add bitScanReverse; bitboardRooks

bitboardRooks.cpp

@@ -0,0 +1,94 @@
+#include "bitboard.cpp" //??
+
+BitboardRooks::BitboardRooks(U64 dec): Bitboard(dec) {}
+
+U64 BitboardRooks::rookRays[4][64];
+
+void BitboardRooks::initializeRookRays() {
+	/* 0:east
+	*  1:west
+	*  2:north
+	*  3:south */
+
+    /*east & west rays*/
+    U64 currentEast = Bitboard::firstRank;
+	U64 currentWest = Bitboard::firstRank;
+    for (int file = 0; file < 8; file++) {
+		currentEast = (currentEast << 1) & Bitboard::notAFile;   
+        currentWest = (currentWest >> 1) & Bitboard::notHFile;
+		U64 tempEast = currentEast;
+		U64 tempWest = currentWest;
+        for (int rank = 0; rank < 8; rank++) { //fill the same file 
+            int index = 8*rank+file;
+            rookRays[0][index] = tempEast;          //8*rank+file
+			rookRays[1][index-2*file+7] = tempWest; //8*rank+(7-file) = (8*rank+file)-2*file+7
+            tempEast <<= 8; //shift "up"    
+			tempWest <<= 8; 
+		}
+    }
+
+	/*north & east rays*/
+	U64 currentNorth = ~Bitboard::notAFile;
+	U64 currentSouth = ~Bitboard::notAFile;
+	for (int rank = 0; rank < 8; rank++) {
+		currentNorth <<= 8;
+		currentSouth >>= 8;
+		U64 tempNorth = currentNorth;
+		U64 tempSouth = currentSouth;
+		for (int file = 0; file < 8; file++) {
+			int index = 8*rank+file;
+			rookRays[2][index] = tempNorth;
+			rookRays[3][8*(7-rank)+file] = tempSouth; 
+			tempNorth = (tempNorth << 1) & Bitboard::notAFile; //shift "right"
+			tempSouth = (tempSouth << 1) & Bitboard::notAFile;
+		}
+	}	
+}
+
+Bitboard BitboardRooks::RookMoves(int index, Bitboard occupiedBitboard) {
+	if ((occupiedBitboard.getBitboard()&(1ULL << index)) == 0) throw std::out_of_range("No rook lies in this index");
+
+	initializeRookRays(); //move to startup
+	int firstBlocker;
+
+	/*east attack-set*/
+	U64 eastAttacks;
+	U64 maskedBlockers = occupiedBitboard.getBitboard() & rookRays[0][index]; 
+	if (maskedBlockers != 0) { 
+		firstBlocker = bitwise::bitScanForward(maskedBlockers);   
+		eastAttacks = rookRays[0][index] ^ rookRays[0][firstBlocker];
+	}
+	else eastAttacks = rookRays[0][index];
+
+	/*west attack-set*/
+	U64 westAttacks;
+	maskedBlockers = occupiedBitboard.getBitboard() & rookRays[1][index];	
+	if (maskedBlockers != 0) { 
+		firstBlocker = bitwise::bitScanReverse(maskedBlockers); 
+		westAttacks = rookRays[1][index] ^ rookRays[1][firstBlocker];	
+	}
+	else westAttacks = rookRays[1][index];
+
+	/*north attack-set*/
+	U64 northAttacks;
+	maskedBlockers = occupiedBitboard.getBitboard() & rookRays[2][index]; 
+	if (maskedBlockers != 0) { 
+		firstBlocker = bitwise::bitScanForward(maskedBlockers);   
+		northAttacks = rookRays[2][index] ^ rookRays[2][firstBlocker];
+	}
+	else northAttacks = rookRays[2][index];	
+
+	/*south attack-set*/
+	U64 southAttacks;
+	maskedBlockers = occupiedBitboard.getBitboard() & rookRays[3][index];	
+	if (maskedBlockers != 0) { 
+		firstBlocker = bitwise::bitScanReverse(maskedBlockers);
+		southAttacks = rookRays[3][index] ^ rookRays[3][firstBlocker]; 
+	}
+	else southAttacks = rookRays[3][index]; 
+
+
+	return Bitboard(eastAttacks|westAttacks|northAttacks|southAttacks);	 
+}
+
+