X-Git-Url: http://winboard.nl/cgi-bin?a=blobdiff_plain;f=hash.c;fp=hash.c;h=4baa0aac68e6a150bcc81c82510e936f93ae455a;hb=e15efca6667b2673b4c1a5879a6917eab6800e58;hp=0000000000000000000000000000000000000000;hpb=0d182b4efac85dce968068bfe4509e52e9a30051;p=polyglot.git

diff --git a/hash.c b/hash.c
new file mode 100644
index 0000000..4baa0aa
--- /dev/null
+++ b/hash.c
@@ -0,0 +1,128 @@
+
+// hash.c
+
+// includes
+
+#include "board.h"
+#include "hash.h"
+#include "piece.h"
+#include "random.h"
+#include "square.h"
+#include "util.h"
+
+// variables
+
+static uint64 Castle64[16];
+
+// prototypes
+
+static uint64 hash_castle_key_debug (int flags);
+
+// functions
+
+// hash_init()
+
+void hash_init() {
+
+   int i;
+
+   for (i = 0; i < 16; i++) Castle64[i] = hash_castle_key_debug(i);
+}
+
+// hash_key()
+
+uint64 hash_key(const board_t * board) {
+
+   uint64 key;
+   int colour;
+   const uint8 * ptr;
+   int sq, piece;
+
+   ASSERT(board_is_ok(board));
+
+   // init
+
+   key = 0;
+
+   // pieces
+
+   for (colour = 1; colour <= 2; colour++) { // HACK
+      for (ptr = board->list[colour]; (sq=*ptr) != SquareNone; ptr++) {
+         piece = board->square[sq];
+         key ^= hash_piece_key(piece,sq);
+      }
+   }
+
+   // castle flags
+
+   key ^= hash_castle_key(board_flags(board));
+
+   // en-passant square
+
+   sq = board->ep_square;
+   if (sq != SquareNone) key ^= hash_ep_key(sq);
+
+   // turn
+
+   key ^= hash_turn_key(board->turn);
+
+   return key;
+}
+
+// hash_piece_key()
+
+uint64 hash_piece_key(int piece, int square) {
+
+   ASSERT(piece_is_ok(piece));
+   ASSERT(square_is_ok(square));
+
+   return random_64(RandomPiece+piece_to_12(piece)*64+square_to_64(square));
+}
+
+// hash_castle_key()
+
+uint64 hash_castle_key(int flags) {
+
+   ASSERT((flags&~0xF)==0);
+
+   return Castle64[flags];
+}
+
+// hash_castle_key_debug()
+
+static uint64 hash_castle_key_debug(int flags) {
+
+   uint64 key;
+   int i;
+
+   ASSERT((flags&~0xF)==0);
+
+   key = 0;
+
+   for (i = 0; i < 4; i++) {
+      if ((flags & (1<<i)) != 0) key ^= random_64(RandomCastle+i);
+   }
+
+   return key;
+}
+
+// hash_ep_key()
+
+uint64 hash_ep_key(int square) {
+
+   ASSERT(square_is_ok(square));
+
+   return random_64(RandomEnPassant+square_file(square));
+}
+
+// hash_turn_key()
+
+uint64 hash_turn_key(int colour) {
+
+   ASSERT(colour_is_ok(colour));
+
+   return (colour_is_white(colour)) ? random_64(RandomTurn) : 0;
+}
+
+// end of hash.cpp
+