board.h

   1 #ifndef ZZGO_BOARD_H
   2 #define ZZGO_BOARD_H
   3
   4 #include <stdbool.h>
   5 #include <stdint.h>
   6
   7 #include "stone.h"
   8 #include "move.h"
   9
  10 #define likely(x) __builtin_expect(!!(x), 1)
  11 #define unlikely(x) __builtin_expect((x), 0)
  12
  13
  14 /* The board implementation has bunch of optional features.
  15  * Turn them on below: */
  16 #define WANT_BOARD_C // required by playout_moggy
  17 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  18
  19
  20 /* Allow board_play_random_move() to return pass even when
  21  * there are other moves available. */
  22 extern bool random_pass;
  23
  24
  25 /* Some engines might normalize their reading and skip symmetrical
  26  * moves. We will tell them how can they do it. */
  27 struct board_symmetry {
  28         /* Playground is in this rectangle. */
  29         int x1, x2, y1, y2;
  30         /* d ==  0: Full rectangle
  31          * d ==  1: Top triangle */
  32         int d;
  33         /* General symmetry type. */
  34         /* Note that the above is redundant to this, but just provided
  35          * for easier usage. */
  36         enum {
  37                 SYM_FULL,
  38                 SYM_DIAG_UP,
  39                 SYM_DIAG_DOWN,
  40                 SYM_HORIZ,
  41                 SYM_VERT,
  42                 SYM_NONE
  43         } type;
  44 };
  45
  46
  47 typedef uint64_t hash_t;
  48
  49
  50 /* Note that "group" is only chain of stones that is solidly
  51  * connected for us. */
  52 typedef coord_t group_t;
  53
  54 struct group {
  55         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  56          * don't care. */
  57         /* _Combination_ of these two values can make some difference
  58          * in performance - fine-tune. */
  59 #define GROUP_KEEP_LIBS 10
  60         // refill lib[] only when we hit this; this must be at least 2!
  61         // Moggy requires at least 3 - see below for semantic impact.
  62 #define GROUP_REFILL_LIBS 5
  63         coord_t lib[GROUP_KEEP_LIBS];
  64         /* libs is only LOWER BOUND for the number of real liberties!!!
  65          * It denotes only number of items in lib[], thus you can rely
  66          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  67         int libs;
  68 };
  69
  70 struct neighbor_colors {
  71         char colors[S_MAX];
  72 };
  73
  74 /* You should treat this struct as read-only. Always call functions below if
  75  * you want to change it. */
  76
  77 struct board {
  78         int size; /* Including S_OFFBOARD margin - see below. */
  79         int size2; /* size^2 */
  80         int captures[S_MAX];
  81         float komi;
  82         int handicap;
  83
  84         int moves;
  85         struct move last_move;
  86         struct move last_move2; /* second-to-last move */
  87         /* Whether we tried to add a hash twice; board_play*() can
  88          * set this, but it will still carry out the move as well! */
  89         bool superko_violation;
  90
  91         /* The following two structures are goban maps and are indexed by
  92          * coord.pos. The map is surrounded by a one-point margin from
  93          * S_OFFBOARD stones in order to speed up some internal loops.
  94          * Some of the foreach iterators below might include these points;
  95          * you need to handle them yourselves, if you need to. */
  96
  97         /* Stones played on the board */
  98         enum stone *b; /* enum stone */
  99         /* Group id the stones are part of; 0 == no group */
 100         group_t *g;
 101         /* Positions of next stones in the stone group; 0 == last stone */
 102         coord_t *p;
 103         /* Neighboring colors; numbers of neighbors of index color */
 104         struct neighbor_colors *n;
 105         /* Zobrist hash for each position */
 106         hash_t *h;
 107
 108         /* Group information - indexed by gid (which is coord of base group stone) */
 109         struct group *gi;
 110
 111         /* Positions of free positions - queue (not map) */
 112         /* Note that free position here is any valid move; including single-point eyes! */
 113         coord_t *f; int flen;
 114
 115 #ifdef WANT_BOARD_C
 116         /* Queue of capturable groups */
 117         group_t *c; int clen;
 118 #endif
 119
 120         /* Symmetry information */
 121         struct board_symmetry symmetry;
 122
 123         /* Last ko played on the board. */
 124         struct move last_ko;
 125         int last_ko_age;
 126
 127         /* Basic ko check */
 128         struct move ko;
 129
 130
 131         /* --- PRIVATE DATA --- */
 132
 133         /* For superko check: */
 134
 135         /* Board "history" - hashes encountered. Size of the hash should be
 136          * >> board_size^2. */
 137 #define history_hash_bits 12
 138 #define history_hash_mask ((1 << history_hash_bits) - 1)
 139 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 140 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 141         hash_t history_hash[1 << history_hash_bits];
 142         /* Hash of current board position. */
 143         hash_t hash;
 144 };
 145
 146 #ifdef BOARD_SIZE
 147 /* Avoid unused variable warnings */
 148 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 149 #define board_size2(b_) (board_size(b_) * board_size(b_))
 150 #else
 151 #define board_size(b_) ((b_)->size)
 152 #define board_size2(b_) ((b_)->size2)
 153 #endif
 154
 155 #define board_at(b_, c) ((b_)->b[coord_raw(c)])
 156 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 157
 158 #define group_at(b_, c) ((b_)->g[coord_raw(c)])
 159 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 160
 161 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 162 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord_raw(coord)].colors[(enum stone) color])
 163 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 164 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 165 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 166 #define immediate_liberty_count(b_, coord) (4 - neighbor_count_at(b_, coord, S_BLACK) - neighbor_count_at(b_, coord, S_WHITE) - neighbor_count_at(b_, coord, S_OFFBOARD))
 167
 168 #define groupnext_at(b_, c) ((b_)->p[coord_raw(c)])
 169 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 170
