Make clcpp::GetTypeNameHash constexpr so that you can use them as

switch case values and parameterise in other ways.

inc/clcpp/clcpp.h

@@ -983,3 +983,6 @@ namespace clcpp
         return 0;
     }
 }
+
+template <typename Type>
+constexpr unsigned int clcppTypeHash();

src/clReflectMerge/CodeGen.cpp

@@ -381,10 +381,118 @@ namespace
             }
 		}
 	}
-}
 
+	void GenGetTypesConstexpr(CodeGen& cg, const std::vector<Primitive>& primitives, unsigned int prim_types)
+	{
+		for (size_t i = 0; i < primitives.size(); i++)
+		{
+			const Primitive& prim = primitives[i];
+			if ((prim.type & prim_types) != 0)
+			{
+				std::string name = NameWithGlobalScope(prim);
+                cg.Line("template <> constexpr unsigned int clcppTypeHash< %s >() { return 0x%x; }", name.c_str(), prim.hash);
+            }
+		}
+	}
+
+	void IncludeDependencies(CodeGen& cg)
+	{
+		// Include clcpp headers
+		cg.Line("// Generated by clmerge.exe - do not edit!");
+		cg.Line("#include <clcpp/clcpp.h>");
+		cg.Line();
+	}
 
-void GenMergedCppImpl(const char* filename, const cldb::Database& db)
+	void ForwardDeclareTypes(CodeGen& cg, Namespace::Map& namespaces)
+	{
+		// Generate forward declarations
+		cg.Line("// Forward declarations for all known types");
+		GenNamespaceForwardDeclare(cg, &namespaces[0], true);
+		cg.Line();
+	}
+
+	void WriteFile(CodeGen& cg, const char* filename)
+	{
+		// Generate the hash for the generated code so far
+		unsigned int hash = cg.GenerateHash();
+		cg.PrefixLine("// %x", hash);
+
+		// If the output file already exists, open it and read its hash
+		unsigned int existing_hash = hash + 1;
+		FILE* fp = fopen(filename, "rb");
+		if (fp != 0)
+		{
+			fscanf(fp, "// %x", &existing_hash);
+			fclose(fp);
+		}
+
+		// Only write if there are changes
+		if (existing_hash != hash)
+		{
+			LOG(main, INFO, "Generating File: %s\n", filename);
+			cg.WriteToFile(filename);
+		}
+	}
+
+	void GenerateCppFile(Namespace::Map& namespaces, const std::vector<Primitive>& primitives, const char* filename)
+	{
+		CodeGen cg;
+
+		IncludeDependencies(cg);
+
+		// Generate arrays
+		cg.Line("// Array of type name pointers");
+		cg.Line("static const int clcppNbTypes = %d;", primitives.size());
+		cg.Line("static const clcpp::Type* clcppTypePtrs[clcppNbTypes] = { 0 };");
+		cg.Line();
+
+		// Generate initialisation function
+		cg.Line("void clcppInitGetType(const clcpp::Database* db)");
+		cg.EnterScope();
+		cg.Line("// Populate the type pointer array if a database is specified");
+		cg.Line("if (db != 0)");
+		cg.EnterScope();
+		for (size_t i = 0; i < primitives.size(); i++)
+			cg.Line("clcppTypePtrs[%d] = db->GetType(0x%x);", i, primitives[i].hash);
+		cg.ExitScope();
+		cg.ExitScope();
+		cg.Line();
+
+		ForwardDeclareTypes(cg, namespaces);
+
+		// Generate the implementations
+		cg.Line("// Specialisations for GetType and GetTypeNameHash");
+		cg.Line("namespace clcpp");
+		cg.EnterScope();
+		GenGetTypes(cg, primitives, PT_Type | PT_Class | PT_Struct);
+		cg.Line("#if defined(CLCPP_USING_MSVC)");
+		GenGetTypes(cg, primitives, PT_Enum);
+		cg.Line("#endif");
+		cg.ExitScope();
+
+		WriteFile(cg, filename);
+	}
+
+	void GenerateHFile(Namespace::Map& namespaces, const std::vector<Primitive>& primitives, const char* filename)
+	{
+		CodeGen cg;
+
+		IncludeDependencies(cg);
+
+		ForwardDeclareTypes(cg, namespaces);
+
+		// Generate the implementations
+		cg.Line("// Specialisations for constexpr clcppTypeHash");
+		GenGetTypesConstexpr(cg, primitives, PT_Type | PT_Class | PT_Struct);
+		cg.Line("#if defined(CLCPP_USING_MSVC)");
+		GenGetTypesConstexpr(cg, primitives, PT_Enum);
+		cg.Line("#endif");
+
+		WriteFile(cg, filename);
+	}
+}
+
+void GenMergedCppImpl(const char* cpp_filename, const char* h_filename, const cldb::Database& db)
 {
 	// Build a light-weight, hierarchical representation of the incoming database
 	Namespace::Map namespaces;
@@ -393,67 +501,13 @@ void GenMergedCppImpl(const char* filename, const cldb::Database& db)
 	BuildNamespaceContents(db, namespaces, primitives);
 	RemoveEmptyNamespaces(&namespaces[0]);
 
