Add Config.wpak unpack, pack and test

A .wpak is a zip whose entries are each Blowfish CFB-64 encrypted with
a zero IV and the client's hardcoded key (sb.exe 0x54DEC0). Pure Python
Blowfish, no new dependencies.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mbEditorPro2.0/arcane/util/ArcWpak.py

@@ -0,0 +1,178 @@
+#  • ▌ ▄ ·. ▄▄▄▄·     ▄▄▄ .·▄▄▄▄  ▪  ▄▄▄▄▄      ▄▄▄       ▄▄▄·▄▄▄
+#  ·██ ▐███▪▐█ ▀█▪    ▀▄.▀·██▪ ██ ██ •██  ▪     ▀▄ █·    ▐█ ▄█▀▄ █·▪
+#  ▐█ ▌▐▌▐█·▐█▀▀█▄    ▐▀▀▪▄▐█· ▐█▌▐█· ▐█.▪ ▄█▀▄ ▐▀▀▄      ██▀·▐▀▀▄  ▄█▀▄
+#  ██ ██▌▐█▌██▄▪▐█    ▐█▄▄▌██. ██ ▐█▌ ▐█▌·▐█▌.▐▌▐█•█▌    ▐█▪·•▐█•█▌▐█▌.▐▌
+#  ▀▀  █▪▀▀▀·▀▀▀▀      ▀▀▀ ▀▀▀▀▀• ▀▀▀ ▀▀▀  ▀█▄▀▪.▀  ▀    .▀   .▀  ▀ ▀█▄▀▪
+#                Magicbane Emulator Project © 2013 - 2022
+#                           www.magicbane.com
+
+import os
+import time
+import zipfile
+
+from .ArcFileCache import next_available_path
+
+# A .wpak is a zip (client uses minizip, ArcWPakFile 0x54D3C0) whose entries are
+# each Blowfish CFB-64 encrypted with a zero IV (BF_cfb64_encrypt 0xCD9000).
+WPAK_KEY = bytes([
+    0x85, 0x71, 0x40, 0x3C, 0x14, 0x50, 0x0B, 0x52,
+    0x73, 0x2D, 0x10, 0x08, 0x63, 0x59, 0x5B, 0xAA,
+])  # hardcoded at 0x54DEC0
+
+WPAK_COMPRESS_LEVEL = 9  # zipOpenNewFileInZip level in ArcWPakFile writer
+
+MASK32 = 0xFFFFFFFF
+
+
+def pi_fraction_words(count):
+    # Blowfish's initial P-array and S-boxes are the hex digits of pi's fraction.
+    guard_bits = 64
+    bits = count * 32 + guard_bits
+    one = 1 << bits
+
+    def arctan_inverse(x):
+        x_squared = x * x
+        term = one // x
+        total = term
+        sign = -1
+        n = 1
+        while term:
+            term //= x_squared
+            total += sign * (term // (2 * n + 1))
+            sign = -sign
+            n += 1
+        return total
+
+    pi = 4 * (4 * arctan_inverse(5) - arctan_inverse(239))
+    fraction = (pi - (3 << bits)) >> guard_bits
+
+    return [(fraction >> (32 * (count - 1 - i))) & MASK32 for i in range(count)]
+
+
+class ArcBlowfish:
+    p_array = None
+    s_boxes = None
+
+    def __init__(self, key):
+        words = pi_fraction_words(18 + 4 * 256)
+        self.p_array = words[:18]
+        self.s_boxes = [words[18 + 256 * i: 18 + 256 * (i + 1)] for i in range(4)]
+        self.set_key(key)
+
+    def set_key(self, key):
+        left = 0
+        right = 0
+
+        for i in range(18):
+            key_word = 0
+            for j in range(4):
+                key_word = (key_word << 8) | key[(i * 4 + j) % len(key)]
+            self.p_array[i] ^= key_word
+
+        for i in range(0, 18, 2):
+            left, right = self.encrypt_block(left, right)
+            self.p_array[i] = left
+            self.p_array[i + 1] = right
+
+        for s_box in self.s_boxes:
+            for i in range(0, 256, 2):
+                left, right = self.encrypt_block(left, right)
+                s_box[i] = left
+                s_box[i + 1] = right
+
+    def encrypt_block(self, left, right):
+        p_array = self.p_array
+        s0, s1, s2, s3 = self.s_boxes
+
+        for i in range(16):
+            left ^= p_array[i]
+            feistel = ((s0[left >> 24] + s1[(left >> 16) & 0xFF]) & MASK32) ^ s2[(left >> 8) & 0xFF]
+            right ^= (feistel + s3[left & 0xFF]) & MASK32
+            left, right = right, left
+
+        return right ^ p_array[17], left ^ p_array[16]
+
+    def keystream_block(self, iv):
+        left, right = self.encrypt_block(
+            int.from_bytes(iv[:4], 'big'),
+            int.from_bytes(iv[4:], 'big')
+        )
+        return left.to_bytes(4, 'big') + right.to_bytes(4, 'big')
+
+    def cfb64_decrypt(self, data):
+        output = bytearray(len(data))
+        iv = bytes(8)
+
+        for offset in range(0, len(data), 8):
+            keystream = self.keystream_block(iv)
+            cipher_block = data[offset:offset + 8]
+            for i, cipher_byte in enumerate(cipher_block):
+                output[offset + i] = cipher_byte ^ keystream[i]
+            iv = cipher_block
+
+        return bytes(output)
+
+    def cfb64_encrypt(self, data):
+        output = bytearray(len(data))
+        iv = bytes(8)
+
+        for offset in range(0, len(data), 8):
+            keystream = self.keystream_block(iv)
+            plain_block = data[offset:offset + 8]
+            for i, plain_byte in enumerate(plain_block):
+                output[offset + i] = plain_byte ^ keystream[i]
+            iv = bytes(output[offset:offset + 8])
+
+        return bytes(output)
+
+
+WPAK_CIPHER = ArcBlowfish(WPAK_KEY)
+
+
+def load_wpak_file(filename):
+    entries = []
+
+    with zipfile.ZipFile(filename) as wpak_file:
+        for info in wpak_file.infolist():
+            if info.is_dir():
+                continue
+            entries.append([
+                info.filename,
+                WPAK_CIPHER.cfb64_decrypt(wpak_file.read(info))
+            ])
+
+    return entries
+
+
+def load_wpak_directory(directory):
+    entries = []
+
+    # Original archives list entries in NTFS directory order (uppercase-folded sort).
+    for filename in sorted(os.listdir(directory), key=str.upper):
+        filepath = os.path.join(directory, filename)
+        if not os.path.isfile(filepath):
+            continue
+        with open(filepath, 'rb') as fp:
+            entries.append([filename, fp.read()])
+
+    return entries
+
+
+def build_wpak_bytes(entries, wpak_file):
+    with zipfile.ZipFile(wpak_file, 'w') as archive:
+        for filename, data in entries:
+            info = zipfile.ZipInfo(filename, date_time=time.localtime()[:6])
+            info.compress_type = zipfile.ZIP_DEFLATED
+            archive.writestr(
+                info,
+                WPAK_CIPHER.cfb64_encrypt(data),
+                compresslevel=WPAK_COMPRESS_LEVEL
+            )
+
+
+def save_wpak_file(filename, entries):
+    filename = next_available_path(filename)
+    print('Packing to ' + filename)
+
+    with open(filename, 'wb') as wpak_file:
+        build_wpak_bytes(entries, wpak_file)

