Added bit_reference-like formatter

Signed-off-by: Vladislav Shchapov <vladislav@shchapov.ru>
fmtlib · Aug 5, 2023 · 85bc49b · 85bc49b
1 parent 64c905e
commit 85bc49b
Showing 1 changed file with 17 additions and 45 deletions.
diff --git a/include/fmt/std.h b/include/fmt/std.h
@@ -394,64 +394,36 @@ struct formatter<
 
 FMT_EXPORT
 
-#ifdef _LIBCPP_VERSION
-
-template <typename C, bool St, typename Char>
-struct formatter<std::__bit_reference<C, St>, Char> : formatter<bool, Char> {
-  template <typename FormatContext>
-  FMT_CONSTEXPR20 auto format(const std::__bit_reference<C, St>& v,
-                              FormatContext& ctx) const -> decltype(ctx.out()) {
-    return formatter<bool, Char>::format(static_cast<bool>(v), ctx);
-  }
-};
-
-template <typename C, typename Char>
-struct formatter<std::__bit_const_reference<C>, Char> : formatter<bool, Char> {
-  template <typename FormatContext>
-  FMT_CONSTEXPR20 auto format(const std::__bit_const_reference<C>& v,
-                              FormatContext& ctx) const -> decltype(ctx.out()) {
-    return formatter<bool, Char>::format(static_cast<bool>(v), ctx);
-  }
-};
-
-#else
+namespace detail {
 
-#  ifdef __GLIBCXX__
+template <typename T, typename Enable = void>
+struct has_flip : std::false_type {};
 
-template <typename Char>
-struct formatter<std::_Bit_reference, Char> : formatter<bool, Char> {
-  template <typename FormatContext>
-  auto format(const std::_Bit_reference& v, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    return formatter<bool, Char>::format(static_cast<bool>(v), ctx);
-  }
-};
+template <typename T>
+struct has_flip<T, void_t<decltype(std::declval<T>().flip())>>
+    : std::true_type {};
 
-#  elif defined(_CPPLIB_VER)
+template <typename T> struct is_bit_reference_like {
+  static constexpr const bool value =
+      std::is_convertible<T, bool>::value &&
+      std::is_nothrow_assignable<T, bool>::value && has_flip<T>::value
 
-template <typename C, typename Char>
-struct formatter<std::_Vb_reference<C>, Char> : formatter<bool, Char> {
-  template <typename FormatContext>
-  FMT_CONSTEXPR20 auto format(const std::_Vb_reference<C>& v,
-                              FormatContext& ctx) const -> decltype(ctx.out()) {
-    return formatter<bool, Char>::format(static_cast<bool>(v), ctx);
-  }
+      ;
 };
 
-#  endif
+}  // namespace detail
 
-template <std::size_t N, typename Char>
-struct formatter<typename std::bitset<N>::reference, Char>
+template <typename BitRef, typename Char>
+struct formatter<BitRef, Char,
+                 enable_if_t<detail::is_bit_reference_like<BitRef>::value>>
     : formatter<bool, Char> {
   template <typename FormatContext>
-  auto format(const typename std::bitset<N>::reference& v,
-              FormatContext& ctx) const -> decltype(ctx.out()) {
+  FMT_CONSTEXPR auto format(const BitRef& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
     return formatter<bool, Char>::format(static_cast<bool>(v), ctx);
   }
 };
 
-#endif
-
 FMT_END_NAMESPACE
 
 #endif  // FMT_STD_H_