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      1 """Macintosh binhex compression/decompression.
      2 
      3 easy interface:
      4 binhex(inputfilename, outputfilename)
      5 hexbin(inputfilename, outputfilename)
      6 """
      7 
      8 #
      9 # Jack Jansen, CWI, August 1995.
     10 #
     11 # The module is supposed to be as compatible as possible. Especially the
     12 # easy interface should work "as expected" on any platform.
     13 # XXXX Note: currently, textfiles appear in mac-form on all platforms.
     14 # We seem to lack a simple character-translate in python.
     15 # (we should probably use ISO-Latin-1 on all but the mac platform).
     16 # XXXX The simple routines are too simple: they expect to hold the complete
     17 # files in-core. Should be fixed.
     18 # XXXX It would be nice to handle AppleDouble format on unix
     19 # (for servers serving macs).
     20 # XXXX I don't understand what happens when you get 0x90 times the same byte on
     21 # input. The resulting code (xx 90 90) would appear to be interpreted as an
     22 # escaped *value* of 0x90. All coders I've seen appear to ignore this nicety...
     23 #
     24 import sys
     25 import os
     26 import struct
     27 import binascii
     28 
     29 __all__ = ["binhex","hexbin","Error"]
     30 
     31 class Error(Exception):
     32     pass
     33 
     34 # States (what have we written)
     35 [_DID_HEADER, _DID_DATA, _DID_RSRC] = range(3)
     36 
     37 # Various constants
     38 REASONABLY_LARGE=32768  # Minimal amount we pass the rle-coder
     39 LINELEN=64
     40 RUNCHAR=chr(0x90)   # run-length introducer
     41 
     42 #
     43 # This code is no longer byte-order dependent
     44 
     45 #
     46 # Workarounds for non-mac machines.
     47 try:
     48     from Carbon.File import FSSpec, FInfo
     49     from MacOS import openrf
     50 
     51     def getfileinfo(name):
     52         finfo = FSSpec(name).FSpGetFInfo()
     53         dir, file = os.path.split(name)
     54         # XXX Get resource/data sizes
     55         fp = open(name, 'rb')
     56         fp.seek(0, 2)
     57         dlen = fp.tell()
     58         fp = openrf(name, '*rb')
     59         fp.seek(0, 2)
     60         rlen = fp.tell()
     61         return file, finfo, dlen, rlen
     62 
     63     def openrsrc(name, *mode):
     64         if not mode:
     65             mode = '*rb'
     66         else:
     67             mode = '*' + mode[0]
     68         return openrf(name, mode)
     69 
     70 except ImportError:
     71     #
     72     # Glue code for non-macintosh usage
     73     #
     74 
     75     class FInfo:
     76         def __init__(self):
     77             self.Type = '????'
     78             self.Creator = '????'
     79             self.Flags = 0
     80 
     81     def getfileinfo(name):
     82         finfo = FInfo()
     83         # Quick check for textfile
     84         fp = open(name)
     85         data = open(name).read(256)
     86         for c in data:
     87             if not c.isspace() and (c<' ' or ord(c) > 0x7f):
     88                 break
     89         else:
     90             finfo.Type = 'TEXT'
     91         fp.seek(0, 2)
     92         dsize = fp.tell()
     93         fp.close()
     94         dir, file = os.path.split(name)
     95         file = file.replace(':', '-', 1)
     96         return file, finfo, dsize, 0
     97 
     98     class openrsrc:
     99         def __init__(self, *args):
    100             pass
    101 
    102         def read(self, *args):
    103             return ''
    104 
    105         def write(self, *args):
    106             pass
    107 
    108         def close(self):
    109             pass
    110 
    111 class _Hqxcoderengine:
    112     """Write data to the coder in 3-byte chunks"""
    113 
    114     def __init__(self, ofp):
    115         self.ofp = ofp
    116         self.data = ''
    117         self.hqxdata = ''
    118         self.linelen = LINELEN-1
    119 
    120     def write(self, data):
    121         self.data = self.data + data
    122         datalen = len(self.data)
    123         todo = (datalen//3)*3
    124         data = self.data[:todo]
    125         self.data = self.data[todo:]
    126         if not data:
    127             return
    128         self.hqxdata = self.hqxdata + binascii.b2a_hqx(data)
    129         self._flush(0)
    130 
    131     def _flush(self, force):
    132         first = 0
    133         while first <= len(self.hqxdata)-self.linelen:
    134             last = first + self.linelen
    135             self.ofp.write(self.hqxdata[first:last]+'\n')
    136             self.linelen = LINELEN
    137             first = last
    138         self.hqxdata = self.hqxdata[first:]
    139         if force:
    140             self.ofp.write(self.hqxdata + ':\n')
    141 
    142     def close(self):
    143         if self.data:
    144             self.hqxdata = \
    145                  self.hqxdata + binascii.b2a_hqx(self.data)
