1 files changed, 88 insertions, 0 deletions
diff --git a/bindings/cpp/include/serd/Flags.hpp b/bindings/cpp/include/serd/Flags.hpp
new file mode 100644
index 00000000..a332ee73
--- /dev/null
+++ b/bindings/cpp/include/serd/Flags.hpp
@@ -0,0 +1,88 @@
+// Copyright 2019-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef SERD_FLAGS_HPP
+#define SERD_FLAGS_HPP
+
+#include <type_traits>
+
+namespace serd {
+
+/**
+   @defgroup serdpp_flags Flags
+   @ingroup serdpp
+   @{
+*/
+
+/**
+   Type-safe bit flags
+
+   This is a minimal interface for type-safe bit flags, which only allows
+   values from the corresponding flags enum to be set.  It functions like a
+   normal unsigned integer bit field, but attempting to get or set a flag with
+   the incorrect type will fail to compile.
+
+   @tparam Flag Strong enumeration type for flag values.
+*/
+template<class Flag>
+class Flags
+{
+public:
+  static_assert(std::is_enum<Flag>::value, "");
+
+  using Value = std::make_unsigned_t<std::underlying_type_t<Flag>>;
+
+  /// Construct with no flags set
+  constexpr Flags() noexcept = default;
+
+  /// Construct from a raw bit field value
+  constexpr explicit Flags(const Value value) noexcept
+    : _value{value}
+  {}
+
+  /// Construct from a single flag
+  // NOLINTNEXTLINE(google-explicit-constructor, hicpp-explicit-conversions)
+  constexpr Flags(const Flag f) noexcept
+    : _value{static_cast<Value>(f)}
+  {}
+
+  /// Set a flag
+  constexpr Flags operator|(const Flag rhs) const noexcept
+  {
+    return Flags{_value | static_cast<Value>(rhs)};
+  }
+
+  /// Set all the flags from another set of flags
+  constexpr Flags operator|(const Flags rhs) const noexcept
+  {
+    return Flags{_value | rhs._value};
+  }
+
+  /// Return true if only the given flag is set
+  constexpr bool operator==(const Flag rhs) const noexcept
+  {
+    return _value == static_cast<Value>(rhs);
+  }
+
+  // NOLINTNEXTLINE(google-explicit-constructor, hicpp-explicit-conversions)
+  constexpr operator Value() const noexcept { return _value; }
+
+private:
+  Value _value{};
+};
+
+/// Make a new Flags by combining two individual flags
+template<class Flag>
+inline constexpr Flags<Flag>
+operator|(const Flag lhs, const Flag rhs) noexcept
+{
+  return Flags<Flag>{lhs} | rhs;
+}
+
+/**
+   @}
+*/
+
+} // namespace serd
+
+#endif // SERD_FLAGS_HPP