mbEditorPro2.0/arcane/util/__init__.py

@@ -7,4 +7,5 @@
 #                           www.magicbane.com
 
 from .ArcFileCache import load_cache_file, save_cache_file, next_available_path
+from .ArcWpak import load_wpak_file, load_wpak_directory, save_wpak_file, build_wpak_bytes
 from .ResStream import ResStream

mbEditorPro2.0/mbEditorPro.py

@@ -45,6 +45,7 @@ MOTION_DIRECTORY = os.path.join(TARGET_DIRECTORY, 'MOTION')
 TILE_DIRECTORY = os.path.join(TARGET_DIRECTORY, 'TILE')
 SKELETON_DIRECTORY = os.path.join(TARGET_DIRECTORY, 'SKELETON')
 RENDER_DIRECTORY = os.path.join(TARGET_DIRECTORY, 'RENDER')
+CONFIG_DIRECTORY = os.path.join(TARGET_DIRECTORY, 'Config')
 COBJECTS_MAGIC = 0x434c4e54
 
 COBJECTS_MAP = {
@@ -85,6 +86,7 @@ EDITOR_TARGETS = [
     'skeleton',
     'terrain',
     'render',
+    'config',
     'all'
 ]
 
@@ -153,6 +155,11 @@ def init_render():
     os.makedirs(directory_path, exist_ok=True)
 
 
+def init_config():
+    directory_path = CONFIG_DIRECTORY
+    os.makedirs(directory_path, exist_ok=True)
+
+
 def unpack_cobjects():
     resources = load_cache_file('CObjects.cache')
     directory = create_unpack_directory(COBJECTS_DIRECTORY)
@@ -841,6 +848,39 @@ def test_render():
             print(res_id, in_stream.buffer.tell(), out_stream.buffer.tell())
 
 
+def unpack_config():
+    entries = load_wpak_file('Config.wpak')
+    directory = create_unpack_directory(CONFIG_DIRECTORY)
+
+    with tqdm(total=len(entries)) as pBar:
+        for filename, data in entries:
+            filepath = os.path.join(directory, filename)
+            with open(filepath, 'wb') as fp:
+                fp.write(data)
+            pBar.update(1)
+
+
+def pack_config():
+    init_config()
+
+    entries = load_wpak_directory(CONFIG_DIRECTORY)
+    save_wpak_file('Config.wpak', entries)
+
+
+def test_config():
+    entries = load_wpak_file('Config.wpak')
+    out_stream = io.BytesIO()
+
+    build_wpak_bytes(entries, out_stream)
+    repacked = dict(load_wpak_file(out_stream))
+
+    for filename, data in entries:
+        try:
+            assert repacked[filename] == data
+        except:
+            print(filename, len(data), len(repacked.get(filename, b'')))
+
+
 def unpack_all():
     for cache_type in EDITOR_TARGETS[:-1]:
         method = 'unpack_' + cache_type + '()'