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         /* Whether we tried to add a hash twice; board_play*() can
  87          * set this, but it will still carry out the move as well! */
  88         bool superko_violation;
  89
  90         /* The following two structures are goban maps and are indexed by
  91          * coord.pos. The map is surrounded by a one-point margin from
  92          * S_OFFBOARD stones in order to speed up some internal loops.
  93          * Some of the foreach iterators below might include these points;
  94          * you need to handle them yourselves, if you need to. */
  95
  96         /* Stones played on the board */
  97         enum stone *b; /* enum stone */
  98         /* Group id the stones are part of; 0 == no group */
  99         group_t *g;
 100         /* Positions of next stones in the stone group; 0 == last stone */
 101         coord_t *p;
 102         /* Neighboring colors; numbers of neighbors of index color */
 103         struct neighbor_colors *n;
 104         /* Zobrist hash for each position */
 105         hash_t *h;
 106
 107         /* Group information - indexed by gid (which is coord of base group stone) */
 108         struct group *gi;
 109
 110         /* Positions of free positions - queue (not map) */
 111         /* Note that free position here is any valid move; including single-point eyes! */
 112         coord_t *f; int flen;
 113
 114 #ifdef WANT_BOARD_C
 115         /* Queue of capturable groups */
 116         group_t *c; int clen;
 117 #endif
 118
 119         /* Symmetry information */
 120         struct board_symmetry symmetry;
 121
 122
 123         /* --- PRIVATE DATA --- */
 124
 125         /* Basic ko check */
 126         struct move ko;
 127
 128         /* For superko check: */
 129
 130         /* Board "history" - hashes encountered. Size of the hash should be
 131          * >> board_size^2. */
 132 #define history_hash_bits 12
 133 #define history_hash_mask ((1 << history_hash_bits) - 1)
 134 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 135 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 136         hash_t history_hash[1 << history_hash_bits];
 137         /* Hash of current board position. */
 138         hash_t hash;
 139 };
 140
 141 #ifdef BOARD_SIZE
 142 /* Avoid unused variable warnings */
 143 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 144 #define board_size2(b_) (board_size(b_) * board_size(b_))
 145 #else
 146 #define board_size(b_) ((b_)->size)
 147 #define board_size2(b_) ((b_)->size2)
 148 #endif
 149
 150 #define board_at(b_, c) ((b_)->b[coord_raw(c)])
 151 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 152
 153 #define group_at(b_, c) ((b_)->g[coord_raw(c)])
 154 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 155
 156 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 157 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord_raw(coord)].colors[(enum stone) color])
 158 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 159 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 160 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 161 #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))
 162
 163 #define groupnext_at(b_, c) ((b_)->p[coord_raw(c)])
 164 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 165
 166 #define group_base(g_) (g_)
 167 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 168 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 169 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 170
 171 #define hash_at(b_, coord, color) (b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord_raw(coord)]
 172
 173 struct board *board_init(void);
 174 struct board *board_copy(struct board *board2, struct board *board1);
 175 void board_done_noalloc(struct board *board);
 176 void board_done(struct board *board);
 177 /* size here is without the S_OFFBOARD margin. */
 178 void board_resize(struct board *board, int size);
 179 void board_clear(struct board *board);
 180
 181 struct FILE;
 182 void board_print(struct board *board, FILE *f);
 183
 184 /* Place given handicap on the board; coordinates are printed to f. */
 185 void board_handicap(struct board *board, int stones, FILE *f);
 186
 187 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 188 int board_play(struct board *board, struct move *m);
 189 /* Like above, but plays random move; the move coordinate is recorded
 190  * to *coord. This method will never fill your own eye. pass is played
 191  * when no move can be played. You can impose extra restrictions if you
 192  * supply your own permit function. */
 193 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 194 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 195
 196 /* Returns true if given move can be played. */
 197 static bool board_is_valid_move(struct board *b, struct move *m);
 198
 199 /* Adjust symmetry information as if given coordinate has been played. */
 200 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 201
 202 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 203 static bool board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color);
 204 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 205  * at least tries to). */
 206 bool board_is_one_point_eye(struct board *board, coord_t *c, enum stone eye_color);
 207 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 208 enum stone board_get_one_point_eye(struct board *board, coord_t *c);
 209
 210 /* Check if group is in atari. This is very fast.
 211  * The last liberty is recorded to lastlib (content is undefined if group
 212  * is not in atari). */
 213 bool board_group_in_atari(struct board *board, group_t group, coord_t *lastlib);
 214
 215 /* Check if group can be put in atari. This is also very fast.
