Replace deprecated std::char_traits calls with custom char_traits

include/nlohmann/detail/input/binary_reader.hpp

@@ -72,7 +72,7 @@ class binary_reader
     using binary_t = typename BasicJsonType::binary_t;
     using json_sax_t = SAX;
     using char_type = typename InputAdapterType::char_type;
-    using char_int_type = typename std::char_traits<char_type>::int_type;
+    using char_int_type = typename char_traits<char_type>::int_type;
 
   public:
     /*!
@@ -145,7 +145,7 @@ class binary_reader
                 get();
             }
 
-            if (JSON_HEDLEY_UNLIKELY(current != std::char_traits<char_type>::eof()))
+            if (JSON_HEDLEY_UNLIKELY(current != char_traits<char_type>::eof()))
             {
                 return sax->parse_error(chars_read, get_token_string(), parse_error::create(110, chars_read,
                                         exception_message(input_format, concat("expected end of input; last byte: 0x", get_token_string()), "value"), nullptr));
@@ -228,7 +228,7 @@ class binary_reader
                                     exception_message(input_format_t::bson, concat("string length must be at least 1, is ", std::to_string(len)), "string"), nullptr));
         }
 
-        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) && get() != std::char_traits<char_type>::eof();
+        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) && get() != char_traits<char_type>::eof();
     }
 
     /*!
@@ -422,7 +422,7 @@ class binary_reader
         switch (get_char ? get() : current)
         {
             // EOF
-            case std::char_traits<char_type>::eof():
+            case char_traits<char_type>::eof():
                 return unexpect_eof(input_format_t::cbor, "value");
 
             // Integer 0x00..0x17 (0..23)
@@ -1197,7 +1197,7 @@ class binary_reader
         switch (get())
         {
             // EOF
-            case std::char_traits<char_type>::eof():
+            case char_traits<char_type>::eof():
                 return unexpect_eof(input_format_t::msgpack, "value");
 
             // positive fixint
@@ -2299,7 +2299,7 @@ class binary_reader
     {
         switch (prefix)
         {
-            case std::char_traits<char_type>::eof():  // EOF
+            case char_traits<char_type>::eof():  // EOF
                 return unexpect_eof(input_format, "value");
 
             case 'T':  // true
@@ -2744,7 +2744,7 @@ class binary_reader
 
     This function provides the interface to the used input adapter. It does
     not throw in case the input reached EOF, but returns a -'ve valued
-    `std::char_traits<char_type>::eof()` in that case.
+    `char_traits<char_type>::eof()` in that case.
 
     @return character read from the input
     */
@@ -2886,7 +2886,7 @@ class binary_reader
     JSON_HEDLEY_NON_NULL(3)
     bool unexpect_eof(const input_format_t format, const char* context) const
     {
-        if (JSON_HEDLEY_UNLIKELY(current == std::char_traits<char_type>::eof()))
+        if (JSON_HEDLEY_UNLIKELY(current == char_traits<char_type>::eof()))
         {
             return sax->parse_error(chars_read, "<end of file>",
                                     parse_error::create(110, chars_read, exception_message(format, "unexpected end of input", context), nullptr));
@@ -2953,7 +2953,7 @@ class binary_reader
     InputAdapterType ia;
 
     /// the current character
-    char_int_type current = std::char_traits<char_type>::eof();
+    char_int_type current = char_traits<char_type>::eof();
 
     /// the number of characters read
     std::size_t chars_read = 0;

include/nlohmann/detail/input/input_adapters.hpp

@@ -133,49 +133,6 @@ class input_stream_adapter
 };
 #endif  // JSON_NO_IO
 
-// Primary template of json_char_traits calls std char_traits
-template<typename T>
-struct char_traits : std::char_traits<T>
-{};
-
-// Explicitly define char traits for unsigned char since it is not standard
-template<>
-struct char_traits<unsigned char> : std::char_traits<char>
-{
-    using char_type = unsigned char;
-    using int_type = uint64_t;
-
-    // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
-    {
-        return static_cast<int_type>(c);
-    }
-
-    static int_type eof()
-    {
-        return static_cast<int_type>(EOF);
-    }
-};
-
-// Explicitly define char traits for signed char since it is not standard
-template<>
-struct char_traits<signed char> : std::char_traits<char>
-{
-    using char_type = signed char;
-    using int_type = uint64_t;
-
-    // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
-    {
-        return static_cast<int_type>(c);
-    }
-
-    static int_type eof()
-    {
-        return static_cast<int_type>(EOF);
-    }
-};
-
 // General-purpose iterator-based adapter. It might not be as fast as
 // theoretically possible for some containers, but it is extremely versatile.
 template<typename IteratorType>

