Various cleanup in book.cpp

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/book.cpp

@@ -42,12 +42,10 @@ using namespace std;
 
 namespace {
 
-  /// Book entry size in bytes
+  // Book entry size in bytes
   const int EntrySize = 16;
 
-
-  /// Random numbers from PolyGlot, used to compute book hash keys
-
+  // Random numbers from PolyGlot, used to compute book hash keys
   const uint64_t Random64[781] = {
     0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL,
     0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL,
@@ -312,17 +310,13 @@ namespace {
     0xF8D626AAAF278509ULL
   };
 
+  // Indices to the Random64[] array
+  const int PieceIdx     = 0;
+  const int CastleIdx    = 768;
+  const int EnPassantIdx = 772;
+  const int TurnIdx      = 780;
 
-  /// Indices to the Random64[] array
-
-  const int RandomPiece     = 0;
-  const int RandomCastle    = 768;
-  const int RandomEnPassant = 772;
-  const int RandomTurn      = 780;
-
-
-  /// Prototypes
-
+  // Local functions
   uint64_t book_key(const Position& pos);
   uint64_t book_piece_key(Piece p, Square s);
   uint64_t book_castle_key(const Position& pos);
@@ -351,6 +345,16 @@ Book::~Book() {
 }
 
 
+/// Book::close() closes the file only if it is open, otherwise
+/// we can end up in a little mess due to how std::ifstream works.
+
+void Book::close() {
+
+  if (is_open())
+      ifstream::close();
+}
+
+
 /// Book::open() opens a book file with a given file name
 
 void Book::open(const string& fName) {
@@ -360,29 +364,19 @@ void Book::open(const string& fName) {
 
   fileName = fName;
   ifstream::open(fileName.c_str(), ifstream::in | ifstream::binary);
-  if (!is_open())
-      return;
 
+  if (is_open())
+  {
       // Get the book size in number of entries
       seekg(0, ios::end);
       bookSize = long(tellg()) / EntrySize;
       seekg(0, ios::beg);
 
-  if (!good())
-  {
+      if (good())
+          return;
+  }
   cerr << "Failed to open book file " << fileName << endl;
   Application::exit_with_failure();
-  }
-}
-
-
-/// Book::close() closes the file only if it is open, otherwise
-/// we can end up in a little mess due to how std::ifstream works.
-
-void Book::close() {
-
-  if (is_open())
-      ifstream::close();
 }
 
 
@@ -438,6 +432,7 @@ Move Book::get_move(const Position& pos, bool findBestMove) {
   if (!bookMove)
       return MOVE_NONE;
 
+  // Verify the book move is legal
   MoveStack mlist[MOVES_MAX];
   MoveStack* last = generate_moves(pos, mlist);
   for (MoveStack* cur = mlist; cur != last; cur++)
@@ -471,6 +466,7 @@ int Book::find_key(uint64_t key) {
       assert(mid >= left && mid < right);
 
       read_entry(entry, mid);
+
       if (key <= entry.key)
           right = mid;
       else
@@ -480,7 +476,7 @@ int Book::find_key(uint64_t key) {
   assert(left == right);
 
   read_entry(entry, left);
-  return (entry.key == key)? left : bookSize;
+  return entry.key == key ? left : bookSize;
 }
 
 
@@ -494,7 +490,9 @@ void Book::read_entry(BookEntry& entry, int idx) {
   assert(is_open());
 
   seekg(idx * EntrySize, ios_base::beg);
+
   *this >> entry;
+
   if (!good())
   {
       cerr << "Failed to read book entry at index " << idx << endl;
@@ -509,10 +507,11 @@ void Book::read_entry(BookEntry& entry, int idx) {
 uint64_t Book::read_integer(int size) {
 
   char buf[8];
+  uint64_t n = 0;
+
   read(buf, size);
 
   // Numbers are stored on disk as a binary byte stream
-  uint64_t n = 0;
   for (int i = 0; i < size; i++)
       n = (n << 8) + (unsigned char)buf[i];
 
@@ -529,22 +528,14 @@ namespace {
   uint64_t book_key(const Position& pos) {
 
     uint64_t result = 0;
-
-    for (Color c = WHITE; c <= BLACK; c++)
-    {
-        Bitboard b = pos.pieces_of_color(c);
+    Bitboard b = pos.pieces_of_color(WHITE) | pos.pieces_of_color(BLACK);
 
     while (b)
     {
         Square s = pop_1st_bit(&b);
-            Piece p = pos.piece_on(s);
-
-            assert(piece_is_ok(p));
-            assert(color_of_piece(p) == c);
-
-            result ^= book_piece_key(p, s);
-        }
+        result ^= book_piece_key(pos.piece_on(s), s);
     }
+
     result ^= book_castle_key(pos);
     result ^= book_ep_key(pos);
     result ^= book_color_key(pos);
@@ -554,10 +545,10 @@ namespace {
 
   uint64_t book_piece_key(Piece p, Square s) {
 
-    /// Convert pieces to the range 0..11
+    // Convert pieces to the range 0..11
     static const int PieceTo12[] = { 0, 0, 2, 4, 6, 8, 10, 0, 0, 1, 3, 5, 7, 9, 11 };
 
-    return Random64[RandomPiece + (PieceTo12[int(p)]^1) * 64 + int(s)];
+    return Random64[PieceIdx + (PieceTo12[int(p)]^1) * 64 + int(s)];
   }
 
 
@@ -566,27 +557,29 @@ namespace {
     uint64_t result = 0;
 
     if (pos.can_castle_kingside(WHITE))
-        result ^= Random64[RandomCastle+0];
+        result ^= Random64[CastleIdx + 0];
 
     if (pos.can_castle_queenside(WHITE))
-        result ^= Random64[RandomCastle+1];
+        result ^= Random64[CastleIdx + 1];
 
     if (pos.can_castle_kingside(BLACK))
-        result ^= Random64[RandomCastle+2];
+        result ^= Random64[CastleIdx + 2];
 
     if (pos.can_castle_queenside(BLACK))
-        result ^= Random64[RandomCastle+3];
+        result ^= Random64[CastleIdx + 3];
 
     return result;
   }
 
 
   uint64_t book_ep_key(const Position& pos) {
-    return pos.ep_square() == SQ_NONE ? 0 : Random64[RandomEnPassant + square_file(pos.ep_square())];
+
+    return pos.ep_square() == SQ_NONE ? 0 : Random64[EnPassantIdx + square_file(pos.ep_square())];
   }
 
 
   uint64_t book_color_key(const Position& pos) {
-    return pos.side_to_move() == WHITE ? Random64[RandomTurn] : 0;
+
+    return pos.side_to_move() == WHITE ? Random64[TurnIdx] : 0;
   }
 }

src/rkiss.h

@@ -72,7 +72,7 @@ class RKISS {
 
       s.a = 0xf1ea5eed;
       s.b = s.c = s.d = 0xd4e12c77;
-      for (uint64_t i = 0; i < 73; i++)
+      for (int i = 0; i < 73; i++)
           rand64();
   }