Merge pull request SqliteModernCpp#203 from marciso/msvc_lang

use _MSVC_LANG to include C++17 headers in Visual Studio

Author: aminroosta

hdr/sqlite_modern_cpp.h

@@ -29,7 +29,7 @@ namespace sqlite {
 	template<class T, bool Name = false>
 	struct index_binding_helper {
 		index_binding_helper(const index_binding_helper &) = delete;
-#if __cplusplus < 201703
+#if __cplusplus < 201703 || _MSVC_LANG <= 201703
 		index_binding_helper(index_binding_helper &&) = default;
 #endif
 		typename std::conditional<Name, const char *, int>::type index;

hdr/sqlite_modern_cpp/type_wrapper.h

@@ -5,20 +5,20 @@
 #include <memory>
 #include <vector>
 #ifdef __has_include
-#if __cplusplus >= 201703 && __has_include(<string_view>)
+#if (__cplusplus >= 201703 || _MSVC_LANG >= 201703) && __has_include(<string_view>)
 #define MODERN_SQLITE_STRINGVIEW_SUPPORT
 #endif
 #endif
 #ifdef __has_include
-#if __cplusplus > 201402 && __has_include(<optional>)
+#if (__cplusplus > 201402 || _MSCV_LANG > 201402) && __has_include(<optional>)
 #define MODERN_SQLITE_STD_OPTIONAL_SUPPORT
 #elif __has_include(<experimental/optional>) && __apple_build_version__ < 11000000
 #define MODERN_SQLITE_EXPERIMENTAL_OPTIONAL_SUPPORT
 #endif
 #endif
 
 #ifdef __has_include
-#if __cplusplus > 201402 && __has_include(<variant>)
+#if (__cplusplus > 201402 || _MSVC_LANG > 201402) && __has_include(<variant>)
 #define MODERN_SQLITE_STD_VARIANT_SUPPORT
 #endif
 #endif

hdr/sqlite_modern_cpp/utility/utf16_utf8.h

@@ -17,7 +17,7 @@ namespace sqlite {
 			std::size_t produced_output = 0;
 			while(true) {
 				char *used_output;
-				switch(codecvt.out(state, remaining_input, &input[input.size()],
+				switch(codecvt.out(state, remaining_input, input.data() + input.size(),
 				                   remaining_input, &result[produced_output],
 				                   &result[result.size() - 1] + 1, used_output)) {
 				case std::codecvt_base::ok:
@@ -33,7 +33,7 @@ namespace sqlite {
 					produced_output = used_output - result.data();
 					result.resize(
 							result.size()
-							+ (std::max)((&input[input.size()] - remaining_input) * 3 / 2,
+							+ (std::max)((input.data() + input.size() - remaining_input) * 3 / 2,
 							           std::ptrdiff_t(4)));
 				}
 			}