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https://github.com/cedricbonhomme/Stegano.git
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130 lines
No EOL
3.1 KiB
Python
130 lines
No EOL
3.1 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# Stéganô - Stéganô is a basic Python Steganography module.
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# Copyright (C) 2010-2011 Cédric Bonhomme - http://cedricbonhomme.org/
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#
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# For more information : http://bitbucket.org/cedricbonhomme/stegano/
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>
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__author__ = "Cedric Bonhomme"
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__version__ = "$Revision: 0.1 $"
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__date__ = "$Date: 2011/12/28 $"
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__license__ = "GPLv3"
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import itertools
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def identity():
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"""
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f(x) = x
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"""
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n = 0
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while True:
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yield n
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n += 1
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def fermat():
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"""
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Generate the n-th Fermat Number.
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"""
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n = 0
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while True:
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n += 1
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yield pow(2, pow(2, n)) + 1
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def mersenne():
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"""
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Generate 2^n-1.
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"""
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n = 0
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while True:
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n += 1
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yield pow(2, n) - 1
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def eratosthenes():
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"""
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Generate the prime numbers with the sieve of Eratosthenes.
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"""
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d = {}
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for i in itertools.count(2):
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if i in d:
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for j in d[i]:
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d[i + j] = d.get(i + j, []) + [j]
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del d[i]
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else:
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d[i * i] = [i]
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yield i
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def eratosthenes_composite():
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"""
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Generate the composite numbers with the sieve of Eratosthenes.
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"""
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p1 = 3
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for p2 in eratosthenes():
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for n in range(p1 + 1, p2):
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yield n
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p1 = p2
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def carmichael():
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for m in eratosthenes_composite():
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for a in range(2, m):
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if pow(a,m,m) != a:
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break
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else:
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yield m
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def ackermann(m, n):
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"""
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Ackermann number.
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"""
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if m == 0:
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return n + 1
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elif n == 0:
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return ackermann(m - 1, 1)
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else:
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return ackermann(m - 1, ackermann(m, n - 1))
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def fibonacci():
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"""
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A generator for Fibonacci numbers, goes to next number in series on each call.
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This generator start at 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, ...
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See: http://oeis.org/A000045
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"""
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a, b = 1, 2
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while True:
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yield a
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a, b = b, a + b
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def syracuse(l=15):
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n = 0
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while True:
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yield syracuse_gen(n, l)
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n += 1
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def syracuse_gen(n, l=15):
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if n == 0:
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return l
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if syracuse_gen(n-1) % 2 == 0:
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return syracuse_gen(n-1)/2
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elif syracuse_gen(n-1) % 2 == 1:
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return 3*syracuse_gen(n-1)+1
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if __name__ == "__main__":
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# Point of entry in execution mode.
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f = fibonacci()
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for x in range(13):
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print f.next(), # 0 1 1 2 3 5 8 13 21 34 55 89 144 |