"""Macintosh binhex compression/decompression.
easy interface:
binhex(inputfilename, outputfilename)
hexbin(inputfilename, outputfilename)
"""
#
# Jack Jansen, CWI, August 1995.
#
# The module is supposed to be as compatible as possible. Especially the
# easy interface should work "as expected" on any platform.
# XXXX Note: currently, textfiles appear in mac-form on all platforms.
# We seem to lack a simple character-translate in python.
# (we should probably use ISO-Latin-1 on all but the mac platform).
# XXXX The simple routines are too simple: they expect to hold the complete
# files in-core. Should be fixed.
# XXXX It would be nice to handle AppleDouble format on unix
# (for servers serving macs).
# XXXX I don't understand what happens when you get 0x90 times the same byte on
# input. The resulting code (xx 90 90) would appear to be interpreted as an
# escaped *value* of 0x90. All coders I've seen appear to ignore this nicety...
#
import io
import os
import struct
import binascii
__all__ = ["binhex","hexbin","Error"]
[docs]class Error(Exception):
pass
# States (what have we written)
_DID_HEADER = 0
_DID_DATA = 1
# Various constants
REASONABLY_LARGE = 32768 # Minimal amount we pass the rle-coder
LINELEN = 64
RUNCHAR = b"\x90"
#
# This code is no longer byte-order dependent
class FInfo:
def __init__(self):
self.Type = '????'
self.Creator = '????'
self.Flags = 0
def getfileinfo(name):
finfo = FInfo()
with io.open(name, 'rb') as fp:
# Quick check for textfile
data = fp.read(512)
if 0 not in data:
finfo.Type = 'TEXT'
fp.seek(0, 2)
dsize = fp.tell()
dir, file = os.path.split(name)
file = file.replace(':', '-', 1)
return file, finfo, dsize, 0
class openrsrc:
def __init__(self, *args):
pass
def read(self, *args):
return b''
def write(self, *args):
pass
def close(self):
pass
class _Hqxcoderengine:
"""Write data to the coder in 3-byte chunks"""
def __init__(self, ofp):
self.ofp = ofp
self.data = b''
self.hqxdata = b''
self.linelen = LINELEN - 1
def write(self, data):
self.data = self.data + data
datalen = len(self.data)
todo = (datalen // 3) * 3
data = self.data[:todo]
self.data = self.data[todo:]
if not data:
return
self.hqxdata = self.hqxdata + binascii.b2a_hqx(data)
self._flush(0)
def _flush(self, force):
first = 0
while first <= len(self.hqxdata) - self.linelen:
last = first + self.linelen
self.ofp.write(self.hqxdata[first:last] + b'\n')
self.linelen = LINELEN
first = last
self.hqxdata = self.hqxdata[first:]
if force:
self.ofp.write(self.hqxdata + b':\n')
def close(self):
if self.data:
self.hqxdata = self.hqxdata + binascii.b2a_hqx(self.data)
self._flush(1)
self.ofp.close()
del self.ofp
class _Rlecoderengine:
"""Write data to the RLE-coder in suitably large chunks"""
def __init__(self, ofp):
self.ofp = ofp
self.data = b''
def write(self, data):
self.data = self.data + data
if len(self.data) < REASONABLY_LARGE:
return
rledata = binascii.rlecode_hqx(self.data)
self.ofp.write(rledata)
self.data = b''
def close(self):
if self.data:
rledata = binascii.rlecode_hqx(self.data)
self.ofp.write(rledata)
self.ofp.close()
del self.ofp
class BinHex:
def __init__(self, name_finfo_dlen_rlen, ofp):
name, finfo, dlen, rlen = name_finfo_dlen_rlen
close_on_error = False
if isinstance(ofp, str):
ofname = ofp
ofp = io.open(ofname, 'wb')
close_on_error = True
try:
ofp.write(b'(This file must be converted with BinHex 4.0)\r\r:')
hqxer = _Hqxcoderengine(ofp)
self.ofp = _Rlecoderengine(hqxer)
self.crc = 0
if finfo is None:
finfo = FInfo()
self.dlen = dlen
self.rlen = rlen
self._writeinfo(name, finfo)
self.state = _DID_HEADER
except:
if close_on_error:
ofp.close()
raise
def _writeinfo(self, name, finfo):
nl = len(name)
if nl > 63:
raise Error('Filename too long')
d = bytes([nl]) + name.encode("latin-1") + b'\0'
tp, cr = finfo.Type, finfo.Creator
if isinstance(tp, str):
tp = tp.encode("latin-1")
if isinstance(cr, str):
cr = cr.encode("latin-1")
d2 = tp + cr
# Force all structs to be packed with big-endian
d3 = struct.pack('>h', finfo.Flags)
d4 = struct.pack('>ii', self.dlen, self.rlen)
info = d + d2 + d3 + d4
self._write(info)
self._writecrc()
def _write(self, data):
self.crc = binascii.crc_hqx(data, self.crc)
self.ofp.write(data)
def _writecrc(self):
