| 4710c53d |
1 | """ Python 'zlib_codec' Codec - zlib compression encoding\r |
| 2 | \r |
| 3 | Unlike most of the other codecs which target Unicode, this codec\r |
| 4 | will return Python string objects for both encode and decode.\r |
| 5 | \r |
| 6 | Written by Marc-Andre Lemburg (mal@lemburg.com).\r |
| 7 | \r |
| 8 | """\r |
| 9 | import codecs\r |
| 10 | import zlib # this codec needs the optional zlib module !\r |
| 11 | \r |
| 12 | ### Codec APIs\r |
| 13 | \r |
| 14 | def zlib_encode(input,errors='strict'):\r |
| 15 | \r |
| 16 | """ Encodes the object input and returns a tuple (output\r |
| 17 | object, length consumed).\r |
| 18 | \r |
| 19 | errors defines the error handling to apply. It defaults to\r |
| 20 | 'strict' handling which is the only currently supported\r |
| 21 | error handling for this codec.\r |
| 22 | \r |
| 23 | """\r |
| 24 | assert errors == 'strict'\r |
| 25 | output = zlib.compress(input)\r |
| 26 | return (output, len(input))\r |
| 27 | \r |
| 28 | def zlib_decode(input,errors='strict'):\r |
| 29 | \r |
| 30 | """ Decodes the object input and returns a tuple (output\r |
| 31 | object, length consumed).\r |
| 32 | \r |
| 33 | input must be an object which provides the bf_getreadbuf\r |
| 34 | buffer slot. Python strings, buffer objects and memory\r |
| 35 | mapped files are examples of objects providing this slot.\r |
| 36 | \r |
| 37 | errors defines the error handling to apply. It defaults to\r |
| 38 | 'strict' handling which is the only currently supported\r |
| 39 | error handling for this codec.\r |
| 40 | \r |
| 41 | """\r |
| 42 | assert errors == 'strict'\r |
| 43 | output = zlib.decompress(input)\r |
| 44 | return (output, len(input))\r |
| 45 | \r |
| 46 | class Codec(codecs.Codec):\r |
| 47 | \r |
| 48 | def encode(self, input, errors='strict'):\r |
| 49 | return zlib_encode(input, errors)\r |
| 50 | def decode(self, input, errors='strict'):\r |
| 51 | return zlib_decode(input, errors)\r |
| 52 | \r |
| 53 | class IncrementalEncoder(codecs.IncrementalEncoder):\r |
| 54 | def __init__(self, errors='strict'):\r |
| 55 | assert errors == 'strict'\r |
| 56 | self.errors = errors\r |
| 57 | self.compressobj = zlib.compressobj()\r |
| 58 | \r |
| 59 | def encode(self, input, final=False):\r |
| 60 | if final:\r |
| 61 | c = self.compressobj.compress(input)\r |
| 62 | return c + self.compressobj.flush()\r |
| 63 | else:\r |
| 64 | return self.compressobj.compress(input)\r |
| 65 | \r |
| 66 | def reset(self):\r |
| 67 | self.compressobj = zlib.compressobj()\r |
| 68 | \r |
| 69 | class IncrementalDecoder(codecs.IncrementalDecoder):\r |
| 70 | def __init__(self, errors='strict'):\r |
| 71 | assert errors == 'strict'\r |
| 72 | self.errors = errors\r |
| 73 | self.decompressobj = zlib.decompressobj()\r |
| 74 | \r |
| 75 | def decode(self, input, final=False):\r |
| 76 | if final:\r |
| 77 | c = self.decompressobj.decompress(input)\r |
| 78 | return c + self.decompressobj.flush()\r |
| 79 | else:\r |
| 80 | return self.decompressobj.decompress(input)\r |
| 81 | \r |
| 82 | def reset(self):\r |
| 83 | self.decompressobj = zlib.decompressobj()\r |
| 84 | \r |
| 85 | class StreamWriter(Codec,codecs.StreamWriter):\r |
| 86 | pass\r |
| 87 | \r |
| 88 | class StreamReader(Codec,codecs.StreamReader):\r |
| 89 | pass\r |
| 90 | \r |
| 91 | ### encodings module API\r |
| 92 | \r |
| 93 | def getregentry():\r |
| 94 | return codecs.CodecInfo(\r |
| 95 | name='zlib',\r |
| 96 | encode=zlib_encode,\r |
| 97 | decode=zlib_decode,\r |
| 98 | incrementalencoder=IncrementalEncoder,\r |
| 99 | incrementaldecoder=IncrementalDecoder,\r |
| 100 | streamreader=StreamReader,\r |
| 101 | streamwriter=StreamWriter,\r |
| 102 | )\r |
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