    146         self._flush(1)
    147         self.ofp.close()
    148         del self.ofp
    149 
    150 class _Rlecoderengine:
    151     """Write data to the RLE-coder in suitably large chunks"""
    152 
    153     def __init__(self, ofp):
    154         self.ofp = ofp
    155         self.data = ''
    156 
    157     def write(self, data):
    158         self.data = self.data + data
    159         if len(self.data) < REASONABLY_LARGE:
    160             return
    161         rledata = binascii.rlecode_hqx(self.data)
    162         self.ofp.write(rledata)
    163         self.data = ''
    164 
    165     def close(self):
    166         if self.data:
    167             rledata = binascii.rlecode_hqx(self.data)
    168             self.ofp.write(rledata)
    169         self.ofp.close()
    170         del self.ofp
    171 
    172 class BinHex:
    173     def __init__(self, name_finfo_dlen_rlen, ofp):
    174         name, finfo, dlen, rlen = name_finfo_dlen_rlen
    175         if type(ofp) == type(''):
    176             ofname = ofp
    177             ofp = open(ofname, 'w')
    178         ofp.write('(This file must be converted with BinHex 4.0)\n\n:')
    179         hqxer = _Hqxcoderengine(ofp)
    180         self.ofp = _Rlecoderengine(hqxer)
    181         self.crc = 0
    182         if finfo is None:
    183             finfo = FInfo()
    184         self.dlen = dlen
    185         self.rlen = rlen
    186         self._writeinfo(name, finfo)
    187         self.state = _DID_HEADER
    188 
    189     def _writeinfo(self, name, finfo):
    190         nl = len(name)
    191         if nl > 63:
    192             raise Error, 'Filename too long'
    193         d = chr(nl) + name + '\0'
    194         d2 = finfo.Type + finfo.Creator
    195 
    196         # Force all structs to be packed with big-endian
    197         d3 = struct.pack('>h', finfo.Flags)
    198         d4 = struct.pack('>ii', self.dlen, self.rlen)
    199         info = d + d2 + d3 + d4
    200         self._write(info)
    201         self._writecrc()
    202 
    203     def _write(self, data):
    204         self.crc = binascii.crc_hqx(data, self.crc)
    205         self.ofp.write(data)
    206 
    207     def _writecrc(self):
    208         # XXXX Should this be here??
    209         # self.crc = binascii.crc_hqx('\0\0', self.crc)
    210         if self.crc < 0:
    211             fmt = '>h'
    212         else:
    213             fmt = '>H'
    214         self.ofp.write(struct.pack(fmt, self.crc))
    215         self.crc = 0
    216 
    217     def write(self, data):
    218         if self.state != _DID_HEADER:
    219             raise Error, 'Writing data at the wrong time'
    220         self.dlen = self.dlen - len(data)
    221         self._write(data)
    222 
    223     def close_data(self):
    224         if self.dlen != 0:
    225             raise Error, 'Incorrect data size, diff=%r' % (self.rlen,)
    226         self._writecrc()
    227         self.state = _DID_DATA
    228 
    229     def write_rsrc(self, data):
    230         if self.state < _DID_DATA:
    231             self.close_data()
    232         if self.state != _DID_DATA:
    233             raise Error, 'Writing resource data at the wrong time'
    234         self.rlen = self.rlen - len(data)
    235         self._write(data)
    236 
    237     def close(self):
    238         if self.state < _DID_DATA:
    239             self.close_data()
    240         if self.state != _DID_DATA:
    241             raise Error, 'Close at the wrong time'
    242         if self.rlen != 0:
    243             raise Error, \
    244                   "Incorrect resource-datasize, diff=%r" % (self.rlen,)
    245         self._writecrc()
    246         self.ofp.close()
    247         self.state = None
    248         del self.ofp
    249 
    250 def binhex(inp, out):
    251     """(infilename, outfilename) - Create binhex-encoded copy of a file"""
    252     finfo = getfileinfo(inp)
    253     ofp = BinHex(finfo, out)
    254 
    255     ifp = open(inp, 'rb')
    256     # XXXX Do textfile translation on non-mac systems
    257     while 1:
    258         d = ifp.read(128000)
    259         if not d: break
    260         ofp.write(d)
    261     ofp.close_data()
    262     ifp.close()
    263 
    264     ifp = openrsrc(inp, 'rb')
    265     while 1:
    266         d = ifp.read(128000)
    267         if not d: break
    268         ofp.write_rsrc(d)
    269     ofp.close()
    270     ifp.close()
    271 
    272 class _Hqxdecoderengine:
    273     """Read data via the decoder in 4-byte chunks"""
    274 
    275     def __init__(self, ifp):
    276         self.ifp = ifp
    277         self.eof = 0
    278 
    279     def read(self, totalwtd):
    280         """Read at least wtd bytes (or until EOF)"""
    281         decdata = ''
    282         wtd = totalwtd
    283         #
    284         # The loop here is convoluted, since we don't really now how
    285         # much to decode: there may be newlines in the incoming data.
