480 lines
14 KiB
Python
480 lines
14 KiB
Python
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"""Macintosh binhex compression/decompression.
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easy interface:
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binhex(inputfilename, outputfilename)
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hexbin(inputfilename, outputfilename)
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"""
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#
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# Jack Jansen, CWI, August 1995.
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#
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# The module is supposed to be as compatible as possible. Especially the
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# easy interface should work "as expected" on any platform.
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# XXXX Note: currently, textfiles appear in mac-form on all platforms.
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# We seem to lack a simple character-translate in python.
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# (we should probably use ISO-Latin-1 on all but the mac platform).
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# XXXX The simple routines are too simple: they expect to hold the complete
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# files in-core. Should be fixed.
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# XXXX It would be nice to handle AppleDouble format on unix
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# (for servers serving macs).
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# XXXX I don't understand what happens when you get 0x90 times the same byte on
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# input. The resulting code (xx 90 90) would appear to be interpreted as an
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# escaped *value* of 0x90. All coders I've seen appear to ignore this nicety...
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#
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import io
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import os
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import struct
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import binascii
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__all__ = ["binhex","hexbin","Error"]
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class Error(Exception):
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pass
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# States (what have we written)
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_DID_HEADER = 0
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_DID_DATA = 1
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# Various constants
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REASONABLY_LARGE = 32768 # Minimal amount we pass the rle-coder
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LINELEN = 64
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RUNCHAR = b"\x90"
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#
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# This code is no longer byte-order dependent
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class FInfo:
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def __init__(self):
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self.Type = '????'
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self.Creator = '????'
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self.Flags = 0
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def getfileinfo(name):
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finfo = FInfo()
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with io.open(name, 'rb') as fp:
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# Quick check for textfile
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data = fp.read(512)
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if 0 not in data:
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finfo.Type = 'TEXT'
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fp.seek(0, 2)
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dsize = fp.tell()
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dir, file = os.path.split(name)
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file = file.replace(':', '-', 1)
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return file, finfo, dsize, 0
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class openrsrc:
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def __init__(self, *args):
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pass
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def read(self, *args):
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return b''
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def write(self, *args):
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pass
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def close(self):
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pass
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class _Hqxcoderengine:
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"""Write data to the coder in 3-byte chunks"""
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def __init__(self, ofp):
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self.ofp = ofp
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self.data = b''
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self.hqxdata = b''
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self.linelen = LINELEN - 1
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def write(self, data):
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self.data = self.data + data
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datalen = len(self.data)
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todo = (datalen // 3) * 3
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data = self.data[:todo]
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self.data = self.data[todo:]
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if not data:
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return
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self.hqxdata = self.hqxdata + binascii.b2a_hqx(data)
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self._flush(0)
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def _flush(self, force):
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first = 0
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while first <= len(self.hqxdata) - self.linelen:
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last = first + self.linelen
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self.ofp.write(self.hqxdata[first:last] + b'\n')
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self.linelen = LINELEN
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first = last
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self.hqxdata = self.hqxdata[first:]
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if force:
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self.ofp.write(self.hqxdata + b':\n')
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def close(self):
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if self.data:
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self.hqxdata = self.hqxdata + binascii.b2a_hqx(self.data)
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self._flush(1)
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self.ofp.close()
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del self.ofp
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class _Rlecoderengine:
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"""Write data to the RLE-coder in suitably large chunks"""
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def __init__(self, ofp):
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self.ofp = ofp
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self.data = b''
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def write(self, data):
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self.data = self.data + data
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if len(self.data) < REASONABLY_LARGE:
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return
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rledata = binascii.rlecode_hqx(self.data)
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self.ofp.write(rledata)
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self.data = b''
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def close(self):
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if self.data:
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rledata = binascii.rlecode_hqx(self.data)
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self.ofp.write(rledata)
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self.ofp.close()
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del self.ofp
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class BinHex:
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def __init__(self, name_finfo_dlen_rlen, ofp):
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name, finfo, dlen, rlen = name_finfo_dlen_rlen
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close_on_error = False
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if isinstance(ofp, str):
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ofname = ofp
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ofp = io.open(ofname, 'wb')
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close_on_error = True
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try:
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ofp.write(b'(This file must be converted with BinHex 4.0)\r\r:')
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hqxer = _Hqxcoderengine(ofp)
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self.ofp = _Rlecoderengine(hqxer)
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self.crc = 0
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if finfo is None:
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finfo = FInfo()
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self.dlen = dlen
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self.rlen = rlen
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self._writeinfo(name, finfo)
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self.state = _DID_HEADER
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except:
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if close_on_error:
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ofp.close()
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raise
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def _writeinfo(self, name, finfo):
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nl = len(name)
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if nl > 63:
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raise Error('Filename too long')
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d = bytes([nl]) + name.encode("latin-1") + b'\0'
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tp, cr = finfo.Type, finfo.Creator
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if isinstance(tp, str):
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tp = tp.encode("latin-1")
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if isinstance(cr, str):
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cr = cr.encode("latin-1")
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d2 = tp + cr
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# Force all structs to be packed with big-endian
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d3 = struct.pack('>h', finfo.Flags)
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d4 = struct.pack('>ii', self.dlen, self.rlen)
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info = d + d2 + d3 + d4
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self._write(info)
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self._writecrc()
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def _write(self, data):
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self.crc = binascii.crc_hqx(data, self.crc)
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self.ofp.write(data)
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def _writecrc(self):
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# XXXX Should this be here??
