1 files changed, 35 insertions, 0 deletions
diff --git a/zap/src/mem/utf8declen.c b/zap/src/mem/utf8declen.c
new file mode 100644
index 0000000..202e995
--- /dev/null
+++ b/zap/src/mem/utf8declen.c
@@ -0,0 +1,35 @@
+/*
+	Copyright 2022 Gabriel Jensen.
+	This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+	If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
+*/
+
+#include <zap/priv.h>
+
+#include <zap/mem.h>
+
+#include <stddef.h>
+
+zap_sz zap_utf8declen(zap_chr8 const * const _in) {
+	zap_sz len = 0x0u;
+	zap_chr8 const * in;
+	for (in = _in;;++len) {
+		zap_chr8 const oct = *in;
+		sus_unlikely (oct == 0x0u) {break;}
+		if (oct >= 0xF0u) {
+			in += 0x4u;
+			continue;
+		}
+		if (oct >= 0xE0u) {
+			in += 0x3u;
+			continue;
+		}
+		if (oct >= 0xC0u) {
+			in += 0x2u;
+			continue;
+		}
+		++in;
+		continue;
+	}
+	return len;
+}