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920dae64 AT |
1 | """ Python 'zlib_codec' Codec - zlib compression encoding |
2 | ||
3 | Unlike most of the other codecs which target Unicode, this codec | |
4 | will return Python string objects for both encode and decode. | |
5 | ||
6 | Written by Marc-Andre Lemburg (mal@lemburg.com). | |
7 | ||
8 | """ | |
9 | import codecs | |
10 | import zlib # this codec needs the optional zlib module ! | |
11 | ||
12 | ### Codec APIs | |
13 | ||
14 | def zlib_encode(input,errors='strict'): | |
15 | ||
16 | """ Encodes the object input and returns a tuple (output | |
17 | object, length consumed). | |
18 | ||
19 | errors defines the error handling to apply. It defaults to | |
20 | 'strict' handling which is the only currently supported | |
21 | error handling for this codec. | |
22 | ||
23 | """ | |
24 | assert errors == 'strict' | |
25 | output = zlib.compress(input) | |
26 | return (output, len(input)) | |
27 | ||
28 | def zlib_decode(input,errors='strict'): | |
29 | ||
30 | """ Decodes the object input and returns a tuple (output | |
31 | object, length consumed). | |
32 | ||
33 | input must be an object which provides the bf_getreadbuf | |
34 | buffer slot. Python strings, buffer objects and memory | |
35 | mapped files are examples of objects providing this slot. | |
36 | ||
37 | errors defines the error handling to apply. It defaults to | |
38 | 'strict' handling which is the only currently supported | |
39 | error handling for this codec. | |
40 | ||
41 | """ | |
42 | assert errors == 'strict' | |
43 | output = zlib.decompress(input) | |
44 | return (output, len(input)) | |
45 | ||
46 | class Codec(codecs.Codec): | |
47 | ||
48 | def encode(self, input, errors='strict'): | |
49 | return zlib_encode(input, errors) | |
50 | def decode(self, input, errors='strict'): | |
51 | return zlib_decode(input, errors) | |
52 | ||
53 | class StreamWriter(Codec,codecs.StreamWriter): | |
54 | pass | |
55 | ||
56 | class StreamReader(Codec,codecs.StreamReader): | |
57 | pass | |
58 | ||
59 | ### encodings module API | |
60 | ||
61 | def getregentry(): | |
62 | ||
63 | return (zlib_encode,zlib_decode,StreamReader,StreamWriter) |