text: import binascii
  import struct
  import time
  
  try:
      import _acb_speedup
  except ImportError:
      _acb_speedup = None
  
  SECTION_SIZES = {
      b"HCA\x00": 8,
      b"fmt\x00": 16,
      b"comp":    16,
      b"dec\x00": 12,
      b"vbr\x00": 8,
      b"ath\x00": 6,
      b"loop":    16,
      b"ciph":    6,
      b"rva\x00": 8,
      b"comm":    5,
      b"pad\x00": 4,
  }
  
  CHECKSUM_TABLE = (
      0x0000,0x8005,0x800F,0x000A,0x801B,0x001E,0x0014,0x8011,0x8033,0x0036,0x003C,0x8039,0x0028,0x802D,0x8027,0x0022,
      0x8063,0x0066,0x006C,0x8069,0x0078,0x807D,0x8077,0x0072,0x0050,0x8055,0x805F,0x005A,0x804B,0x004E,0x0044,0x8041,
      0x80C3,0x00C6,0x00CC,0x80C9,0x00D8,0x80DD,0x80D7,0x00D2,0x00F0,0x80F5,0x80FF,0x00FA,0x80EB,0x00EE,0x00E4,0x80E1,
      0x00A0,0x80A5,0x80AF,0x00AA,0x80BB,0x00BE,0x00B4,0x80B1,0x8093,0x0096,0x009C,0x8099,0x0088,0x808D,0x8087,0x0082,
      0x8183,0x0186,0x018C,0x8189,0x0198,0x819D,0x8197,0x0192,0x01B0,0x81B5,0x81BF,0x01BA,0x81AB,0x01AE,0x01A4,0x81A1,
      0x01E0,0x81E5,0x81EF,0x01EA,0x81FB,0x01FE,0x01F4,0x81F1,0x81D3,0x01D6,0x01DC,0x81D9,0x01C8,0x81CD,0x81C7,0x01C2,
      0x0140,0x8145,0x814F,0x014A,0x815B,0x015E,0x0154,0x8151,0x8173,0x0176,0x017C,0x8179,0x0168,0x816D,0x8167,0x0162,
      0x8123,0x0126,0x012C,0x8129,0x0138,0x813D,0x8137,0x0132,0x0110,0x8115,0x811F,0x011A,0x810B,0x010E,0x0104,0x8101,
      0x8303,0x0306,0x030C,0x8309,0x0318,0x831D,0x8317,0x0312,0x0330,0x8335,0x833F,0x033A,0x832B,0x032E,0x0324,0x8321,
      0x0360,0x8365,0x836F,0x036A,0x837B,0x037E,0x0374,0x8371,0x8353,0x0356,0x035C,0x8359,0x0348,0x834D,0x8347,0x0342,
      0x03C0,0x83C5,0x83CF,0x03CA,0x83DB,0x03DE,0x03D4,0x83D1,0x83F3,0x03F6,0x03FC,0x83F9,0x03E8,0x83ED,0x83E7,0x03E2,
      0x83A3,0x03A6,0x03AC,0x83A9,0x03B8,0x83BD,0x83B7,0x03B2,0x0390,0x8395,0x839F,0x039A,0x838B,0x038E,0x0384,0x8381,
      0x0280,0x8285,0x828F,0x028A,0x829B,0x029E,0x0294,0x8291,0x82B3,0x02B6,0x02BC,0x82B9,0x02A8,0x82AD,0x82A7,0x02A2,
      0x82E3,0x02E6,0x02EC,0x82E9,0x02F8,0x82FD,0x82F7,0x02F2,0x02D0,0x82D5,0x82DF,0x02DA,0x82CB,0x02CE,0x02C4,0x82C1,
      0x8243,0x0246,0x024C,0x8249,0x0258,0x825D,0x8257,0x0252,0x0270,0x8275,0x827F,0x027A,0x826B,0x026E,0x0264,0x8261,
      0x0220,0x8225,0x822F,0x022A,0x823B,0x023E,0x0234,0x8231,0x8213,0x0216,0x021C,0x8219,0x0208,0x820D,0x8207,0x0202 )
  
  def checksum(buf):
      sum = 0
      for byte in buf:
          sum = ((sum << 8) ^ CHECKSUM_TABLE[(sum >> 8) ^ byte]) & 0xffff
      return sum
  
  def sub1_rollover(i: int) -> int:
      if i == 0:
          return 0xffffffff
      return i - 1
  
  def small_rng(seed: int) -> bytearray:
      a = ((seed & 1) << 3) | 0b0101
      c = (seed & 0xe) | 1
      seed >>= 4
  
      table = bytearray(16)
      for i in range(16):
          seed = (seed * a + c) & 0xf
          table[i] = seed
      return table
  
  def mix_header_key(kl, hk):
      k2p = (hk << 16) | (((hk ^ 0xffff) + 2) & 0xffff)
      return (kl * k2p) & 0xffffffffffffffff
  
  class DisarmContext(object):
      KEY_TABLE_1 = None
  
      @classmethod
      def init_table1(cls) -> bytearray:
          t = bytearray(256)
          t[0x00] = 0
          t[0xff] = 0xff
          seed = 0
  
          for i in range(1, 255):
              seed = (seed * 13 + 11) & 0xff
              if seed == 0 or seed == 0xff:
                  seed = (seed * 13 + 11) & 0xff
              t[i] = seed
  
          return t
  
      def __init__(self, keyspec: str, header_key: int = None):
          if "," in keyspec:
              keya_, keyb_ = keyspec.split(",")
              keya = int(keya_, 16)
              keyb = int(keyb_, 16)
  
