options: split up value.hpp header

Also combine the traits classes and make them more useful.

1 files changed, 50 insertions, 0 deletions

diff --git a/options/value-traits.hpp b/options/value-traits.hpp
new file mode 100644
index 00000000..cf12649c
--- /dev/null
+++ b/options/value-traits.hpp
@@ -0,0 +1,50 @@
+#include "export.hpp"
+
+#include "compat/functional.hpp"
+#include "slider.hpp"
+
+#include <QString>
+
+#include <type_traits>
+
+namespace options {
+namespace detail {
+
+template<typename t, typename u = t, typename Enable = void>
+struct default_value_traits
+{
+    using element_type = remove_qualifiers<t>;
+    using value_type = u;
+
+    static inline value_type from_value(const value_type& val, const value_type&) { return val; }
+    static inline value_type from_storage(const element_type& x) { return static_cast<value_type>(x); }
+    static inline element_type to_storage(const value_type& val) { return static_cast<element_type>(val); }
+};
+
+template<typename t, typename u = t, typename Enable = void>
+struct value_traits : default_value_traits<t, u, Enable>
+{
+};
+
+template<>
+struct value_traits<slider_value> : default_value_traits<slider_value>
+{
+    static inline slider_value from_value(const slider_value& val, const slider_value& def)
+    {
+        return slider_value(val.cur(), def.min(), def.max());
+    }
+};
+
+// Qt uses int a lot in slots so use it for all enums
+template<typename t>
+struct value_traits<t, t, std::enable_if_t<std::is_enum<t>::value>> : public default_value_traits<int, t>
+{
+};
+
+template<>
+struct value_traits<float> : public default_value_traits<float, double, void>
+{
+};
+
+} // ns detail
+} // ns options