Constexpr typename helpers

3 files changed, 86 insertions, 1 deletions

diff --git a/icespider/core/Jamfile.jam b/icespider/core/Jamfile.jam
index 15648b8..7b7bd19 100644
--- a/icespider/core/Jamfile.jam
+++ b/icespider/core/Jamfile.jam
@@ -2,9 +2,11 @@ lib adhocutil : : : : <include>/usr/include/adhocutil ;
 lib slicer : : : : <include>/usr/include/slicer ;
 lib stdc++fs ;
 
+obj util-test : util-test.cpp ;
+
 obj routeOptions : routeOptions.ice : <toolset>tidy:<checker>none ;
 lib icespider-core :
-	[ glob *.cpp ]
+	[ glob *.cpp : *-test.cpp ]
 	routeOptions
 	:
 	<library>../common//icespider-common
diff --git a/icespider/core/util-test.cpp b/icespider/core/util-test.cpp
new file mode 100644
index 0000000..32a7c42
--- /dev/null
+++ b/icespider/core/util-test.cpp
@@ -0,0 +1,12 @@
+#include "util.h"
+
+namespace foo ::bar {
+	class really;
+}
+
+static_assert(type_names<int>::name() == "int");
+static_assert(type_names<int>::namespaces() == 0);
+static_assert(TypeName<int>::str() == "int");
+static_assert(type_names<foo::bar::really>::name() == "foo::bar::really");
+static_assert(type_names<foo::bar::really>::namespaces() == 2);
+static_assert(TypeName<foo::bar::really>::str() == "foo.bar.really");
diff --git a/icespider/core/util.h b/icespider/core/util.h
index 2089ce0..ca1350b 100644
--- a/icespider/core/util.h
+++ b/icespider/core/util.h
@@ -2,6 +2,8 @@
 #define ICESPIDER_CORE_UTIL_H
 
 #include <Ice/Optional.h>
+#include <array>
+#include <string_view>
 
 namespace std::experimental::Ice {
 	template<typename T, typename TF>
@@ -37,4 +39,73 @@ orelse(const T & a, const T & b)
 	return b;
 }
 
+template<typename T> struct type_names {
+	static constexpr auto
+	pf()
+	{
+		return std::string_view {&__PRETTY_FUNCTION__[0], sizeof(__PRETTY_FUNCTION__)};
+	}
+
+	static constexpr auto
+	name()
+	{
+		const std::string_view with_T {"T = "};
+		const auto start {pf().find(with_T) + with_T.length()};
+		const auto end {pf().find(']', start)};
+		return pf().substr(start, end - start);
+	}
+
+	static constexpr auto
+	namespaces()
+	{
+		auto ns {0U};
+		for (const auto & c : name()) {
+			// cppcheck-suppress useStlAlgorithm; (not constexpr)
+			ns += (c == ':') ? 1 : 0;
+		}
+		return ns / 2;
+	}
+
+	using char_type = typename decltype(name())::value_type;
+};
+
+template<typename T> class TypeName : type_names<T> {
+public:
+	constexpr static inline auto
+	str()
+	{
+		return std::string_view {buf.data(), buf.size() - 1};
+	}
+
+	constexpr static inline auto
+	c_str()
+	{
+		return buf.data();
+	}
+
+private:
+	using tn = type_names<T>;
+
+	constexpr static auto buf {[]() {
+		std::array<typename tn::char_type, tn::name().length() - tn::namespaces() + 1> buf {};
+		auto out {buf.begin()};
+		auto cln {false};
+		for (const auto & in : tn::name()) {
+			if (in == ':') {
+				if (cln) {
+					*out++ = '.';
+				}
+				else {
+					cln = true;
+				}
+			}
+			else {
+				*out++ = in;
+				cln = false;
+			}
+		}
+		return buf;
+	}()};
+};
+
 #endif