From 6240dd36e524ff2ec8ed6401baa9fa366c7392f7 Mon Sep 17 00:00:00 2001
From: ChillerDragon <ChillerDragon@gmail.com>
Date: Sun, 19 Mar 2023 11:40:15 +0100
Subject: [PATCH] Polish and test int packer

---
 tests/int_packer_test.py | 45 ++++++++++++++++++++++++++++++++++++++++
 twnet_parser/packer.py   | 27 +-----------------------
 2 files changed, 46 insertions(+), 26 deletions(-)
 create mode 100644 tests/int_packer_test.py

diff --git a/tests/int_packer_test.py b/tests/int_packer_test.py
new file mode 100644
index 0000000..5704b26
--- /dev/null
+++ b/tests/int_packer_test.py
@@ -0,0 +1,45 @@
+from twnet_parser.packer import *
+
+def test_pack_small_positive_ints():
+    assert pack_int(1) == b'\x01'
+    assert pack_int(2) == b'\x02'
+    assert pack_int(3) == b'\x03'
+
+    assert pack_int(44) == b'\x2C'
+    assert pack_int(45) == b'\x2D'
+    assert pack_int(46) == b'\x2E'
+
+def test_pack_multi_byte_positive_ints():
+    assert pack_int(63) == b'\x3F'
+    assert pack_int(64) == b'\x80\x01'
+    assert pack_int(65) == b'\x81\x01'
+
+def test_pack_small_negative_ints():
+    assert pack_int(-1) == b'\x40'
+    assert pack_int(-2) == b'\x41'
+    assert pack_int(-3) == b'\x42'
+
+    assert pack_int(-44) == b'\x6B'
+    assert pack_int(-45) == b'\x6C'
+    assert pack_int(-46) == b'\x6D'
+
+def test_pack_multi_byte_negative_ints():
+    assert pack_int(-63) == b'\x7E'
+    assert pack_int(-64) == b'\x7F'
+    assert pack_int(-65) == b'\xC0\x01'
+
+def test_pack_multi_byte_positive_and_negative():
+    assert pack_int(-66663) == b'\xe6\x91\x08'
+    assert pack_int(66663) == b'\xa7\x91\x08'
+
+    assert pack_int(-8866663) == b'\xe6\xad\xba\x08'
+    assert pack_int(8866663) == b'\xa7\xad\xba\x08'
+
+# TODO: should we just pack numbers bigger than 4 bytes?
+#       since the official tw client and server are written in C++
+#       they do not support such big numbers
+#       we could also throw an error here instead
+def test_pack_too_big_positive_and_negative():
+    assert pack_int(-98866996963) == b'\xe2\x9b\xf5\xce\xe0\x05'
+    assert pack_int(98866996963) == b'\xa3\x9b\xf5\xce\xe0\x05'
+
diff --git a/twnet_parser/packer.py b/twnet_parser/packer.py
index 45a30a8..91c2dea 100644
--- a/twnet_parser/packer.py
+++ b/twnet_parser/packer.py
@@ -1,45 +1,20 @@
 #!/usr/bin/env python
 
-from textwrap import wrap
-
-def dbg(raw: bytearray) -> None:
-    bits_str = ''
-    annotation_str = ''
-    for byte in raw:
-        bits_str += ' '.join(wrap(f"{byte:08b} ", 2))
-        annotation_str += 'ES DD DD DD '
-    print(f"  {bits_str}   {bytes(raw)!r}")
-    print(f"  {annotation_str}")
-
+# TODO: optimize performance and benchmark in tests
 def pack_int(num: int) -> bytes:
-    print(f"packing {num}")
     res: bytearray = bytearray(b'\x00')
     if num < 0:
         res[0] |= 0x40 # set sign bit
-        print(f"num={num}")
         num = ~num
-        # print(f"num num={num}")
-
-    # print("--- signed:")
-    # dbg(res)
 
     res[0] |= num & 0x3F # pack 6bit into res
     num >>= 6 # discard 6 bits
 
-    print("--- pack 6 bit:")
-    dbg(res)
-
     i = 0
     while num != 0:
         res[i] |= 0x80 # set extend bit
         i += 1
         res.extend(bytes([num & 0x7F])) # pack 7 bit
         num >>= 7 # discard 7 bits
-        print(num)
-
     return bytes(res)
 
-print(pack_int(63))
-print(pack_int(64))
-print(pack_int(65))
-