include/nlohmann/detail/meta/type_traits.hpp

@@ -12,6 +12,7 @@
 #include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
 #include <utility> // declval
 #include <tuple> // tuple
+#include <string> // char_traits
 
 #include <nlohmann/detail/iterators/iterator_traits.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
@@ -181,6 +182,53 @@ struct actual_object_comparator
 template<typename BasicJsonType>
 using actual_object_comparator_t = typename actual_object_comparator<BasicJsonType>::type;
 
+/////////////////
+// char_traits //
+/////////////////
+
+// Primary template of char_traits calls std char_traits
+template<typename T>
+struct char_traits : std::char_traits<T>
+{};
+
+// Explicitly define char traits for unsigned char since it is not standard
+template<>
+struct char_traits<unsigned char> : std::char_traits<char>
+{
+    using char_type = unsigned char;
+    using int_type = uint64_t;
+
+    // Redefine to_int_type function
+    static int_type to_int_type(char_type c)
+    {
+        return static_cast<int_type>(c);
+    }
+
+    static constexpr int_type eof()
+    {
+        return static_cast<int_type>(EOF);
+    }
+};
+
+// Explicitly define char traits for signed char since it is not standard
+template<>
+struct char_traits<signed char> : std::char_traits<char>
+{
+    using char_type = signed char;
+    using int_type = uint64_t;
+
+    // Redefine to_int_type function
+    static int_type to_int_type(char_type c)
+    {
+        return static_cast<int_type>(c);
+    }
+
+    static constexpr int_type eof()
+    {
+        return static_cast<int_type>(EOF);
+    }
+};
+
 ///////////////////
 // is_ functions //
 ///////////////////

single_include/nlohmann/json.hpp

@@ -3242,6 +3242,7 @@ NLOHMANN_JSON_NAMESPACE_END
 #include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
 #include <utility> // declval
 #include <tuple> // tuple
+#include <string> // char_traits
 
 // #include <nlohmann/detail/iterators/iterator_traits.hpp>
 //     __ _____ _____ _____
@@ -3594,6 +3595,53 @@ struct actual_object_comparator
 template<typename BasicJsonType>
 using actual_object_comparator_t = typename actual_object_comparator<BasicJsonType>::type;
 
+/////////////////
+// char_traits //
+/////////////////
+
+// Primary template of char_traits calls std char_traits
+template<typename T>
+struct char_traits : std::char_traits<T>
+{};
+
+// Explicitly define char traits for unsigned char since it is not standard
+template<>
+struct char_traits<unsigned char> : std::char_traits<char>
+{
+    using char_type = unsigned char;
+    using int_type = uint64_t;
+
+    // Redefine to_int_type function
+    static int_type to_int_type(char_type c)
+    {
+        return static_cast<int_type>(c);
+    }
+
+    static constexpr int_type eof()
+    {
+        return static_cast<int_type>(EOF);
+    }
+};
+
+// Explicitly define char traits for signed char since it is not standard
+template<>
+struct char_traits<signed char> : std::char_traits<char>
+{
+    using char_type = signed char;
+    using int_type = uint64_t;
+
+    // Redefine to_int_type function
+    static int_type to_int_type(char_type c)
+    {
+        return static_cast<int_type>(c);
+    }
+
+    static constexpr int_type eof()
+    {
+        return static_cast<int_type>(EOF);
+    }
+};
+
 ///////////////////
 // is_ functions //
 ///////////////////
@@ -6216,49 +6264,6 @@ class input_stream_adapter
 };
 #endif  // JSON_NO_IO
 