              if header_key:
                  keylong = mix_header_key(keya | (keyb << 32), header_key)
                  keya = keylong & 0xffffffff
                  keyb = (keylong >> 32) & 0xffffffff
          else:
              keylong = int(keyspec, 16)
              if header_key:
                  keylong = mix_header_key(keylong, header_key)
  
              keya = keylong & 0xffffffff
              keyb = (keylong >> 32) & 0xffffffff
  
          self.keya = keya
          self.keyb = keyb
          self.tables()
  
      def tables(self):
          if self.__class__.KEY_TABLE_1 is None:
              self.__class__.KEY_TABLE_1 = self.init_table1()
  
          self.key_table_2 = self.init_table2()
  
      def init_table2(self) -> bytearray:
          keya = self.keya
          keyb = self.keyb
  
          if keya == 0:
              keyb = sub1_rollover(keyb)
          keya = sub1_rollover(keya)
  
          stage1 = bytearray(8)
          for i in range(7):
              stage1[i] = keya & 0xff
              keya = ((keya >> 8) | (keyb << 24)) & 0xffffffff
              keyb >>= 8
  
          s2_ri = (1, 2, 3, 4, 5, 6, 1)
          s2_li = (0, 6, 1, 2, 3, 4, 5)
          stage2 = bytearray(16)
  
          for i in range(0, 16, 3):
              stage2[i] = stage1[i // 3 + 1]
  
          for i in range(1, 16, 3):
              j = i // 3 + 1
              stage2[i] = stage1[j] ^ stage1[s2_li[j]]
  
          for i in range(2, 16, 3):
              j = i // 3 + 2
              stage2[i] = stage1[j] ^ stage1[s2_ri[j]]
  
          stage3 = bytearray(256)
          high = small_rng(stage1[0])
          for i in range(16):
              base = 16 * i
              low = small_rng(stage2[i])
              hi = high[i] << 4
              for j in range(16):
                  stage3[base + j] = hi | low[j]
  
          key_table_2 = bytearray(256)
          key_table_2[0x00] = 0
          key_table_2[0xff] = 0xff
          srci = 0x11
          for i in range(1, 255):
              while stage3[srci] in (0x0, 0xff):
                  srci = (srci + 0x11) & 0xff
  
              key_table_2[i] = stage3[srci]
              srci = (srci + 0x11) & 0xff
  
          return key_table_2
  
      def disarm(self, buf: bytearray, no_unmask: bool=False):
          magic = buf[:4]
          masked = True if magic[0] & 0x80 else False
          header_size = struct.unpack(">H", buf[6:8])[0]
  
          if not no_unmask:
              self.unmask_header(buf, header_size)
              masked = False
  
          try:
              comp_seg = buf.index(b"\xe3\xef\xed\xf0" if masked else b"comp", 0, header_size)
          except ValueError:
              try:
                  comp_seg = buf.index(b"\xe4\xe5\xe3\x00" if masked else b"dec\x00", 0, header_size)
              except ValueError:
                  raise ValueError("cannot find a segment containing the block size")
  
          try:
              ciph_seg = buf.index(b"\xe3\xe9\xf0\xe8" if masked else b"ciph", 0, header_size)
          except ValueError:
              return
  
          try:
              fmt_seg = buf.index(b"\xe6\xed\xf4\x00" if masked else b"fmt\x00", 0, header_size)
          except ValueError:
              raise ValueError("cannot find the fmt segment")
  
          block_cnt = struct.unpack(">I", buf[fmt_seg + 8:fmt_seg + 12])[0]
          block_size = struct.unpack(">H", buf[comp_seg + 4:comp_seg + 6])[0]
          ciph_type = struct.unpack(">H", buf[ciph_seg + 4:ciph_seg + 6])[0]
  
          if ciph_type == 0:
              return
  
          if ciph_type == 1:
              self.disarm_actual(buf, header_size, block_cnt, block_size, self.KEY_TABLE_1)
          elif ciph_type == 56:
              self.disarm_actual(buf, header_size, block_cnt, block_size, self.key_table_2)
          else:
              raise ValueError("unknown cipher type")
  
          buf[ciph_seg + 4:ciph_seg + 6] = b"\x00\x00"
  
          end = header_size - 2
          if _acb_speedup:
              _acb_speedup.checksum_block_fast(memoryview(buf)[:end])
          else:
              buf[end:end + 2] = checksum(memoryview(buf)[:end]).to_bytes(2, "big")
  
      def unmask_header(self, buf, header_size):
          base = 0
          while base < header_size:
              tag = bytes(x & 0x7f for x in buf[base:base + 4])
              buf[base:base + 4] = tag
  
              if tag == b"pad\x00":
                  break
              if tag == b"comm":
                  base += buf[base + 4]
  
              base += SECTION_SIZES.get(tag, 4)
  
      def disarm_actual(self, buf, frompos, blockcnt, blocksize, usetable):
          base = frompos
          stop = frompos + (blocksize * blockcnt)
          while base < stop:
              if _acb_speedup:
                  _acb_speedup.disarm_block_fast(memoryview(buf)[base:base + blocksize], usetable)
              else:
                  for i in range(base, base + blocksize - 2):
                      buf[i] = usetable[buf[i]]
  
                  end = base + blocksize - 2
                  buf[end:end + 2] = checksum(memoryview(buf)[base:end]).to_bytes(2, "big")
  
              base += blocksize
  