-	// Include clcpp headers
-	CodeGen cg;
-	cg.Line("// Generated by clmerge.exe - do not edit!");
-	cg.Line("#include <clcpp/clcpp.h>");
-	cg.Line();
-
-	// Generate arrays
-	cg.Line("// Array of type name hases and pointers");
-	cg.Line("static const int clcppNbTypes = %d;", primitives.size());
-	cg.Line("static unsigned int clcppTypeNameHashes[clcppNbTypes] = { 0 };");
-	cg.Line("static const clcpp::Type* clcppTypePtrs[clcppNbTypes] = { 0 };");
-	cg.Line();
-
-	// Generate initialisation function
-	cg.Line("void clcppInitGetType(const clcpp::Database* db)");
-	cg.EnterScope();
-	cg.Line("// Specify hashes for all known types");
-	for (size_t i = 0; i < primitives.size(); i++)
-		cg.Line("clcppTypeNameHashes[%d] = 0x%x;", i, primitives[i].hash);
-	cg.Line();
-	cg.Line("// Populate the type pointer array if a database is specified");
-	cg.Line("if (db != 0)");
-	cg.EnterScope();
-	cg.Line("for (int i = 0; i < clcppNbTypes; i++)");
-	cg.Line("\tclcppTypePtrs[i] = db->GetType(clcppTypeNameHashes[i]);");
-	cg.ExitScope();
-	cg.ExitScope();
-	cg.Line();
-
-	// Generate forward declarations
-	cg.Line("// Forward declarations for all known types");
-	GenNamespaceForwardDeclare(cg, &namespaces[0], true);
-	cg.Line();
-
-	// Generate the implementations
-	cg.Line("// Specialisations for GetType and GetTypeNameHash");
-	cg.Line("namespace clcpp");
-	cg.EnterScope();
-	GenGetTypes(cg, primitives, PT_Type | PT_Class | PT_Struct);
-	cg.Line("#if defined(CLCPP_USING_MSVC)");
-	GenGetTypes(cg, primitives, PT_Enum);
-	cg.Line("#endif");
-	cg.ExitScope();
-
-	// Generate the hash for the generated code so far
-	unsigned int hash = cg.GenerateHash();
-	cg.PrefixLine("// %x", hash);
-
-	// If the output file already exists, open it and read its hash
-	unsigned int existing_hash = hash + 1;
-	FILE* fp = fopen(filename, "rb");
-	if (fp != 0)
+	if (cpp_filename != nullptr)
 	{
-		fscanf(fp, "// %x", &existing_hash);
-		fclose(fp);
+		GenerateCppFile(namespaces, primitives, cpp_filename);
 	}
 
