X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=0b687a8d1496e797e22983b36ca7b0819fd92ea8;hp=e1f07bfb4857292bfb7d479cd9f270d05668fd60;hb=49e110c52b19f5c99954d4797b8e991b0b60007c;hpb=23b6809f3dffe8c93b7edef4e5d47925920e5031

diff --git a/src/position.cpp b/src/position.cpp
index e1f07bfb..0b687a8d 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1149,9 +1149,9 @@ void Position::clear() {
   startState.epSquare = SQ_NONE;
   st = &startState;
 
-  for (int i = 0; i < 8; i++)
+  for (int i = 0; i < PIECE_TYPE_NB; i++)
       for (int j = 0; j < 16; j++)
-          pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
+          pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE;
 }
 
 
@@ -1223,6 +1223,7 @@ Key Position::compute_material_key() const {
 /// game and the endgame. These functions are used to initialize the incremental
 /// scores when a new position is set up, and to verify that the scores are correctly
 /// updated by do_move and undo_move when the program is running in debug mode.
+
 Score Position::compute_psq_score() const {
 
   Score score = SCORE_ZERO;
@@ -1254,21 +1255,14 @@ Value Position::compute_non_pawn_material(Color c) const {
 }
 
 
-/// Position::is_draw() tests whether the position is drawn by material,
-/// repetition, or the 50 moves rule. It does not detect stalemates, this
-/// must be done by the search.
-bool Position::is_draw() const {
+/// Position::is_draw() tests whether the position is drawn by 50 moves rule
+/// or by repetition. It does not detect stalemates.
 
-  // Draw by material?
-  if (   !pieces(PAWN)
-      && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg))
-      return true;
+bool Position::is_draw() const {
 
-  // Draw by the 50 moves rule?
   if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
       return true;
 
-  // Draw by repetition?
   int i = 4, e = std::min(st->rule50, st->pliesFromNull);
 
   if (i <= e)
@@ -1279,7 +1273,7 @@ bool Position::is_draw() const {
           stp = stp->previous->previous;
 
           if (stp->key == st->key)
-              return true;
+              return true; // Draw after first repetition
 
           i += 2;
 
@@ -1294,7 +1288,7 @@ bool Position::is_draw() const {
 /// is only useful for debugging especially for finding evaluation symmetry bugs.
 
 static char toggle_case(char c) {
-  return isupper(c) ? tolower(c) : toupper(c);
+  return char(islower(c) ? toupper(c) : tolower(c));
 }
 
 void Position::flip() {
@@ -1302,24 +1296,24 @@ void Position::flip() {
   string f, token;
   std::stringstream ss(fen());
 
-  for (int i = 0; i < 8; i++)
+  for (Rank rank = RANK_8; rank >= RANK_1; rank--) // Piece placement
   {
-      std::getline(ss, token, i < 7 ? '/' : ' ');
-      std::transform(token.begin(), token.end(), token.begin(), toggle_case);
-      f.insert(0, token + (i ? "/" : " "));
+      std::getline(ss, token, rank > RANK_1 ? '/' : ' ');
+      f.insert(0, token + (f.empty() ? " " : "/"));
   }
 
-  ss >> token; // Side to move
-  f += (token == "w" ? "b " : "w ");
+  ss >> token; // Active color
+  f += (token == "w" ? "B " : "W "); // Will be lowercased later
 
-  ss >> token; // Castling flags
-  std::transform(token.begin(), token.end(), token.begin(), toggle_case);
+  ss >> token; // Castling availability
   f += token + " ";
 
-  ss >> token; // En-passant square
+  std::transform(f.begin(), f.end(), f.begin(), toggle_case);
+
+  ss >> token; // En passant square
   f += (token == "-" ? token : token.replace(1, 1, token[1] == '3' ? "6" : "3"));
 
-  std::getline(ss, token); // Full and half moves
+  std::getline(ss, token); // Half and full moves
   f += token;
 
   set(f, is_chess960(), this_thread());