Some progress on packing (pack() and unpack raw)

tests/repack_chunks7_test.py

@@ -0,0 +1,23 @@
+from twnet_parser.packet import *
+
+from twnet_parser.messages7.system.map_change import MsgMapChange
+
+def test_parse_7_real_map_change():
+    msg = MsgMapChange()
+    msg.unpack(
+            b'BlmapChill\x00' \
+            b'\xde\xcf\xaa\xee\x0b' \
+            b'\x8b\xbe\x8a\x01' \
+            b'\x08' \
+            b'\xa8\x15' \
+            b'\x81\x7d\xbf\x48\xc5\xf1\x94\x37\xc4\x58\x2c\x6f\x98\xc9\xc2\x04\xc1\xf1\x69\x76\x32\xf0\x44\x58\x74\x54\x55\x89\x84\x00\xfb\x28')
+
+    assert msg.message_name == 'map_change'
+
+    assert msg.name == 'BlmapChill'
+    assert msg.crc == -1592087519
+    assert msg.size == 1134475
+    assert msg.chunks_per_request == 8
+    assert msg.chunk_size == 1384
+    # TODO: fix sha unpack
+    # assert msg.sha256 == b'\x81\x7d\xbf\x48\xc5\xf1\x94\x37\xc4\x58\x2c\x6f\x98\xc9\xc2\x04\xc1\xf1\x69\x76\x32\xf0\x44\x58\x74\x54\x55\x89\x84\x00\xfb\x28'

tests/unpacker_state_test.py

@@ -1,6 +1,6 @@
 from twnet_parser.packer import *
 
-def test_unpack_ints_and_strings():
+def test_unpack_ints_and_strings() -> None:
     u = Unpacker(b'\x01\x02\x03\x01foo\x00bar\x00')
     assert u.get_int() == 1
     assert u.get_int() == 2
@@ -8,3 +8,60 @@ def test_unpack_ints_and_strings():
     assert u.get_int() == 1
     assert u.get_str() == 'foo'
     assert u.get_str() == 'bar'
+
+def test_simple_repack() -> None:
+    data: bytes = pack_str('hello world')
+    assert data == b'hello world\x00'
+    data += pack_int(22)
+
+    u = Unpacker(data)
+    assert u.get_str() == 'hello world'
+    assert u.get_int() == 22
+
+def test_non_ascii_repack() -> None:
+    data: bytes = pack_str('💩')
+    assert data == '💩'.encode('utf-8') + b'\x00'
+
+    u = Unpacker(data)
+    assert u.get_str() == '💩'
+
+def test_multi_repack() -> None:
+    strs: list[str] = [
+            'foo',
+            'bar',
+            'baz',
+            '',
+            'yeeeeeeeeeeeeeeeeeee' \
+            'eeeeeeeeeeeeeeeeeeee' \
+            'eeeeeeeeeeeeeeeeeeee' \
+            'eeeeeeeeeeeeeeeeeeee' \
+            'eeeeeeeeeeeeeeeeeeee' \
+            'eeeeeeeeeeeeeeeeeeee' \
+            'eeeppiiiiiiiiiiiiiii',
+            'a b c d e f',
+            'nameless tee',
+            '(1)nameless tee',
+            '[D](1)nameless t']
+
+    ints: list[int] = [
+            0,
+            111111111,
+            222222222,
+            649010,
+            -1,
+            -19882,
+            29299]
+
+    # pack
+    data: bytes = b''
+    for string in strs:
+        data += pack_str(string)
+    for num in ints:
+        data += pack_int(num)
+
+    # unpack
+    u = Unpacker(data)
+    for string in strs:
+        assert u.get_str() == string
+    for num in ints:
+        assert u.get_int() == num

twnet_parser/messages7/system/map_change.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 from twnet_parser.pretty_print import PrettyPrint
-from twnet_parser.packer import Unpacker
+from twnet_parser.packer import Unpacker, pack_str, pack_int
 
 class MsgMapChange(PrettyPrint):
     def __init__(
@@ -30,10 +30,15 @@ class MsgMapChange(PrettyPrint):
         self.crc = unpacker.get_int()
         self.size = unpacker.get_int()
         self.chunks_per_request = unpacker.get_int()
+        self.sha256 = unpacker.get_raw()
         return True
 
     def pack(self) -> bytes:
-        return b'todo'
+        return pack_str(self.name) + \
+            pack_int(self.crc) + \
+            pack_int(self.size) + \
+            pack_int(self.chunks_per_request) + \
+            self.sha256
 
 # msg = MsgMapChange()
 # msg.unpack(
@@ -44,4 +49,5 @@ class MsgMapChange(PrettyPrint):
 #         b'\xa8\x15' \
 #         b'\x81\x7d\xbf\x48\xc5\xf1\x94\x37\xc4\x58\x2c\x6f\x98\xc9\xc2\x04\xc1\xf1\x69\x76\x32\xf0\x44\x58\x74\x54\x55\x89\x84\x00\xfb\x28')
 # 
+# print(msg.pack())
 # print(msg)

twnet_parser/packer.py

@@ -25,6 +25,14 @@ class Unpacker():
     def data(self) -> bytes:
         return self._data[self.idx:]
 
+    def get_raw(self, size: int = -1) -> bytes:
+        if size == -1:
+            return self.data()
+        end: int = self.idx + size
+        data: bytes = self._data[self.idx:end]
+        self.idx = end
+        return data
+
     def get_int(self) -> int:
         sign = (self.byte() >> 6) & 1
         res = self.byte() & 0x3F
@@ -81,6 +89,9 @@ def pack_int(num: int) -> bytes:
         num >>= 7 # discard 7 bits
     return bytes(res)
 
+def pack_str(data: str) -> bytes:
+    return data.encode('utf-8') + b'\x00'
+
 # TODO: optimize performance and benchmark in tests
 def unpack_int(data: bytes) -> int:
     sign = (data[0] >> 6) & 1