-	// Only write if there are changes
-	if (existing_hash != hash)
+	if (h_filename != nullptr)
 	{
-		LOG(main, INFO, "Generating C++ file: %s\n", filename);
-		cg.WriteToFile(filename);
+		GenerateHFile(namespaces, primitives, h_filename);
 	}
 }

src/clReflectMerge/CodeGen.h

@@ -42,5 +42,4 @@ class CodeGen
 	int m_Indent;
 };
 
-
-void GenMergedCppImpl(const char* filename, const cldb::Database& db);
+void GenMergedCppImpl(const char* cpp_filename, const char* h_filename, const cldb::Database& db);

src/clReflectMerge/Main.cpp

@@ -38,8 +38,11 @@ int main(int argc, const char* argv[])
 	std::string cpp_codegen = args.GetProperty("-cpp_codegen");
 	if (cpp_codegen != "")
 		arg_start += 2;
+    std::string h_codegen = args.GetProperty("-h_codegen");
+    if (h_codegen != "")
+        arg_start += 2;
 
-	cldb::Database db;
+    cldb::Database db;
 	for (size_t i = arg_start; i < args.Count(); i++)
 	{
 		const char* filename = args[i].c_str();
@@ -64,8 +67,8 @@ int main(int argc, const char* argv[])
 	cldb::WriteTextDatabase(output_filename, db);
 
 	// Generate any required C++ code
-	if (cpp_codegen != "")
-		GenMergedCppImpl(cpp_codegen.c_str(), db);
+    if (cpp_codegen != "" || h_codegen != "")
+        GenMergedCppImpl(cpp_codegen.c_str(), h_codegen.c_str(), db);
 
-	return 0;
+    return 0;
 }

src/clReflectTest/TestConstexprGetType.cpp

@@ -0,0 +1,53 @@
+
+#include "clcppcodegen.h"
+#include <cstdio>
+
+struct Base
+{
+    const clcpp::Type* type = nullptr;
+};
+
+struct attrReflect FirstType : public Base
+{
+};
+
+struct attrReflect SecondType : public Base
+{
+};
+
+struct attrReflect ThirdType : public Base
+{
+};
+
+template <typename Type>
+Type* New()
+{
+    auto* object = new Type();
+    object->type = clcpp::GetType<Type>();
+    return object;
+}
+
+void TestConstexprGetType()
+{
+    Base* objects[] = {
+        New<FirstType>(),
+        New<SecondType>(),
+        New<ThirdType>(),
+    };
+
+    for (Base* object : objects)
+    {
+        switch (object->type->name.hash)
+        {
+        case clcppTypeHash<FirstType>():
+            printf("Do something with the first type\n");
+            break;
+        case clcppTypeHash<SecondType>():
+            printf("Do something with the second type\n");
+            break;
+        case clcppTypeHash<ThirdType>():
+            printf("Do something with the third type\n");
+            break;
+        }
+    }
+}

src/clReflectTest/clReflectTest.pibfile

@@ -66,6 +66,7 @@ config.LinkOptions.MapFile = True
 cltest = CppBuild(env, [ "." ], "cltest.exe", libs, build = False)
 
 cpp_codegen = "clcppcodegen.cpp"
+h_codegen = "clcppcodegen.h"
 
 # Generate the list of C++ files to scan - this excludes the generated C++ file
 # Only add the generated C++ file to the compilation list if it's not already there
@@ -75,7 +76,7 @@ if len(scan_cpp_files) == len(cltest.cpp_files):
 
 # Run clscan on all C++ located files, merge the result into one database and generate the C++ file
 clr_scan = [ clReflect.CppScan(sys_include_paths, include_paths, [ ], env.NewFile(i)) for i in scan_cpp_files ]
-clr_merge = clReflect.Merge("clRefectTest.csv", clr_scan, env.NewFile(cpp_codegen))
+clr_merge = clReflect.Merge("clRefectTest.csv", clr_scan, env.NewFile(cpp_codegen), env.NewFile(h_codegen))
 
 # Generate the exported reflection database
 cpp_map_file = env.NewFile(cltest.output.GetOutputFiles(env)[1])