fluxtoimd.py

#!/usr/bin/env python3
# data extraction from floppy disk flux transition images
# Copyright 2016 Eric Smith <spacewar@gmail.com>

#    This program is free software: you can redistribute it and/or
#    modify it under the terms of version 3 of the GNU General Public
#    License as published by the Free Software Foundation.

#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    General Public License for more details.

#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see
#    <http://www.gnu.org/licenses/>.

import argparse
import re
from collections import OrderedDict

from dfi import DFI      # DiscFerret image format
from kfsf import KFSF    # KryoFlux stream format
from adpll import ADPLL
from crc import CRC
from modulation import FM, MFM, IntelM2FM, HPM2FM
from imagedisk import ImageDisk


def hex_dump(b, prefix = ''):
    for i in range(0, len(b), 16):
        print(prefix + '%02x: ' % i, end='')
        for j in range(16):
            if (i + j) < len(b):
                print('%02x ' % b[i+j], end='')
            else:
                print('   ', end='')
        for j in range(16):
            if (i + j) < len(b):
                if 0x20 <= b[i+j] <= 0x7e:
                    print('%c' % b[i+j], end='')
                else:
                    print('.', end='')
        print()


def dump_track(modulation,
               image,
               track,
               side,  # 0 or 1
               sectors_per_track = None,
               require_index_mark = False):

    if sectors_per_track is None:
        sectors_per_track = modulation.default_sectors_per_track

    sectors = OrderedDict()

    block = image.blocks[(track, side, 1)]

    di = block.get_delta_iter()

    adpll = ADPLL(di,
                  osc_period = hbc,
                  max_adj_pct = 3.0,
                  window_pct = 50.0,
                  freq_adj_factor = 0.005,
                  phase_adj_factor = 0.1)


    bits = ''
    for b in adpll:
        bits += '01'[b]
    #print(len(bits))
    #print(bits)

    if require_index_mark:
        index_address_mark_locs = [m.start() for m in re.finditer(modulation.index_address_mark, bits)]
        if not index_address_mark_locs:
            print('track %d: no index address mark found' % track)
            return sectors

    id_address_mark_locs = [m.start() for m in re.finditer(modulation.id_address_mark, bits)]
    #print('id address marks at: ', id_address_mark_locs)

    for id_pos in id_address_mark_locs:
        #print('id address mark at channel bit %d' % id_pos)
        id_field = modulation.decode(bits[id_pos: id_pos + len(modulation.id_address_mark) + 16 * (modulation.id_field_length + 2)])
        crc.reset()
        if (modulation.crc_includes_address_mark):
            crc.comp(id_field)
        else:
            crc.comp(id_field[1:])
        if crc.get() != 0:
            print("*** bad ID field CRC %04x" % crc.get())
            hex_dump(id_field)
            continue
        if modulation.id_field_length == 2:
            # HP M2FM ID field only contains two bytes for track and sector
            id_track, id_sector = id_field[1:3]
            if id_sector < 0x80:
                id_head = 0
            else:
                id_sector -= 0x80
                id_head = 1
            id_size = 1
        else:
            id_track, id_head, id_sector, id_size = id_field[1:5]
        #print('head %d track %02d sector %02d' % (id_head, id_track, id_sector))
        if id_head != side:
            print("*** ID field with wrong head number")
            hex_dump(id_field)
            continue
        if id_track != track:
            print("*** ID field with wrong track number")
            hex_dump(id_field)
            continue

        bc = 128 << id_size
        if bc not in modulation.expected_sector_sizes:
            print("*** ID field with unexpected sector size")
            hex_dump(id_field)
        if (id_sector in sectors) and (sectors[id_sector][1] is not None) and not sectors[id_sector][2]:
            continue  # already have this one and it was a good read
        # Mark sector bad to start with
        sectors[id_sector] = [False, None, True]

        deleted = False
        data_pos = bits.find(modulation.data_address_mark, id_pos + len(modulation.id_address_mark) + 16 * (modulation.id_field_length + 2))
        if (modulation.id_to_data_half_bits - 50) <= (data_pos - id_pos) <= (modulation.id_to_data_half_bits + 50):
            #print('  data address mark at channel bit offset %d' % (data_pos - id_pos))
            pass
        elif hasattr(modulation, 'deleted_data_address_mark'):
            data_pos = bits.find(modulation.deleted_data_address_mark, id_pos + len(modulation.id_address_mark) + 96)
            if (modulation.id_to_data_half_bits - 50) <= (data_pos - id_pos) <= (modulation.id_to_data_half_bits + 50):
                #print('  deleted data address mark at channel bit offset %d' % (deleted_data_pos - id_pos))
                deleted = True
            else:
                print('*** ID field without data field ***')
                hex_dump(id_field)
                continue
        else:
            print('*** ID field without data field ***')
            hex_dump(id_field)
            continue

        data_field = modulation.decode(bits[data_pos: data_pos + len(modulation.id_address_mark) + (bc + 2) * 16])
        crc.reset()
        if (modulation.crc_includes_address_mark):
            crc.comp(data_field)
        else:
            crc.comp(data_field[1:])
        if crc.get() == 0:
            sectors [id_sector] = (deleted, data_field[1:bc+1], False)
        else:
            print("*** bad data field CRC track %d side %d sector %d" % (track, side, id_sector))
            # Only update sector if bad to prevent overwriting good with bad
            if sectors[id_sector][2]:
                sectors [id_sector] = (deleted, data_field[1:bc+1], True)

