Merge pull request #169 from neilmacintosh/dev/neilmac/to-string-test

Added workaround for MSVC 2013 compiler bug.

include/string_span.h

@@ -22,6 +22,16 @@
 #include "span.h"
 #include <cstring>
 
+// VS 2013 workarounds
+#ifdef _MSC_VER
+#if _MSC_VER <= 1800
+
+#pragma push_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
+#define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+#endif // _MSC_VER <= 1800
+#endif // _MSC_VER
+
 namespace gsl
 {
 //
@@ -34,16 +44,16 @@ namespace gsl
 // type system for these types that will not either incur significant runtime costs or
 // (sometimes needlessly) break existing programs when introduced.
 //
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using czstring = const char*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using cwzstring = const wchar_t*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using zstring = char*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using wzstring = wchar_t*;
 
 //
@@ -134,12 +144,37 @@ basic_string_span<typename std::remove_pointer<typename Cont::pointer>::type, dy
 //
 // to_string() allow (explicit) conversions from string_span to string
 //
-template<class CharT, size_t Extent>
+#ifndef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+template<class CharT, ptrdiff_t Extent>
 std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_span<CharT, Extent> view)
+{
+    return{ view.data(), static_cast<size_t>(view.length()) };
+}
+
+#else
+
+std::string to_string(cstring_span<> view)
 {
     return{ view.data(), view.length() };
 }
 
+std::string to_string(string_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+std::wstring to_string(cwstring_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+std::wstring to_string(wstring_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+#endif 
 
 template<class CharT, size_t Extent = dynamic_range>
 class basic_zstring_builder
@@ -178,4 +213,15 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
+// VS 2013 workarounds
+#ifdef _MSC_VER
+#if _MSC_VER <= 1800
+
+#pragma pop_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
+#undef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+#endif // _MSC_VER <= 1800
+#endif // _MSC_VER
+
+
 #endif // GSL_STRING_SPAN_H

tests/string_span_tests.cpp

@@ -22,6 +22,7 @@
 using namespace std;
 using namespace gsl;
 
+
 SUITE(string_span_tests)
 {
 
@@ -104,6 +105,18 @@ SUITE(string_span_tests)
         string_span<> v3 = "Hello";
 #endif
     }
+
+    TEST(TestToString)
+    {
+        auto s = gsl::to_string(cstring_span<>{});
+        CHECK(s.length() == 0);
+
+        char stack_string[] = "Hello";
+        cstring_span<> v = ensure_z(stack_string);
+        auto s2 = gsl::to_string(v);
+        CHECK(s2.length() == v.length());
+        CHECK(s2.length() == 5);
+    }
 }
 
 int main(int, const char *[])