X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=c121c49734f2eac41f3616af2e5c098c82c93880;hp=4184e494c924d198156d1e1b06415d5442f970ff;hb=27619830d428693b4871ce58770705b30ba84c99;hpb=9144e48eb63587bde7379c16ddb3defea4b0e409

diff --git a/src/position.cpp b/src/position.cpp
index 4184e494..c121c497 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008 Marco Costalba
+  Copyright (C) 2008-2009 Marco Costalba
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -35,13 +35,13 @@
 #include "san.h"
 #include "ucioption.h"
 
+using std::string;
+
 
 ////
 //// Variables
 ////
 
-extern SearchStack EmptySearchStack;
-
 int Position::castleRightsMask[64];
 
 Key Position::zobrist[2][8][64];
@@ -65,7 +65,7 @@ Position::Position(const Position& pos) {
   copy(pos);
 }
 
-Position::Position(const std::string& fen) {
+Position::Position(const string& fen) {
   from_fen(fen);
 }
 
@@ -74,9 +74,9 @@ Position::Position(const std::string& fen) {
 /// string. This function is not very robust - make sure that input FENs are
 /// correct (this is assumed to be the responsibility of the GUI).
 
-void Position::from_fen(const std::string& fen) {
+void Position::from_fen(const string& fen) {
 
-  static const std::string pieceLetters = "KQRBNPkqrbnp";
+  static const string pieceLetters = "KQRBNPkqrbnp";
   static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
 
   clear();
@@ -100,7 +100,7 @@ void Position::from_fen(const std::string& fen) {
           continue;
       }
       size_t idx = pieceLetters.find(fen[i]);
-      if (idx == std::string::npos)
+      if (idx == string::npos)
       {
            std::cout << "Error in FEN at character " << i << std::endl;
            return;
@@ -221,10 +221,10 @@ void Position::from_fen(const std::string& fen) {
 /// Position::to_fen() converts the position object to a FEN string. This is
 /// probably only useful for debugging.
 
-const std::string Position::to_fen() const {
+const string Position::to_fen() const {
 
-  static const std::string pieceLetters = " PNBRQK  pnbrqk";
-  std::string fen;
+  static const string pieceLetters = " PNBRQK  pnbrqk";
+  string fen;
   int skip;
 
   for (Rank rank = RANK_8; rank >= RANK_1; rank--)
@@ -274,7 +274,7 @@ const std::string Position::to_fen() const {
 
 void Position::print(Move m) const {
 
-  static const std::string pieceLetters = " PNBRQK  PNBRQK .";
+  static const string pieceLetters = " PNBRQK  PNBRQK .";
 
   // Check for reentrancy, as example when called from inside
   // MovePicker that is used also here in move_to_san()
@@ -286,7 +286,7 @@ void Position::print(Move m) const {
   std::cout << std::endl;
   if (m != MOVE_NONE)
   {
-      std::string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
+      string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
       std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl;
   }
   for (Rank rank = RANK_8; rank >= RANK_1; rank--)
@@ -1511,7 +1511,7 @@ int Position::see(Square from, Square to) const {
     0, 0
   };
 
-  Bitboard attackers, occ, b;
+  Bitboard attackers, stmAttackers, occ, b;
 
   assert(square_is_ok(from) || from == SQ_NONE);
   assert(square_is_ok(to));
@@ -1535,7 +1535,6 @@ int Position::see(Square from, Square to) const {
 
       Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S);
       capture = piece_on(capQq);
-
       assert(type_of_piece_on(capQq) == PAWN);
 
       // Remove the captured pawn
@@ -1570,7 +1569,8 @@ int Position::see(Square from, Square to) const {
   }
 
   // If the opponent has no attackers we are finished
-  if ((attackers & pieces_of_color(them)) == EmptyBoardBB)
+  stmAttackers = attackers & pieces_of_color(them);
+  if (!stmAttackers)
       return seeValues[capture];
 
   attackers &= occ; // Remove the moving piece
@@ -1592,12 +1592,12 @@ int Position::see(Square from, Square to) const {
       // Locate the least valuable attacker for the side to move. The loop
       // below looks like it is potentially infinite, but it isn't. We know
       // that the side to move still has at least one attacker left.
-      for (pt = PAWN; !(attackers & pieces_of_color_and_type(c, pt)); pt++)
+      for (pt = PAWN; !(stmAttackers & pieces_of_type(pt)); pt++)
           assert(pt < KING);
 
       // Remove the attacker we just found from the 'attackers' bitboard,
       // and scan for new X-ray attacks behind the attacker.
-      b = attackers & pieces_of_color_and_type(c, pt);
+      b = stmAttackers & pieces_of_type(pt);
       occ ^= (b & (~b + 1));
       attackers |=  (rook_attacks_bb(to, occ) & rooks_and_queens())
                   | (bishop_attacks_bb(to, occ) & bishops_and_queens());
@@ -1613,15 +1613,16 @@ int Position::see(Square from, Square to) const {
       // before beginning the next iteration
       lastCapturingPieceValue = seeValues[pt];
       c = opposite_color(c);
+      stmAttackers = attackers & pieces_of_color(c);
 
       // Stop after a king capture
-      if (pt == KING && (attackers & pieces_of_color(c)))
+      if (pt == KING && stmAttackers)
       {
           assert(n < 32);
           swapList[n++] = 100;
           break;
       }
-  } while (attackers & pieces_of_color(c));
+  } while (stmAttackers);
 
   // Having built the swap list, we negamax through it to find the best
   // achievable score from the point of view of the side to move