X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipher.py;h=c5d542bb915b4cfd0775d5c100e8dce46a271d88;hb=afd131a6e6bc7468bbd15d962468b675754b18b2;hp=d2619029de591af1d07e5f85160e187629332751;hpb=c03fdcbe5891f43ce328f33121105a71c01eef86;p=cipher-tools.git

diff --git a/cipher.py b/cipher.py
index d261902..c5d542b 100644
--- a/cipher.py
+++ b/cipher.py
@@ -1,6 +1,7 @@
 import string
 import collections
 import logging
+import math
 from itertools import zip_longest, cycle, chain
 from language_models import *
 
@@ -18,18 +19,6 @@ for a in range(26):
         modular_division_table[b][c] = a
 
 
-def ngrams(text, n):
-    """Returns all n-grams of a text
-    
-    >>> ngrams(sanitise('the quick brown fox'), 2) # doctest: +NORMALIZE_WHITESPACE
-    ['th', 'he', 'eq', 'qu', 'ui', 'ic', 'ck', 'kb', 'br', 'ro', 'ow', 'wn', 
-     'nf', 'fo', 'ox']
-    >>> ngrams(sanitise('the quick brown fox'), 4) # doctest: +NORMALIZE_WHITESPACE
-    ['theq', 'hequ', 'equi', 'quic', 'uick', 'ickb', 'ckbr', 'kbro', 'brow', 
-     'rown', 'ownf', 'wnfo', 'nfox']
-    """
-    return [text[i:i+n] for i in range(len(text)-n+1)]
-
 def every_nth(text, n, fillvalue=''):
     """Returns n strings, each of which consists of every nth character, 
     starting with the 0th, 1st, 2nd, ... (n-1)th character
@@ -324,46 +313,29 @@ def keyword_decipher(message, keyword, wrap_alphabet=0):
     cipher_translation = ''.maketrans(cipher_alphabet, string.ascii_lowercase)
     return message.lower().translate(cipher_translation)
 
-def scytale_encipher(message, rows):
-    """Enciphers using the scytale transposition cipher.
-    Message is padded with spaces to allow all rows to be the same length.
 
-    >>> scytale_encipher('thequickbrownfox', 3)
-    'tcnhkfeboqrxuo iw '
-    >>> scytale_encipher('thequickbrownfox', 4)
-    'tubnhirfecooqkwx'
-    >>> scytale_encipher('thequickbrownfox', 5)
-    'tubn hirf ecoo qkwx '
-    >>> scytale_encipher('thequickbrownfox', 6)
-    'tqcrnxhukof eibwo '
-    >>> scytale_encipher('thequickbrownfox', 7)
-    'tqcrnx hukof  eibwo  '
+def vigenere_encipher(message, keyword):
+    """Vigenere encipher
+
+    >>> vigenere_encipher('hello', 'abc')
+    'hfnlp'
     """
-    if len(message) % rows != 0:
-        message += ' '*(rows - len(message) % rows)
-    row_length = round(len(message) / rows)
-    slices = [message[i:i+row_length] 
-              for i in range(0, len(message), row_length)]
-    return ''.join([''.join(r) for r in zip_longest(*slices, fillvalue='')])
+    shifts = [ord(l) - ord('a') for l in sanitise(keyword)]
+    pairs = zip(message, cycle(shifts))
+    return ''.join([caesar_encipher_letter(l, k) for l, k in pairs])
 
-def scytale_decipher(message, rows):
-    """Deciphers using the scytale transposition cipher.
-    Assumes the message is padded so that all rows are the same length.
-    
-    >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3)
-    'thequickbrownfox  '
-    >>> scytale_decipher('tubnhirfecooqkwx', 4)
-    'thequickbrownfox'
-    >>> scytale_decipher('tubn hirf ecoo qkwx ', 5)
-    'thequickbrownfox    '
-    >>> scytale_decipher('tqcrnxhukof eibwo ', 6)
-    'thequickbrownfox  '
-    >>> scytale_decipher('tqcrnx hukof  eibwo  ', 7)
-    'thequickbrownfox     '
+def vigenere_decipher(message, keyword):
+    """Vigenere decipher
+
+    >>> vigenere_decipher('hfnlp', 'abc')
+    'hello'
     """
-    cols = round(len(message) / rows)
-    columns = [message[i:i+rows] for i in range(0, cols * rows, rows)]
-    return ''.join([''.join(c) for c in zip_longest(*columns, fillvalue='')])
+    shifts = [ord(l) - ord('a') for l in sanitise(keyword)]
+    pairs = zip(message, cycle(shifts))
+    return ''.join([caesar_decipher_letter(l, k) for l, k in pairs])
+
+beaufort_encipher=vigenere_decipher
+beaufort_decipher=vigenere_encipher
 
