53 lines
1.8 KiB
Python
53 lines
1.8 KiB
Python
# A part of pdfrw (pdfrw.googlecode.com)
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# Copyright (C) 2006-2009 Patrick Maupin, Austin, Texas
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# MIT license -- See LICENSE.txt for details
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'''
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Currently, this sad little file only knows how to decompress
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using the flate (zlib) algorithm. Maybe more later, but it's
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not a priority for me...
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'''
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import zlib
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from pdfrw.objects import PdfDict, PdfName
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from pdfrw.errors import log
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def streamobjects(mylist, isinstance=isinstance, PdfDict=PdfDict):
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for obj in mylist:
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if isinstance(obj, PdfDict) and obj.stream is not None:
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yield obj
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def uncompress(mylist, warnings=set(), flate = PdfName.FlateDecode,
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decompress=zlib.decompressobj, isinstance=isinstance, list=list, len=len):
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ok = True
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for obj in streamobjects(mylist):
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ftype = obj.Filter
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if ftype is None:
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continue
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if isinstance(ftype, list) and len(ftype) == 1:
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# todo: multiple filters
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ftype = ftype[0]
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parms = obj.DecodeParms
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if ftype != flate or parms is not None:
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msg = 'Not decompressing: cannot use filter %s with parameters %s' % (repr(ftype), repr(parms))
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if msg not in warnings:
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warnings.add(msg)
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log.warning(msg)
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ok = False
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else:
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dco = decompress()
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error = None
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try:
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data = dco.decompress(obj.stream)
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except Exception, s:
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error = str(s)
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if error is None:
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assert not dco.unconsumed_tail
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if dco.unused_data.strip():
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error = 'Unconsumed compression data: %s' % repr(dco.unused_data[:20])
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if error is None:
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obj.Filter = None
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obj.stream = data
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else:
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log.error('%s %s' % (error, repr(obj.indirect)))
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return ok
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