# XXXX Should this be here??
# self.crc = binascii.crc_hqx('\0\0', self.crc)
if self.crc < 0:
fmt = '>h'
else:
fmt = '>H'
self.ofp.write(struct.pack(fmt, self.crc))
self.crc = 0
def write(self, data):
if self.state != _DID_HEADER:
raise Error('Writing data at the wrong time')
self.dlen = self.dlen - len(data)
self._write(data)
def close_data(self):
if self.dlen != 0:
raise Error('Incorrect data size, diff=%r' % (self.rlen,))
self._writecrc()
self.state = _DID_DATA
def write_rsrc(self, data):
if self.state < _DID_DATA:
self.close_data()
if self.state != _DID_DATA:
raise Error('Writing resource data at the wrong time')
self.rlen = self.rlen - len(data)
self._write(data)
def close(self):
if self.state is None:
return
try:
if self.state < _DID_DATA:
self.close_data()
if self.state != _DID_DATA:
raise Error('Close at the wrong time')
if self.rlen != 0:
raise Error("Incorrect resource-datasize, diff=%r" % (self.rlen,))
self._writecrc()
finally:
self.state = None
ofp = self.ofp
del self.ofp
ofp.close()
[docs]def binhex(inp, out):
"""binhex(infilename, outfilename): create binhex-encoded copy of a file"""
finfo = getfileinfo(inp)
ofp = BinHex(finfo, out)
with io.open(inp, 'rb') as ifp:
# XXXX Do textfile translation on non-mac systems
while True:
d = ifp.read(128000)
if not d: break
ofp.write(d)
ofp.close_data()
ifp = openrsrc(inp, 'rb')
while True:
d = ifp.read(128000)
if not d: break
ofp.write_rsrc(d)
ofp.close()
ifp.close()
class _Hqxdecoderengine:
"""Read data via the decoder in 4-byte chunks"""
def __init__(self, ifp):
self.ifp = ifp
self.eof = 0
def read(self, totalwtd):
"""Read at least wtd bytes (or until EOF)"""
decdata = b''
wtd = totalwtd
#
# The loop here is convoluted, since we don't really now how
# much to decode: there may be newlines in the incoming data.
while wtd > 0:
if self.eof: return decdata
wtd = ((wtd + 2) // 3) * 4
data = self.ifp.read(wtd)
#
# Next problem: there may not be a complete number of
# bytes in what we pass to a2b. Solve by yet another
# loop.
#
while True:
try:
decdatacur, self.eof = binascii.a2b_hqx(data)
break
except binascii.Incomplete:
pass
newdata = self.ifp.read(1)
if not newdata:
raise Error('Premature EOF on binhex file')
data = data + newdata
decdata = decdata + decdatacur
wtd = totalwtd - len(decdata)
if not decdata and not self.eof:
raise Error('Premature EOF on binhex file')
return decdata
def close(self):
self.ifp.close()
class _Rledecoderengine:
"""Read data via the RLE-coder"""
def __init__(self, ifp):
self.ifp = ifp
self.pre_buffer = b''
self.post_buffer = b''
self.eof = 0
def read(self, wtd):
if wtd > len(self.post_buffer):
self._fill(wtd - len(self.post_buffer))
rv = self.post_buffer[:wtd]
self.post_buffer = self.post_buffer[wtd:]
return rv
def _fill(self, wtd):
self.pre_buffer = self.pre_buffer + self.ifp.read(wtd + 4)
if self.ifp.eof:
self.post_buffer = self.post_buffer + \
binascii.rledecode_hqx(self.pre_buffer)
self.pre_buffer = b''
