Lib/binhex.py

"""binhex - 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 simeple 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 sys
import os
import struct
import string
import binascii

DEBUG=1

testf = open('@xx', 'w')	# XXXX

Error = 'binhex.Error'

# 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=48		# What we pass to hqx-coder at once
			# *NOTE* Must be divisible by 3!
RUNCHAR=chr(0x90)	# run-length introducer

#
# The code is currently byte-order dependent
if struct.pack('i', 0177) != '\0\0\0\177':
    raise ImportError, 'Module binhex is big-endian only'

#
# Workarounds for non-mac machines.
if os.name == 'mac':
    import macfs

    def FInfo():
		return macfs.FInfo()

    def getfileinfo(name):
		finfo = macfs.FSSpec(name).GetFInfo()
		dir, file = os.path.split(name)
		# XXXX Get resource/data sizes
		fp = open(name, 'rb')
		fp.seek(0, 2)
		dlen = fp.tell()
		fp = open(name, '*rb')
		fp.seek(0, 2)
		rlen = fp.tell()
		return file, finfo, dlen, rlen

    def openrsrc(name, *mode):
		if mode:
		    mode = mode[0]
		else:
		    mode = 'rb'
		mode = '*' + mode
		return open(name, mode)

else:
    #
    # Glue code for non-macintosh useage
    #
    import regsub
    
    class FInfo:
		def __init__(self):
		    self.Type = '????'
		    self.Creator = '????'
		    self.Flags = 0

    def getfileinfo(name):
		finfo = FInfo()
		# Quick check for textfile
		fp = open(name)
		data = open(name).read(256)
		for c in data:
		    if not c in string.whitespace and (c<' ' or ord(c) > 0177):
			break
		else:
		    finfo.Type = 'TEXT'
		fp.seek(0, 2)
		dsize = fp.tell()
		fp.close()
		dir, file = os.path.split(name)
		file = regsub.sub(':', '-', file)
		return file, finfo, dsize, 0

    class openrsrc:
		def __init__(self, *args):
		    pass
	
		def read(self, *args):
		    return ''
	
		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 = ''

    def write(self, data):
		self.data = self.data + data
		while len(self.data) > LINELEN:
		    hqxdata = binascii.b2a_hqx(self.data[:LINELEN])
		    self.ofp.write(hqxdata+'\n')
		    self.data = self.data[LINELEN:]

    def close(self):
		if self.data:
		    self.ofp.write(binascii.b2a_hqx(self.data))
		self.ofp.write(':\n')
		self.ofp.close()

class _Rlecoderengine:
    """Write data to the RLE-coder in suitably large chunks"""

    def __init__(self, ofp):
		self.ofp = ofp
		self.data = ''

    def write(self, data):
		testf.write(data) # XXXX
		self.data = self.data + data
		if len(self.data) < REASONABLY_LARGE:
		    return
		rledata = binascii.rlecode_hqx(self.data)
		self.ofp.write(rledata)
		self.data = ''

    def close(self):
		if self.data:
		    rledata = binascii.rlecode_hqx(self.data)
		    self.ofp.write(rledata)
		self.ofp.close()

class BinHex:
    def __init__(self, (name, finfo, dlen, rlen), ofp):
	    if type(ofp) == type(''):
	    	ofname = ofp
	    	ofp = open(ofname, 'w')
	    	if os.name == 'mac':
	    		fss = macfs.FSSpec(ofname)
	    		fss.SetCreatorType('BnHq', 'TEXT')
		ofp.write('(This file may be decompressed with BinHex 4.0)\n\n:')
		hqxer = _Hqxcoderengine(ofp)
		self.ofp = _Rlecoderengine(hqxer)
		self.crc = 0
		if finfo == None:
		    finfo = FInfo()
		self.dlen = dlen
		self.rlen = rlen
		self._writeinfo(name, finfo)
		self.state = _DID_HEADER

    def _writeinfo(self, name, finfo):
		if DEBUG:
			print 'binhex info:', name, finfo.Type, finfo.Creator, self.dlen, self.rlen
		name = name
		nl = len(name)
		if nl > 63:
		    raise Error, 'Filename too long'
		d = chr(nl) + name + '\0'
		d2 = finfo.Type + finfo.Creator
		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):
		self.ofp.write(struct.pack('h', 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='+`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="+`self.rlen`
		self._writecrc()
		self.ofp.close()
		self.state = None
	
