Allow Position::init() to be called more than once

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index bc04d306815657a7944b4ad39b8efb133f9a32a8..5a98821d493dde10d9fe2bd020ba17467c1d7ea5 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -149,6 +149,7 @@ void Position::init() {
 
   for (int cr = NO_CASTLING; cr <= ANY_CASTLING; ++cr)
   {
+      Zobrist::castling[cr] = 0;
       Bitboard b = cr;
       while (b)
       {
@@ -684,13 +685,7 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
 /// to a StateInfo object. The move is assumed to be legal. Pseudo-legal
 /// moves should be filtered out before this function is called.
 
-void Position::do_move(Move m, StateInfo& newSt) {
-
-  CheckInfo ci(*this);
-  do_move(m, newSt, ci, gives_check(m, ci));
-}
-
-void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool givesCheck) {
+void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
 
   assert(is_ok(m));
   assert(&newSt != st);
@@ -848,32 +843,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool gives
   // Update the key with the final value
   st->key = k;
 
-  // Update checkers bitboard: piece must be already moved due to attacks_from()
-  st->checkersBB = 0;
-
-  if (givesCheck)
-  {
-      if (type_of(m) != NORMAL)
-          st->checkersBB = attackers_to(king_square(them)) & pieces(us);
-      else
-      {
-          // Direct checks
-          if (ci.checkSq[pt] & to)
-              st->checkersBB |= to;
-
-          // Discovered checks
-          if (ci.dcCandidates && (ci.dcCandidates & from))
-          {
-              assert(pt != QUEEN);
-
-              if (pt != ROOK)
-                  st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(us, QUEEN, ROOK);
-
-              if (pt != BISHOP)
-                  st->checkersBB |= attacks_from<BISHOP>(king_square(them)) & pieces(us, QUEEN, BISHOP);
-          }
-      }
-  }
+  // Calculate checkers bitboard (if move gives check)
+  st->checkersBB = givesCheck ? attackers_to(king_square(them)) & pieces(us) : 0;
 
   sideToMove = ~sideToMove;
 
@@ -1108,8 +1079,8 @@ Value Position::see(Move m) const {
 }
 
 
-/// Position::is_draw() tests whether the position is drawn by material, 50 moves
-/// rule or repetition. It does not detect stalemates.
+/// Position::is_draw() tests whether the position is drawn by 50-move rule
+/// or by repetition. It does not detect stalemates.
 
 bool Position::is_draw() const {