Add to_char_type function to custom char_traits

Author: colbychaskell

include/nlohmann/detail/meta/type_traits.hpp

@@ -199,12 +199,17 @@ struct char_traits<unsigned char> : std::char_traits<char>
     using int_type = uint64_t;
 
     // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
+    static int_type to_int_type(char_type c) noexcept
     {
         return static_cast<int_type>(c);
     }
 
-    static constexpr int_type eof()
+    static char_type to_char_type(int_type i) noexcept
+    {
+        return static_cast<char_type>(i);
+    }
+
+    static constexpr int_type eof() noexcept
     {
         return static_cast<int_type>(EOF);
     }
@@ -218,12 +223,17 @@ struct char_traits<signed char> : std::char_traits<char>
     using int_type = uint64_t;
 
     // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
+    static int_type to_int_type(char_type c) noexcept
     {
         return static_cast<int_type>(c);
     }
 
-    static constexpr int_type eof()
+    static char_type to_char_type(int_type i) noexcept
+    {
+        return static_cast<char_type>(i);
+    }
+
+    static constexpr int_type eof() noexcept
     {
         return static_cast<int_type>(EOF);
     }

single_include/nlohmann/json.hpp

@@ -3606,12 +3606,17 @@ struct char_traits<unsigned char> : std::char_traits<char>
     using int_type = uint64_t;
 
     // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
+    static int_type to_int_type(char_type c) noexcept
     {
         return static_cast<int_type>(c);
     }
 
-    static constexpr int_type eof()
+    static char_type to_char_type(int_type i) noexcept
+    {
+        return static_cast<char_type>(i);
+    }
+
+    static constexpr int_type eof() noexcept
     {
         return static_cast<int_type>(EOF);
     }
@@ -3625,12 +3630,17 @@ struct char_traits<signed char> : std::char_traits<char>
     using int_type = uint64_t;
 
     // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
+    static int_type to_int_type(char_type c) noexcept
     {
         return static_cast<int_type>(c);
     }
 
-    static constexpr int_type eof()
+    static char_type to_char_type(int_type i) noexcept
+    {
+        return static_cast<char_type>(i);
+    }
+
+    static constexpr int_type eof() noexcept
     {
         return static_cast<int_type>(EOF);
     }