src/hlvariant/crazyhouse/legalitycheck.h

   1 /*
   2   Copyright (c) 2007 Paolo Capriotti <p.capriotti@sns.it>
   3             (c) 2007 Maurizio Monge <maurizio.monge@kdemail.net>
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9 */
  10
  11 #ifndef HLVARIANT__CRAZYHOUSE__LEGALITYCHECK_H
  12 #define HLVARIANT__CRAZYHOUSE__LEGALITYCHECK_H
  13
  14 namespace HLVariant {
  15 namespace Crazyhouse {
  16
  17 template <typename _GameState>
  18 class LegalityCheck : public Chess::LegalityCheck<_GameState> {
  19 public:
  20   typedef _GameState GameState;
  21 private:
  22   typedef Chess::LegalityCheck<GameState> Base;
  23   typedef typename Base::Board Board;
  24   typedef typename Base::Move Move;
  25   typedef typename Base::Piece Piece;
  26 protected:
  27   using Base::m_state;
  28 public:
  29   LegalityCheck(const GameState& state);
  30
  31   virtual bool pseudolegal(Move& move) const;
  32   virtual typename Piece::Color mover(const Move& move) const;
  33 };
  34
  35 // IMPLEMENTATION
  36
  37 template <typename GameState>
  38 LegalityCheck<GameState>::LegalityCheck(const GameState& state)
  39 : Base(state) { }
  40
  41 template <typename GameState>
  42 bool LegalityCheck<GameState>::pseudolegal(Move& move) const {
  43   // add drop information to move, if missing
  44   if (move.drop() == Piece() &&
  45       move.pool() != Piece::INVALID_COLOR &&
  46       move.index() != -1) {
  47     move.setDrop(m_state.pools().pool(move.pool()).get(move.index()));
  48   }
  49
  50   Piece dropped = move.drop();
  51
  52   if (dropped == Piece()) {
  53     return Base::pseudolegal(move);
  54   }
  55   else {
  56     // dropping on a valid square
  57     if (!m_state.board().valid(move.to()))
  58       return false;
  59
  60     // cannot drop on occupied squares
  61     if (m_state.board().get(move.to()) != Piece())
  62       return false;
  63
  64     // cannot drop pawns in first or eighth rank
  65     if (dropped.type() == Piece::PAWN &&
  66           (move.to().y == m_state.startingRank(Piece::WHITE) ||
  67            move.to().y == m_state.promotionRank(Piece::WHITE)))
  68       return false;
  69
  70     return true;
  71   }
  72 }
  73
  74 template <typename GameState>
  75 typename LegalityCheck<GameState>::Piece::Color
  76 LegalityCheck<GameState>::mover(const Move& move) const {
  77   if (move.drop() != Piece())
  78     return move.drop().color();
  79   else
  80     return Base::mover(move);
  81 }
  82
  83 } // namespace Crazyhouse
  84 } // namespace HLVariant
  85
  86
  87 #endif // HLVARIANT__CRAZYHOUSE__LEGALITYCHECK_H