Simplify generate_evasions()

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index c24d5675d8c1dadbb1de958a5fdd65c276a02be7..b9a8bf8bf26f47d365eb70110714ca9846fd1937 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -60,11 +60,11 @@ static bool RequestPending = false;
 
 /// Constructors
 
-Position::Position(const Position &pos) {
+Position::Position(const Position& pos) {
   copy(pos);
 }
 
-Position::Position(const std::string &fen) {
+Position::Position(const std::string& fen) {
   from_fen(fen);
 }
 
@@ -73,7 +73,7 @@ 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 std::string& fen) {
 
   static const std::string pieceLetters = "KQRBNPkqrbnp";
   static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
@@ -1626,6 +1626,21 @@ int Position::see(Square from, Square to) const {
   // Find all attackers to the destination square, with the moving piece
   // removed, but possibly an X-ray attacker added behind it.
   occ = occupied_squares();
+
+  // Handle enpassant moves
+  if (ep_square() == to && type_of_piece_on(from) == PAWN)
+  {
+      assert(capture == EMPTY);
+
+      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
+      clear_bit(&occ, capQq);
+  }
+
   while (true)
   {
       clear_bit(&occ, from);
@@ -1952,7 +1967,7 @@ Value Position::compute_non_pawn_material(Color c) const {
 /// side to move is checkmated. Note that this function is currently very
 /// slow, and shouldn't be used frequently inside the search.
 
-bool Position::is_mate() {
+bool Position::is_mate() const {
 
   if (is_check())
   {