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         if type(ofp) == type(''):
 175             ofname = ofp
 176             ofp = open(ofname, 'w')
 177             if os.name == 'mac':
 178                 fss = FSSpec(ofname)
 179                 fss.SetCreatorType('BnHq', 'TEXT')
 180         ofp.write('(This file must be converted with BinHex 4.0)\n\n:')
 181         hqxer = _Hqxcoderengine(ofp)
 182         self.ofp = _Rlecoderengine(hqxer)
 183         self.crc = 0
 184         if finfo is None:
 185             finfo = FInfo()
 186         self.dlen = dlen
 187         self.rlen = rlen
 188         self._writeinfo(name, finfo)
 189         self.state = _DID_HEADER
 190
 191     def _writeinfo(self, name, finfo):
 192         nl = len(name)
 193         if nl > 63:
 194             raise Error, 'Filename too long'
 195         d = chr(nl) + name + '\0'
 196         d2 = finfo.Type + finfo.Creator
 197
 198         # Force all structs to be packed with big-endian
 199         d3 = struct.pack('>h', finfo.Flags)
 200         d4 = struct.pack('>ii', self.dlen, self.rlen)
 201         info = d + d2 + d3 + d4
 202         self._write(info)
 203         self._writecrc()
 204
 205     def _write(self, data):
 206         self.crc = binascii.crc_hqx(data, self.crc)
 207         self.ofp.write(data)
 208
 209     def _writecrc(self):
 210         # XXXX Should this be here??
 211         # self.crc = binascii.crc_hqx('\0\0', self.crc)
 212         if self.crc < 0:
 213             fmt = '>h'
 214         else:
 215             fmt = '>H'
 216         self.ofp.write(struct.pack(fmt, self.crc))
 217         self.crc = 0
 218
 219     def write(self, data):
 220         if self.state != _DID_HEADER:
 221             raise Error, 'Writing data at the wrong time'
 222         self.dlen = self.dlen - len(data)
 223         self._write(data)
 224
 225     def close_data(self):
 226         if self.dlen != 0:
 227             raise Error, 'Incorrect data size, diff=%r' % (self.rlen,)
 228         self._writecrc()
 229         self.state = _DID_DATA
 230
 231     def write_rsrc(self, data):
 232         if self.state < _DID_DATA:
 233             self.close_data()
 234         if self.state != _DID_DATA:
 235             raise Error, 'Writing resource data at the wrong time'
 236         self.rlen = self.rlen - len(data)
 237         self._write(data)
 238
 239     def close(self):
 240         if self.state < _DID_DATA:
 241             self.close_data()
 242         if self.state != _DID_DATA:
 243             raise Error, 'Close at the wrong time'
 244         if self.rlen != 0:
 245             raise Error, \
 246                   "Incorrect resource-datasize, diff=%r" % (self.rlen,)
 247         self._writecrc()
 248         self.ofp.close()
 249         self.state = None
 250         del self.ofp
 251
 252 def binhex(inp, out):
 253     """(infilename, outfilename) - Create binhex-encoded copy of a file"""
 254     finfo = getfileinfo(inp)
 255     ofp = BinHex(finfo, out)
 256
 257     ifp = open(inp, 'rb')
 258     # XXXX Do textfile translation on non-mac systems
 259     while 1:
 260         d = ifp.read(128000)
 261         if not d: break
 262         ofp.write(d)
 263     ofp.close_data()
 264     ifp.close()
 265
 266     ifp = openrsrc(inp, 'rb')
 267     while 1:
 268         d = ifp.read(128000)
 269         if not d: break
 270         ofp.write_rsrc(d)
 271     ofp.close()
 272     ifp.close()
 273
 274 class _Hqxdecoderengine:
 275     """Read data via the decoder in 4-byte chunks"""
 276
 277     def __init__(self, ifp):
 278         self.ifp = ifp
 279         self.eof = 0
 280
 281     def read(self, totalwtd):
 282         """Read at least wtd bytes (or until EOF)"""
 283         decdata = ''
 284         wtd = totalwtd
 285         #
 286         # The loop here is convoluted, since we don't really now how
 287         # much to decode: there may be newlines in the incoming data.
