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annotate docs/keylist.rst @ 64:72e0bda6df40

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Split key list docs into own source file.
author Brian Neal <bgneal@gmail.com>
date Sat, 20 Jul 2013 13:26:25 -0500
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children 256b3f3e35e9
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bgneal@64 1 Key lists
bgneal@64 2 ---------
bgneal@64 3
bgneal@64 4 Key lists are represented as a named tuple called ``KeyList``.
bgneal@64 5
bgneal@64 6 .. class:: m209.keylist.KeyList(indicator, lugs, pin_list, letter_check)
bgneal@64 7
bgneal@64 8 As a named tuple, ``KeyList`` has the following attributes:
bgneal@64 9
bgneal@64 10 * ``indicator`` - the string name for the ``KeyList``; must be 2 letters in
bgneal@64 11 the range ``AA`` - ``ZZ``
bgneal@64 12 * ``lugs`` - a string representing the drum lug settings; see below
bgneal@64 13 * ``pin_list`` - a list of six strings which represent key wheel pin
bgneal@64 14 settings; see below
bgneal@64 15 * ``letter_check`` - a string representing the letter check used to verify
bgneal@64 16 operator settings; if unknown this can be ``None`` or an empty string
bgneal@64 17
bgneal@64 18 Lug settings format
bgneal@64 19 ~~~~~~~~~~~~~~~~~~~
bgneal@64 20
bgneal@64 21 Drum lug settings are often conveniently represented as strings consisting of
bgneal@64 22 at most 27 whitespace-separated pairs of integers separated by dashes. For
bgneal@64 23 example::
bgneal@64 24
bgneal@64 25 lugs = '1-0 2-0 2-0 0-3 0-5 0-5 0-5 0-6 2-4 3-6'
bgneal@64 26
bgneal@64 27 Each integer pair must be in the form ``m-n`` where m & n are integers
bgneal@64 28 between 0 and 6, inclusive. Each integer represents a lug position where
bgneal@64 29 0 is a neutral position, and 1-6 correspond to key wheel positions. If
bgneal@64 30 m & n are both non-zero, they cannot be equal.
bgneal@64 31
bgneal@64 32 If a string has less than 27 pairs, it is assumed all remaining bars have both
bgneal@64 33 lugs in the neutral (0) positions.
bgneal@64 34
bgneal@64 35 Order of the pairs within the string does not matter.
bgneal@64 36
bgneal@64 37 To reduce typing and to aid in readability, an alternate shortcut notation is
bgneal@64 38 supported::
bgneal@64 39
bgneal@64 40 lugs = '1-0 2-0*2 0-3 0-5*3 0-6 2-4 3-6'
bgneal@64 41
bgneal@64 42 Any pair that is suffixed by ``*k``, where k is a positive integer, means there
bgneal@64 43 are ``k`` copies of the preceeding lug pair combination. For example, these two
bgneal@64 44 strings describe identical drum configurations::
bgneal@64 45
bgneal@64 46 lugs1 = '2-4 2-4 2-4 0-1 0-1'
bgneal@64 47 lugs2 = '2-4*3 0-1*2'
bgneal@64 48
bgneal@64 49 Key wheel pin settings
bgneal@64 50 ~~~~~~~~~~~~~~~~~~~~~~
bgneal@64 51
bgneal@64 52 Key wheel pin settings are represented as iterables of letters whose pins are
bgneal@64 53 slid to the "effective" position (to the right). Letters not appearing in this
bgneal@64 54 sequence are considered to be in the "ineffective" position (to the left). If
bgneal@64 55 None or empty, all pins are set to be ineffective.
bgneal@64 56
bgneal@64 57 Examples::
bgneal@64 58
bgneal@64 59 all_ineffective = ''
bgneal@64 60 wheel1 = 'ABDEFHIJMQSUXZ'
bgneal@64 61 wheel2 = 'EINPQRTVXZ'
bgneal@64 62 wheel3 = 'DEFGIKNOSUX'
bgneal@64 63 wheel4 = 'BFGJKRS'
bgneal@64 64 wheel5 = 'ABCDFGHIJMPS'
bgneal@64 65 wheel6 = 'ADEFHIJKN'
bgneal@64 66
bgneal@64 67 Key list example
bgneal@64 68 ~~~~~~~~~~~~~~~~
bgneal@64 69
bgneal@64 70 An example of using the :class:`~m209.keylist.KeyList` is:
bgneal@64 71
bgneal@64 72 .. code-block:: python
bgneal@64 73
bgneal@64 74 from m209.keylist import KeyList
bgneal@64 75
bgneal@64 76 key_list1 = KeyList(
bgneal@64 77 indicator='AA',
bgneal@64 78 lugs='0-4 0-5*4 0-6*6 1-0*5 1-2 1-5*4 3-0*3 3-4 3-6 5-6',
bgneal@64 79 pin_list=[
bgneal@64 80 'FGIKOPRSUVWYZ',
bgneal@64 81 'DFGKLMOTUY',
bgneal@64 82 'ADEFGIORTUVX',
bgneal@64 83 'ACFGHILMRSU',
bgneal@64 84 'BCDEFJKLPS',
bgneal@64 85 'EFGHIJLMNP'
bgneal@64 86 ],
bgneal@64 87 letter_check='QLRRN TPTFU TRPTN MWQTV JLIJE J')
bgneal@64 88
bgneal@64 89 Key list file I/O
bgneal@64 90 ~~~~~~~~~~~~~~~~~
bgneal@64 91
bgneal@64 92 Key lists can be stored in files in config file ("INI") style format using
bgneal@64 93 functions found in the ``m209.keylist.config`` module.
