← Back to branch summary

~bzr-pqm/bzr/bzr.dev

« back to all changes in this revision

Viewing changes to effbot/org/gzip_consumer.py

  • Committer: Martin Pool
  • Date: 2005-08-12 15:41:44 UTC
  • Revision ID: mbp@sourcefrog.net-20050812154144-bc98570a78b8f633
- merge in deferred revfile work

Show diffs side-by-side

added added

removed removed

Lines of Context:
effbot/org/gzip_consumer.py
 
1
# $Id: gzip_consumer.py 271 2004-10-09 10:50:59Z fredrik $
 
2
# gzip consumer
 
3
#
 
4
# Copyright (c) 2001-2004 by Fredrik Lundh.  All rights reserved.
 
5
#
 
6
 
 
7
##
 
8
# Consumer wrapper for GZIP streams.
 
9
 
 
10
class GzipConsumer:
 
11
 
 
12
    def __init__(self, consumer):
 
13
        self.__consumer = consumer
 
14
        self.__decoder = None
 
15
        self.__data = ""
 
16
 
 
17
    def __getattr__(self, key):
 
18
        return getattr(self.__consumer, key)
 
19
 
 
20
    def feed(self, data):
 
21
        if self.__decoder is None:
 
22
            # check if we have a full gzip header
 
23
            data = self.__data + data
 
24
            try:
 
25
                i = 10
 
26
                flag = ord(data[3])
 
27
                if flag & 4: # extra
 
28
                    x = ord(data[i]) + 256*ord(data[i+1])
 
29
                    i = i + 2 + x
 
30
                if flag & 8: # filename
 
31
                    while ord(data[i]):
 
32
                        i = i + 1
 
33
                    i = i + 1
 
34
                if flag & 16: # comment
 
35
                    while ord(data[i]):
 
36
                        i = i + 1
 
37
                    i = i + 1
 
38
                if flag & 2: # crc
 
39
                    i = i + 2
 
40
                if len(data) < i:
 
41
                    raise IndexError("not enough data")
 
42
                if data[:3] != "\x1f\x8b\x08":
 
43
                    raise IOError("invalid gzip data")
 
44
                data = data[i:]
 
45
            except IndexError:
 
46
                self.__data = data
 
47
                return # need more data
 
48
            import zlib
 
49
            self.__data = ""
 
50
            self.__decoder = zlib.decompressobj(-zlib.MAX_WBITS)
 
51
        data = self.__decoder.decompress(data)
 
52
        if data:
 
53
            self.__consumer.feed(data)
 
54
 
 
55
    def close(self):
 
56
        if self.__decoder:
 
57
            data = self.__decoder.flush()
 
58
            if data:
 
59
                self.__consumer.feed(data)
 
60
        self.__consumer.close()