-// Primary template of json_char_traits calls std char_traits
-template<typename T>
-struct char_traits : std::char_traits<T>
-{};
-
-// Explicitly define char traits for unsigned char since it is not standard
-template<>
-struct char_traits<unsigned char> : std::char_traits<char>
-{
-    using char_type = unsigned char;
-    using int_type = uint64_t;
-
-    // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
-    {
-        return static_cast<int_type>(c);
-    }
-
-    static int_type eof()
-    {
-        return static_cast<int_type>(EOF);
-    }
-};
-
-// Explicitly define char traits for signed char since it is not standard
-template<>
-struct char_traits<signed char> : std::char_traits<char>
-{
-    using char_type = signed char;
-    using int_type = uint64_t;
-
-    // Redefine to_int_type function
-    static int_type to_int_type(char_type c)
-    {
-        return static_cast<int_type>(c);
-    }
-
-    static int_type eof()
-    {
-        return static_cast<int_type>(EOF);
-    }
-};
-
 // General-purpose iterator-based adapter. It might not be as fast as
 // theoretically possible for some containers, but it is extremely versatile.
 template<typename IteratorType>
@@ -9200,7 +9205,7 @@ class binary_reader
     using binary_t = typename BasicJsonType::binary_t;
     using json_sax_t = SAX;
     using char_type = typename InputAdapterType::char_type;
-    using char_int_type = typename std::char_traits<char_type>::int_type;
+    using char_int_type = typename char_traits<char_type>::int_type;
 
   public:
     /*!
@@ -9273,7 +9278,7 @@ class binary_reader
                 get();
             }
 
-            if (JSON_HEDLEY_UNLIKELY(current != std::char_traits<char_type>::eof()))
+            if (JSON_HEDLEY_UNLIKELY(current != char_traits<char_type>::eof()))
             {
                 return sax->parse_error(chars_read, get_token_string(), parse_error::create(110, chars_read,
                                         exception_message(input_format, concat("expected end of input; last byte: 0x", get_token_string()), "value"), nullptr));
@@ -9356,7 +9361,7 @@ class binary_reader
                                     exception_message(input_format_t::bson, concat("string length must be at least 1, is ", std::to_string(len)), "string"), nullptr));
         }
 
-        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) && get() != std::char_traits<char_type>::eof();
+        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) && get() != char_traits<char_type>::eof();
     }
 
     /*!
@@ -9550,7 +9555,7 @@ class binary_reader
         switch (get_char ? get() : current)
         {
             // EOF
-            case std::char_traits<char_type>::eof():
+            case char_traits<char_type>::eof():
                 return unexpect_eof(input_format_t::cbor, "value");
 
             // Integer 0x00..0x17 (0..23)
@@ -10325,7 +10330,7 @@ class binary_reader
         switch (get())
         {
             // EOF
-            case std::char_traits<char_type>::eof():
+            case char_traits<char_type>::eof():
                 return unexpect_eof(input_format_t::msgpack, "value");
 
             // positive fixint
@@ -11427,7 +11432,7 @@ class binary_reader
     {
         switch (prefix)
         {
-            case std::char_traits<char_type>::eof():  // EOF
+            case char_traits<char_type>::eof():  // EOF
                 return unexpect_eof(input_format, "value");
 
             case 'T':  // true
@@ -11872,7 +11877,7 @@ class binary_reader
 
     This function provides the interface to the used input adapter. It does
     not throw in case the input reached EOF, but returns a -'ve valued
-    `std::char_traits<char_type>::eof()` in that case.
+    `char_traits<char_type>::eof()` in that case.
 
     @return character read from the input
     */
@@ -12014,7 +12019,7 @@ class binary_reader
     JSON_HEDLEY_NON_NULL(3)
     bool unexpect_eof(const input_format_t format, const char* context) const
     {
-        if (JSON_HEDLEY_UNLIKELY(current == std::char_traits<char_type>::eof()))
+        if (JSON_HEDLEY_UNLIKELY(current == char_traits<char_type>::eof()))
         {
             return sax->parse_error(chars_read, "<end of file>",
                                     parse_error::create(110, chars_read, exception_message(format, "unexpected end of input", context), nullptr));
@@ -12081,7 +12086,7 @@ class binary_reader
     InputAdapterType ia;
 
     /// the current character
-    char_int_type current = std::char_traits<char_type>::eof();
+    char_int_type current = char_traits<char_type>::eof();
 
     /// the number of characters read
     std::size_t chars_read = 0;