private static bool Read(ref BookEntry e, BinaryReader br)
{
if (br.BaseStream.Length == br.BaseStream.Position)
{
return(false);
}
byte[] t = br.ReadBytes((int)SIZE_OF_BOOKENTRY);
e.key =
(((UInt64)t[0]) << 56) |
(((UInt64)t[1]) << 48) |
(((UInt64)t[2]) << 40) |
(((UInt64)t[3]) << 32) |
(((UInt64)t[4]) << 24) |
(((UInt64)t[5]) << 16) |
(((UInt64)t[6]) << 8) |
(((UInt64)t[7]) << 0);
e.move = (UInt16)(
(((UInt64)t[8]) << 8) |
(((UInt64)t[9]) << 0));
e.count = (UInt16)(
(((UInt64)t[10]) << 8) |
(((UInt64)t[11]) << 0));
e.learn = (UInt32)(
(((UInt64)t[12]) << 24) |
(((UInt64)t[13]) << 16) |
(((UInt64)t[14]) << 8) |
(((UInt64)t[15]) << 0));
return(true);
}
/// Book::binary_search() takes a book key as input, and does a binary search
/// through the book file for the given key. File stream current position is set
/// to the leftmost book entry with the same key as the input.
private static void binary_search(UInt64 key, UInt64 size, BinaryReader br)
{
UInt64 low, high, mid;
BookEntry e = new BookEntry();
low = 0;
high = (ulong)(size - 1);
Debug.Assert(low <= high);
while (low < high)
{
mid = (low + high) / 2;
Debug.Assert(mid >= low && mid < high);
br.BaseStream.Seek((long)(mid * SIZE_OF_BOOKENTRY), SeekOrigin.Begin);
Read(ref e, br);
if (key <= e.key)
{
high = mid;
}
else
{
low = mid + 1;
}
}
Debug.Assert(low == high);
br.BaseStream.Seek((long)(low * SIZE_OF_BOOKENTRY), SeekOrigin.Begin);
}
/// Book::probe() tries to find a book move for the given position. If no move
/// is found returns MOVE_NONE. If pickBest is true returns always the highest
/// rated move, otherwise randomly chooses one, based on the move score.
internal static Move probe(Position pos, string filename, bool pickBest)
{
#if WINDOWS_RT
#region DLL book (local)
if (bookNotExists)
{
return(MoveC.MOVE_NONE);
}
BookEntry e = new BookEntry();
UInt16 best = 0;
uint sum = 0;
Move move = MoveC.MOVE_NONE;
UInt64 key = book_key(pos);
using (Stream fs = typeof(Engine).GetTypeInfo().Assembly.GetManifestResourceStream("SethRocks.book.bin"))
{
if (fs == null)
{
bookNotExists = true;
return(MoveC.MOVE_NONE);
}
UInt64 size = (UInt64)(fs.Length / SIZE_OF_BOOKENTRY);
using (BinaryReader br = new BinaryReader(fs))
{
binary_search(key, size, br);
while (Read(ref e, br) && (e.key == key))
{
best = Math.Max(best, e.count);
sum += e.count;
// Choose book move according to its score. If a move has a very
// high score it has higher probability to be choosen than a move
// with lower score. Note that first entry is always chosen.
if ((RKiss.rand() % sum < e.count) ||
(pickBest && e.count == best))
{
move = e.move;
}
}
}
}
#endregion
#elif PORTABLE
#region DLL book
if (bookNotExists)
{
return(MoveC.MOVE_NONE);
}
BookEntry e = new BookEntry();
UInt16 best = 0;
uint sum = 0;
Move move = MoveC.MOVE_NONE;
UInt64 key = book_key(pos);
try
{
System.Reflection.Assembly bookAssembly = System.Reflection.Assembly.Load("SethRocksBook");
using (Stream fs = bookAssembly.GetManifestResourceStream("SethRocksBook.book.bin"))
{
UInt64 size = (UInt64)(fs.Length / SIZE_OF_BOOKENTRY);
using (BinaryReader br = new BinaryReader(fs))
{
binary_search(key, size, br);
while (Read(ref e, br) && (e.key == key))
{
best = Math.Max(best, e.count);
sum += e.count;
// Choose book move according to its score. If a move has a very
// high score it has higher probability to be choosen than a move
// with lower score. Note that first entry is always chosen.
if ((RKiss.rand() % sum < e.count) ||
(pickBest && e.count == best))
{
move = e.move;
}
}
}
}
}
catch (System.IO.FileNotFoundException)
{
bookNotExists = true;
return(MoveC.MOVE_NONE);
}
#endregion
#else
#region File system read
if (!System.IO.File.Exists(filename))
{
return(MoveC.MOVE_NONE);
}
BookEntry e = new BookEntry();
UInt16 best = 0;
uint sum = 0;
Move move = MoveC.MOVE_NONE;
UInt64 key = book_key(pos);
using (FileStream fs = new FileStream(filename, FileMode.Open))
{
UInt64 size = (UInt64)(fs.Length / SIZE_OF_BOOKENTRY);
using (BinaryReader br = new BinaryReader(fs))
{
binary_search(key, size, br);
while (Read(ref e, br) && (e.key == key))
{
best = Math.Max(best, e.count);
sum += e.count;
// Choose book move according to its score. If a move has a very
// high score it has higher probability to be choosen than a move
// with lower score. Note that first entry is always chosen.
if (((sum != 0) && (RKiss.rand() % sum < e.count)) ||
(pickBest && e.count == best))
{
move = e.move;
}
}
br.Close();
}
fs.Close();
}
#endregion
#endif
if (move != 0)
{
// A PolyGlot book move is encoded as follows:
//
// bit 0- 5: destination square (from 0 to 63)
// bit 6-11: origin square (from 0 to 63)
// bit 12-14: promotion piece (from KNIGHT == 1 to QUEEN == 4)
//
// Castling moves follow "king captures rook" representation. So in case book
// move is a promotion we have to convert to our representation, in all the
// other cases we can directly compare with a Move after having masked out
// the special Move's flags (bit 14-15) that are not supported by PolyGlot.
int pt = (move >> 12) & 7;
if (pt != 0)
{
move = Utils.make_promotion(Utils.from_sq(move), Utils.to_sq(move), (pt + 1));
}
// Add 'special move' flags and verify it is legal
MList mlist = MListBroker.GetObject(); mlist.pos = 0;
Movegen.generate_legal(pos, mlist.moves, ref mlist.pos);
for (int i = 0; i < mlist.pos; i++)
{
if (move == (mlist.moves[i].move & 0x3FFF))
{
Move retval = mlist.moves[i].move;
MListBroker.Free();
return(retval);
}
}
MListBroker.Free();
}
return(MoveC.MOVE_NONE);
}