From c9d9bddf3df97ef7987c9824747ec1602522b542 Mon Sep 17 00:00:00 2001
From: Aargh Rai <aargh.rai+git@gmail.com>
Date: Sat, 18 Jul 2026 18:45:15 +0530
Subject: zobrist hashing

---
 include/bitboard.h                   |  2 ++
 include/engine/magic.h               |  1 +
 include/engine/moves.h               |  1 +
 include/engine/transposition_table.h | 16 ++++++++++++++++
 include/random.h                     | 10 ++++++++++
 5 files changed, 30 insertions(+)
 create mode 100644 include/engine/transposition_table.h
 create mode 100644 include/random.h

(limited to 'include')

diff --git a/include/bitboard.h b/include/bitboard.h
index 3e1118d..b1ddcf0 100644
--- a/include/bitboard.h
+++ b/include/bitboard.h
@@ -27,11 +27,13 @@ enum {
   WHITE_LONG_CASTLE   =  1  <<  1,
   BLACK_SHORT_CASTLE  =  1  <<  2,
   BLACK_LONG_CASTLE   =  1  <<  3,
+  CASTLE_COUNT = 4,
 };
 
 enum {
   WHITE_TURN,
   BLACK_TURN,
+  TURN_COUNT,
 };
 
 #define BITMASK_RANK_1 255ULL
diff --git a/include/engine/magic.h b/include/engine/magic.h
index 7f584a9..1c9f303 100644
--- a/include/engine/magic.h
+++ b/include/engine/magic.h
@@ -3,6 +3,7 @@
 
 #include "ints.h"
 #include "bitboard.h"
+#include "random.h"
 
 typedef struct {
   bitboard_t mask;
diff --git a/include/engine/moves.h b/include/engine/moves.h
index 755a77a..cd71cdc 100644
--- a/include/engine/moves.h
+++ b/include/engine/moves.h
@@ -68,6 +68,7 @@ void get_moves(moves_t *moves, position_t position);
 
 bool square_attacked(position_t position, square_t square, u8 by_color);
 void get_legal_moves(moves_t *moves, position_t position);
+int find_piece_on_square(position_t* p, int square);
 
 #ifdef MOVES_INTERNAL
 void __forloop_rook_moves_gen(
diff --git a/include/engine/transposition_table.h b/include/engine/transposition_table.h
new file mode 100644
index 0000000..f06ddbe
--- /dev/null
+++ b/include/engine/transposition_table.h
@@ -0,0 +1,16 @@
+#ifndef TRANSPOSITION_TABLE_H
+#define TRANSPOSITION_TABLE_H
+
+#include "bitboard.h"
+
+static struct zobrist_keys {
+  u64 piece[PIECE_TYPE_COUNT][64];
+  u64 castle[CASTLE_COUNT];
+  u64 turn[TURN_COUNT];
+  u64 en_passant[64];
+} zobrist_keys;
+
+void transposition_table_init();
+u64 zobrist_hash(position_t position);
+
+#endif // TRANSPOSITION_TABLE_H
diff --git a/include/random.h b/include/random.h
new file mode 100644
index 0000000..633c015
--- /dev/null
+++ b/include/random.h
@@ -0,0 +1,10 @@
+#ifndef RANDOM_H
+#define RANDOM_H
+
+#include "ints.h"
+
+u64 random_u64();
+u64 random_magic();
+
+#endif // RANDOM_H
+
-- 
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