 288         while wtd > 0:
 289             if self.eof: return decdata
 290             wtd = ((wtd+2)//3)*4
 291             data = self.ifp.read(wtd)
 292             #
 293             # Next problem: there may not be a complete number of
 294             # bytes in what we pass to a2b. Solve by yet another
 295             # loop.
 296             #
 297             while 1:
 298                 try:
 299                     decdatacur, self.eof = \
 300                             binascii.a2b_hqx(data)
 301                     break
 302                 except binascii.Incomplete:
 303                     pass
 304                 newdata = self.ifp.read(1)
 305                 if not newdata:
 306                     raise Error, \
 307                           'Premature EOF on binhex file'
 308                 data = data + newdata
 309             decdata = decdata + decdatacur
 310             wtd = totalwtd - len(decdata)
 311             if not decdata and not self.eof:
 312                 raise Error, 'Premature EOF on binhex file'
 313         return decdata
 314
 315     def close(self):
 316         self.ifp.close()
 317
 318 class _Rledecoderengine:
 319     """Read data via the RLE-coder"""
 320
 321     def __init__(self, ifp):
 322         self.ifp = ifp
 323         self.pre_buffer = ''
 324         self.post_buffer = ''
 325         self.eof = 0
 326
 327     def read(self, wtd):
 328         if wtd > len(self.post_buffer):
 329             self._fill(wtd-len(self.post_buffer))
 330         rv = self.post_buffer[:wtd]
 331         self.post_buffer = self.post_buffer[wtd:]
 332         return rv
 333
 334     def _fill(self, wtd):
 335         self.pre_buffer = self.pre_buffer + self.ifp.read(wtd+4)
 336         if self.ifp.eof:
 337             self.post_buffer = self.post_buffer + \
 338                 binascii.rledecode_hqx(self.pre_buffer)
 339             self.pre_buffer = ''
 340             return
 341
 342         #
 343         # Obfuscated code ahead. We have to take care that we don't
 344         # end up with an orphaned RUNCHAR later on. So, we keep a couple
 345         # of bytes in the buffer, depending on what the end of
 346         # the buffer looks like:
 347         # '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)
 348         # '?\220' - Keep 2 bytes: repeated something-else
 349         # '\220\0' - Escaped \220: Keep 2 bytes.
 350         # '?\220?' - Complete repeat sequence: decode all
 351         # otherwise: keep 1 byte.
 352         #
 353         mark = len(self.pre_buffer)
 354         if self.pre_buffer[-3:] == RUNCHAR + '\0' + RUNCHAR:
 355             mark = mark - 3
 356         elif self.pre_buffer[-1] == RUNCHAR:
 357             mark = mark - 2
 358         elif self.pre_buffer[-2:] == RUNCHAR + '\0':
 359             mark = mark - 2
 360         elif self.pre_buffer[-2] == RUNCHAR:
 361             pass # Decode all
 362         else:
 363             mark = mark - 1
 364
 365         self.post_buffer = self.post_buffer + \
 366             binascii.rledecode_hqx(self.pre_buffer[:mark])
 367         self.pre_buffer = self.pre_buffer[mark:]
 368
 369     def close(self):
 370         self.ifp.close()
 371
 372 class HexBin:
 373     def __init__(self, ifp):
 374         if type(ifp) == type(''):
 375             ifp = open(ifp)
 376         #
 377         # Find initial colon.
 378         #
 379         while 1:
 380             ch = ifp.read(1)
 381             if not ch:
 382                 raise Error, "No binhex data found"
 383             # Cater for \r\n terminated lines (which show up as \n\r, hence
 384             # all lines start with \r)
 385             if ch == '\r':
 386                 continue
 387             if ch == ':':
 388                 break
 389             if ch != '\n':
 390                 dummy = ifp.readline()
 391
 392         hqxifp = _Hqxdecoderengine(ifp)
 393         self.ifp = _Rledecoderengine(hqxifp)
 394         self.crc = 0
 395         self._readheader()
 396
 397     def _read(self, len):
 398         data = self.ifp.read(len)
 399         self.crc = binascii.crc_hqx(data, self.crc)
 400         return data
 401
 402     def _checkcrc(self):
 403         filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff
 404         #self.crc = binascii.crc_hqx('\0\0', self.crc)
 405         # XXXX Is this needed??
