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[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index c09a953b62e3a7612d53f03069266a2a00493d6d..325ffd1114892aa0e4f1598acc74bc877d430adf 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -32,6 +32,7 @@
 #include "thread.h"
 #include "tt.h"
 #include "uci.h"
+#include "syzygy/tbprobe.h"
 
 using std::string;
 
@@ -51,7 +52,7 @@ namespace {
 
 const string PieceToChar(" PNBRQK  pnbrqk");
 
-// min_attacker() is a helper function used by see() to locate the least
+// 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
 // from the bitboards and scan for new X-ray attacks behind it.
 
@@ -85,7 +86,7 @@ PieceType min_attacker<KING>(const Bitboard*, Square, Bitboard, Bitboard&, Bitbo
 
 /// operator<<(Position) returns an ASCII representation of the position
 
-std::ostream& operator<<(std::ostream& os, const Position& pos) {
+std::ostream& operator<<(std::ostream& os, Position& pos) {
 
   os << "\n +---+---+---+---+---+---+---+---+\n";
 
@@ -98,11 +99,22 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) {
   }
 
   os << "\nFen: " << pos.fen() << "\nKey: " << std::hex << std::uppercase
-     << std::setfill('0') << std::setw(16) << pos.key() << std::dec << "\nCheckers: ";
+     << std::setfill('0') << std::setw(16) << pos.key()
+     << std::setfill(' ') << std::dec << "\nCheckers: ";
 
   for (Bitboard b = pos.checkers(); b; )
       os << UCI::square(pop_lsb(&b)) << " ";
 
+  if (    int(Tablebases::MaxCardinality) >= popcount(pos.pieces())
+      && !pos.can_castle(ANY_CASTLING))
+  {
+      Tablebases::ProbeState s1, s2;
+      Tablebases::WDLScore wdl = Tablebases::probe_wdl(pos, &s1);
+      int dtz = Tablebases::probe_dtz(pos, &s2);
+      os << "\nTablebases WDL: " << std::setw(4) << wdl << " (" << s1 << ")"
+         << "\nTablebases DTZ: " << std::setw(4) << dtz << " (" << s2 << ")";
+  }
+
   return os;
 }
 
@@ -164,8 +176,9 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
 
    4) En passant target square (in algebraic notation). If there's no en passant
       target square, this is "-". If a pawn has just made a 2-square move, this
-      is the position "behind" the pawn. This is recorded regardless of whether
-      there is a pawn in position to make an en passant capture.
+      is the position "behind" the pawn. This is recorded only if there is a pawn
+      in position to make an en passant capture, and if there really is a pawn
+      that might have advanced two squares.
 
    5) Halfmove clock. This is the number of halfmoves since the last pawn advance
       or capture. This is used to determine if a draw can be claimed under the
@@ -242,7 +255,8 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
   {
       st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
 
-      if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN)))
+      if (   !(attackers_to(st->epSquare) & pieces(sideToMove, PAWN))
+          || !(pieces(~sideToMove, PAWN) & (st->epSquare + pawn_push(~sideToMove))))
           st->epSquare = SQ_NONE;
   }
   else
@@ -357,6 +371,28 @@ void Position::set_state(StateInfo* si) const {
 }
 
 
+/// Position::set() is an overload to initialize the position object with
+/// the given endgame code string like "KBPKN". It is manily an helper to
+/// get the material key out of an endgame code. Position is not playable,
+/// indeed is even not guaranteed to be legal.
+
+Position& Position::set(const string& code, Color c, StateInfo* si) {
+
+  assert(code.length() > 0 && code.length() < 8);
+  assert(code[0] == 'K');
+
+  string sides[] = { code.substr(code.find('K', 1)),      // Weak
+                     code.substr(0, code.find('K', 1)) }; // Strong
+
+  std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
+
+  string fenStr =  sides[0] + char(8 - sides[0].length() + '0') + "/8/8/8/8/8/8/"
+                 + sides[1] + char(8 - sides[1].length() + '0') + " w - - 0 10";
+
+  return set(fenStr, false, si, nullptr);
+}
+
+
 /// Position::fen() returns a FEN representation of the position. In case of
 /// Chess960 the Shredder-FEN notation is used. This is mainly a debugging function.