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1#!/usr/bin/env python
2""" Python Character Mapping Codec for ROT13.
3
4    See http://ucsub.colorado.edu/~kominek/rot13/ for details.
5
6    Written by Marc-Andre Lemburg (mal@lemburg.com).
7
8"""#"
9
10import codecs
11
12### Codec APIs
13
14class Codec(codecs.Codec):
15
16    def encode(self,input,errors='strict'):
17        return codecs.charmap_encode(input,errors,encoding_map)
18
19    def decode(self,input,errors='strict'):
20        return codecs.charmap_decode(input,errors,decoding_map)
21
22class IncrementalEncoder(codecs.IncrementalEncoder):
23    def encode(self, input, final=False):
24        return codecs.charmap_encode(input,self.errors,encoding_map)[0]
25
26class IncrementalDecoder(codecs.IncrementalDecoder):
27    def decode(self, input, final=False):
28        return codecs.charmap_decode(input,self.errors,decoding_map)[0]
29
30class StreamWriter(Codec,codecs.StreamWriter):
31    pass
32
33class StreamReader(Codec,codecs.StreamReader):
34    pass
35
36### encodings module API
37
38def getregentry():
39    return codecs.CodecInfo(
40        name='rot-13',
41        encode=Codec().encode,
42        decode=Codec().decode,
43        incrementalencoder=IncrementalEncoder,
44        incrementaldecoder=IncrementalDecoder,
45        streamwriter=StreamWriter,
46        streamreader=StreamReader,
47        _is_text_encoding=False,
48    )
49
50### Decoding Map
51
52decoding_map = codecs.make_identity_dict(range(256))
53decoding_map.update({
54   0x0041: 0x004e,
55   0x0042: 0x004f,
56   0x0043: 0x0050,
57   0x0044: 0x0051,
58   0x0045: 0x0052,
59   0x0046: 0x0053,
60   0x0047: 0x0054,
61   0x0048: 0x0055,
62   0x0049: 0x0056,
63   0x004a: 0x0057,
64   0x004b: 0x0058,
65   0x004c: 0x0059,
66   0x004d: 0x005a,
67   0x004e: 0x0041,
68   0x004f: 0x0042,
69   0x0050: 0x0043,
70   0x0051: 0x0044,
71   0x0052: 0x0045,
72   0x0053: 0x0046,
73   0x0054: 0x0047,
74   0x0055: 0x0048,
75   0x0056: 0x0049,
76   0x0057: 0x004a,
77   0x0058: 0x004b,
78   0x0059: 0x004c,
79   0x005a: 0x004d,
80   0x0061: 0x006e,
81   0x0062: 0x006f,
82   0x0063: 0x0070,
83   0x0064: 0x0071,
84   0x0065: 0x0072,
85   0x0066: 0x0073,
86   0x0067: 0x0074,
87   0x0068: 0x0075,
88   0x0069: 0x0076,
89   0x006a: 0x0077,
90   0x006b: 0x0078,
91   0x006c: 0x0079,
92   0x006d: 0x007a,
93   0x006e: 0x0061,
94   0x006f: 0x0062,
95   0x0070: 0x0063,
96   0x0071: 0x0064,
97   0x0072: 0x0065,
98   0x0073: 0x0066,
99   0x0074: 0x0067,
100   0x0075: 0x0068,
101   0x0076: 0x0069,
102   0x0077: 0x006a,
103   0x0078: 0x006b,
104   0x0079: 0x006c,
105   0x007a: 0x006d,
106})
107
108### Encoding Map
109
110encoding_map = codecs.make_encoding_map(decoding_map)
111
112### Filter API
113
114def rot13(infile, outfile):
115    outfile.write(infile.read().encode('rot-13'))
116
117if __name__ == '__main__':
118    import sys
119    rot13(sys.stdin, sys.stdout)
120