 406         self.crc = self.crc & 0xffff
 407         if filecrc != self.crc:
 408             raise Error, 'CRC error, computed %x, read %x' \
 409                   %(self.crc, filecrc)
 410         self.crc = 0
 411
 412     def _readheader(self):
 413         len = self._read(1)
 414         fname = self._read(ord(len))
 415         rest = self._read(1+4+4+2+4+4)
 416         self._checkcrc()
 417
 418         type = rest[1:5]
 419         creator = rest[5:9]
 420         flags = struct.unpack('>h', rest[9:11])[0]
 421         self.dlen = struct.unpack('>l', rest[11:15])[0]
 422         self.rlen = struct.unpack('>l', rest[15:19])[0]
 423
 424         self.FName = fname
 425         self.FInfo = FInfo()
 426         self.FInfo.Creator = creator
 427         self.FInfo.Type = type
 428         self.FInfo.Flags = flags
 429
 430         self.state = _DID_HEADER
 431
 432     def read(self, *n):
 433         if self.state != _DID_HEADER:
 434             raise Error, 'Read data at wrong time'
 435         if n:
 436             n = n[0]
 437             n = min(n, self.dlen)
 438         else:
 439             n = self.dlen
 440         rv = ''
 441         while len(rv) < n:
 442             rv = rv + self._read(n-len(rv))
 443         self.dlen = self.dlen - n
 444         return rv
 445
 446     def close_data(self):
 447         if self.state != _DID_HEADER:
 448             raise Error, 'close_data at wrong time'
 449         if self.dlen:
 450             dummy = self._read(self.dlen)
 451         self._checkcrc()
 452         self.state = _DID_DATA
 453
 454     def read_rsrc(self, *n):
 455         if self.state == _DID_HEADER:
 456             self.close_data()
 457         if self.state != _DID_DATA:
 458             raise Error, 'Read resource data at wrong time'
 459         if n:
 460             n = n[0]
 461             n = min(n, self.rlen)
 462         else:
 463             n = self.rlen
 464         self.rlen = self.rlen - n
 465         return self._read(n)
 466
 467     def close(self):
 468         if self.rlen:
 469             dummy = self.read_rsrc(self.rlen)
 470         self._checkcrc()
 471         self.state = _DID_RSRC
 472         self.ifp.close()
 473
 474 def hexbin(inp, out):
 475     """(infilename, outfilename) - Decode binhexed file"""
 476     ifp = HexBin(inp)
 477     finfo = ifp.FInfo
 478     if not out:
 479         out = ifp.FName
 480     if os.name == 'mac':
 481         ofss = FSSpec(out)
 482         out = ofss.as_pathname()
 483
 484     ofp = open(out, 'wb')
 485     # XXXX Do translation on non-mac systems
 486     while 1:
 487         d = ifp.read(128000)
 488         if not d: break
 489         ofp.write(d)
 490     ofp.close()
 491     ifp.close_data()
 492
 493     d = ifp.read_rsrc(128000)
 494     if d:
 495         ofp = openrsrc(out, 'wb')
 496         ofp.write(d)
 497         while 1:
 498             d = ifp.read_rsrc(128000)
 499             if not d: break
 500             ofp.write(d)
 501         ofp.close()
 502
 503     if os.name == 'mac':
 504         nfinfo = ofss.GetFInfo()
 505         nfinfo.Creator = finfo.Creator
 506         nfinfo.Type = finfo.Type
 507         nfinfo.Flags = finfo.Flags
 508         ofss.SetFInfo(nfinfo)
 509
 510     ifp.close()
 511
 512 def _test():
 513     fname = sys.argv[1]
 514     binhex(fname, fname+'.hqx')
 515     hexbin(fname+'.hqx', fname+'.viahqx')
 516     #hexbin(fname, fname+'.unpacked')
 517     sys.exit(1)
 518
 519 if __name__ == '__main__':
 520     _test()