Fixed support for volatile float and double (fixes #1557)

src/ArduinoJson/Polyfills/type_traits/is_floating_point.hpp

@@ -5,15 +5,16 @@
 #pragma once
 
 #include "integral_constant.hpp"
+#include "is_same.hpp"
+#include "remove_cv.hpp"
 
 namespace ARDUINOJSON_NAMESPACE {
 
-template <typename>
-struct is_floating_point : false_type {};
+template <class T>
+struct is_floating_point
+    : integral_constant<
+          bool,  //
+          is_same<float, typename remove_cv<T>::type>::value ||
+              is_same<double, typename remove_cv<T>::type>::value> {};
 
-template <>
-struct is_floating_point<float> : true_type {};
-
-template <>
-struct is_floating_point<double> : true_type {};
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Polyfills/type_traits/is_integral.hpp

@@ -5,29 +5,33 @@
 #pragma once
 
 #include <ArduinoJson/Configuration.hpp>
+
+#include "integral_constant.hpp"
 #include "is_same.hpp"
+#include "remove_cv.hpp"
 
 namespace ARDUINOJSON_NAMESPACE {
 
-// A meta-function that returns true if T is an integral type.
+// clang-format off
 template <typename T>
-struct is_integral {
-  static const bool value =
-      is_same<T, signed char>::value || is_same<T, unsigned char>::value ||
-      is_same<T, signed short>::value || is_same<T, unsigned short>::value ||
-      is_same<T, signed int>::value || is_same<T, unsigned int>::value ||
-      is_same<T, signed long>::value || is_same<T, unsigned long>::value ||
+struct is_integral : integral_constant<bool,
+    is_same<typename remove_cv<T>::type, signed char>::value ||
+    is_same<typename remove_cv<T>::type, unsigned char>::value ||
+    is_same<typename remove_cv<T>::type, signed short>::value ||
+    is_same<typename remove_cv<T>::type, unsigned short>::value ||
+    is_same<typename remove_cv<T>::type, signed int>::value ||
+    is_same<typename remove_cv<T>::type, unsigned int>::value ||
+    is_same<typename remove_cv<T>::type, signed long>::value ||
+    is_same<typename remove_cv<T>::type, unsigned long>::value ||
 #if ARDUINOJSON_HAS_LONG_LONG
-      is_same<T, signed long long>::value ||
-      is_same<T, unsigned long long>::value ||
+    is_same<typename remove_cv<T>::type, signed long long>::value ||
+    is_same<typename remove_cv<T>::type, unsigned long long>::value ||
 #endif
 #if ARDUINOJSON_HAS_INT64
-      is_same<T, signed __int64>::value ||
-      is_same<T, unsigned __int64>::value ||
+    is_same<typename remove_cv<T>::type, signed __int64>::value ||
+    is_same<typename remove_cv<T>::type, unsigned __int64>::value ||
 #endif
-      is_same<T, char>::value || is_same<T, bool>::value;
-};
-
-template <typename T>
-struct is_integral<const T> : is_integral<T> {};
+    is_same<typename remove_cv<T>::type, char>::value ||
+    is_same<typename remove_cv<T>::type, bool>::value> {};
+// clang-format on
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Polyfills/type_traits/is_signed.hpp

@@ -5,39 +5,26 @@
 #pragma once
 
 #include "integral_constant.hpp"
+#include "is_same.hpp"
+#include "remove_cv.hpp"
+
 namespace ARDUINOJSON_NAMESPACE {
 
-template <typename>
-struct is_signed : false_type {};
-
-template <>
-struct is_signed<char> : true_type {};
-
-template <>
-struct is_signed<signed char> : true_type {};
-
-template <>
-struct is_signed<signed short> : true_type {};
-
-template <>
-struct is_signed<signed int> : true_type {};
-
-template <>
-struct is_signed<signed long> : true_type {};
-
-template <>
-struct is_signed<float> : true_type {};
-
-template <>
-struct is_signed<double> : true_type {};
-
+// clang-format off
+template <typename T>
+struct is_signed : integral_constant<bool, 
+    is_same<typename remove_cv<T>::type, char>::value ||
+    is_same<typename remove_cv<T>::type, signed char>::value ||
+    is_same<typename remove_cv<T>::type, signed short>::value ||
+    is_same<typename remove_cv<T>::type, signed int>::value ||
+    is_same<typename remove_cv<T>::type, signed long>::value ||
 #if ARDUINOJSON_HAS_LONG_LONG
-template <>
-struct is_signed<signed long long> : true_type {};
+    is_same<typename remove_cv<T>::type, signed long long>::value ||
 #endif
-
 #if ARDUINOJSON_HAS_INT64
-template <>
-struct is_signed<signed __int64> : true_type {};
+    is_same<typename remove_cv<T>::type, signed __int64>::value ||
 #endif
+    is_same<typename remove_cv<T>::type, float>::value ||
+    is_same<typename remove_cv<T>::type, double>::value> {};
+// clang-format on
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Polyfills/type_traits/is_unsigned.hpp

@@ -5,33 +5,24 @@
 #pragma once
 
 #include "integral_constant.hpp"
+#include "is_same.hpp"
+#include "remove_cv.hpp"
+
 namespace ARDUINOJSON_NAMESPACE {
 
-template <typename>
-struct is_unsigned : false_type {};
-
-template <>
-struct is_unsigned<bool> : true_type {};
-
-template <>
-struct is_unsigned<unsigned char> : true_type {};
-
-template <>
-struct is_unsigned<unsigned short> : true_type {};
-
-template <>
-struct is_unsigned<unsigned int> : true_type {};
-
-template <>
-struct is_unsigned<unsigned long> : true_type {};
-
+// clang-format off
+template <typename T>
+struct is_unsigned : integral_constant<bool,
+    is_same<typename remove_cv<T>::type, unsigned char>::value ||
+    is_same<typename remove_cv<T>::type, unsigned short>::value ||
+    is_same<typename remove_cv<T>::type, unsigned int>::value ||
+    is_same<typename remove_cv<T>::type, unsigned long>::value ||
 #if ARDUINOJSON_HAS_INT64
-template <>
-struct is_unsigned<unsigned __int64> : true_type {};
+    is_same<typename remove_cv<T>::type, unsigned __int64>::value ||
 #endif
-
 #if ARDUINOJSON_HAS_LONG_LONG
-template <>
-struct is_unsigned<unsigned long long> : true_type {};
+    is_same<typename remove_cv<T>::type, unsigned long long>::value ||
 #endif
+    is_same<typename remove_cv<T>::type, bool>::value> {};
+// clang-format on
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp

@@ -0,0 +1,27 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Namespace.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename T>
+struct remove_cv {
+  typedef T type;
+};
+template <typename T>
+struct remove_cv<const T> {
+  typedef T type;
+};
+template <typename T>
+struct remove_cv<volatile T> {
+  typedef T type;
+};
+template <typename T>
+struct remove_cv<const volatile T> {
+  typedef T type;
+};
+}  // namespace ARDUINOJSON_NAMESPACE