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# self.crc = binascii.crc_hqx('\0\0', self.crc)
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if self.crc < 0:
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fmt = '>h'
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else:
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fmt = '>H'
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self.ofp.write(struct.pack(fmt, self.crc))
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self.crc = 0
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def write(self, data):
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if self.state != _DID_HEADER:
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raise Error('Writing data at the wrong time')
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self.dlen = self.dlen - len(data)
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self._write(data)
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def close_data(self):
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if self.dlen != 0:
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raise Error('Incorrect data size, diff=%r' % (self.rlen,))
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self._writecrc()
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self.state = _DID_DATA
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def write_rsrc(self, data):
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if self.state < _DID_DATA:
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self.close_data()
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if self.state != _DID_DATA:
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raise Error('Writing resource data at the wrong time')
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self.rlen = self.rlen - len(data)
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self._write(data)
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def close(self):
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if self.state is None:
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return
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try:
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if self.state < _DID_DATA:
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self.close_data()
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if self.state != _DID_DATA:
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raise Error('Close at the wrong time')
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if self.rlen != 0:
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raise Error("Incorrect resource-datasize, diff=%r" % (self.rlen,))
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self._writecrc()
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finally:
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self.state = None
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ofp = self.ofp
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del self.ofp
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ofp.close()
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def binhex(inp, out):
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"""binhex(infilename, outfilename): create binhex-encoded copy of a file"""
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finfo = getfileinfo(inp)
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ofp = BinHex(finfo, out)
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with io.open(inp, 'rb') as ifp:
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# XXXX Do textfile translation on non-mac systems
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while True:
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d = ifp.read(128000)
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if not d: break
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ofp.write(d)
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ofp.close_data()
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ifp = openrsrc(inp, 'rb')
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while True:
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d = ifp.read(128000)
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if not d: break
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ofp.write_rsrc(d)
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ofp.close()
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ifp.close()
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class _Hqxdecoderengine:
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"""Read data via the decoder in 4-byte chunks"""
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def __init__(self, ifp):
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self.ifp = ifp
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self.eof = 0
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def read(self, totalwtd):
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"""Read at least wtd bytes (or until EOF)"""
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decdata = b''
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wtd = totalwtd
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#
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# The loop here is convoluted, since we don't really now how
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# much to decode: there may be newlines in the incoming data.
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while wtd > 0:
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if self.eof: return decdata
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wtd = ((wtd + 2) // 3) * 4
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data = self.ifp.read(wtd)
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#
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# Next problem: there may not be a complete number of
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# bytes in what we pass to a2b. Solve by yet another
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# loop.
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#
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while True:
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try:
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decdatacur, self.eof = binascii.a2b_hqx(data)
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break
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except binascii.Incomplete:
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pass
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newdata = self.ifp.read(1)
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if not newdata:
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raise Error('Premature EOF on binhex file')
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data = data + newdata
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decdata = decdata + decdatacur
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wtd = totalwtd - len(decdata)
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if not decdata and not self.eof:
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raise Error('Premature EOF on binhex file')
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return decdata
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def close(self):
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self.ifp.close()
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class _Rledecoderengine:
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"""Read data via the RLE-coder"""
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def __init__(self, ifp):
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self.ifp = ifp
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self.pre_buffer = b''
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self.post_buffer = b''
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self.eof = 0
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def read(self, wtd):
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if wtd > len(self.post_buffer):
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self._fill(wtd - len(self.post_buffer))
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rv = self.post_buffer[:wtd]
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self.post_buffer = self.post_buffer[wtd:]
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return rv
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def _fill(self, wtd):
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self.pre_buffer = self.pre_buffer + self.ifp.read(wtd + 4)
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if self.ifp.eof:
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self.post_buffer = self.post_buffer + \
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binascii.rledecode_hqx(self.pre_buffer)
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self.pre_buffer = b''
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return
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#
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# Obfuscated code ahead. We have to take care that we don't
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# end up with an orphaned RUNCHAR later on. So, we keep a couple
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# of bytes in the buffer, depending on what the end of
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# the buffer looks like:
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# '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)
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# '?\220' - Keep 2 bytes: repeated something-else
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# '\220\0' - Escaped \220: Keep 2 bytes.
