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https://github.com/a2-4am/passport.py.git
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64 lines
2.7 KiB
Python
64 lines
2.7 KiB
Python
from passport.rwts import RWTS
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class UniversalRWTS(RWTS):
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acceptable_address_prologues = ((0xD4,0xAA,0x96), (0xD5,0xAA,0x96))
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def __init__(self, g):
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RWTS.__init__(self, g, address_epilogue=[], data_epilogue=[])
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def find_address_prologue(self, track):
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starting_revolutions = track.revolutions
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seen = [0,0,0]
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while (track.revolutions < starting_revolutions + 2):
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del seen[0]
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seen.append(next(track.nibble()))
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if tuple(seen) in self.acceptable_address_prologues: return True
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return False
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def verify_address_epilogue_at_point(self, track, logical_track_num, physical_sector_num):
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# return True
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if not self.address_epilogue:
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self.address_epilogue = [next(track.nibble())]
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result = True
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else:
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result = RWTS.verify_address_epilogue_at_point(self, track, logical_track_num, physical_sector_num)
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next(track.nibble())
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next(track.nibble())
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return result
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def verify_data_epilogue_at_point(self, track, logical_track_num, physical_sector_num):
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if not self.data_epilogue:
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self.data_epilogue = [next(track.nibble())]
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result = True
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else:
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result = RWTS.verify_data_epilogue_at_point(self, track, logical_track_num, physical_sector_num)
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next(track.nibble())
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next(track.nibble())
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return result
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class UniversalRWTSIgnoreEpilogues(UniversalRWTS):
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def verify_address_epilogue_at_point(self, track, logical_track_num, physical_sector_num):
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return True
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def verify_data_epilogue_at_point(self, track, logical_track_num, physical_sector_num):
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return True
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class Track00RWTS(UniversalRWTSIgnoreEpilogues):
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def data_field_at_point(self, track, logical_track_num, physical_sector_num):
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start_index = track.bit_index
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start_revolutions = track.revolutions
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decoded = UniversalRWTS.data_field_at_point(self, track, logical_track_num, physical_sector_num)
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if not decoded:
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# If the sector didn't decode properly, rewind to the
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# beginning of the data field before returning to the
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# caller. This is for disks with a fake T00,S0A that
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# is full of consecutive 0s, where if we consume the bitstream
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# as nibbles, we'll end up consuming the next address field
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# and it will seem like that sector doesn't exist. And that
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# is generally logical sector 2, which is important not to
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# miss at this stage because its absence triggers a different
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# code path and everything falls apart.
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track.bit_index = start_index
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track.revolutions = start_revolutions
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return decoded
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