    return sectors


parser = argparse.ArgumentParser(description = 'DFI library test, prints flux transition time histogram for a chosen track',
                                     formatter_class = argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('flux_image', type=argparse.FileType('rb'))
parser.add_argument('imagedisk_image', type=argparse.FileType('wb'))
parser.add_argument('-C', '--comment', action = 'store')

parser.add_argument('-F', '--flux_format', choices=['dfi', 'ksf'], default = 'dfi')

parser_modulation = parser.add_mutually_exclusive_group(required = False)
parser_modulation.add_argument('--fm',   action = 'store_const', const = FM,   dest = 'modulation', help = 'FM modulation, IBM 3740 single density')
parser_modulation.add_argument('--mfm',  action = 'store_const', const = MFM,  dest = 'modulation', help = 'MFM modulation, IBM System/34 double density')
parser_modulation.add_argument('--intelm2fm', action = 'store_const', const = IntelM2FM, dest = 'modulation', help = 'M2FM modulation, Intel MDS, SBC 202 double density')
parser_modulation.add_argument('--hpm2fm', action = 'store_const', const = HPM2FM, dest = 'modulation', help = 'M2FM modulation, HP 7902/9885/9895 double density')

parser.set_defaults(modulation = FM)

parser.add_argument('-s', '--sides',      type=int, default = 1, choices = [1, 2], help='number of sides')
parser.add_argument('-t', '--tracks',     type=int, default = 77, help='number of tracks')

parser.add_argument('-f', '--frequency',  type=float, help = 'sample rate in MHz', default=25.0)
parser.add_argument('-b', '--bit-rate',   type=float, help = 'bit rate in Kbps')
parser.add_argument('--index',            action = 'store_true', help = 'require tracks to have index address marks')
parser.add_argument('-v', '--verbose',    action = 'store_true')
args = parser.parse_args()

if args.flux_format == 'dfi':
    flux_image = DFI(args.flux_image, frequency = args.frequency * 1.0e6)
elif args.flux_format == 'ksf':
    flux_image = KFSF(args.flux_image)

if args.modulation == HPM2FM and args.index:
    print("index mark option ignored, as HP M2FM doesn't use index marks")
    args.index = False

if args.imagedisk_image is not None:
    if args.comment is not None:
        imd = ImageDisk(comment=args.comment)
    else:
        imd = ImageDisk()

if args.bit_rate is None:
    args.bit_rate = args.modulation.default_bit_rate_kbps


crc_param = CRC.CRCParam(name = 'CRC-16-CCITT',
                         order = 16,
                         poly = 0x1021,
                         init = args.modulation.crc_init,
                         xorot = 0x0000,
                         refin = args.modulation.lsb_first,
                         refot = False)


crc = CRC(crc_param)
crc.make_table(8)


hbr = args.bit_rate * 2000   # half-bit rate in Hz
hbc = 1/hbr                  # half-bit cycle in s


first_sector = args.modulation.default_first_sector
sectors_per_track = args.modulation.default_sectors_per_track

bad_sectors = 0
data_sectors = 0
deleted_sectors = 0
total_sectors = 0


#tracks = { }
for track_num in range(args.tracks):
    for side_num in range(args.sides):
        track = dump_track(args.modulation, flux_image, track_num, side_num, require_index_mark = args.index)
        #tracks[(track_num, side_num)] = track
        if args.verbose:
            print('track %2d' % track_num, end='')
            if args.sides > 1:
                print(' side %d' % side_num, end='')
            print(': ', end='')
        for sector_num in range(first_sector, first_sector + sectors_per_track):
            total_sectors += 1
            # If sector not found or bad data (CRC error)
            if sector_num not in track or track[sector_num][2]:
                if args.verbose:
                    print('*', end='')
                bad_sectors += 1
                continue
            sector = track[sector_num]
            if sector[0]:
                if args.verbose:
                    print('D', end='')
                deleted_sectors += 1
            else:
                if args.verbose:
                    print('.', end='')
                data_sectors += 1
        if args.verbose:
            print()

        if args.imagedisk_image is not None:
            for sector_num in range(first_sector, first_sector + sectors_per_track):
                if sector_num not in track:
                    print('*** BAD nodata: track %02d sector %02d\n' % (track_num, sector_num))
            for sector_num in track:
                deleted = track[sector_num][0]
                data = track[sector_num][1]
                bad = track[sector_num][2]
                if data is not None:
                    #print('writing track %02d sector %02d\n' % (track_num, sector_num))
                    if bad:
                        print('*** BAD: track %02d sector %02d\n' % (track_num, sector_num))
                    imd.write_sector(args.modulation.imagedisk_mode,
                                     track_num,  # cylinder
                                     side_num,   # head
                                     sector_num,
                                     bytes(data),
                                     deleted = deleted,
                                     bad = bad)
                else:
                    # If sector not found then no data written to file for sector
                    print('*** BAD nodata: track %02d sector %02d\n' % (track_num, sector_num))
                    pass

if args.imagedisk_image is not None:
    imd.write(args.imagedisk_image)

print('%d data sectors, %d deleted data sectors, %d bad sectors, out of %d' % (data_sectors, deleted_sectors, bad_sectors, total_sectors))