Merge pull request #34 from jromang/repetition

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index b3e86c853f0a90ebb58fb565d2785e5ed30711b6..feaeee22c606309a474c917bad77bfcc310d9b5d 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -400,10 +400,8 @@ void Position::print(Move move) const {
   sync_cout;
 
   if (move)
-  {
-      Position p(*this);
-      cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move);
-  }
+      cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "")
+           << move_to_san(*const_cast<Position*>(this), move);
 
   for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
       if (piece_on(sq) != NO_PIECE)
@@ -1347,9 +1345,6 @@ void Position::clear() {
   for (int i = 0; i < 8; i++)
       for (int j = 0; j < 16; j++)
           pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
-
-  for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
-      board[sq] = NO_PIECE;
 }
 
 
@@ -1472,7 +1467,7 @@ Value Position::compute_non_pawn_material(Color c) const {
 /// Position::is_draw() tests whether the position is drawn by material,
 /// repetition, or the 50 moves rule. It does not detect stalemates, this
 /// must be done by the search.
-template<bool SkipRepetition>
+template<bool SkipRepetition, bool SkipThreeFoldCheck>
 bool Position::is_draw() const {
 
   // Draw by material?
@@ -1487,7 +1482,7 @@ bool Position::is_draw() const {
   // Draw by repetition?
   if (!SkipRepetition)
   {
-      int i = 4, e = std::min(st->rule50, st->pliesFromNull);
+      int i = 4, e = std::min(st->rule50, st->pliesFromNull), rep_count=0;
 
       if (i <= e)
       {
@@ -1497,7 +1492,10 @@ bool Position::is_draw() const {
               stp = stp->previous->previous;
 
               if (stp->key == st->key)
-                  return true;
+              {
+                if(SkipThreeFoldCheck) return true;
+                else if(++rep_count>=2) return true;
+              }
 
               i +=2;
 
@@ -1509,8 +1507,9 @@ bool Position::is_draw() const {
 }
 
 // Explicit template instantiations
-template bool Position::is_draw<false>() const;
-template bool Position::is_draw<true>() const;
+template bool Position::is_draw<false,true>() const;
+template bool Position::is_draw<true,true>() const;
+template bool Position::is_draw<false,false>() const;
 
 
 /// Position::flip() flips position with the white and black sides reversed. This