Major refactoring to support MYDOS images

This commit is contained in:
Rob McMullen 2015-05-19 15:16:19 -07:00
parent 903590bd62
commit ecf25c07fc

View File

@ -17,6 +17,7 @@ class FileNumberMismatchError164(AtrError):
class AtrHeader(object):
format = "<hhhBLLB"
file_format = "ATR"
def __init__(self, bytes=None):
self.size_in_bytes = 0
@ -42,7 +43,22 @@ class AtrHeader(object):
raise InvalidAtrHeader
def __str__(self):
return "size=%d, sector size=%d, crc=%d flags=%d unused=%d" % (self.size_in_bytes, self.sector_size, self.crc, self.flags, self.unused)
return "%s Disk Image (size=%d, sector size=%d, crc=%d flags=%d unused=%d)" % (self.file_format, self.size_in_bytes, self.sector_size, self.crc, self.flags, self.unused)
def check_size(self, size):
if self.size_in_bytes == 0:
if size == 92160:
self.size_in_bytes = size
self.sector_size = 128
elif size == 184320:
self.size_in_bytes = size
self.sector_size = 256
class XfdHeader(AtrHeader):
file_format = "XFD"
def __str__(self):
return "%s Disk Image (size=%d, sector size=%d)" % (self.file_format, self.size_in_bytes, self.sector_size)
class AtrDirent(object):
format = "<Bhh8s3s"
@ -77,6 +93,7 @@ class AtrDirent(object):
self.starting_sector = values[2]
self.filename = values[3].rstrip()
self.ext = values[4].rstrip()
self.current_sector = 0
def __str__(self):
locked = "*" if self.locked else ""
@ -85,18 +102,38 @@ class AtrDirent(object):
return "File #%-2d: %1s%-8s%-3s %03d %s" % (self.file_num, locked, self.filename, self.ext, self.num_sectors, dos)
return
def process_raw_sector(self, bytes):
file_num = ord(bytes[-3]) >> 2
def start_read(self):
self.current_sector = self.starting_sector
self.current_read = self.num_sectors
def read_sector(self, disk):
raw = disk.get_raw_bytes(self.current_sector)
bytes = self.process_raw_sector(disk, raw)
return (bytes, self.current_sector == 0)
def process_raw_sector(self, disk, raw):
file_num = ord(raw[-3]) >> 2
if file_num != self.file_num:
raise FileNumberMismatchError164()
sector = ((ord(bytes[-3]) & 0x3) << 8) + ord(bytes[-2])
num_bytes = ord(bytes[-1])
return sector, bytes[0:num_bytes]
self.current_sector = ((ord(raw[-3]) & 0x3) << 8) + ord(raw[-2])
num_bytes = ord(raw[-1])
return raw[0:num_bytes]
def get_filename(self):
ext = ("." + self.ext) if self.ext else ""
return self.filename + ext
class MydosDirent(AtrDirent):
def process_raw_sector(self, disk, raw):
self.current_read -= 1
if self.current_read == 0:
self.current_sector = 0
else:
self.current_sector += 1
if self.current_sector == disk.first_vtoc:
self.current_sector = disk.first_data_after_vtoc
return raw
class AtrFile(object):
pass
@ -104,12 +141,19 @@ class AtrDiskImage(object):
def __init__(self, fh):
self.fh = fh
self.header = None
self.first_vtoc = 360
self.first_data_after_vtoc = 369
self.total_sectors = 0
self.unused_sectors = 0
self.files = []
self.setup()
def __str__(self):
return "%s %d total sectors (%d free), %d files" % (self.header, self.total_sectors, self.unused_sectors, len(self.files))
def dir(self):
lines = []
lines.append("ATR Disk Image (%s) %d files" % (self.header, len(self.files)))
lines.append(str(self))
for dirent in self.files:
if dirent.in_use:
lines.append(str(dirent))
@ -121,6 +165,7 @@ class AtrDiskImage(object):
self.read_atr_header()
self.check_size()
self.get_vtoc()
self.get_directory()
def read_atr_header(self):
@ -129,16 +174,10 @@ class AtrDiskImage(object):
try:
self.header = AtrHeader(bytes)
except InvalidAtrHeader:
self.header = AtrHeader()
self.header = XfdHeader()
def check_size(self):
if self.header.size_in_bytes == 0:
if self.size == 92160:
self.header.size_in_bytes = self.size
self.header.sector_size = 128
elif self.size == 184320:
self.header.size_in_bytes = self.size
self.header.sector_size = 256
self.header.check_size(self.size)
self.initial_sector_size = self.header.sector_size
self.num_initial_sectors = 0
@ -152,7 +191,13 @@ class AtrDiskImage(object):
pos += self.header.atr_header_offset
return pos, size
def get_sectors(self, start, end):
def get_raw_bytes(self, sector):
pos, size = self.get_pos(sector)
self.fh.seek(pos)
raw = self.fh.read(size)
return raw
def get_sectors(self, start, end=None):
""" Get contiguous sectors
:param start: first sector number to read (note: numbering starts from 1)
@ -162,6 +207,8 @@ class AtrDiskImage(object):
output = StringIO()
pos, size = self.get_pos(start)
self.fh.seek(pos)
if end is None:
end = start
while start <= end:
bytes = self.fh.read(size)
output.write(bytes)
@ -169,6 +216,18 @@ class AtrDiskImage(object):
pos, size = self.get_pos(start)
return output.getvalue()
def get_vtoc(self):
bytes = self.get_sectors(360)
values = struct.unpack("<BHH", bytes[0:5])
code = values[0]
if code == 0 or code == 2:
num = 1
else:
num = (code * 2) - 3
self.first_vtoc = 360 - num + 1
self.total_sectors = values[1]
self.unused_sectors = values[2]
def get_directory(self):
dir_bytes = self.get_sectors(361, 368)
i = 0
@ -176,6 +235,9 @@ class AtrDiskImage(object):
files = []
while i < len(dir_bytes):
dirent = AtrDirent(num, dir_bytes[i:i+16])
if dirent.mydos:
dirent = MydosDirent(num, dir_bytes[i:i+16])
if dirent.in_use:
files.append(dirent)
elif dirent.flag == 0:
@ -186,13 +248,12 @@ class AtrDiskImage(object):
def get_file(self, dirent):
output = StringIO()
sector = dirent.starting_sector
while sector > 0:
pos, size = self.get_pos(sector)
self.fh.seek(pos)
raw = self.fh.read(size)
sector, bytes = dirent.process_raw_sector(raw)
dirent.start_read()
while True:
bytes, last = dirent.read_sector(self)
output.write(bytes)
if last:
break
return output.getvalue()
def find_file(self, filename):
@ -243,10 +304,10 @@ if __name__ == "__main__":
parser.add_argument("files", metavar="ATR", nargs="+", help="an ATR image file [or a list of them]")
options, extra_args = parser.parse_known_args()
for args in options.files:
print args
with open(args, "rb") as fh:
for filename in options.files:
with open(filename, "rb") as fh:
atr = AtrDiskImage(fh)
print "%s: %s" % (filename, atr)
for dirent in atr.files:
try:
process(dirent, options)