Add bitWidth function acting on values type control.

include/crap/bit.d/bitwidthvalue.h

@@ -9,10 +9,13 @@
 #if (crap_lib_int_pow2 >= 202002L)
 #include <bit>
 #else
+#include <climits>
+
 #include "../functional.d/plusvalue.h"
 #include "../numbers.d/zero.h"
 #include "../numeric.d/iotavalue.h"
-#include <climits>
+#include "../version.d/char8t.h"
+#include "../version.d/unicodecharacters.h"
 #endif
 
 namespace crap
@@ -23,6 +26,18 @@ namespace crap
 #else
  template <class Type, Type Value> struct bitWidthValue
  {
+  static_assert((std :: is_integral <Type> :: value) && (std :: is_unsigned <Type> :: value) &&
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, bool> :: value) &&
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, char> :: value) &&
+#if (crap_char8_t >= 201811L)
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, char8_t> :: value) &&
+#endif
+#if (crap_unicode_characters >= 200704L)
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, char16_t> :: value) &&
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, char32_t> :: value) &&
+#endif
+		  !(std :: is_same <typename std :: remove_cv <Type> :: type, wchar_t> :: value),
+		  "Unsupported type.");
   private:
   constexpr const static Type any = zero <Type> :: value;
   constexpr const static Type zeros = any ^ any;