[string] add to_upper

dune/xt/common/string.cc

@@ -29,6 +29,14 @@ std::string to_lower(const std::string& ss)
 }
 
 
+std::string to_upper(const std::string& ss)
+{
+  std::string out(ss);
+  std::transform(out.begin(), out.end(), out.begin(), ::toupper);
+  return out;
+}
+
+
 } // namespace Common
 } // namespace XT
 } // namespace Dune

dune/xt/common/string.hh

@@ -119,6 +119,15 @@ static inline std::string to_string(const T& ss, const size_t precision = defaul
 std::string to_lower(const std::string& ss);
 
 
+/**
+ * \brief Converts each character of a string to upper case using std::toupper.
+ * \note  This might not do what you expect, given your locale.
+ * \sa    http://en.cppreference.com/w/cpp/string/byte/tolower
+ * /sa    ::toupper
+ */
+std::string to_upper(const std::string& ss);
+
+
 /**
   \brief Returns a string of lengths t' whitespace (or whitespace chars).
   \param[in]  t          defines the length of the return string (after conversion to string)