1 files changed, 28 insertions, 0 deletions
diff --git a/include/dux/str.d/issurro.hh b/include/dux/str.d/issurro.hh
new file mode 100644
index 0000000..115bc0f
--- /dev/null
+++ b/include/dux/str.d/issurro.hh
@@ -0,0 +1,28 @@
+/*
+	Copyright 2021 Gabriel Jensen
+
+	This file is part of dux.
+
+	dux is free software: you can redistribute it and/or modify it under the
+	terms of the GNU Affero General Public License as published by the Free
+	Software Foundation, either version 3 of the License, or (at your
+	option) any later version.
+
+	dux is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or
+	FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+	License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with dux. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+constexpr auto ::dux::issurro(char32_t const _chr) -> bool {
+	if(_chr > ::dux::unimax) [[unlikely]] {
+		throw ::dux::outofdomain("Unicode codepoint too big!");
+	}
+	if(_chr >= U'\xD800' && _chr <= U'\xDFFF') [[unlikely]] {
+		return true;
+	}
+	return false;
+}