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# '?\220?' - Complete repeat sequence: decode all
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# otherwise: keep 1 byte.
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#
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mark = len(self.pre_buffer)
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if self.pre_buffer[-3:] == RUNCHAR + b'\0' + RUNCHAR:
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mark = mark - 3
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elif self.pre_buffer[-1:] == RUNCHAR:
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mark = mark - 2
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elif self.pre_buffer[-2:] == RUNCHAR + b'\0':
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mark = mark - 2
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elif self.pre_buffer[-2:-1] == RUNCHAR:
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pass # Decode all
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else:
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mark = mark - 1
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self.post_buffer = self.post_buffer + \
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binascii.rledecode_hqx(self.pre_buffer[:mark])
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self.pre_buffer = self.pre_buffer[mark:]
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def close(self):
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self.ifp.close()
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class HexBin:
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def __init__(self, ifp):
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if isinstance(ifp, str):
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ifp = io.open(ifp, 'rb')
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#
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# Find initial colon.
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#
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while True:
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ch = ifp.read(1)
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if not ch:
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raise Error("No binhex data found")
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# Cater for \r\n terminated lines (which show up as \n\r, hence
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# all lines start with \r)
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if ch == b'\r':
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continue
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if ch == b':':
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break
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hqxifp = _Hqxdecoderengine(ifp)
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self.ifp = _Rledecoderengine(hqxifp)
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self.crc = 0
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self._readheader()
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def _read(self, len):
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data = self.ifp.read(len)
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self.crc = binascii.crc_hqx(data, self.crc)
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return data
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def _checkcrc(self):
|
||
|
|
filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff
|
||
|
|
#self.crc = binascii.crc_hqx('\0\0', self.crc)
|
||
|
|
# XXXX Is this needed??
|
||
|
|
self.crc = self.crc & 0xffff
|
||
|
|
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]
|
||
|
|
|
||
|
|
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
|
||
|
|
rv = b''
|
||
|
|
while len(rv) < n:
|
||
|
|
rv = rv + self._read(n-len(rv))
|
||
|
|
self.dlen = self.dlen - n
|
||
|
|
return rv
|
||
|
|
|
||
|
|
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.state is None:
|
||
|
|
return
|
||
|
|
try:
|
||
|
|
if self.rlen:
|
||
|
|
dummy = self.read_rsrc(self.rlen)
|
||
|
|
self._checkcrc()
|
||
|
|
finally:
|
||
|
|
self.state = None
|
||
|
|
self.ifp.close()
|
||
|
|
|
||
|
|
def hexbin(inp, out):
|
||
|
|
"""hexbin(infilename, outfilename) - Decode binhexed file"""
|
||
|
|
ifp = HexBin(inp)
|
||
|
|
finfo = ifp.FInfo
|
||
|
|
if not out:
|
||
|
|
out = ifp.FName
|
||
|
|
|
||
|
|
with io.open(out, 'wb') as ofp:
|
||
|
|
# XXXX Do translation on non-mac systems
|
||
|
|
while True:
|
||
|
|
d = ifp.read(128000)
|
||
|
|
if not d: break
|
||
|
|
ofp.write(d)
|
||
|
|
ifp.close_data()
|
||
|
|
|
||
|
|
d = ifp.read_rsrc(128000)
|
||
|
|
if d:
|
||
|
|
ofp = openrsrc(out, 'wb')
|
||
|
|
ofp.write(d)
|
||
|
|
while True:
|
||
|
|
d = ifp.read_rsrc(128000)
|
||
|
|
if not d: break
|
||
|
|
ofp.write(d)
|
||
|
|
ofp.close()
|
||
|
|
|
||
|
|
ifp.close()
|