X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbook.cpp;h=40b647cfe44a8ad27e1dc33965f0867d6377d531;hp=fbb1984cf5cba6ca183465f7b58b5d4bbeaedb0a;hb=0412f4a1ee1b738441490dd6f3d324c21ee75987;hpb=61a054b17002a167a09ce09eb9a7d820d792c680

diff --git a/src/book.cpp b/src/book.cpp
index fbb1984c..40b647cf 100644
--- a/src/book.cpp
+++ b/src/book.cpp
@@ -306,11 +306,6 @@ namespace {
   const Key* ZobEnPassant = PolyGlotRandoms + 772;
   const Key* ZobTurn      = PolyGlotRandoms + 780;
 
-  // PieceOffset is calculated as 64 * (PolyPiece ^ 1) where PolyPiece
-  // is: BP = 0, WP = 1, BN = 2, WN = 3 ... BK = 10, WK = 11
-  const int PieceOffset[] = { 0, 64, 192, 320, 448, 576, 704, 0,
-                              0,  0, 128, 256, 384, 512, 640 };
-
   // book_key() returns the PolyGlot hash key of the given position
   uint64_t book_key(const Position& pos) {
 
@@ -319,8 +314,12 @@ namespace {
 
     while (b)
     {
+        // Piece offset is at 64 * polyPiece where polyPiece is defined as:
+        // BP = 0, WP = 1, BN = 2, WN = 3, ... BK = 10, WK = 11
         Square s = pop_1st_bit(&b);
-        key ^= ZobPiece[PieceOffset[pos.piece_on(s)] + s];
+        Piece p = pos.piece_on(s);
+        int polyPiece = 2 * (type_of(p) - 1) + (color_of(p) == WHITE);
+        key ^= ZobPiece[64 * polyPiece + s];
     }
 
     b = pos.can_castle(ALL_CASTLES);
@@ -379,7 +378,10 @@ bool Book::open(const char* fName) {
   ifstream::open(fName, ifstream::in | ifstream::binary | ios::ate);
 
   if (!is_open())
+  {
+      clear();
       return false; // Silently fail if the file is not found
+  }
 
   // Get the book size in number of entries, we are already at the end of file
   size = (size_t)tellg() / sizeof(BookEntry);