mem_patch.py

import mmap

import pefile


def create_patch(infile, outfile):
    with open(infile, "r+b") as bm2dx:
        with open(outfile, "w", newline="\r\n") as patches:
            mm = mmap.mmap(bm2dx.fileno(), length=0, access=mmap.ACCESS_READ)
            pe = pefile.PE(infile, fast_load=True)

            mm.seek(mm.find((b"\x67\x72\x61\x70\x68\x69\x63\x00"), 0))
            start = mm.tell() + 8

            mm.seek(mm.find((b"\x00"), start))
            end = mm.tell()

            mm.seek(mm.find((b"\x67\x72\x61\x70\x68\x69\x63\x00"), 0) + 8)
            full_title = mm.read(end - start).decode("cp932").replace(" main", "")
            game_version = int(full_title[15:][:2])

            print("# === Omnimix changes. DO NOT TOUCH!! ===", file=patches)

            if game_version >= 30:
                # X rev
                mm.seek(
                    mm.find(b"\x44\x24\x40\x85\xC0\x0F\x84\xF8\x00\x00\x00", 0x650000)
                    + 5
                )
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 90E948 {mm.read(3).hex().upper()}",
                    file=patches,
                )
                mm.seek(mm.find(b"\xC6\x40\x05\x41", mm.tell()) + 3)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 58 {mm.read(1).hex().upper()}",
                    file=patches,
                )

                # song limit
                mm.seek(mm.find(b"\x2C\x08\x07\x00\x00\x7F\x0A", 0x650000) + 5)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 9090 {mm.read(2).hex().upper()}",
                    file=patches,
                )
                mm.seek(mm.find(b"\x00\x00\x7E", mm.tell()) + 2)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} EB {mm.read(1).hex().upper()}",
                    file=patches,
                )

            elif game_version in (27, 28, 29):
                # X rev
                mm.seek(
                    mm.find(
                        b"\xC3\xCC\xCC\xCC\xCC\xCC\xCC\xCC\xCC\xCC\x40\x53\x48\x83\xEC\x20\x0F\xB6\xD9\xE8\x22\x01\x00\x00\x84\xC0\x74\x14\x0F\xB6\xCB\xE8\x16\x00\x00\x00\x84\xC0\x74\x08\xB0\x01\x48\x83\xC4\x20\x5B\xC3\x32\xC0\x48\x83\xC4\x20\x5B\xC3",
                        0,
                    )
                )
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} C6470558C3 {mm.read(5).hex().upper()}",
                    file=patches,
                )

                # song limit
                mm.seek(mm.find(b"\x66\x39\x48\x08\x7F", 0) + 4)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 9090 {mm.read(2).hex().upper()}",
                    file=patches,
                )

            # mdato.ifs
            mm.seek(mm.find(str.encode("mdata.ifs"), 0) + 4)
            print(
                f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 6F {mm.read(1).hex().upper()}",
                file=patches,
            )

            # music_omni.bin
            mm.seek(mm.find(str.encode("music_data.bin"), 0) + 6)
            offset = pe.get_rva_from_offset(mm.tell())
            print(
                f"bm2dx.dll {hex(offset)[2:].upper()} 6F6D6E69 {mm.read(4).hex().upper()}",
                file=patches,
            )

            # music_diff.bin
            print(
                f"#bm2dx.dll {hex(offset)[2:].upper()} 64696666 6F6D6E69", file=patches
            )

            if game_version >= 28:
                # music_title_omni.xml
                mm.seek(mm.find(str.encode("music_title_yomi.xml"), 0) + 12)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 6F6D6E69 {mm.read(4).hex().upper()}",
                    file=patches,
                )

                # music_artist_omni.xml
                mm.seek(mm.find(str.encode("music_artist_yomi.xml"), 0) + 13)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 6F6D6E69 {mm.read(4).hex().upper()}",
                    file=patches,
                )

                # video_music_omni.xml
                mm.seek(mm.find(str.encode("video_music_list.xml"), 0) + 12)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} 6F6D6E69 {mm.read(4).hex().upper()}",
                    file=patches,
                )

            # omni songs in legg folder
            if game_version >= 30:
                # fixed dp result screen crash
                mm.seek(
                    mm.find(
                        b"\x41\xB9\x04\x00\x00\x00\x4C\x8B\x44\x24\x70\xBA\x0D\x00\x00\x00\x48\x8B\x4C\x24\x50\xE8",
                        0x500000,
                    )
                    + 2
                )
                while mm.read(5) != b"\x0F\xB6\xC0\x85\xC0":
                    mm.seek(mm.tell() - 6)
                mm.seek(mm.tell() - 10)
                print(
                    f"bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} B801000000 {mm.read(5).hex().upper()}",
                    file=patches,
                )

            # elif game_version in (27, 28, 29):
            #     # WARNING: dp result screen crash + unknown bugs from ~15 subroutines affected
            #     mm.seek(mm.find(b'\x7C\xED\x32\xC0\xC3', 0) + 2)
            #     print(f'bm2dx.dll {hex(pe.get_rva_from_offset(mm.tell()))[2:].upper()} B001 {mm.read(2).hex().upper()}', file=patches)

            print("# === Omnimix changes end ===", file=patches)

            pe.close()
            mm.close()


if __name__ == "__main__":
    create_patch("bm2dx.dll", "iidx_omnimix_30.txt")