Georg Brandl | 0252462 | 2010-12-02 18:06:51 +0000 | [diff] [blame] | 1 | """Python 'zlib_codec' Codec - zlib compression encoding. |
| 2 | |
R David Murray | e5cb836 | 2014-03-13 20:54:30 -0400 | [diff] [blame] | 3 | This codec de/encodes from bytes to bytes. |
Georg Brandl | 0252462 | 2010-12-02 18:06:51 +0000 | [diff] [blame] | 4 | |
| 5 | Written by Marc-Andre Lemburg (mal@lemburg.com). |
| 6 | """ |
| 7 | |
| 8 | import codecs |
| 9 | import zlib # this codec needs the optional zlib module ! |
| 10 | |
| 11 | ### Codec APIs |
| 12 | |
| 13 | def zlib_encode(input, errors='strict'): |
| 14 | assert errors == 'strict' |
| 15 | return (zlib.compress(input), len(input)) |
| 16 | |
| 17 | def zlib_decode(input, errors='strict'): |
| 18 | assert errors == 'strict' |
| 19 | return (zlib.decompress(input), len(input)) |
| 20 | |
| 21 | class Codec(codecs.Codec): |
| 22 | def encode(self, input, errors='strict'): |
| 23 | return zlib_encode(input, errors) |
| 24 | def decode(self, input, errors='strict'): |
| 25 | return zlib_decode(input, errors) |
| 26 | |
| 27 | class IncrementalEncoder(codecs.IncrementalEncoder): |
| 28 | def __init__(self, errors='strict'): |
| 29 | assert errors == 'strict' |
| 30 | self.errors = errors |
| 31 | self.compressobj = zlib.compressobj() |
| 32 | |
| 33 | def encode(self, input, final=False): |
| 34 | if final: |
| 35 | c = self.compressobj.compress(input) |
| 36 | return c + self.compressobj.flush() |
| 37 | else: |
| 38 | return self.compressobj.compress(input) |
| 39 | |
| 40 | def reset(self): |
| 41 | self.compressobj = zlib.compressobj() |
| 42 | |
| 43 | class IncrementalDecoder(codecs.IncrementalDecoder): |
| 44 | def __init__(self, errors='strict'): |
| 45 | assert errors == 'strict' |
| 46 | self.errors = errors |
| 47 | self.decompressobj = zlib.decompressobj() |
| 48 | |
| 49 | def decode(self, input, final=False): |
| 50 | if final: |
| 51 | c = self.decompressobj.decompress(input) |
| 52 | return c + self.decompressobj.flush() |
| 53 | else: |
| 54 | return self.decompressobj.decompress(input) |
| 55 | |
| 56 | def reset(self): |
| 57 | self.decompressobj = zlib.decompressobj() |
| 58 | |
| 59 | class StreamWriter(Codec, codecs.StreamWriter): |
| 60 | charbuffertype = bytes |
| 61 | |
| 62 | class StreamReader(Codec, codecs.StreamReader): |
| 63 | charbuffertype = bytes |
| 64 | |
| 65 | ### encodings module API |
| 66 | |
| 67 | def getregentry(): |
| 68 | return codecs.CodecInfo( |
| 69 | name='zlib', |
| 70 | encode=zlib_encode, |
| 71 | decode=zlib_decode, |
| 72 | incrementalencoder=IncrementalEncoder, |
| 73 | incrementaldecoder=IncrementalDecoder, |
| 74 | streamreader=StreamReader, |
| 75 | streamwriter=StreamWriter, |
Serhiy Storchaka | 94ee389 | 2014-02-24 14:43:03 +0200 | [diff] [blame] | 76 | _is_text_encoding=False, |
Georg Brandl | 0252462 | 2010-12-02 18:06:51 +0000 | [diff] [blame] | 77 | ) |