From aa935088811c0b47a3b590d2e1fae36d03afaadf Mon Sep 17 00:00:00 2001
From: Mylloon <kennel.anri@tutanota.com>
Date: Tue, 4 Jul 2023 13:12:45 +0200
Subject: [PATCH] fix: decode of the compressed name

---
 lib/response.ml | 11 ++++++++---
 lib/utils.ml    |  6 ++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/response.ml b/lib/response.ml
index a478551..1cc3e2a 100644
--- a/lib/response.ml
+++ b/lib/response.ml
@@ -27,7 +27,9 @@ and decode_name reader =
     then 1, parts
     else if length land 0b1100_0000 <> 0
     then (
-      let decoded_name = decode_compressed_name reader length in
+      let decoded_name =
+        decode_compressed_name { reader with pointer = reader.pointer + pos } length
+      in
       2, decoded_name :: parts)
     else (
       let part = Bytes.sub_string reader.data (reader.pointer + pos + 1) length in
@@ -38,9 +40,12 @@ and decode_name reader =
   String.to_bytes (String.concat "." parts), offset
 
 and decode_compressed_name reader length =
-  let pointer =
-    (length land 0b0011_1111) + int_of_char (Bytes.get reader.data (reader.pointer + 1))
+  let pointer_bytes =
+    Bytes.cat
+      (int_to_bytes (length land 0b0011_1111))
+      (Bytes.sub reader.data (reader.pointer + 1) 1)
   in
+  let pointer = unpack_short_be pointer_bytes 0 in
   String.of_bytes (fst (decode_name { reader with pointer }))
 ;;
 
diff --git a/lib/utils.ml b/lib/utils.ml
index 896ded7..bae90de 100644
--- a/lib/utils.ml
+++ b/lib/utils.ml
@@ -51,6 +51,12 @@ let unpack_short_be data offset =
   (msb lsl 8) + lsb
 ;;
 
+let int_to_bytes n =
+  let byte_array = Bytes.create 1 in
+  Bytes.set byte_array 0 (Char.chr (n land 255));
+  byte_array
+;;
+
 let unpack_int_be data offset =
   let byte1 = int_of_char (Bytes.get data offset) in
   let byte2 = int_of_char (Bytes.get data (offset + 1)) in