    286         while wtd > 0:
    287             if self.eof: return decdata
    288             wtd = ((wtd+2)//3)*4
    289             data = self.ifp.read(wtd)
    290             #
    291             # Next problem: there may not be a complete number of
    292             # bytes in what we pass to a2b. Solve by yet another
    293             # loop.
    294             #
    295             while 1:
    296                 try:
    297                     decdatacur, self.eof = \
    298                             binascii.a2b_hqx(data)
    299                     break
    300                 except binascii.Incomplete:
    301                     pass
    302                 newdata = self.ifp.read(1)
    303                 if not newdata:
    304                     raise Error, \
    305                           'Premature EOF on binhex file'
    306                 data = data + newdata
    307             decdata = decdata + decdatacur
    308             wtd = totalwtd - len(decdata)
    309             if not decdata and not self.eof:
    310                 raise Error, 'Premature EOF on binhex file'
    311         return decdata
    312 
    313     def close(self):
    314         self.ifp.close()
    315 
    316 class _Rledecoderengine:
    317     """Read data via the RLE-coder"""
    318 
    319     def __init__(self, ifp):
    320         self.ifp = ifp
    321         self.pre_buffer = ''
    322         self.post_buffer = ''
    323         self.eof = 0
    324 
    325     def read(self, wtd):
    326         if wtd > len(self.post_buffer):
    327             self._fill(wtd-len(self.post_buffer))
    328         rv = self.post_buffer[:wtd]
    329         self.post_buffer = self.post_buffer[wtd:]
    330         return rv
    331 
    332     def _fill(self, wtd):
    333         self.pre_buffer = self.pre_buffer + self.ifp.read(wtd+4)
    334         if self.ifp.eof:
    335             self.post_buffer = self.post_buffer + \
    336                 binascii.rledecode_hqx(self.pre_buffer)
    337             self.pre_buffer = ''
    338             return
    339 
    340         #
    341         # Obfuscated code ahead. We have to take care that we don't
    342         # end up with an orphaned RUNCHAR later on. So, we keep a couple
    343         # of bytes in the buffer, depending on what the end of
    344         # the buffer looks like:
    345         # '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)
    346         # '?\220' - Keep 2 bytes: repeated something-else
    347         # '\220\0' - Escaped \220: Keep 2 bytes.
    348         # '?\220?' - Complete repeat sequence: decode all
    349         # otherwise: keep 1 byte.
    350         #
    351         mark = len(self.pre_buffer)
    352         if self.pre_buffer[-3:] == RUNCHAR + '\0' + RUNCHAR:
    353             mark = mark - 3
    354         elif self.pre_buffer[-1] == RUNCHAR:
    355             mark = mark - 2
    356         elif self.pre_buffer[-2:] == RUNCHAR + '\0':
    357             mark = mark - 2
    358         elif self.pre_buffer[-2] == RUNCHAR:
    359             pass # Decode all
    360         else:
    361             mark = mark - 1
    362 
    363         self.post_buffer = self.post_buffer + \
    364             binascii.rledecode_hqx(self.pre_buffer[:mark])
    365         self.pre_buffer = self.pre_buffer[mark:]
    366 
    367     def close(self):
    368         self.ifp.close()
    369 
    370 class HexBin:
    371     def __init__(self, ifp):
    372         if type(ifp) == type(''):
    373             ifp = open(ifp)
    374         #
    375         # Find initial colon.