return
#
# Obfuscated code ahead. We have to take care that we don't
# end up with an orphaned RUNCHAR later on. So, we keep a couple
# of bytes in the buffer, depending on what the end of
# the buffer looks like:
# '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)
# '?\220' - Keep 2 bytes: repeated something-else
# '\220\0' - Escaped \220: Keep 2 bytes.
# '?\220?' - Complete repeat sequence: decode all
# otherwise: keep 1 byte.
#
mark = len(self.pre_buffer)
if self.pre_buffer[-3:] == RUNCHAR + b'\0' + RUNCHAR:
mark = mark - 3
elif self.pre_buffer[-1:] == RUNCHAR:
mark = mark - 2
elif self.pre_buffer[-2:] == RUNCHAR + b'\0':
mark = mark - 2
elif self.pre_buffer[-2:-1] == RUNCHAR:
pass # Decode all
else:
mark = mark - 1
self.post_buffer = self.post_buffer + \
binascii.rledecode_hqx(self.pre_buffer[:mark])
self.pre_buffer = self.pre_buffer[mark:]
def close(self):
self.ifp.close()
class HexBin:
def __init__(self, ifp):
if isinstance(ifp, str):
ifp = io.open(ifp, 'rb')
#
# Find initial colon.
#
while True:
ch = ifp.read(1)
if not ch:
raise Error("No binhex data found")
# Cater for \r\n terminated lines (which show up as \n\r, hence
# all lines start with \r)
if ch == b'\r':
continue
if ch == b':':
break
hqxifp = _Hqxdecoderengine(ifp)
self.ifp = _Rledecoderengine(hqxifp)
self.crc = 0
self._readheader()
def _read(self, len):
data = self.ifp.read(len)
self.crc = binascii.crc_hqx(data, self.crc)
return data
def _checkcrc(self):
filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff
#self.crc = binascii.crc_hqx('\0\0', self.crc)
# XXXX Is this needed??
self.crc = self.crc & 0xffff
if filecrc != self.crc:
raise Error('CRC error, computed %x, read %x'
% (self.crc, filecrc))
self.crc = 0
def _readheader(self):
len = self._read(1)
fname = self._read(ord(len))
rest = self._read(1 + 4 + 4 + 2 + 4 + 4)
self._checkcrc()
type = rest[1:5]
creator = rest[5:9]
flags = struct.unpack('>h', rest[9:11])[0]
self.dlen = struct.unpack('>l', rest[11:15])[0]
self.rlen = struct.unpack('>l', rest[15:19])[0]
self.FName = fname
self.FInfo = FInfo()
self.FInfo.Creator = creator
self.FInfo.Type = type
self.FInfo.Flags = flags
self.state = _DID_HEADER
def read(self, *n):
if self.state != _DID_HEADER:
raise Error('Read data at wrong time')
if n:
n = n[0]
n = min(n, self.dlen)
else:
n = self.dlen
rv = b''
while len(rv) < n:
rv = rv + self._read(n-len(rv))
self.dlen = self.dlen - n
return rv
def close_data(self):
if self.state != _DID_HEADER:
raise Error('close_data at wrong time')
if self.dlen:
dummy = self._read(self.dlen)
self._checkcrc()
self.state = _DID_DATA
def read_rsrc(self, *n):
if self.state == _DID_HEADER:
self.close_data()
if self.state != _DID_DATA:
raise Error('Read resource data at wrong time')
if n:
n = n[0]
n = min(n, self.rlen)
else:
n = self.rlen
self.rlen = self.rlen - n
return self._read(n)
def close(self):
if self.state is None:
return
try:
if self.rlen:
dummy = self.read_rsrc(self.rlen)
self._checkcrc()
finally:
self.state = None
self.ifp.close()
[docs]def hexbin(inp, out):
"""hexbin(infilename, outfilename) - Decode binhexed file"""
ifp = HexBin(inp)
finfo = ifp.FInfo
if not out:
out = ifp.FName
with io.open(out, 'wb') as ofp:
# XXXX Do translation on non-mac systems
while True:
d = ifp.read(128000)
if not d: break
ofp.write(d)
ifp.close_data()
d = ifp.read_rsrc(128000)
if d:
ofp = openrsrc(out, 'wb')
ofp.write(d)
while True:
d = ifp.read_rsrc(128000)
if not d: break
ofp.write(d)
ofp.close()
ifp.close()