X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=599d0120da852fb4b379d27430a3b174e8055537;hp=b8eb3220a776b026a890d031af7e6db7368fac69;hb=4dded4e72f9b9582db8adc9a478e9eda5841d8c5;hpb=f08a6eed0d3938e451b6da384ae39ffb58f25dd4

diff --git a/src/bitboard.h b/src/bitboard.h
index b8eb3220..599d0120 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -90,6 +90,7 @@ extern Bitboard RookPseudoAttacks[64];
 extern Bitboard QueenPseudoAttacks[64];
 
 extern uint8_t BitCount8Bit[256];
+extern int8_t DirectionTable[64][64];
 
 
 ////
@@ -297,6 +298,24 @@ inline Bitboard attack_span_mask(Color c, Square s) {
 }
 
 
+/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
+/// either on a straight or on a diagonal line.
+
+inline bool squares_aligned(Square s1, Square s2, Square s3) {
+  return   DirectionTable[s1][s2] != DELTA_NONE
+        && abs(DirectionTable[s1][s2]) ==  abs(DirectionTable[s2][s3]);
+}
+
+
+/// squares_straight_aligned returns true if the squares s1 and s2 are aligned
+/// on a straight line, either veritical or horizontal.
+
+inline bool squares_straight_aligned(Square s1, Square s2) {
+  return   abs(DirectionTable[s1][s2]) == DELTA_N
+        || abs(DirectionTable[s1][s2]) == DELTA_E;
+}
+
+
 /// first_1() finds the least significant nonzero bit in a nonzero bitboard.
 /// pop_1st_bit() finds and clears the least significant nonzero bit in a
 /// nonzero bitboard.