 
 def transpositions_of(keyword):
@@ -471,13 +443,6 @@ def column_transposition_decipher(message, keyword, fillvalue=' ',
     >>> column_transposition_decipher('hleolteher', 'clever', fillcolumnwise=False, emptycolumnwise=False)
     'hellothere'
     """
-    # >>> column_transposition_decipher('hleolteher', 'clever')
-    # 'hellothere'
-    # >>> column_transposition_decipher('hleolthre!e!', 'cleverly', fillvalue='?')
-    # 'hellothere!!'
-    # >>> column_transposition_decipher('htleehoelr', 'clever', columnwise=True)
-    # 'hellothere'
-    # """
     transpositions = transpositions_of(keyword)
     message += pad(len(message), len(transpositions), '*')
     if emptycolumnwise:
@@ -490,29 +455,43 @@ def column_transposition_decipher(message, keyword, fillvalue=' ',
     else:
         return ''.join(chain(*untransposed))
 
+def scytale_encipher(message, rows, fillvalue=' '):
+    """Enciphers using the scytale transposition cipher.
+    Message is padded with spaces to allow all rows to be the same length.
 
-def vigenere_encipher(message, keyword):
-    """Vigenere encipher
-
-    >>> vigenere_encipher('hello', 'abc')
-    'hfnlp'
+    >>> scytale_encipher('thequickbrownfox', 3)
+    'tcnhkfeboqrxuo iw '
+    >>> scytale_encipher('thequickbrownfox', 4)
+    'tubnhirfecooqkwx'
+    >>> scytale_encipher('thequickbrownfox', 5)
+    'tubnhirfecooqkwx'
+    >>> scytale_encipher('thequickbrownfox', 6)
+    'tqcrnxhukof eibwo '
+    >>> scytale_encipher('thequickbrownfox', 7)
+    'tqcrnxhukof eibwo '
     """
-    shifts = [ord(l) - ord('a') for l in sanitise(keyword)]
-    pairs = zip(message, cycle(shifts))
-    return ''.join([caesar_encipher_letter(l, k) for l, k in pairs])
-
-def vigenere_decipher(message, keyword):
-    """Vigenere decipher
+    transpositions = [i for i in range(math.ceil(len(message) / rows))]
+    return column_transposition_encipher(message, transpositions, 
+        fillcolumnwise=False, emptycolumnwise=True)
 
-    >>> vigenere_decipher('hfnlp', 'abc')
-    'hello'
+def scytale_decipher(message, rows):
+    """Deciphers using the scytale transposition cipher.
+    Assumes the message is padded so that all rows are the same length.
+    
+    >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3)
+    'thequickbrownfox  '
+    >>> scytale_decipher('tubnhirfecooqkwx', 4)
+    'thequickbrownfox'
+    >>> scytale_decipher('tubnhirfecooqkwx', 5)
+    'thequickbrownfox'
+    >>> scytale_decipher('tqcrnxhukof eibwo ', 6)
+    'thequickbrownfox  '
+    >>> scytale_decipher('tqcrnxhukof eibwo ', 7)
+    'thequickbrownfox  '
     """
-    shifts = [ord(l) - ord('a') for l in sanitise(keyword)]
-    pairs = zip(message, cycle(shifts))
-    return ''.join([caesar_decipher_letter(l, k) for l, k in pairs])
-
-beaufort_encipher=vigenere_decipher
-beaufort_decipher=vigenere_encipher
+    transpositions = [i for i in range(math.ceil(len(message) / rows))]
+    return column_transposition_decipher(message, transpositions, 
+        fillcolumnwise=False, emptycolumnwise=True)
 
 
 if __name__ == "__main__":