Adding the proper polyfill for older standard libs used by GCC and Clang.

Author: nfrechette

includes/sjson/platform.h renamed to includes/sjson/impl/compiler_utils.h

@@ -24,42 +24,33 @@
 // SOFTWARE.
 ////////////////////////////////////////////////////////////////////////////////
 
-// NVIDIA CodeWorks used for Android has an old version of Clang that does not fully support C++11
-#if defined(__clang__) && __clang_major__ <= 3 && __clang_minor__ <= 8
-	#include <stdlib.h>
-#else
+#if !defined(__GNUG__) || defined(_LIBCPP_VERSION) || defined(_GLIBCXX_USE_CXX11_ABI)
 	#include <cstdlib>
+#else
+	#include <stdlib.h>
 #endif
 
 namespace sjson
 {
-	namespace impl
+	//////////////////////////////////////////////////////////////////////////
+	// The version of the STL shipped with versions of GCC older than 5.1 are missing a number of type traits and functions,
+	// such as std::is_trivially_default_constructible.
+	// In this case, we polyfill the proper standard names using the deprecated std::has_trivial_default_constructor.
+	// This must also be done when the compiler is clang when it makes use of the GCC implementation of the STL,
+	// which is the default behavior on linux. Properly detecting the version of the GCC STL used by clang cannot
+	// be done with the __GNUC__  macro, which are overridden by clang. Instead, we check for the definition
+	// of the macro ``_GLIBCXX_USE_CXX11_ABI`` which is only defined with GCC versions greater than 5.
+	//////////////////////////////////////////////////////////////////////////
+	namespace sjson_impl
 	{
-		inline unsigned long long int strtoull(const char* str, char** endptr, int base)
-		{
-#if defined(__clang__) && __clang_major__ <= 3 && __clang_minor__ <= 8
-			return ::strtoull(str, endptr, base);
-#else
-			return std::strtoull(str, endptr, base);
-#endif
-		}
-
-		inline long long int strtoll(const char* str, char** endptr, int base)
-		{
-#if defined(__clang__) && __clang_major__ <= 3 && __clang_minor__ <= 8
-			return ::strtoll(str, endptr, base);
-#else
-			return std::strtoll(str, endptr, base);
-#endif
-		}
-
-		inline float strtof(const char* str, char** endptr)
-		{
-#if defined(__clang__) && __clang_major__ <= 3 && __clang_minor__ <= 8
-			return ::strtof(str, endptr);
+#if !defined(__GNUG__) || defined(_LIBCPP_VERSION) || defined(_GLIBCXX_USE_CXX11_ABI)
+		using std::strtoull;
+		using std::strtoll;
+		using std::strtof;
 #else
-			return std::strtof(str, endptr);
+		using ::strtoull;
+		using ::strtoll;
+		using ::strtof;
 #endif
-		}
 	}
 }

includes/sjson/parser.h

@@ -31,7 +31,7 @@
 
 #include "sjson/parser_error.h"
 #include "sjson/parser_state.h"
-#include "sjson/platform.h"
+#include "sjson/impl/compiler_utils.h"
 #include "sjson/string_view.h"
 
 #include <cctype>
@@ -723,7 +723,7 @@ namespace sjson
 			if (dbl_value != nullptr)
 				*dbl_value = std::strtod(slice, &last_used_symbol);
 			else
-				*flt_value = impl::strtof(slice, &last_used_symbol);
+				*flt_value = sjson_impl::strtof(slice, &last_used_symbol);
 
 			if (last_used_symbol != slice + length)
 			{
@@ -800,7 +800,7 @@ namespace sjson
 			char* last_used_symbol = nullptr;
 			if (std::is_unsigned<IntegralType>::value)
 			{
-				const uint64_t raw_value = impl::strtoull(slice, &last_used_symbol, base);
+				const uint64_t raw_value = sjson_impl::strtoull(slice, &last_used_symbol, base);
 				value = static_cast<IntegralType>(raw_value);
 
 				if (static_cast<uint64_t>(value) != raw_value)
@@ -811,7 +811,7 @@ namespace sjson
 			}
 			else
 			{
-				const int64_t raw_value = impl::strtoll(slice, &last_used_symbol, base);
+				const int64_t raw_value = sjson_impl::strtoll(slice, &last_used_symbol, base);
 				value = static_cast<IntegralType>(raw_value);
 
 				if (static_cast<int64_t>(value) != raw_value)