Factor out Position::do_capture_move()

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index ee7d906e61698010afd4b7e64336c44505493b2e..fca3d2c9dbc431a89f1acdf9e764fa0f18ada6fd 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1,13 +1,14 @@
 /*
-  Glaurung, a UCI chess playing engine.
-  Copyright (C) 2004-2008 Tord Romstad
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+  Copyright (C) 2008 Marco Costalba
 
-  Glaurung is free software: you can redistribute it and/or modify
+  Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
-  Glaurung is distributed in the hope that it will be useful,
+  Stockfish is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
@@ -301,7 +302,7 @@ History H;  // Should be made local?
 //// Functions
 ////
 
-/// think() is the external interface to Glaurung's search, and is called when
+/// think() is the external interface to Stockfish's search, and is called when
 /// the program receives the UCI 'go' command.  It initializes various
 /// search-related global variables, and calls root_search()
 
@@ -930,6 +931,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
+      bool lastMinuteSurprise = (depth <= OnePly && mp.current_move_type() == MovePicker::PH_GOOD_CAPTURES);
       bool singleReply = (pos.is_check() && mp.number_of_moves() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
       bool moveIsCapture = pos.move_is_capture(move);
@@ -941,7 +943,7 @@ namespace {
         PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
 
       // Decide the new search depth
-      Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat);
+      Depth ext = extension(pos, move, true, moveIsCheck, singleReply || lastMinuteSurprise, mateThreat);
       Depth newDepth = depth - OnePly + ext;
 
       // Make and search the move
@@ -1995,26 +1997,35 @@ namespace {
 
   Depth extension(const Position &pos, Move m, bool pvNode,
                   bool check, bool singleReply, bool mateThreat) {
+
     Depth result = Depth(0);
 
-    if(check)
-      result += CheckExtension[pvNode];
-    if(singleReply)
-      result += SingleReplyExtension[pvNode];
-    if(pos.move_is_pawn_push_to_7th(m))
-      result += PawnPushTo7thExtension[pvNode];
-    if(pos.move_is_passed_pawn_push(m))
-      result += PassedPawnExtension[pvNode];
-    if(mateThreat)
-      result += MateThreatExtension[pvNode];
-    if(pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame
-       && (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
-           - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
-       && !move_promotion(m))
-      result += PawnEndgameExtension[pvNode];
-    if(pvNode && pos.move_is_capture(m)
-       && pos.type_of_piece_on(move_to(m)) != PAWN && pos.see(m) >= 0)
-      result += OnePly/2;
+    if (check)
+        result += CheckExtension[pvNode];
+
+    if (singleReply)
+        result += SingleReplyExtension[pvNode];
+
+    if (pos.move_is_pawn_push_to_7th(m))
+        result += PawnPushTo7thExtension[pvNode];
+
+    if (pos.move_is_passed_pawn_push(m))
+        result += PassedPawnExtension[pvNode];
+
+    if (mateThreat)
+        result += MateThreatExtension[pvNode];
+
+    if (   pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame\r
+        && (  pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)\r
+            - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))\r
+        && !move_promotion(m))
+        result += PawnEndgameExtension[pvNode];
+    
+    if (   pvNode
+        && pos.move_is_capture(m)
+        && pos.type_of_piece_on(move_to(m)) != PAWN
+        && pos.see(m) >= 0)
+        result += OnePly/2;
 
     return Min(result, OnePly);
   }