From: Marco Costalba <mcostalba@gmail.com>
Date: Sun, 10 Feb 2013 18:10:01 +0000 (+0100)
Subject: Rename and de-templetize sort()
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=733d0099b2a3e3ad594bb551d37c8a06c62f13db

Rename and de-templetize sort()

Rename to insertion_sort so to avoid confusion
with std::sort, also move it to movepicker.cpp
and use the bit slower std::stable_sort in
search.cpp where it is used in not performance
critical paths.

No functional change.
---

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 72601bb3..5c8338c0 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -35,6 +35,20 @@ namespace {
     STOP
   };
 
+  // Our insertion sort, guaranteed to be stable, as is needed
+  void insertion_sort(MoveStack* begin, MoveStack* end)
+  {
+    MoveStack tmp, *p, *q;
+
+    for (p = begin + 1; p < end; ++p)
+    {
+        tmp = *p;
+        for (q = p; q != begin && *(q-1) < tmp; --q)
+            *q = *(q-1);
+        *q = tmp;
+    }
+  }
+
   // Unary predicate used by std::partition to split positive scores from remaining
   // ones so to sort separately the two sets, and with the second sort delayed.
   inline bool has_positive_score(const MoveStack& ms) { return ms.score > 0; }
@@ -230,14 +244,14 @@ void MovePicker::generate_next() {
       endQuiets = end = generate<QUIETS>(pos, moves);
       score<QUIETS>();
       end = std::partition(cur, end, has_positive_score);
-      sort<MoveStack>(cur, end);
+      insertion_sort(cur, end);
       return;
 
   case QUIETS_2_S1:
       cur = end;
       end = endQuiets;
       if (depth >= 3 * ONE_PLY)
-          sort<MoveStack>(cur, end);
+          insertion_sort(cur, end);
       return;
 
   case BAD_CAPTURES_S1:
diff --git a/src/position.cpp b/src/position.cpp
index 310e46e3..ad0a621d 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -802,7 +802,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
       // Update piece list, move the last piece at index[capsq] position and
       // shrink the list.
       //
-      // WARNING: This is a not revresible operation. When we will reinsert the
+      // WARNING: This is a not reversible operation. When we will reinsert the
       // captured piece in undo_move() we will put it at the end of the list and
       // not in its original place, it means index[] and pieceList[] are not
       // guaranteed to be invariant to a do_move() + undo_move() sequence.
diff --git a/src/search.cpp b/src/search.cpp
index 091c00fe..74dc9e29 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -354,7 +354,7 @@ namespace {
                 // we want to keep the same order for all the moves but the new
                 // PV that goes to the front. Note that in case of MultiPV search
                 // the already searched PV lines are preserved.
-                sort<RootMove>(RootMoves.begin() + PVIdx, RootMoves.end());
+                std::stable_sort(RootMoves.begin() + PVIdx, RootMoves.end());
 
                 // Write PV back to transposition table in case the relevant
                 // entries have been overwritten during the search.
@@ -399,7 +399,7 @@ namespace {
             }
 
             // Sort the PV lines searched so far and update the GUI
-            sort<RootMove>(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
+            std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
 
             if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000)
                 sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
diff --git a/src/search.h b/src/search.h
index 600d7a75..4a66b11f 100644
--- a/src/search.h
+++ b/src/search.h
@@ -56,12 +56,11 @@ struct Stack {
 /// all non-pv moves.
 struct RootMove {
 
-  RootMove(){} // Needed by sort()
   RootMove(Move m) : score(-VALUE_INFINITE), prevScore(-VALUE_INFINITE) {
     pv.push_back(m); pv.push_back(MOVE_NONE);
   }
 
-  bool operator<(const RootMove& m) const { return score < m.score; }
+  bool operator<(const RootMove& m) const { return score > m.score; } // Ascending sort
   bool operator==(const Move& m) const { return pv[0] == m; }
 
   void extract_pv_from_tt(Position& pos);
diff --git a/src/types.h b/src/types.h
index b7bcb4e8..aa1f34fc 100644
--- a/src/types.h
+++ b/src/types.h
@@ -489,21 +489,4 @@ inline const std::string square_to_string(Square s) {
   return ch;
 }
 
-/// Our insertion sort implementation, works with pointers and iterators and is
-/// guaranteed to be stable, as is needed.
-template<typename T, typename K>
-void sort(K begin, K end)
-{
-  T tmp;
-  K p, q;
-
-  for (p = begin + 1; p < end; p++)
-  {
-      tmp = *p;
-      for (q = p; q != begin && *(q-1) < tmp; --q)
-          *q = *(q-1);
-      *q = tmp;
-  }
-}
-
 #endif // !defined(TYPES_H_INCLUDED)