Add pack softpal text dat script

pack_softpal_text_dat.py

@@ -0,0 +1,69 @@
+import struct
+from os.path import splitext
+import json
+import sys
+
+
+def rotate_right(val, rshift):
+    return ((val >> rshift) | ((val << (8 - rshift)) & 0xFF)) & 0xFF
+
+
+def encrypt_bytes(data: bytes) -> bytes:
+    # Matches inverse of decrypt in unpack_softpal_text_dat.py
+    CONST = 0x084DF873 ^ 0xFF987DEE
+    b = bytearray(data)
+    pos = 0x10
+    shift = 4
+    while pos + 4 <= len(b):
+        val = struct.unpack('<I', b[pos:pos+4])[0]
+        val ^= CONST
+        packed = bytearray(struct.pack('<I', val))
+        packed[0] = rotate_right(packed[0], shift)
+        b[pos:pos+4] = packed
+        pos += 4
+        shift = (shift + 1) % 8
+    return bytes(b)
+
+
+def pack_table(table: dict, encoding: str = 'cp932', encrypt: bool = True) -> bytes:
+    # header: 12 bytes (unused by unpack)
+    header = b"\x00" * 12
+    items = sorted(((int(k), v) for k, v in table.items()), key=lambda x: x[0])
+    count = len(items)
+    out = bytearray()
+    out += header
+    out += struct.pack('<I', count)
+    # After this, the first u32 at offset 16 will be the first key
+    # We'll write entries immediately after (so first key sits at offset 16)
+    for key, s in items:
+        out += struct.pack('<I', key)
+        if isinstance(s, str):
+            encoded = s.encode(encoding)
+        else:
+            encoded = bytes(s)
+        out += encoded + b'\x00'
+    if encrypt:
+        out = encrypt_bytes(bytes(out))
+    return bytes(out)
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print("Usage: python pack_softpal_text_dat.py <input.json> [<output.dat>] [<encoding>] [--no-encrypt]")
+        sys.exit(1)
+
+    infile = sys.argv[1]
+    outfile = sys.argv[2] if len(sys.argv) > 2 else splitext(infile)[0] + '.dat'
+    encoding = sys.argv[3] if len(sys.argv) > 3 and not sys.argv[3].startswith('--') else 'cp932'
+    encrypt = True
+    if '--no-encrypt' in sys.argv:
+        encrypt = False
+
+    with open(infile, 'r', encoding='utf-8') as f:
+        table = json.load(f)
+
+    data = pack_table(table, encoding=encoding, encrypt=encrypt)
+    with open(outfile, 'wb') as f:
+        f.write(data)
+
+    print(f'Wrote {outfile} ({len(data)} bytes)')