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Viewing changes to effbot/org/gzip_consumer.py

  • Committer: Martin Pool
  • Date: 2005-07-07 10:22:02 UTC
  • Revision ID: mbp@sourcefrog.net-20050707102201-2d2a13a25098b101
- rearrange and clear up merged weave

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effbot/org/gzip_consumer.py
 
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# $Id: gzip_consumer.py 271 2004-10-09 10:50:59Z fredrik $
 
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# gzip consumer
 
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#
 
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# Copyright (c) 2001-2004 by Fredrik Lundh.  All rights reserved.
 
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#
 
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##
 
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# Consumer wrapper for GZIP streams.
 
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class GzipConsumer:
 
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    def __init__(self, consumer):
 
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        self.__consumer = consumer
 
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        self.__decoder = None
 
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        self.__data = ""
 
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    def __getattr__(self, key):
 
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        return getattr(self.__consumer, key)
 
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    def feed(self, data):
 
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        if self.__decoder is None:
 
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            # check if we have a full gzip header
 
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            data = self.__data + data
 
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            try:
 
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                i = 10
 
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                flag = ord(data[3])
 
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                if flag & 4: # extra
 
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                    x = ord(data[i]) + 256*ord(data[i+1])
 
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                    i = i + 2 + x
 
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                if flag & 8: # filename
 
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                    while ord(data[i]):
 
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                        i = i + 1
 
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                    i = i + 1
 
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                if flag & 16: # comment
 
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                    while ord(data[i]):
 
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                        i = i + 1
 
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                    i = i + 1
 
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                if flag & 2: # crc
 
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                    i = i + 2
 
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                if len(data) < i:
 
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                    raise IndexError("not enough data")
 
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                if data[:3] != "\x1f\x8b\x08":
 
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                    raise IOError("invalid gzip data")
 
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                data = data[i:]
 
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            except IndexError:
 
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                self.__data = data
 
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                return # need more data
 
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            import zlib
 
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            self.__data = ""
 
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            self.__decoder = zlib.decompressobj(-zlib.MAX_WBITS)
 
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        data = self.__decoder.decompress(data)
 
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        if data:
 
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            self.__consumer.feed(data)
 
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    def close(self):
 
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        if self.__decoder:
 
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            data = self.__decoder.flush()
 
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            if data:
 
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                self.__consumer.feed(data)
 
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        self.__consumer.close()