ircd: Add string_view based tolower()/toupper().

include/ircd/stringops.h

@@ -91,6 +91,14 @@ namespace ircd
 	string_view replace(const mutable_buffer &, const char &before, const char &after);
 	string_view replace(const mutable_buffer &out, const string_view &in, const char &before, const char &after);
 
+	// Change a single character's case
+	using std::tolower;
+	using std::toupper;
+
+	// Change case for all characters.
+	string_view tolower(const mutable_buffer &out, const string_view &in) noexcept;
+	string_view toupper(const mutable_buffer &out, const string_view &in) noexcept;
+
 	// Truncate view at maximum length
 	string_view trunc(const string_view &, const size_t &max);
 }

ircd/stringops.cc

@@ -8,6 +8,56 @@
 // copyright notice and this permission notice is present in all copies. The
 // full license for this software is available in the LICENSE file.
 
+ircd::string_view
+ircd::toupper(const mutable_buffer &out,
+              const string_view &in)
+noexcept
+{
+	const auto stop
+	{
+		std::next(begin(in), std::min(size(in), size(out)))
+	};
+
+	const auto end
+	{
+		std::transform(begin(in), stop, begin(out), []
+		(const auto &c)
+		{
+			return std::toupper(c);
+		})
+	};
+
+	return string_view
+	{
+		data(out), std::distance(begin(out), end)
+	};
+}
+
+ircd::string_view
+ircd::tolower(const mutable_buffer &out,
+              const string_view &in)
+noexcept
+{
+	const auto stop
+	{
+		std::next(begin(in), std::min(size(in), size(out)))
+	};
+
+	const auto end
+	{
+		std::transform(begin(in), stop, begin(out), []
+		(const auto &c)
+		{
+			return std::tolower(c);
+		})
+	};
+
+	return string_view
+	{
+		data(out), std::distance(begin(out), end)
+	};
+}
+
 std::string
 ircd::replace(const string_view &s,
               const char &before,