Detach the state when copying a position

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 6e6bf38b3dda159a5703386f3d7e1fe192d693ab..480a92ec9cfcd1a7e3850aea8fbc94f61c570ece 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -315,9 +315,10 @@ void Position::print(Move m) const {
 
 /// Position::copy() creates a copy of the input position.
 
-void Position::copy(const Position &pos) {
+void Position::copy(const Position& pos) {
 
   memcpy(this, &pos, sizeof(Position));
+  saveState(); // detach and copy state info
 }
 
 
@@ -1607,15 +1608,16 @@ int Position::see(Square from, Square to) const {
 }
 
 
-/// Position::setStartState() copies the content of the argument
+/// Position::saveState() copies the content of the current state
 /// inside startState and makes st point to it. This is needed
 /// when the st pointee could become stale, as example because
 /// the caller is about to going out of scope.
 
-void Position::setStartState(const StateInfo& s) {
+void Position::saveState() {
 
-  startState = s;
+  startState = *st;
   st = &startState;
+  st->previous = NULL; // as a safe guard
 }
 
 
@@ -1966,7 +1968,7 @@ void Position::init_piece_square_tables() {
 /// the white and black sides reversed. This is only useful for debugging,
 /// especially for finding evaluation symmetry bugs.
 
-void Position::flipped_copy(const Position &pos) {
+void Position::flipped_copy(const Position& pos) {
 
   assert(pos.is_ok());
 
@@ -2091,7 +2093,7 @@ bool Position::is_ok(int* failedStep) const {
 
   // Is there more than 2 checkers?
   if (failedStep) (*failedStep)++;
-  if (debugCheckerCount && count_1s<false>(st->checkersBB) > 2)
+  if (debugCheckerCount && count_1s(st->checkersBB) > 2)
       return false;
 
   // Bitboards OK?
@@ -2166,7 +2168,7 @@ bool Position::is_ok(int* failedStep) const {
   if (debugPieceCounts)
       for (Color c = WHITE; c <= BLACK; c++)
           for (PieceType pt = PAWN; pt <= KING; pt++)
-              if (pieceCount[c][pt] != count_1s<false>(pieces_of_color_and_type(c, pt)))
+              if (pieceCount[c][pt] != count_1s(pieces_of_color_and_type(c, pt)))
                   return false;
 
   if (failedStep) (*failedStep)++;