X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=0be309ee60cac3d0ea78bcec0ad6c38237e7768b;hp=fdae0ae0bf211999f9c2ee69472c4f151af0f8a0;hb=108f0da4d7f993732aa2e854b8f3fa8ca6d3b46c;hpb=a09eee579810fe446e34d0004e5716191310f4e4

diff --git a/src/position.cpp b/src/position.cpp
index fdae0ae0..0be309ee 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -52,8 +52,8 @@ namespace {
 
 const string PieceToChar(" PNBRQK  pnbrqk");
 
-const Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
-                         B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING };
+constexpr Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
+                             B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING };
 
 // min_attacker() is a helper function used by see_ge() to locate the least
 // valuable attacker for the side to move, remove the attacker we just found
@@ -322,8 +322,8 @@ void Position::set_castling_right(Color c, Square rfrom) {
 
 void Position::set_check_info(StateInfo* si) const {
 
-  si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square<KING>(WHITE), si->pinnersForKing[WHITE]);
-  si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square<KING>(BLACK), si->pinnersForKing[BLACK]);
+  si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square<KING>(WHITE), si->pinners[BLACK]);
+  si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square<KING>(BLACK), si->pinners[WHITE]);
 
   Square ksq = square<KING>(~sideToMove);
 
@@ -464,7 +464,7 @@ const string Position::fen() const {
 
 Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const {
 
-  Bitboard result = 0;
+  Bitboard blockers = 0;
   pinners = 0;
 
   // Snipers are sliders that attack 's' when a piece is removed
@@ -476,14 +476,14 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners
     Square sniperSq = pop_lsb(&snipers);
     Bitboard b = between_bb(s, sniperSq) & pieces();
 
-    if (!more_than_one(b))
+    if (b && !more_than_one(b))
     {
-        result |= b;
+        blockers |= b;
         if (b & pieces(color_of(piece_on(s))))
             pinners |= sniperSq;
     }
   }
-  return result;
+  return blockers;
 }
 
 
@@ -540,7 +540,7 @@ bool Position::legal(Move m) const {
 
   // A non-king move is legal if and only if it is not pinned or it
   // is moving along the ray towards or away from the king.
-  return   !(pinned_pieces(us) & from)
+  return   !(blockers_for_king(us) & from)
         ||  aligned(from, to_sq(m), square<KING>(us));
 }
 
@@ -632,7 +632,7 @@ bool Position::gives_check(Move m) const {
       return true;
 
   // Is there a discovered check?
-  if (   (discovered_check_candidates() & from)
+  if (   (st->blockersForKing[~sideToMove] & from)
       && !aligned(from, to, square<KING>(~sideToMove)))
       return true;
 
@@ -1037,7 +1037,7 @@ bool Position::see_ge(Move m, Value threshold) const {
 
       // Don't allow pinned pieces to attack (except the king) as long as
       // all pinners are on their original square.
-      if (!(st->pinnersForKing[stm] & ~occupied))
+      if (!(st->pinners[~stm] & ~occupied))
           stmAttackers &= ~st->blockersForKing[stm];
 
       // If stm has no more attackers then give up: stm loses
@@ -1105,6 +1105,35 @@ bool Position::is_draw(int ply) const {
 }
 
 
+// Position::has_repeated() tests whether there has been at least one repetition
+// of positions since the last capture or pawn move.
+
+bool Position::has_repeated() const {
+
+    StateInfo* stc = st;
+    while (true)
+    {
+        int i = 4, e = std::min(stc->rule50, stc->pliesFromNull);
+
+        if (e < i)
+            return false;
+
+        StateInfo* stp = st->previous->previous;
+
+        do {
+            stp = stp->previous->previous;
+
+            if (stp->key == stc->key)
+                return true;
+
+            i += 2;
+        } while (i <= e);
+
+        stc = stc->previous;
+    }
+}
+
+
 /// Position::flip() flips position with the white and black sides reversed. This
 /// is only useful for debugging e.g. for finding evaluation symmetry bugs.
 
@@ -1146,7 +1175,7 @@ void Position::flip() {
 
 bool Position::pos_is_ok() const {
 
-  const bool Fast = true; // Quick (default) or full check?
+  constexpr bool Fast = true; // Quick (default) or full check?
 
   if (   (sideToMove != WHITE && sideToMove != BLACK)
       || piece_on(square<KING>(WHITE)) != W_KING