Better castle move detector in move_to_san()

[stockfish] / src / san.cpp

diff --git a/src/san.cpp b/src/san.cpp
index 222a10431be9a74f5f77223376739e87172de0a5..c8292462ad5019c264ff1901a0c2c9f63f7d77ca 100644 (file)
--- a/src/san.cpp
+++ b/src/san.cpp
@@ -70,23 +70,28 @@ const std::string move_to_san(const Position& pos, Move m) {
   assert(pos.is_ok());
   assert(move_is_ok(m));
 
+  Square from, to;
+  PieceType pt;
+
+  from = move_from(m);
+  to = move_to(m);
+  pt = type_of_piece(pos.piece_on(move_from(m)));
+
   std::string san = "";
 
   if (m == MOVE_NONE)
       return "(none)";
   else if (m == MOVE_NULL)
       return "(null)";
-  else if (move_is_long_castle(m))
+  else if (move_is_long_castle(m) || (int(to - from) == -2 && pt == KING))
       san = "O-O-O";
-  else if (move_is_short_castle(m))
+  else if (move_is_short_castle(m) || (int(to - from) == 2 && pt == KING))
       san = "O-O";
   else
   {
-      Piece pc = pos.piece_on(move_from(m));
-      if (type_of_piece(pc) != PAWN)
+      if (pt != PAWN)
       {
-          san += piece_type_to_char(type_of_piece(pc), true);
-          Square from = move_from(m);
+          san += piece_type_to_char(pt, true);
           switch (move_ambiguity(pos, m)) {
           case AMBIGUITY_NONE:
             break;
@@ -105,7 +110,7 @@ const std::string move_to_san(const Position& pos, Move m) {
       }
       if (pos.move_is_capture(m))
       {
-          if (type_of_piece(pc) == PAWN)
+          if (pt == PAWN)
               san += file_to_char(square_file(move_from(m)));
           san += "x";
       }
@@ -119,9 +124,9 @@ const std::string move_to_san(const Position& pos, Move m) {
   // Is the move check?  We don't use pos.move_is_check(m) here, because
   // Position::move_is_check doesn't detect all checks (not castling moves,
   // promotions and en passant captures).
-  UndoInfo u;
+  StateInfo st;
   Position p(pos);
-  p.do_move(m, u);
+  p.do_move(m, st);
   if (p.is_check())
       san += p.is_mate()? "#" : "+";
 
@@ -290,7 +295,7 @@ Move move_from_san(const Position& pos, const std::string& movestr) {
 
 const std::string line_to_san(const Position& pos, Move line[], int startColumn, bool breakLines) {
 
-  UndoInfo u;
+  StateInfo st;
   std::stringstream s;
   std::string moveStr;
   size_t length = 0;
@@ -309,9 +314,9 @@ const std::string line_to_san(const Position& pos, Move line[], int startColumn,
       s << moveStr << ' ';
 
       if (line[i] == MOVE_NULL)
-          p.do_null_move(u);
+          p.do_null_move(st);
       else
-          p.do_move(line[i], u);
+          p.do_move(line[i], st);
   }
   return s.str();
 }