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#!/usr/bin/env python
""" Python Character Mapping Codec for ROT13.
This codec de/encodes from str to str and is therefore usable with
str.transform() and str.untransform().
Written by Marc-Andre Lemburg (mal@lemburg.com).
"""
import codecs
### Codec APIs
class Codec(codecs.Codec):
def encode(self, input, errors='strict'):
return (input.translate(rot13_map), len(input))
def decode(self, input, errors='strict'):
return (input.translate(rot13_map), len(input))
class IncrementalEncoder(codecs.IncrementalEncoder):
def encode(self, input, final=False):
return input.translate(rot13_map)
class IncrementalDecoder(codecs.IncrementalDecoder):
def decode(self, input, final=False):
return input.translate(rot13_map)
class StreamWriter(Codec,codecs.StreamWriter):
pass
class StreamReader(Codec,codecs.StreamReader):
pass
### encodings module API
def getregentry():
return codecs.CodecInfo(
name='rot-13',
encode=Codec().encode,
decode=Codec().decode,
incrementalencoder=IncrementalEncoder,
incrementaldecoder=IncrementalDecoder,
streamwriter=StreamWriter,
streamreader=StreamReader,
)
### Map
rot13_map = codecs.make_identity_dict(range(256))
rot13_map.update({
0x0041: 0x004e,
0x0042: 0x004f,
0x0043: 0x0050,
0x0044: 0x0051,
0x0045: 0x0052,
0x0046: 0x0053,
0x0047: 0x0054,
0x0048: 0x0055,
0x0049: 0x0056,
0x004a: 0x0057,
0x004b: 0x0058,
0x004c: 0x0059,
0x004d: 0x005a,
0x004e: 0x0041,
0x004f: 0x0042,
0x0050: 0x0043,
0x0051: 0x0044,
0x0052: 0x0045,
0x0053: 0x0046,
0x0054: 0x0047,
0x0055: 0x0048,
0x0056: 0x0049,
0x0057: 0x004a,
0x0058: 0x004b,
0x0059: 0x004c,
0x005a: 0x004d,
0x0061: 0x006e,
0x0062: 0x006f,
0x0063: 0x0070,
0x0064: 0x0071,
0x0065: 0x0072,
0x0066: 0x0073,
0x0067: 0x0074,
0x0068: 0x0075,
0x0069: 0x0076,
0x006a: 0x0077,
0x006b: 0x0078,
0x006c: 0x0079,
0x006d: 0x007a,
0x006e: 0x0061,
0x006f: 0x0062,
0x0070: 0x0063,
0x0071: 0x0064,
0x0072: 0x0065,
0x0073: 0x0066,
0x0074: 0x0067,
0x0075: 0x0068,
0x0076: 0x0069,
0x0077: 0x006a,
0x0078: 0x006b,
0x0079: 0x006c,
0x007a: 0x006d,
})
### Filter API
def rot13(infile, outfile):
outfile.write(infile.read().encode('rot-13'))
if __name__ == '__main__':
import sys
rot13(sys.stdin, sys.stdout)
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