add pgn-extract 22.11

pgn-extract/hashing.h

@@ -0,0 +1,66 @@
+/*
+ *  This file is part of pgn-extract: a Portable Game Notation (PGN) extractor.
+ *  Copyright (C) 1994-2022 David J. Barnes
+ *
+ *  pgn-extract is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  pgn-extract is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with pgn-extract. If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  David J. Barnes may be contacted as d.j.barnes@kent.ac.uk
+ *  https://www.cs.kent.ac.uk/people/staff/djb/
+ */
+
+        /* Define a type to hold hash values of interest.
+         * This is used both to aid in duplicate detection
+         * and in finding positional variations.
+         */
+#ifndef HASHING_H
+#define HASHING_H
+
+typedef struct HashLog {
+    /* Store both the final position hash value and
+     * the cumulative hash value for a game.
+     */
+    HashCode final_hash_value;
+    HashCode cumulative_hash_value;
+    /* Record the file list index for the file this game was first found in. */
+    unsigned file_number;
+    struct HashLog *next;
+} HashLog;
+
+/*
+ * A structure for counting the number of times a position arises
+ * in a game.
+ */
+typedef struct PositionCount {
+    HashCode hash_value;
+    Colour to_move;
+    unsigned short castling_rights;
+    Rank ep_rank;
+    Col ep_col;
+    unsigned count;
+    struct PositionCount *next;
+} PositionCount;
+
+
+Boolean check_duplicate_setup(const Game *game_details);
+Boolean check_for_only_repetition(PositionCount *position_counts);
+void clear_duplicate_hash_table(void);
+PositionCount *copy_position_count_list(PositionCount *original);
+void free_position_count_list(PositionCount *position_counts);
+void init_duplicate_hash_table(void);
+PositionCount *new_position_count_list(const Board *board);
+const char *previous_occurance(Game game_details, unsigned plycount);
+unsigned update_position_counts(PositionCount *position_counts, const Board *board);
+
+#endif	// HASHING_H
+