    376         #
    377         while 1:
    378             ch = ifp.read(1)
    379             if not ch:
    380                 raise Error, "No binhex data found"
    381             # Cater for \r\n terminated lines (which show up as \n\r, hence
    382             # all lines start with \r)
    383             if ch == '\r':
    384                 continue
    385             if ch == ':':
    386                 break
    387             if ch != '\n':
    388                 dummy = ifp.readline()
    389 
    390         hqxifp = _Hqxdecoderengine(ifp)
    391         self.ifp = _Rledecoderengine(hqxifp)
    392         self.crc = 0
    393         self._readheader()
    394 
    395     def _read(self, len):
    396         data = self.ifp.read(len)
    397         self.crc = binascii.crc_hqx(data, self.crc)
    398         return data
    399 
    400     def _checkcrc(self):
    401         filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff
    402         #self.crc = binascii.crc_hqx('\0\0', self.crc)
    403         # XXXX Is this needed??
    404         self.crc = self.crc & 0xffff
    405         if filecrc != self.crc:
    406             raise Error, 'CRC error, computed %x, read %x' \
    407                   %(self.crc, filecrc)
    408         self.crc = 0
    409 
    410     def _readheader(self):
    411         len = self._read(1)
    412         fname = self._read(ord(len))
    413         rest = self._read(1+4+4+2+4+4)
    414         self._checkcrc()
    415 
    416         type = rest[1:5]
    417         creator = rest[5:9]
    418         flags = struct.unpack('>h', rest[9:11])[0]
    419         self.dlen = struct.unpack('>l', rest[11:15])[0]
    420         self.rlen = struct.unpack('>l', rest[15:19])[0]
    421 
    422         self.FName = fname
    423         self.FInfo = FInfo()
    424         self.FInfo.Creator = creator
    425         self.FInfo.Type = type
    426         self.FInfo.Flags = flags
    427 
    428         self.state = _DID_HEADER
    429 
    430     def read(self, *n):
    431         if self.state != _DID_HEADER:
    432             raise Error, 'Read data at wrong time'
    433         if n:
    434             n = n[0]
    435             n = min(n, self.dlen)
    436         else:
    437             n = self.dlen
    438         rv = ''
    439         while len(rv) < n:
    440             rv = rv + self._read(n-len(rv))
    441         self.dlen = self.dlen - n
    442         return rv
    443 
    444     def close_data(self):
    445         if self.state != _DID_HEADER:
    446             raise Error, 'close_data at wrong time'
    447         if self.dlen:
    448             dummy = self._read(self.dlen)
    449         self._checkcrc()
    450         self.state = _DID_DATA
    451 
    452     def read_rsrc(self, *n):
    453         if self.state == _DID_HEADER:
    454             self.close_data()
    455         if self.state != _DID_DATA:
    456             raise Error, 'Read resource data at wrong time'
    457         if n:
    458             n = n[0]
    459             n = min(n, self.rlen)
    460         else:
    461             n = self.rlen
    462         self.rlen = self.rlen - n
    463         return self._read(n)
    464 
    465     def close(self):
    466         if self.rlen:
    467             dummy = self.read_rsrc(self.rlen)
    468         self._checkcrc()
    469         self.state = _DID_RSRC
    470         self.ifp.close()
    471 
    472 def hexbin(inp, out):
    473     """(infilename, outfilename) - Decode binhexed file"""
    474     ifp = HexBin(inp)
    475     finfo = ifp.FInfo
    476     if not out:
    477         out = ifp.FName
    478 
    479     ofp = open(out, 'wb')
    480     # XXXX Do translation on non-mac systems
    481     while 1:
    482         d = ifp.read(128000)
    483         if not d: break
    484         ofp.write(d)
    485     ofp.close()
    486     ifp.close_data()
    487 
    488     d = ifp.read_rsrc(128000)
    489     if d:
    490         ofp = openrsrc(out, 'wb')
    491         ofp.write(d)
    492         while 1:
    493             d = ifp.read_rsrc(128000)
    494             if not d: break
    495             ofp.write(d)
    496         ofp.close()
    497 
    498     ifp.close()
    499 
    500 def _test():
    501     fname = sys.argv[1]
    502     binhex(fname, fname+'.hqx')
    503     hexbin(fname+'.hqx', fname+'.viahqx')
    504     #hexbin(fname, fname+'.unpacked')
    505     sys.exit(1)
    506 
    507 if __name__ == '__main__':
    508     _test()
    509