def binhex(inp, out):
	"""(infilename, outfilename) - Create binhex-encoded copy of a file"""
	finfo = getfileinfo(inp)
	ofp = BinHex(finfo, out)
	
	ifp = open(inp, 'rb')
	# XXXX Do textfile translation on non-mac systems
	d = ifp.read()
	ofp.write(d)
	ofp.close_data()
	ifp.close()

	ifp = openrsrc(inp, 'rb')
	d = ifp.read()
	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, wtd):
		"""Read at least wtd bytes (or until EOF)"""
		decdata = ''
		#
		# 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 1:
				try:
					decdatacur, self.eof = binascii.a2b_hqx(data)
					if self.eof: print 'EOF'
					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 = wtd - 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 = ''
		self.post_buffer = ''
		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:]
		print 'WTD', wtd, 'GOT', len(rv)
		return rv

    def _fill(self, wtd):
		#
		# Obfuscated code ahead. We keep at least one byte in the pre_buffer,
		# so we don't stumble over an orphaned RUNCHAR later on. If the
		# last or second-last char is a RUNCHAR we keep more bytes.
		#
		self.pre_buffer = self.pre_buffer + self.ifp.read(wtd+2)
		if self.ifp.eof:
			self.post_buffer = self.post_buffer + \
				binascii.rledecode_hqx(self.pre_buffer)
			self.pre_buffer = ''
			return
			
		lastrle = string.rfind(self.pre_buffer, RUNCHAR)
		if lastrle > 0 and lastrle == len(self.pre_buffer)-1:
			# Last byte is an RLE, keep two bytes
			mark = len(self.pre_buffer)-2
		elif lastrle > 0 and lastrle == len(self.pre_buffer)-2:
			# second-last byte is an RLE. Decode all.
			mark = len(self.pre_buffer)
		else:
			mark = len(self.pre_buffer)-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 type(ifp) == type(''):
		    ifp = open(ifp)
		#
		# Find initial colon.
		#
		while 1:
			ch = ifp.read(1)
			if not ch:
				raise Error, "No binhex data found"
			if ch == ':':
				break
			if ch != '\n':
				dummy = ifp.readline()
				if DEBUG:
					print 'SKIP:', ch+dummy
			
		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 = self.crc & 0xffff
		if DEBUG:
			print 'DBG CRC %x %x'%(self.crc, filecrc)
		#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]
		
		if DEBUG:
			print 'DATA, RLEN', self.dlen, self.rlen
		
		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
		self.dlen = self.dlen - n
		return self._read(n)
		
    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):
	"""(infilename, outfilename) - Decode binhexed file"""
	ifp = HexBin(inp)
	finfo = ifp.FInfo
	if not out:
		out = ifp.FName
	if os.name == 'mac':
		ofss = macfs.FSSpec(out)
		out = ofss.as_pathname()

	ofp = open(out, 'wb')
	# XXXX Do translation on non-mac systems
	d = ifp.read()
	ofp.write(d)
	ofp.close()
	ifp.close_data()
	
	d = ifp.read_rsrc()
	if d:
		ofp = openrsrc(out, 'wb')
		ofp.write(d)
		ofp.close()

	if os.name == 'mac':
		nfinfo = ofss.GetFInfo()
		nfinfo.Creator = finfo.Creator
		nfinfo.Type = finfo.Type
		nfinfo.Flags = finfo.Flags
		ofss.SetFInfo(nfinfo)
	
	ifp.close()

def _test():
	if os.name == 'mac':
		fss, ok = macfs.StandardGetFile()
		if not ok:
			sys.exit(0)
		fname = fss.as_pathname()
	else:
		fname = sys.argv[1]
	#binhex(fname, fname+'.hqx')
	#hexbin(fname+'.hqx', fname+'.viahqx')
	hexbin(fname, fname+'.unpacked')
	sys.exit(1)
	
if __name__ == '__main__':
	_test()