diff --git a/src/main/c/util/buffer.c b/src/main/c/util/buffer.c
index 6440414..bddd4d5 100644
--- a/src/main/c/util/buffer.c
+++ b/src/main/c/util/buffer.c
@@ -16,4 +16,39 @@ int hbu_buffer_compare_lit(hbu_buffer_t a, const char *b) {
   return strcmp((char *) a->data, b);
 }
 
+// Logic copied from https://gist.github.com/MightyPork/52eda3e5677b4b03524e40c9f0ab1da5
+int hbu_buffer_append_unicode(hbu_buffer_t buffer, uint32_t code_point) {
+   if (code_point <= 0x7F) {
+    // Plain ASCII
+    hbu_buffer_append(buffer, (hb_char_t) code_point);
+    return 1;
+  }
+
+  if (code_point <= 0x07FF) {
+    // 2-byte unicode
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >> 6) & 0x1F) | 0xC0));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >> 0) & 0x3F) | 0x80));
+    return 2;
+  }
+
+  if (code_point <= 0xFFFF) {
+    // 3-byte unicode
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >> 12) & 0x0F) | 0xE0));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >>  6) & 0x3F) | 0x80));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >>  0) & 0x3F) | 0x80));
+    return 3;
+  }
+
+  if (code_point <= 0x10FFFF) {
+    // 4-byte unicode
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >> 18) & 0x07) | 0xF0));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >> 12) & 0x3F) | 0x80));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >>  6) & 0x3F) | 0x80));
+    hbu_buffer_append(buffer, (hb_char_t) (((code_point >>  0) & 0x3F) | 0x80));
+    return 4;
+  }
+
+  return 0;
+}
+
 #endif