♻️ move wrapped binary type to separate file

include/nlohmann/detail/wrapped_binary_t.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <cstdint> // uint8_t
+#include <utility> // move
+
+namespace nlohmann
+{
+namespace detail
+{
+
+/*!
+@brief an internal type for a backed binary type
+
+This type is designed to be `binary_t` but with the subtype implementation
+detail.  This type exists so that the user does not have to specify a struct
+his- or herself with a specific naming scheme in order to override the
+binary type.  I.e. it's for ease of use.
+*/
+template<typename BinaryType>
+struct wrapped_binary_t : public BinaryType
+{
+    using binary_t = BinaryType;
+
+    wrapped_binary_t() noexcept(noexcept(binary_t())) = default;
+
+    wrapped_binary_t(const binary_t& bint) noexcept(noexcept(binary_t(bint)))
+        : binary_t(bint)
+    {}
+
+    wrapped_binary_t(binary_t&& bint) noexcept(noexcept(binary_t(std::move(bint))))
+        : binary_t(std::move(bint))
+    {}
+
+    wrapped_binary_t(const binary_t& bint,
+                     std::uint8_t st) noexcept(noexcept(binary_t(bint)))
+        : binary_t(bint)
+        , subtype(st)
+        , has_subtype(true)
+    {}
+
+    wrapped_binary_t(binary_t&& bint, std::uint8_t st) noexcept(noexcept(binary_t(std::move(bint))))
+        : binary_t(std::move(bint))
+        , subtype(st)
+        , has_subtype(true)
+    {}
+
+    std::uint8_t subtype = 0;
+    bool has_subtype = false;
+};
+
+}  // namespace detail
+}  // namespace nlohmann