 171 #define group_base(g_) (g_)
 172 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 173 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 174 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 175
 176 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord_raw(coord)])
 177
 178 struct board *board_init(void);
 179 struct board *board_copy(struct board *board2, struct board *board1);
 180 void board_done_noalloc(struct board *board);
 181 void board_done(struct board *board);
 182 /* size here is without the S_OFFBOARD margin. */
 183 void board_resize(struct board *board, int size);
 184 void board_clear(struct board *board);
 185
 186 struct FILE;
 187 void board_print(struct board *board, FILE *f);
 188
 189 /* Place given handicap on the board; coordinates are printed to f. */
 190 void board_handicap(struct board *board, int stones, FILE *f);
 191
 192 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 193 int board_play(struct board *board, struct move *m);
 194 /* Like above, but plays random move; the move coordinate is recorded
 195  * to *coord. This method will never fill your own eye. pass is played
 196  * when no move can be played. You can impose extra restrictions if you
 197  * supply your own permit function. */
 198 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 199 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 200
 201 /* Returns true if given move can be played. */
 202 static bool board_is_valid_move(struct board *b, struct move *m);
 203
 204 /* Adjust symmetry information as if given coordinate has been played. */
 205 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 206
 207 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 208 static bool board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color);
 209 /* Returns true if given coordinate could be a false eye; this check makes
 210  * sense only if you already know the coordinate is_eyelike(). */
 211 bool board_is_false_eyelike(struct board *board, coord_t *coord, enum stone eye_color);
 212 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 213  * at least tries to). */
 214 bool board_is_one_point_eye(struct board *board, coord_t *c, enum stone eye_color);
 215 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 216 enum stone board_get_one_point_eye(struct board *board, coord_t *c);
 217
 218 /* board_official_score() is the scoring method for yielding score suitable
 219  * for external presentation. For fast scoring of entirely filled boards
 220  * (e.g. playouts), use board_fast_score(). */
 221 /* Positive: W wins */
 222 /* Compare number of stones + 1pt eyes. */
 223 float board_fast_score(struct board *board);
 224 /* Tromp-Taylor scoring. */
 225 float board_official_score(struct board *board);
 226
 227
 228 /** Iterators */
 229
 230 #define foreach_point(board_) \
 231         do { \
 232                 coord_t c; coord_pos(c, 0, (board_)); \
 233                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 234 #define foreach_point_and_pass(board_) \
 235         do { \
 236                 coord_t c; coord_pos(c, -1, (board_)); \
 237                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 238 #define foreach_point_end \
 239         } while (0)
 240
 241 #define foreach_in_group(board_, group_) \
 242         do { \
 243                 struct board *board__ = board_; \
 244                 coord_t c = group_base(group_); \
 245                 coord_t c2 = c; coord_raw(c2) = groupnext_at(board__, c2); \
 246                 do {
 247 #define foreach_in_group_end \
 248                         c = c2; coord_raw(c2) = groupnext_at(board__, c2); \
 249                 } while (coord_raw(c) != 0); \
 250         } while (0)
 251
 252 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 253  * on S_OFFBOARD coordinates. */
 254 #define foreach_neighbor(board_, coord_, loop_body) \
 255         do { \
 256                 struct board *board__ = board_; \
 257                 coord_t coord__ = coord_; \
 258                 coord_t c; \
 259                 coord_pos(c, coord_raw(coord__) - 1, (board__)); do { loop_body } while (0); \
 260                 coord_pos(c, coord_raw(coord__) - board_size(board__), (board__)); do { loop_body } while (0); \
 261                 coord_pos(c, coord_raw(coord__) + 1, (board__)); do { loop_body } while (0); \
 262                 coord_pos(c, coord_raw(coord__) + board_size(board__), (board__)); do { loop_body } while (0); \
 263         } while (0)
 264
 265 #define foreach_diag_neighbor(board_, coord_) \
 266         do { \
 267                 coord_t q__[4]; int q__i = 0; \
 268                 coord_pos(q__[q__i++], coord_raw(coord_) - board_size(board_) - 1, (board_)); \
 269                 coord_pos(q__[q__i++], coord_raw(coord_) - board_size(board_) + 1, (board_)); \
 270                 coord_pos(q__[q__i++], coord_raw(coord_) + board_size(board_) - 1, (board_)); \
 271                 coord_pos(q__[q__i++], coord_raw(coord_) + board_size(board_) + 1, (board_)); \
 272                 int fn__i; \
 273                 for (fn__i = 0; fn__i < q__i; fn__i++) { \
 274                         coord_t c = q__[fn__i];
 275 #define foreach_diag_neighbor_end \
 276                 } \
 277         } while (0)
 278
 279
 280 static inline bool
 281 board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color)
 282 {
 283         return (neighbor_count_at(board, *coord, eye_color)
 284                 + neighbor_count_at(board, *coord, S_OFFBOARD)) == 4;
 285 }
 286
 287 static inline bool
 288 board_is_valid_move(struct board *board, struct move *m)
 289 {
 290         if (board_at(board, m->coord) != S_NONE)
 291                 return false;
 292         if (!board_is_eyelike(board, &m->coord, stone_other(m->color)))
 293                 return true;
 294         /* Play within {true,false} eye-ish formation */
 295         if (board->ko.coord == m->coord && board->ko.color == m->color)
 296                 return false;
 297         int groups_in_atari = 0;
 298         foreach_neighbor(board, m->coord, {
 299                 group_t g = group_at(board, c);
 300                 groups_in_atari += (board_group_info(board, g).libs == 1);
 301         });
 302         return !!groups_in_atari;
 303 }
 304
 305 #endif