passport.py/passport/eddimage.py
2018-05-31 10:55:29 -04:00

25 lines
969 B
Python

from passport.wozimage import DiskImage, Track, WozError, raise_if
import bitarray
class EDDReader(DiskImage):
def __init__(self, filename=None, stream=None):
DiskImage.__init__(self, filename, stream)
with stream or open(filename, 'rb') as f:
for i in range(137):
raw_bytes = f.read(16384)
raise_if(len(raw_bytes) != 16384, WozError, "Bad EDD file (did you image by quarter tracks?)")
bits = bitarray.bitarray(endian="big")
bits.frombytes(raw_bytes)
self.tracks.append(Track(bits, 131072))
def seek(self, track_num):
if type(track_num) != float:
track_num = float(track_num)
if track_num < 0.0 or \
track_num > 35.0 or \
track_num.as_integer_ratio()[1] not in (1,2,4):
raise WozError("Invalid track %s" % track_num)
trk_id = int(track_num * 4)
return self.tracks[trk_id]