 216  * The last two liberties are recorded to lastlib (content is undefined if group
 217  * can't be put in atari). */
 218 bool board_group_can_atari(struct board *board, group_t group, coord_t lastlib[2]);
 219
 220 /* board_official_score() is the scoring method for yielding score suitable
 221  * for external presentation. For fast scoring of entirely filled boards
 222  * (e.g. playouts), use board_fast_score(). */
 223 /* Positive: W wins */
 224 /* Tromp-Taylor scoring. */
 225 float board_official_score(struct board *board);
 226 /* Compare number of stones + 1pt eyes. */
 227 float board_fast_score(struct board *board);
 228
 229 /* Check if this move is undesirable self-atari (resulting group would have
 230  * only single liberty and not capture anything; ko is allowed); we mostly
 231  * want to avoid these moves. The function actually does a rather elaborate
 232  * tactical check, allowing self-atari moves that are nakade, eye falsification
 233  * or throw-ins. */
 234 bool is_bad_selfatari(struct board *b, enum stone color, coord_t to);
 235
 236 /* Checks if there are any stones in n-vincinity of coord. */
 237 bool board_stone_radar(struct board *b, coord_t coord, int distance);
 238
 239
 240 /** Iterators */
 241
 242 #define foreach_point(board_) \
 243         do { \
 244                 coord_t c; coord_pos(c, 0, (board_)); \
 245                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 246 #define foreach_point_end \
 247         } while (0)
 248
 249 #define foreach_in_group(board_, group_) \
 250         do { \
 251                 struct board *board__ = board_; \
 252                 coord_t c = group_base(group_); \
 253                 coord_t c2 = c; coord_raw(c2) = groupnext_at(board__, c2); \
 254                 do {
 255 #define foreach_in_group_end \
 256                         c = c2; coord_raw(c2) = groupnext_at(board__, c2); \
 257                 } while (coord_raw(c) != 0); \
 258         } while (0)
 259
 260 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 261  * on S_OFFBOARD coordinates. */
 262 #define foreach_neighbor(board_, coord_, loop_body) \
 263         do { \
 264                 struct board *board__ = board_; \
 265                 coord_t coord__ = coord_; \
 266                 coord_t c; \
 267                 coord_pos(c, coord_raw(coord__) - 1, (board__)); do { loop_body } while (0); \
 268                 coord_pos(c, coord_raw(coord__) - board_size(board__), (board__)); do { loop_body } while (0); \
 269                 coord_pos(c, coord_raw(coord__) + 1, (board__)); do { loop_body } while (0); \
 270                 coord_pos(c, coord_raw(coord__) + board_size(board__), (board__)); do { loop_body } while (0); \
 271         } while (0)
 272
 273 #define foreach_diag_neighbor(board_, coord_) \
 274         do { \
 275                 coord_t q__[4]; int q__i = 0; \
 276                 coord_pos(q__[q__i++], coord_raw(coord_) - board_size(board_) - 1, (board_)); \
 277                 coord_pos(q__[q__i++], coord_raw(coord_) - board_size(board_) + 1, (board_)); \
 278                 coord_pos(q__[q__i++], coord_raw(coord_) + board_size(board_) - 1, (board_)); \
 279                 coord_pos(q__[q__i++], coord_raw(coord_) + board_size(board_) + 1, (board_)); \
 280                 int fn__i; \
 281                 for (fn__i = 0; fn__i < q__i; fn__i++) { \
 282                         coord_t c = q__[fn__i];
 283 #define foreach_diag_neighbor_end \
 284                 } \
 285         } while (0)
 286
 287
 288 static inline bool
 289 board_is_valid_move(struct board *board, struct move *m)
 290 {
 291         if (board_at(board, m->coord) != S_NONE)
 292                 return false;
 293         if (!board_is_eyelike(board, &m->coord, stone_other(m->color)))
 294                 return true;
 295         /* Play within {true,false} eye-ish formation */
 296         if (board->ko.coord == m->coord && board->ko.color == m->color)
 297                 return false;
 298         int groups_in_atari = 0;
 299         foreach_neighbor(board, m->coord, {
 300                 group_t g = group_at(board, c);
 301                 groups_in_atari += (board_group_info(board, g).libs == 1);
 302         });
 303         return !!groups_in_atari;
 304 }
 305
 306 static inline bool
 307 board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color)
 308 {
 309         return (neighbor_count_at(board, *coord, eye_color)
 310                 + neighbor_count_at(board, *coord, S_OFFBOARD)) == 4;
 311 }
 312
 313 #endif