1 files changed, 33 insertions, 0 deletions
diff --git a/src/tree_sitter/utf16.c b/src/tree_sitter/utf16.c
new file mode 100644
index 0000000000..3956c01cb9
--- /dev/null
+++ b/src/tree_sitter/utf16.c
@@ -0,0 +1,33 @@
+#include "./utf16.h"
+
+utf8proc_ssize_t utf16_iterate(
+  const utf8proc_uint8_t *string,
+  utf8proc_ssize_t length,
+  utf8proc_int32_t *code_point
+) {
+  if (length < 2) {
+    *code_point = -1;
+    return 0;
+  }
+
+  uint16_t *units = (uint16_t *)string;
+  uint16_t unit = units[0];
+
+  if (unit < 0xd800 || unit >= 0xe000) {
+    *code_point = unit;
+    return 2;
+  }
+
+  if (unit < 0xdc00) {
+    if (length >= 4) {
+      uint16_t next_unit = units[1];
+      if (next_unit >= 0xdc00 && next_unit < 0xe000) {
+        *code_point = 0x10000 + ((unit - 0xd800) << 10) + (next_unit - 0xdc00);
+        return 4;
+      }
+    }
+  }
+
+  *code_point = -1;
+  return 2;
+}