel
 {
@@ -243,7 +245,7 @@ protected:
 	// Get the object model table entry for the current level object in the query
 	const ObjectModelTableEntry *FindObjectModelTableEntry(uint8_t tableNumber, const char *idString) const noexcept;
 
-	virtual const ObjectModelTableEntry *GetObjectModelTable(const uint8_t*& descriptor) const noexcept = 0;
+	virtual const ObjectModelClassDescriptor *GetObjectModelClassDescriptor() const noexcept = 0;
 
 private:
 	__attribute__ ((noinline)) static void ReportDateTime(OutputBuffer *buf, ExpressionValue val) noexcept;
@@ -309,30 +311,48 @@ public:
 	}
 };
 
+struct ObjectModelClassDescriptor
+{
+	const ObjectModelTableEntry *omt;
+	const uint8_t *omd;
+	const ObjectModelClassDescriptor *parent;
+};
+
 // Use this macro to inherit form ObjectModel
 #define INHERIT_OBJECT_MODEL	: public ObjectModel
 
 // Use this macro in the 'protected' section of every class declaration that derived from ObjectModel
 #define DECLARE_OBJECT_MODEL \
-	const ObjectModelTableEntry *GetObjectModelTable(const uint8_t*& descriptor) const noexcept override; \
+	const ObjectModelClassDescriptor *GetObjectModelClassDescriptor() const noexcept override; \
 	static const ObjectModelTableEntry objectModelTable[]; \
-	static const uint8_t objectModelTableDescriptor[];
+	static const uint8_t objectModelTableDescriptor[]; \
+	static const ObjectModelClassDescriptor objectModelClassDescriptor;
 
 #define DECLARE_OBJECT_MODEL_VIRTUAL \
-	virtual const ObjectModelTableEntry *GetObjectModelTable(const uint8_t*& descriptor) const noexcept override = 0;
+	virtual const ObjectModelClassDescriptor *GetObjectModelClassDescriptor() const noexcept override = 0;
 
 #define DESCRIPTOR_OK(_class) 	(ARRAY_SIZE(_class::objectModelTableDescriptor) == _class::objectModelTableDescriptor[0] + 1)
 #define OMT_SIZE_OK(_class)		(ARRAY_SIZE(_class::objectModelTable) == ArraySum(_class::objectModelTableDescriptor + 1, ARRAY_SIZE(_class::objectModelTableDescriptor) - 1))
 #define OMT_ORDERING_OK(_class)	(ObjectModelTableEntry::IsOrdered(_class::objectModelTableDescriptor, _class::objectModelTable))
 
 #define DEFINE_GET_OBJECT_MODEL_TABLE(_class) \
-	const ObjectModelTableEntry *_class::GetObjectModelTable(const uint8_t*& descriptor) const noexcept \
+	const ObjectModelClassDescriptor _class::objectModelClassDescriptor = { _class::objectModelTable, _class::objectModelTableDescriptor, nullptr }; \
+	const ObjectModelClassDescriptor *_class::GetObjectModelClassDescriptor() const noexcept \
+	{ \
+		static_assert(DESCRIPTOR_OK(_class), "Bad descriptor length"); \
+		static_assert(!DESCRIPTOR_OK(_class) || OMT_SIZE_OK(_class), "Mismatched object model table and descriptor"); \
+		static_assert(!DESCRIPTOR_OK(_class) || !OMT_SIZE_OK(_class) || OMT_ORDERING_OK(_class), "Object model table must be ordered"); \
+		return &objectModelClassDescriptor; \
+	}
+
+#define DEFINE_GET_OBJECT_MODEL_TABLE_WITH_PARENT(_class, _parent) \
+	const ObjectModelClassDescriptor _class::objectModelClassDescriptor = { _class::objectModelTable, _class::objectModelTableDescriptor, &_parent::objectModelClassDescriptor }; \
+	const ObjectModelClassDescriptor *_class::GetObjectModelClassDescriptor() const noexcept \
 	{ \
 		static_assert(DESCRIPTOR_OK(_class), "Bad descriptor length"); \
 		static_assert(!DESCRIPTOR_OK(_class) || OMT_SIZE_OK(_class), "Mismatched object model table and descriptor"); \
 		static_assert(!DESCRIPTOR_OK(_class) || !OMT_SIZE_OK(_class) || OMT_ORDERING_OK(_class), "Object model table must be ordered"); \
-		descriptor = objectModelTableDescriptor; \
-		return objectModelTable; \
+		return &objectModelClassDescriptor; \
 	}
 
 #define OBJECT_MODEL_FUNC_BODY(_class,...) [] (const ObjectModel* arg, ObjectExplorationContext& context) noexcept \