bgneal@64 94
bgneal@64 95 .. function:: m209.keylist.config.read_key_list(fname[, indicator=None])
bgneal@64 96
bgneal@64 97 Reads key list information from the file given by ``fname``.
bgneal@64 98
bgneal@64 99 Searches the config file for the key list with the given indicator. If
bgneal@64 100 found, returns a :class:`~m209.keylist.KeyList` object. Returns ``None`` if
bgneal@64 101 not found.
bgneal@64 102
bgneal@64 103 If ``indicator`` is ``None``, a key list is chosen from the file at random.
bgneal@64 104
bgneal@64 105 .. function:: m209.keylist.config.write(fname, key_lists)
bgneal@64 106
bgneal@64 107 Writes the key lists to the file named ``fname`` in config file format.
bgneal@64 108
bgneal@64 109 ``key_lists`` must be an iterable of :class:`~m209.keylist.KeyList` objects.
bgneal@64 110
bgneal@64 111 Key list file format
bgneal@64 112 ++++++++++++++++++++
bgneal@64 113
bgneal@64 114 An example key list file in config file format is presented below. The label
bgneal@64 115 for each section of the file is the key list indicator.
bgneal@64 116
bgneal@64 117 ::
bgneal@64 118
bgneal@64 119 [CA]
bgneal@64 120 lugs = 0-5*5 0-6*2 1-0*7 1-2 1-3*3 1-6 2-0 3-0*3 3-5*2 3-6 4-5
bgneal@64 121 wheel1 = ABCDFGHJLOPRVWYZ
bgneal@64 122 wheel2 = BCDEIJKPQSUVX
bgneal@64 123 wheel3 = ACDGLNQRSTUV
bgneal@64 124 wheel4 = FGHIJNQRSU
bgneal@64 125 wheel5 = DEIJOQS
bgneal@64 126 wheel6 = BCDEILMNOP
bgneal@64 127 check = RGPRO RTYOO TWYSN GXTPF PNWIH P
bgneal@64 128
bgneal@64 129 [CD]
bgneal@64 130 lugs = 0-4*4 0-5 1-0*7 1-2*2 1-4*3 2-0*2 2-4*2 2-6*2 3-0*4
bgneal@64 131 wheel1 = AEFHIKMPQRSUVZ
bgneal@64 132 wheel2 = ABFGHINORSUVZ
bgneal@64 133 wheel3 = BDEHJKLMNOQRSU
bgneal@64 134 wheel4 = CDEFGHJKMRU
bgneal@64 135 wheel5 = FGHIJOQS
bgneal@64 136 wheel6 = EGIJKLP
bgneal@64 137 check = ZRLWL YRMIZ RZOPN UWMVZ DVGPM H
bgneal@64 138
bgneal@64 139 Generating key lists
bgneal@64 140 ~~~~~~~~~~~~~~~~~~~~
bgneal@64 141
bgneal@64 142 The ``m209`` library contains a function to pseudo-randomly generate a key list
bgneal@64 143 that is based on the procedure described in the 1944 M-209 manual.
bgneal@64 144
bgneal@64 145 .. function:: m209.keylist.generate.generate_key_list(indicator[, lug_selection=None, max_lug_attempts=MAX_LUG_ATTEMPTS, max_pin_attempts=MAX_PIN_ATTEMPTS])
bgneal@64 146
bgneal@64 147 The only required parameter is ``indicator``, the two-letter indicator for
bgneal@64 148 the key list.
bgneal@64 149
bgneal@64 150 If successful, a :class:`~m209.keylist.KeyList` object is returned.
bgneal@64 151
bgneal@64 152 If a :class:`~m209.keylist.KeyList` could not be generated
bgneal@64 153 a ``KeyListGenError`` exception is raised.
bgneal@64 154
bgneal@64 155 The algorithm is heuristic-based and makes random decisions based upon the
bgneal@64 156 1944 procedure. The actual procedure is loosely specified in the manual, and
bgneal@64 157 much is left up to the human operator. It is possible that the algorithm
bgneal@64 158 cannot find a solution to meet the key list requirements specified in the
bgneal@64 159 manual, in which case it simply tries again up to some set of limits. These
bgneal@64 160 limits can be tweaked using the optional parameters to the algorithm. If no
bgneal@64 161 solution is found after exhausting the limits, a ``KeyListGenError`` is
bgneal@64 162 raised.
bgneal@64 163
bgneal@64 164 The optional parameters are:
bgneal@64 165
bgneal@64 166 * ``lug_selection`` - a list of 6 integers used to drive the lug settings
bgneal@64 167 portion of the algorithm. If not supplied, a list of 6 integers is chosen
bgneal@64 168 from data tables that appear in the 1944 manual. For more information on
bgneal@64 169 the requirements for these integers, see the manual.
bgneal@64 170
bgneal@64 171 * ``max_lug_attempts`` - the maximum number of times to attempt to create
bgneal@64 172 lug settings before giving up
bgneal@64 173
bgneal@64 174 * ``max_pin_attempts`` - the maximum number of times to attempt to generate
bgneal@64 175 key wheel pin settings before giving up
bgneal@64 176