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0 #ifndef STELLAR_ZOBRIST_H

1 #define STELLAR_ZOBRIST_H

2

3 #include "piece.hpp"

4 #include "random.hpp"

5

6 #include <algorithm>

7 #include <array>

8 #include <random>

9

10 class Board;

11 class Zobrist {

12 public:

13 Zobrist() = delete;

14

15 static inline U64 hash(const Board &board);

16 static inline constexpr U64 key_side(void) { return keys_side; }

17 static inline constexpr U64 key_castle(int exp) { return keys_castle[exp]; }

18 static inline constexpr U64 key_enpassant(square::Square square) {

19 return keys_enpassant[to_underlying(square)];

20 }

21 static inline constexpr U64 key_piece(piece::Type type, color::Color color, square::Square square) {

22 return keys_piece[piece::get_index(type, color)][to_underlying(square)];

23 }

24

25 private:

26 typedef std::array<std::array<U64, 64>, 12> key_piece_array;

27 static inline constexpr const key_piece_array keys_piece = []() constexpr -> key_piece_array {

28 key_piece_array key_piece;

29 Random gen(C64(1804289383));

30 for (piece::Type type : piece::TypeIter()) {

31 int piece_index_white = piece::get(type, color::Color::WHITE).index;

32 int piece_index_black = piece::get(type, color::Color::BLACK).index;

33 for (int square = 0; square < 64; square++) {

34 key_piece[piece_index_white][square] = gen();

35 key_piece[piece_index_black][square] = gen();

36 }

37 }

38 return key_piece;

39 }();

40

41 typedef std::array<U64, 64> key_enpassant_array;

42 static inline constexpr const key_enpassant_array keys_enpassant = []() constexpr -> key_enpassant_array {

43 key_enpassant_array key_enpassant;

44 Random gen(C32(337245213));

45 for (int castle = 0; castle < 64; castle++) {

46 key_enpassant[castle] = gen();

47 }

48 return key_enpassant;

49 }();

50

51 typedef std::array<U64, 16> key_castle_array;

52 static inline constexpr const key_castle_array keys_castle = []() constexpr -> key_castle_array {

53 key_castle_array key_castle;

54 Random gen(C32(3642040919));

55 for (int castle = 0; castle < 16; castle++) {

56 key_castle[castle] = gen();

57 }

58 return key_castle;

59 }();

60

61 static inline constexpr const U64 keys_side = Random(C32(1699391443))();

62 };

63

64 #endif