69 lines
2.7 KiB
Python
Executable File
69 lines
2.7 KiB
Python
Executable File
from passport.wozardry import Track, raise_if
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from passport import a2rchery
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import bitarray
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import collections
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class A2RSeekError(a2rchery.A2RError): pass
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class A2RImage:
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def __init__(self, iostream):
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self.tracks = collections.OrderedDict()
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self.a2r_image = a2rchery.A2RReader(stream=iostream)
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self.speed = 32
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def to_json(self):
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return self.a2r_image.to_json()
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def to_bits(self, flux_record):
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"""|flux_record| is a dictionary of 'capture_type', 'data_length', 'tick_count', and 'data'"""
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bits = bitarray.bitarray()
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if not flux_record or flux_record["capture_type"] != a2rchery.kCaptureTiming:
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return bits
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fluxxen = flux_record["data"][1:]
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if not self.speed:
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speeds = [(len([1 for i in fluxxen[:8192] if i%t==0]), t) for t in range(0x1e,0x23)]
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speeds.sort()
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self.speed = speeds[-1][1]
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speed = self.speed
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flux_total = flux_start = -speed//2
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for flux_value in fluxxen:
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flux_total += flux_value
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if flux_value == 0xFF:
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continue
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if flux_total >= speed:
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bits.extend("0" * (flux_total // speed))
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bits.extend("1")
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flux_total = flux_start
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return bits
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def seek(self, track_num):
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if type(track_num) != float:
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track_num = float(track_num)
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if track_num < 0.0 or \
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track_num > 35.0 or \
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track_num.as_integer_ratio()[1] not in (1,2,4):
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raise A2RSeekError("Invalid track %s" % track_num)
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location = int(track_num * 4)
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if not self.tracks.get(location):
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# just return the bits from the first flux read
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# (if the caller determines that they're not good, it will call reseek()
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# which is smarter but takes longer)
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bits = bitarray.bitarray()
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if location in self.a2r_image.flux:
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bits = self.to_bits(self.a2r_image.flux[location][0])
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self.tracks[location] = Track(bits, len(bits))
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return self.tracks[location]
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def reseek(self, track_num):
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location = int(track_num * 4)
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# reset cached speed so we'll recalculate it
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self.speed = 0
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# read the rest of the flux records and concatenate them on the end
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# of the existing bitstream (this assumes you've called seek() before
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# on this track)
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all_bits = self.tracks[location].bits
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for flux_record in self.a2r_image.flux[location][1:]:
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all_bits.extend(self.to_bits(flux_record))
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self.tracks[location] = Track(all_bits, len(all_bits))
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return self.tracks[location]
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