| 1 | r"""Routines to decode AppleSingle files
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| 2 | """
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| 3 | import struct
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| 4 | import sys
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| 5 | try:
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| 6 | import MacOS
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| 7 | import Carbon.File
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| 8 | except:
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| 9 | class MacOS:
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| 10 | def openrf(path, mode):
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| 11 | return open(path + '.rsrc', mode)
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| 12 | openrf = classmethod(openrf)
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| 13 | class Carbon:
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| 14 | class File:
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| 15 | class FSSpec:
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| 16 | pass
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| 17 | class FSRef:
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| 18 | pass
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| 19 | class Alias:
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| 20 | pass
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| 21 |
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| 22 | # all of the errors in this module are really errors in the input
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| 23 | # so I think it should test positive against ValueError.
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| 24 | class Error(ValueError):
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| 25 | pass
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| 26 |
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| 27 | # File header format: magic, version, unused, number of entries
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| 28 | AS_HEADER_FORMAT=">LL16sh"
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| 29 | AS_HEADER_LENGTH=26
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| 30 | # The flag words for AppleSingle
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| 31 | AS_MAGIC=0x00051600
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| 32 | AS_VERSION=0x00020000
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| 33 |
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| 34 | # Entry header format: id, offset, length
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| 35 | AS_ENTRY_FORMAT=">lll"
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| 36 | AS_ENTRY_LENGTH=12
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| 37 |
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| 38 | # The id values
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| 39 | AS_DATAFORK=1
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| 40 | AS_RESOURCEFORK=2
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| 41 | AS_IGNORE=(3,4,5,6,8,9,10,11,12,13,14,15)
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| 42 |
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| 43 | class AppleSingle(object):
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| 44 | datafork = None
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| 45 | resourcefork = None
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| 46 |
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| 47 | def __init__(self, fileobj, verbose=False):
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| 48 | header = fileobj.read(AS_HEADER_LENGTH)
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| 49 | try:
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| 50 | magic, version, ig, nentry = struct.unpack(AS_HEADER_FORMAT, header)
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| 51 | except ValueError, arg:
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| 52 | raise Error, "Unpack header error: %s" % (arg,)
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| 53 | if verbose:
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| 54 | print 'Magic: 0x%8.8x' % (magic,)
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| 55 | print 'Version: 0x%8.8x' % (version,)
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| 56 | print 'Entries: %d' % (nentry,)
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| 57 | if magic != AS_MAGIC:
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| 58 | raise Error, "Unknown AppleSingle magic number 0x%8.8x" % (magic,)
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| 59 | if version != AS_VERSION:
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| 60 | raise Error, "Unknown AppleSingle version number 0x%8.8x" % (version,)
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| 61 | if nentry <= 0:
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| 62 | raise Error, "AppleSingle file contains no forks"
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| 63 | headers = [fileobj.read(AS_ENTRY_LENGTH) for i in xrange(nentry)]
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| 64 | self.forks = []
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| 65 | for hdr in headers:
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| 66 | try:
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| 67 | restype, offset, length = struct.unpack(AS_ENTRY_FORMAT, hdr)
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| 68 | except ValueError, arg:
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| 69 | raise Error, "Unpack entry error: %s" % (arg,)
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| 70 | if verbose:
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| 71 | print "Fork %d, offset %d, length %d" % (restype, offset, length)
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| 72 | fileobj.seek(offset)
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| 73 | data = fileobj.read(length)
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| 74 | if len(data) != length:
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| 75 | raise Error, "Short read: expected %d bytes got %d" % (length, len(data))
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| 76 | self.forks.append((restype, data))
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| 77 | if restype == AS_DATAFORK:
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| 78 | self.datafork = data
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| 79 | elif restype == AS_RESOURCEFORK:
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| 80 | self.resourcefork = data
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| 81 |
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| 82 | def tofile(self, path, resonly=False):
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| 83 | outfile = open(path, 'wb')
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| 84 | data = False
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| 85 | if resonly:
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| 86 | if self.resourcefork is None:
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| 87 | raise Error, "No resource fork found"
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| 88 | fp = open(path, 'wb')
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| 89 | fp.write(self.resourcefork)
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| 90 | fp.close()
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| 91 | elif (self.resourcefork is None and self.datafork is None):
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| 92 | raise Error, "No useful forks found"
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| 93 | else:
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| 94 | if self.datafork is not None:
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| 95 | fp = open(path, 'wb')
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| 96 | fp.write(self.datafork)
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| 97 | fp.close()
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| 98 | if self.resourcefork is not None:
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| 99 | fp = MacOS.openrf(path, '*wb')
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| 100 | fp.write(self.resourcefork)
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| 101 | fp.close()
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| 102 |
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| 103 | def decode(infile, outpath, resonly=False, verbose=False):
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| 104 | """decode(infile, outpath [, resonly=False, verbose=False])
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| 105 |
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| 106 | Creates a decoded file from an AppleSingle encoded file.
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| 107 | If resonly is True, then it will create a regular file at
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| 108 | outpath containing only the resource fork from infile.
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| 109 | Otherwise it will create an AppleDouble file at outpath
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| 110 | with the data and resource forks from infile. On platforms
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| 111 | without the MacOS module, it will create inpath and inpath+'.rsrc'
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| 112 | with the data and resource forks respectively.
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| 113 |
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| 114 | """
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| 115 | if not hasattr(infile, 'read'):
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| 116 | if isinstance(infile, Carbon.File.Alias):
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| 117 | infile = infile.ResolveAlias()[0]
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| 118 | if isinstance(infile, (Carbon.File.FSSpec, Carbon.File.FSRef)):
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| 119 | infile = infile.as_pathname()
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| 120 | infile = open(infile, 'rb')
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| 121 |
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| 122 | asfile = AppleSingle(infile, verbose=verbose)
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| 123 | asfile.tofile(outpath, resonly=resonly)
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| 124 |
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| 125 | def _test():
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| 126 | if len(sys.argv) < 3 or sys.argv[1] == '-r' and len(sys.argv) != 4:
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| 127 | print 'Usage: applesingle.py [-r] applesinglefile decodedfile'
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| 128 | sys.exit(1)
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| 129 | if sys.argv[1] == '-r':
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| 130 | resonly = True
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| 131 | del sys.argv[1]
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| 132 | else:
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| 133 | resonly = False
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| 134 | decode(sys.argv[1], sys.argv[2], resonly=resonly)
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| 135 |
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| 136 | if __name__ == '__main__':
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| 137 | _test()
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