passport.py/passport/a2rimage.py
2018-09-10 21:03:44 -04:00

51 lines
1.9 KiB
Python
Executable File

from passport.wozimage import DiskImage, Track, WozError, raise_if
from passport import a2rchery
import bitarray
import collections
class A2RImage:
def __init__(self, filename=None, stream=None):
self.filename = filename
self.tracks = collections.OrderedDict()
self.a2r_image = a2rchery.A2RReader(filename, stream)
def to_bits(self, flux_record):
"""|flux_record| is a dictionary of 'capture_type', 'data_length', 'tick_count', and 'data'"""
if not flux_record or flux_record["capture_type"] != a2rchery.kCaptureTiming:
return [], 0
bits = bitarray.bitarray()
track_length = 0
ticks = 0
flux_total = 0
fluxxen = flux_record["data"]
speeds = [(len([1 for i in fluxxen if i%t==0]), t) for t in range(0x1e,0x23)]
speeds.sort()
speed = speeds[-1][1]
for flux_value in fluxxen:
ticks += flux_value
if not track_length and ticks > flux_record["tick_count"]:
track_length = len(bits)
flux_total += flux_value
if flux_value == 0xFF:
continue
bits.extend([0] * ((flux_total - speed//2) // speed))
bits.append(1)
flux_total = 0
return bits, track_length
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)
location = int(track_num * 4)
if not self.tracks.get(location):
all_bits = bitarray.bitarray()
for flux_record in self.a2r_image.flux.get(location, [{}]):
bits, track_length = self.to_bits(flux_record)
all_bits.extend(bits)
self.tracks[location] = Track(all_bits, len(all_bits))
return self.tracks[location]