From de58594b0f95115109d0c8aeb56a6c5c85b94b9f Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 8 May 2011 10:40:30 +0100 Subject: [PATCH] Use standard naming conventions in book.cpp No functional change. Signed-off-by: Marco Costalba --- src/book.cpp | 61 +++++++++++++++++++++++++++------------------------- src/book.h | 2 +- 2 files changed, 33 insertions(+), 30 deletions(-) diff --git a/src/book.cpp b/src/book.cpp index 757c8238..8944b31b 100644 --- a/src/book.cpp +++ b/src/book.cpp @@ -35,7 +35,7 @@ using namespace std; namespace { // Random numbers from PolyGlot, used to compute book hash keys - const uint64_t Random64[781] = { + const Key PolyGlotRandoms[781] = { 0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL, 0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL, 0x0FBBAD1F61042279ULL, 0xE83A908FF2FB60CAULL, 0x0D7E765D58755C10ULL, @@ -299,55 +299,54 @@ namespace { 0xF8D626AAAF278509ULL }; - // Indices to the Random64[] array - const int PieceIdx = 0; - const int CastleIdx = 768; - const int EnPassantIdx = 772; - const int TurnIdx = 780; + // Offsets to the PolyGlotRandoms[] array of zobrist keys + const Key* ZobPiece = PolyGlotRandoms + 0; + const Key* ZobCastle = PolyGlotRandoms + 768; + const Key* ZobEnPassant = PolyGlotRandoms + 772; + const Key* ZobTurn = PolyGlotRandoms + 780; + + // Piece offset is calculated as 64 * (PolyPiece ^ 1) where + // PolyPiece is: BP = 0, WP = 1, BN = 2, WN = 3 ... BK = 10, WK = 11 + const int PieceOfs[] = { 0, 64, 192, 320, 448, 576, 704, 0, + 0, 0, 128, 256, 384, 512, 640 }; // book_key() builds up a PolyGlot hash key out of a position uint64_t book_key(const Position& pos) { - // Piece offset is calculated as (64 * PolyPieceType + square), where - // PolyPieceType is: BP = 0, WP = 1, BN = 2, WN = 3 .... BK = 10, WK = 11 - static const int PieceToPoly[] = { 0, 1, 3, 5, 7, 9, 11, 0, 0, 0, 2, 4, 6, 8, 10 }; - uint64_t result = 0; Bitboard b = pos.occupied_squares(); while (b) { Square s = pop_1st_bit(&b); - int p = PieceToPoly[int(pos.piece_on(s))]; - result ^= Random64[PieceIdx + 64 * p + int(s)]; + result ^= ZobPiece[PieceOfs[pos.piece_on(s)] + s]; } if (pos.can_castle_kingside(WHITE)) - result ^= Random64[CastleIdx + 0]; + result ^= ZobCastle[0]; if (pos.can_castle_queenside(WHITE)) - result ^= Random64[CastleIdx + 1]; + result ^= ZobCastle[1]; if (pos.can_castle_kingside(BLACK)) - result ^= Random64[CastleIdx + 2]; + result ^= ZobCastle[2]; if (pos.can_castle_queenside(BLACK)) - result ^= Random64[CastleIdx + 3]; + result ^= ZobCastle[3]; if (pos.ep_square() != SQ_NONE) - result ^= Random64[EnPassantIdx + square_file(pos.ep_square())]; + result ^= ZobEnPassant[square_file(pos.ep_square())]; if (pos.side_to_move() == WHITE) - result ^= Random64[TurnIdx]; + result ^= ZobTurn[0]; return result; } - } /// Book c'tor. Make random number generation less deterministic, for book moves -Book::Book() { +Book::Book() : bookSize(0) { for (int i = abs(get_system_time() % 10000); i > 0; i--) RKiss.rand(); @@ -371,6 +370,7 @@ void Book::close() { bookFile.close(); bookName = ""; + bookSize = 0; } @@ -408,7 +408,7 @@ void Book::open(const string& fileName) { Move Book::get_move(const Position& pos, bool findBestMove) { - if (!bookFile.is_open() || bookSize == 0) + if (!bookSize || !bookFile.is_open()) return MOVE_NONE; BookEntry entry; @@ -417,7 +417,7 @@ Move Book::get_move(const Position& pos, bool findBestMove) { uint64_t key = book_key(pos); // Choose a book move among the possible moves for the given position - for (int idx = find_entry(key); idx < bookSize; idx++) + for (int idx = first_entry(key); idx < bookSize; idx++) { entry = read_entry(idx); @@ -429,8 +429,8 @@ Move Book::get_move(const Position& pos, bool findBestMove) { if (!findBestMove) { // Choose book move according to its score. If a move has a very - // high score it has more probability to be choosen then a one with - // lower score. Note that first entry is always chosen. + // high score it has higher probability to be choosen than a move + // with lower score. Note that first entry is always chosen. scoresSum += score; if (RKiss.rand() % scoresSum < score) bookMove = entry.move; @@ -442,6 +442,9 @@ Move Book::get_move(const Position& pos, bool findBestMove) { } } + if (!bookMove) + return MOVE_NONE; + // A PolyGlot book move is encoded as follows: // // bit 0- 5: destination square (from 0 to 63) @@ -469,16 +472,16 @@ Move Book::get_move(const Position& pos, bool findBestMove) { } -/// Book::find_entry() takes a book key as input, and does a binary search -/// through the book file for the given key. The index to the first book -/// entry with the same key as the input is returned. When the key is not +/// Book::first_entry() takes a book key as input, and does a binary search +/// through the book file for the given key. The index to the first (leftmost) +/// book entry with the same key as the input is returned. When the key is not /// found in the book file, bookSize is returned. -int Book::find_entry(uint64_t key) { +int Book::first_entry(uint64_t key) { int left, right, mid; - // Binary search (finds the leftmost entry) + // Binary search (finds the leftmost entry with given key) left = 0; right = bookSize - 1; diff --git a/src/book.h b/src/book.h index 0101bcf2..38804f9a 100644 --- a/src/book.h +++ b/src/book.h @@ -51,7 +51,7 @@ private: template Book& operator>>(T& n); BookEntry read_entry(int idx); - int find_entry(uint64_t key); + int first_entry(uint64_t key); std::ifstream bookFile; std::string bookName; -- 2.39.2