[Board] Implement piece and setPiece

Board.cpp

@@ -3,17 +3,32 @@
 #include <ostream>
 #include <cassert>
 #include <cmath>
+#include <bitset>
+#include <algorithm>
 
 Board::Board() {
 }
 
 void Board::setPiece(const Square &square, const Piece::Optional &piece) {
-    (void) square;
-    (void) piece;
+
+    auto index = square.index();
+    for (auto &item : mPieceBBs) {
+        clearIndex(item, index);
+    }
+
+    setIndex(mPieceBBs[piece->typeVal() + piece->colorVal()], index);
 }
 
 Piece::Optional Board::piece(const Square &square) const {
-    (void) square;
+    int i = 0;
+    BitBoard mask = indexToBitBoard(square.index());
+    for (const auto &kPieceBb : mPieceBBs) {
+        if (kPieceBb & mask) {
+            return Piece(indexToColor(i), indexToType(i));
+        }
+
+        i++;
+    }
     return std::nullopt;
 }
 

Board.hpp

@@ -10,12 +10,19 @@
 #include <iosfwd>
 #include <vector>
 
+#define IDX_TO_COLOR(i) static_cast<PieceColor>(i % 2)
+#define IDX_TO_TYPE(i) static_cast<PieceType>(i - (i % 2))
+
+#define BB_NUM 12 // 6 pieces, 2 colors
+
 class Board {
 public:
 
     using Optional = std::optional<Board>;
     using MoveVec = std::vector<Move>;
 
+    using BitBoard = uint64_t;
+
     Board();
 
     void setPiece(const Square &square, const Piece::Optional &piece);
@@ -32,6 +39,29 @@ public:
     void pseudoLegalMoves(MoveVec &moves) const;
     void pseudoLegalMovesFrom(const Square &from, MoveVec &moves) const;
 
+private:
+
+    BitBoard mPieceBBs[BB_NUM] = {};
+
+    static inline void clearIndex(BitBoard &b, unsigned int i) {
+        b &= ~(1ULL << i);
+    }
+
+    static inline void setIndex(BitBoard &b, unsigned int i) {
+        b |= 1ULL << i;
+    }
+
+    static inline BitBoard indexToBitBoard(unsigned int i) {
+        return (1ULL << i);
+    }
+
+    static inline PieceColor indexToColor(unsigned int i) {
+        return static_cast<PieceColor>(i % 2);
+    }
+
+    static inline PieceType indexToType(unsigned int i) {
+        return static_cast<PieceType>(i - (i % 2));
+    }
 };
 
 std::ostream &operator<<(std::ostream &os, const Board &board);