Lib/binhex.py

   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()