ENCODING.txt

LOG FILES
---------
Lines contain up to 80 characters. Lines starting with a hash character ('#')
are comments or metadata and should be ignored. Other lines contain
space-separated moves in standard format, in the order they are played.

STATE DESCRIPTION
-----------------
A state is described as a sequence of 50 digits in base 62, which are encoded
with characters from the following 62-character sequence:
    ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
(This is a standard Base64 encoding without the two non-standard characters.)

Digit 0 is encoded as 2*game_phase + next_player, where:
  game_phase = 0 when placing pieces, 1 when stacking pieces, 2 when finished.
  next_player = 0 for white, 1 for black.

Digit 1 through 49 describe the fields of the board in row-major order, one
digit per field, with each field encoded as:
  0 if it is empty;
  1 if it contains just a Dvonn piece;
  n otherwise, where n = 4*pieces + 2*dvonn + player - 2, where:
    player: 0 for white or 1 for black;
    dvonn: 0 if the stack contains no Dvonn piece, 1 otherwise;
    pieces = the number of pieces in the stack.

Note that `dvonn' is 1 even if the stack contains more than one Dvonn piece and
`pieces' is the total number of pieces in the stack (including white, black and
Dvonn pieces). This encoding limits stacks to a maximum height of 15, which is
insufficient for all possible states, but states with very high stacks occur
rarely in practice.