Implement binhex protocol.

Note: binhex works, hexbin does not work yet.

Lib/binhex.py

@@ -0,0 +1,485 @@
+"""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()
+