(*

 * Hedgewars, a worms-like game

 * Copyright (c) 2006 Andrey Korotaev <unC0Rr@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 of the License

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

 *)

unit uAIThinkStack;

interface

uses uAIActions, uGears;

{$INCLUDE options.inc}

const cBranchStackSize = 12;

type TStackEntry = record

                   WastedTicks: Longword;

                   MadeActions: TActions;

                   Hedgehog: TGear;

                   end;

var ThinkStack: record

                Count: Longword;

                States: array[0..Pred(cBranchStackSize)] of TStackEntry;

                end;

function  Push(Ticks: Longword; const Actions: TActions; const Me: TGear; Dir: integer): boolean;

function  Pop(out Ticks: Longword; out Actions: TActions; out Me: TGear): boolean;

function  PosInThinkStack(Me: PGear): boolean;

procedure ClearThinkStack;

implementation

function Push(Ticks: Longword; const Actions: TActions; const Me: TGear; Dir: integer): boolean;

begin

Result:= (ThinkStack.Count < cBranchStackSize) and (Actions.Count < MAXACTIONS - 5);

if Result then

   with ThinkStack.States[ThinkStack.Count] do

        begin

        WastedTicks:= Ticks;

        MadeActions:= Actions;

        Hedgehog:= Me;

        Hedgehog.Message:= Dir;

        inc(ThinkStack.Count)

        end

end;

function Pop(out Ticks: Longword; out Actions: TActions; out Me: TGear): boolean;

begin

Result:= ThinkStack.Count > 0;

if Result then

   begin

   dec(ThinkStack.Count);

   with ThinkStack.States[ThinkStack.Count] do

        begin

        Ticks:= WastedTicks;

        Actions:= MadeActions;

        Me:= Hedgehog

        end

   end

end;

function PosInThinkStack(Me: PGear): boolean;

var i: Longword;

begin

i:= 0;

Result:= false;

while (i < ThinkStack.Count) and not Result do

      begin

      Result:= (abs(ThinkStack.States[i].Hedgehog.X - Me.X) +

                abs(ThinkStack.States[i].Hedgehog.Y - Me.Y) <= 2)

                and (ThinkStack.States[i].Hedgehog.Message = Me.Message);

      inc(i)

      end

end;

procedure ClearThinkStack;

begin

ThinkStack.Count:= 0

end;

end.