"""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 sys

import struct

import binascii

__all__ = ["binhex","hexbin","Error"]

class Error(Exception):

pass

# States (what have we written)

[_DID_HEADER, _DID_DATA, _DID_RSRC] = range(3)

# 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 < _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()

self.ofp.close()

self.state = None

del self.ofp

def binhex(inp, out):

"""binhex(infilename, outfilename): create binhex-encoded copy of a file"""

finfo = getfileinfo(inp)

ofp = BinHex(finfo, out)

ifp = io.open(inp, 'rb')

# 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.close()

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.rlen:

dummy = self.read_rsrc(self.rlen)

self._checkcrc()

self.state = _DID_RSRC

self.ifp.close()

def hexbin(inp, out):

"""hexbin(infilename, outfilename) - Decode binhexed file"""

ifp = HexBin(inp)

finfo = ifp.FInfo

if not out:

out = ifp.FName

ofp = io.open(out, 'wb')

# XXXX Do translation on non-mac systems

while True:

d = ifp.read(128000)

if not d: break

ofp.write(d)

ofp.close()

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()