abk_base.lua

-- Lua (www.lua.org) chess opening reader
-- for Arena standard
-- http://chessforeva.blogspot.com
-- original algorithm source: http://www.talkchess.com/forum/viewtopic.php?t=20661&postdays=0&postorder=asc&topic_view=flat&start=20


-- this loads and executes other .lua file
function dofile (filename)
  local f = assert(loadfile(filename))
  return f()
end
dofile( "c0_chess_subroutine.lua" );	-- chess logic


function readNumb(s,from,to)
  local b=1;
  local r=0;
  local i=from;
  while i<=to do
    r=r+(b*string.byte(s,i));
    i=i+1;
	b=b*256;
  end
  if string.byte(s,to)==255 then
    r=r-b;
  end
  return r;
end

-- this reads all games from memory
function getallvariants()

  c0_LuaChess.c0_get_moves_from_PGN("");
  c0_LuaChess.c0_PG_viewer = false; -- prep.

  local ply = 1;
  local errors = 0;
  local moves = {};
  local node = {};
  local z ={};
  local i = 0;
  node[1]=900;
  print( "Prepares list of variants");
  while(ply > 0) do
    z[ply] = binBase[node[ply]-900+1];
    moves[ply]= z[ply].uci;
    if z[ply].first_child>0 then
	  node[ply+1] =  z[ply].first_child;
	  ply=ply+1;
	else
	  node[ply] =  z[ply].next_sibling;

	  local m=1;
	  local mlist = "";
	  while(m<=ply) do
	    local uci = moves[m];
		if string.len(uci)>4 then
		  uci = string.sub(uci,1,4) ..
		  "[" .. string.upper( string.sub(uci,5,5) ) .. "]";
		end
	    mlist=mlist .. uci;
		m = m + 1;
	  end

	  local PGN = c0_LuaChess.c0_put_to_PGN(mlist);
	  if c0_LuaChess.c0_errflag then
	    errors = errors + 1;
	  else
	    i = i + 1;
	    variants[i] = PGN;
    	    if i%100==0 then
    	       print(i);
    	    end
	  end

	  while(ply>0 and node[ply]<0) do
	    ply = ply-1;
	    if ply>0 then
		node[ply] = binBase[node[ply]-900+1].next_sibling;
	    end
	  end

	end

  end
  print( c0_LuaChess.ToString(i) .." variants in memory, " ..
      c0_LuaChess.ToString(errors)  .. " could not read");
  printallvariants();
end

-- this prints all games
function printallvariants()
  local i=1;
  print( "Printing" );
  while i<=table.getn(variants) do
    print(variants[i]);
    i = i + 1;
  end
end

-- this reads all the .abk file into memory
function readAbkFile(filename)
  local in_file = assert(io.open(filename, "rb"));
  local header = in_file:read(13);
  local Comment = in_file:read(121);
  local Author = in_file:read(81);
  local skipheader = in_file:read(0x6270-(13+121+81)); -- 900 x 28
  -- comment at
  local k=0;
  local buf;
  print( "Reading from file " .. filename);
  while true do
    buf = in_file:read(28);
    if not buf then break end;
    k = k+1;
	local move_from=string.byte( buf,1);
	local move_fh=(move_from % 8);
	local move_fv=(move_from-move_fh)/8;
	local move_to=string.byte( buf,2);
	local move_th=(move_to % 8);
	local move_tv=(move_to-move_th)/8;
	binBase[k]={};
	local uci=string.char(97+move_fh)..string.char(49+move_fv)..
		string.char(97+move_th)..string.char(49+move_tv);
	local promoted=math.abs(string.byte( buf,3));
	if promoted~=0 then
		uci = uci .. string.sub("rnbq",promoted);
	end
	binBase[k].uci = uci;
	binBase[k].priority=string.byte( buf,4);
	binBase[k].cnt_games=readNumb(buf,5,8);
	binBase[k].won_games=readNumb(buf,9,12);
	binBase[k].lost_games=readNumb(buf,13,16);
	binBase[k].hz=readNumb(buf,17,20);
	binBase[k].first_child=readNumb(buf,21,22); -- next move (answer)
	binBase[k].next_sibling=readNumb(buf,25,28); -- other legal move at the same ply

    if k%1000==0 then
      print(k);
    end
  end
  in_file:close();
  getallvariants();

end


binBase = {};
variants = {};

-- scan .abk file
readAbkFile("abk_sample.abk");