1 files changed, 81 insertions, 0 deletions
diff --git a/board.cpp b/board.cpp
new file mode 100644
index 0000000..5afcea1
--- /dev/null
+++ b/board.cpp
@@ -0,0 +1,81 @@
+#include <array>
+#include "board.h"
+
+using namespace std;
+
+
+Board Board::empty() {
+	Board B;
+	B.bd[0] = B.bd[1] = 0;
+	return B;
+}
+
+Board Board::uninitialised() {
+	return Board();
+}
+
+void Board::drop(int xy, int v) {
+	uint64_t mask = 0xfULL << (4 * xy), stkbot = 0x1ULL << (4 * xy);
+	uint64_t bit = ((bd[0] | bd[1]) & mask) + stkbot;
+	bd[v] |= bit;
+}
+
+bool Board::stkFull(int xy) const {
+	uint64_t mask = 0xfULL << (4 * xy);
+	return ((bd[0] | bd[1]) & mask) == mask;
+}
+
+static array<uint64_t, 61> winmasks = {
+	0xfULL, 0xf0ULL, 0xf00ULL, 0x1111ULL,
+	0x2222ULL, 0x4444ULL, 0x8421ULL, 0x8888ULL,
+	0xf000ULL, 0xf0000ULL, 0xf00000ULL, 0xf000000ULL,
+	0x11110000ULL, 0x22220000ULL, 0x44440000ULL, 0x84210000ULL,
+	0x88880000ULL, 0xf0000000ULL, 0xf00000000ULL, 0xf000000000ULL,
+	0xf0000000000ULL, 0x111100000000ULL, 0x222200000000ULL, 0x444400000000ULL,
+	0x842100000000ULL, 0x888800000000ULL, 0xf00000000000ULL, 0x1000100010001ULL,
+	0x2000200020002ULL, 0x4000400040004ULL, 0x8000400020001ULL, 0x8000800080008ULL,
+	0xf000000000000ULL, 0x10001000100010ULL, 0x20002000200020ULL, 0x40004000400040ULL,
+	0x80004000200010ULL, 0x80008000800080ULL, 0xf0000000000000ULL, 0x100010001000100ULL,
+	0x200020002000200ULL, 0x400040004000400ULL, 0x800040002000100ULL, 0x800080008000800ULL,
+	0xf00000000000000ULL, 0x1000010000100001ULL, 0x1000100010001000ULL, 0x1111000000000000ULL,
+	0x2000020000200002ULL, 0x2000200020002000ULL, 0x2222000000000000ULL, 0x4000040000400004ULL,
+	0x4000400040004000ULL, 0x4444000000000000ULL, 0x8000040000200001ULL, 0x8000080000800008ULL,
+	0x8000400020001000ULL, 0x8000800080008000ULL, 0x8421000000000000ULL, 0x8888000000000000ULL,
+	0xf000000000000000ULL,
+};
+
+win_t Board::checkWin() const {
+	if ((bd[0] | bd[1]) == ~0ULL) return WIN_DRAW;
+
+	for (int i = 0; i < (int)winmasks.size(); i++) {
+		if ((bd[0] & winmasks[i]) == winmasks[i]) return WIN_P0;
+		if ((bd[1] & winmasks[i]) == winmasks[i]) return WIN_P1;
+	}
+
+	return WIN_NONE;
+}
+
+uint64_t Board::hash() const {
+	return bd[0] ^ ((bd[1] << 29) | (bd[1] >> (64 - 29)));
+}
+
+int Board::numFilled() const {
+	return __builtin_popcountll(bd[0] | bd[1]);
+}
+
+bool Board::isEmpty() const {
+	return bd[0] == 0 && bd[1] == 0;
+}
+
+int Board::numValidMoves() const {
+	uint64_t topsMask = 0x8888'8888'8888'8888ULL;
+	return 16 - __builtin_popcountll((bd[0] | bd[1]) & topsMask);
+}
+
+int Board::playerToMove() const {
+	return numFilled() % 2;
+}
+
+bool Board::operator==(const Board &other) const {
+	return bd[0] == other.bd[0] && bd[1] == other.bd[1];
+}