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other/tm2ctool.py

@@ -0,0 +1,96 @@
+import argparse
+import os
+
+
+def decompress_tm2c(data):
+    # 001724d0 in SLUS_216.08 from PS2 DDR SN2 US
+    assert(data[0:4] == b"TGCD")
+
+    decompress_size = int.from_bytes(data[0x04:0x08], 'little')
+    data_end_offset = int.from_bytes(data[0x08:0x0c], 'little')
+    data_checksum = int.from_bytes(data[0x1c:0x20], 'little')
+
+    # The game is programmed to check that these values are a specific hardcoded value,
+    # but I'm pretty sure these should control lookback buffer size and such
+    comp_param_unk1 = int.from_bytes(data[0x0c:0x10], 'little')
+    comp_param_unk2 = int.from_bytes(data[0x10:0x14], 'little')
+    comp_param_unk3 = int.from_bytes(data[0x14:0x18], 'little')
+    comp_param_unk4 = int.from_bytes(data[0x18:0x1c], 'little')
+
+    calculated_checksum = sum(data[0x20:])
+    assert(data_checksum == calculated_checksum)
+
+    # 001889c0 in SLUS_216.08 from PS2 DDR SN2 US
+    # This verification function checks with hardcoded values
+    assert(data[0:4] == b"TGCD")
+    assert(decompress_size > 0)
+    assert(data_end_offset >= 0x20)
+    assert(comp_param_unk1 == 0x7fff)
+    assert(comp_param_unk2 == 0xffff)
+    assert(comp_param_unk3 == 0xff)
+    assert(comp_param_unk4 == 0x8000)
+
+    output = bytearray()
+    if decompress_size <= 0:
+        return output
+
+    idx = 0x20
+    while idx < data_end_offset:
+        cmd_bits = int.from_bytes(data[idx:idx+2], 'little')
+        idx += 2
+
+        if (cmd_bits & 0x8000) == 0:
+            output_len = len(output)
+            lookback_offset = 0
+
+            if output_len >= 0x7fff:
+                lookback_offset = output_len - 0x7fff
+
+            lookback_offset += int.from_bytes(data[idx-2:idx], 'little')
+            copy_len = data[idx]
+            last_byte = data[idx+1]
+            idx += 2
+
+            for j in range(copy_len):
+                output.append(output[lookback_offset+j])
+
+            output.append(last_byte)
+
+        else:
+            l = int.from_bytes(data[idx:idx+2], 'little')
+            idx += 2
+
+            output += data[idx:idx+l]
+            idx += l
+
+            if (l & 0xf) != 0:
+                # Why would they pad blocks in a compressed file???
+                idx += 0x10 - (l & 0xf)
+
+    return output
+
+
+def main():
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument('-i', '--input', help='Input file', required=True)
+    parser.add_argument('-o', '--output', help='Output file', default=None)
+
+    args = parser.parse_args()
+
+    input_filename = args.input
+    output_filename = args.output
+
+    if output_filename is None:
+        output_filename = os.path.splitext(input_filename)[0] + ".tm2"
+
+    data = bytearray(open(input_filename, "rb").read())
+    decompressed = decompress_tm2c(data)
+
+    print("Decompressed", input_filename)
+
+    open(output_filename, "wb").write(decompressed)
+
+
+if __name__ == "__main__":
+    main()