Remove recursion when stringifying std::tuple

src/catch2/catch_tostring.cpp

@@ -57,6 +57,36 @@ namespace Detail {
         }
     } // end unnamed namespace
 
+    std::size_t catch_strnlen( const char* str, std::size_t n ) {
+        auto ret = std::char_traits<char>::find( str, n, '\0' );
+        if ( ret != nullptr ) { return static_cast<std::size_t>( ret - str ); }
+        return n;
+    }
+
+    std::string formatTimeT(std::time_t time) {
+#ifdef _MSC_VER
+        std::tm timeInfo = {};
+        const auto err = gmtime_s( &timeInfo, &time );
+        if ( err ) {
+            return "gmtime from provided timepoint has failed. This "
+                   "happens e.g. with pre-1970 dates using Microsoft libc";
+        }
+#else
+        std::tm* timeInfo = std::gmtime( &time );
+#endif
+
+        auto const timeStampSize = sizeof( "2017-01-16T17:06:45Z" );
+        char timeStamp[timeStampSize];
+        const char* const fmt = "%Y-%m-%dT%H:%M:%SZ";
+
+#ifdef _MSC_VER
+        std::strftime( timeStamp, timeStampSize, fmt, &timeInfo );
+#else
+        std::strftime( timeStamp, timeStampSize, fmt, timeInfo );
+#endif
+        return std::string( timeStamp, timeStampSize - 1 );
+    }
+
     std::string convertIntoString(StringRef string, bool escapeInvisibles) {
         std::string ret;
         // This is enough for the "don't escape invisibles" case, and a good

src/catch2/catch_tostring.hpp

@@ -8,7 +8,7 @@
 #ifndef CATCH_TOSTRING_HPP_INCLUDED
 #define CATCH_TOSTRING_HPP_INCLUDED
 
-
+#include <ctime>
 #include <vector>
 #include <cstddef>
 #include <type_traits>
@@ -40,13 +40,9 @@ namespace Catch {
 
     namespace Detail {
 
-        inline std::size_t catch_strnlen(const char *str, std::size_t n) {
-            auto ret = std::char_traits<char>::find(str, n, '\0');
-            if (ret != nullptr) {
-                return static_cast<std::size_t>(ret - str);
-            }
-            return n;
-        }
+        std::size_t catch_strnlen(const char *str, std::size_t n);
+
+        std::string formatTimeT( std::time_t time );
 
         constexpr StringRef unprintableString = "{?}"_sr;
 
@@ -412,43 +408,37 @@ namespace Catch {
 // Separate std::tuple specialization
 #if defined(CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER)
 #    include <tuple>
+#    include <utility>
 namespace Catch {
     namespace Detail {
-        template<
-            typename Tuple,
-            std::size_t N = 0,
-            bool = (N < std::tuple_size<Tuple>::value)
-            >
-            struct TupleElementPrinter {
-            static void print(const Tuple& tuple, std::ostream& os) {
-                os << (N ? ", " : " ")
-                    << ::Catch::Detail::stringify(std::get<N>(tuple));
-                TupleElementPrinter<Tuple, N + 1>::print(tuple, os);
-            }
-        };
-
-        template<
-            typename Tuple,
-            std::size_t N
-        >
-            struct TupleElementPrinter<Tuple, N, false> {
-            static void print(const Tuple&, std::ostream&) {}
-        };
-
+        template <typename Tuple, std::size_t... Is>
+        void PrintTuple( const Tuple& tuple,
+                         std::ostream& os,
+                         std::index_sequence<Is...> ) {
+            // 1 + Account for when the tuple is empty
+            char a[1 + sizeof...( Is )] = {
+                ( ( os << ( Is ? ", " : " " )
+                       << ::Catch::Detail::stringify( std::get<Is>( tuple ) ) ),
+                  '\0' )... };
+            (void)a;
         }
 
+    } // namespace Detail
 
     template <typename... Types>
     struct StringMaker<std::tuple<Types...>> {
         static std::string convert( const std::tuple<Types...>& tuple ) {
             ReusableStringStream rss;
             rss << '{';
-            Detail::TupleElementPrinter<std::tuple<Types...>>::print(tuple, rss.get());
+            Detail::PrintTuple(
+                tuple,
+                rss.get(),
+                std::make_index_sequence<sizeof...( Types )>{} );
             rss << " }";
             return rss.str();
         }
     };
-}
+} // namespace Catch
 #endif // CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER
 
 #if defined(CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER) && defined(CATCH_CONFIG_CPP17_VARIANT)
@@ -635,28 +625,7 @@ struct ratio_string<std::milli> {
             const auto systemish = std::chrono::time_point_cast<
                 std::chrono::system_clock::duration>( time_point );
             const auto as_time_t = std::chrono::system_clock::to_time_t( systemish );
-
-#ifdef _MSC_VER
-            std::tm timeInfo = {};
-            const auto err = gmtime_s( &timeInfo, &as_time_t );
-            if ( err ) {
-                return "gmtime from provided timepoint has failed. This "
-                       "happens e.g. with pre-1970 dates using Microsoft libc";
-            }
-#else
-            std::tm* timeInfo = std::gmtime( &as_time_t );
-#endif
-
-            auto const timeStampSize = sizeof("2017-01-16T17:06:45Z");
-            char timeStamp[timeStampSize];
-            const char * const fmt = "%Y-%m-%dT%H:%M:%SZ";
-
-#ifdef _MSC_VER
-            std::strftime(timeStamp, timeStampSize, fmt, &timeInfo);
-#else
-            std::strftime(timeStamp, timeStampSize, fmt, timeInfo);
-#endif
-            return std::string(timeStamp, timeStampSize - 1);
+            return ::Catch::Detail::formatTimeT( as_time_t );
         }
     };
 }