board.h

   1 #ifndef ZZGO_BOARD_H
   2 #define ZZGO_BOARD_H
   3
   4 #include <inttypes.h>
   5 #include <stdbool.h>
   6 #include <stdint.h>
   7
   8 #include "stone.h"
   9 #include "move.h"
  10 #include "probdist.h"
  11 #include "util.h"
  12
  13 struct features_gamma;
  14
  15
  16 /* The board implementation has bunch of optional features.
  17  * Turn them on below: */
  18
  19 #define WANT_BOARD_C // capturable groups queue
  20
  21 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  22
  23 //#define BOARD_SPATHASH // incremental patternsp.h hashes
  24 #define BOARD_SPATHASH_MAXD 3 // maximal diameter
  25
  26 #define BOARD_PAT3 // incremental 3x3 pattern codes
  27
  28 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  29 //#define BOARD_GAMMA 1 // incremental probability distribution (requires BOARD_TRAITS, BOARD_PAT3)
  30
  31
  32 /* Allow board_play_random_move() to return pass even when
  33  * there are other moves available. */
  34 extern bool random_pass;
  35
  36
  37 /* Some engines might normalize their reading and skip symmetrical
  38  * moves. We will tell them how can they do it. */
  39 struct board_symmetry {
  40         /* Playground is in this rectangle. */
  41         int x1, x2, y1, y2;
  42         /* d ==  0: Full rectangle
  43          * d ==  1: Top triangle */
  44         int d;
  45         /* General symmetry type. */
  46         /* Note that the above is redundant to this, but just provided
  47          * for easier usage. */
  48         enum {
  49                 SYM_FULL,
  50                 SYM_DIAG_UP,
  51                 SYM_DIAG_DOWN,
  52                 SYM_HORIZ,
  53                 SYM_VERT,
  54                 SYM_NONE
  55         } type;
  56 };
  57
  58
  59 typedef uint64_t hash_t;
  60 #define PRIhash PRIx64
  61
  62
  63 /* Note that "group" is only chain of stones that is solidly
  64  * connected for us. */
  65 typedef coord_t group_t;
  66
  67 struct group {
  68         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  69          * don't care. */
  70         /* _Combination_ of these two values can make some difference
  71          * in performance - fine-tune. */
  72 #define GROUP_KEEP_LIBS 10
  73         // refill lib[] only when we hit this; this must be at least 2!
  74         // Moggy requires at least 3 - see below for semantic impact.
  75 #define GROUP_REFILL_LIBS 5
  76         coord_t lib[GROUP_KEEP_LIBS];
  77         /* libs is only LOWER BOUND for the number of real liberties!!!
  78          * It denotes only number of items in lib[], thus you can rely
  79          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  80         int libs;
  81 };
  82
  83 struct neighbor_colors {
  84         char colors[S_MAX];
  85 };
  86
  87
  88 /* Point traits bitmap; we update this information incrementally,
  89  * it can be used e.g. for fast pattern.h features matching. */
  90 struct btraits {
  91         /* Number of neighbors we can capture. 0=this move is
  92          * not capturing, 1..4=this many neighbors we can capture
  93          * (can be multiple neighbors of same group). */
  94         unsigned cap:3;
  95         /* Whether it is SAFE to play here. This is essentially just
  96          * cached result of the macro below. (Of course the concept
  97          * of "safety" is not perfect here, but it's the cheapest
  98          * reasonable thing we can do.) */
  99         bool safe:1;
 100 #define board_safe_to_play(b_, coord_, color_) \
 101                 (( \
 102                   /* number of free neighbors, except us */ \
 103                   immediate_liberty_count(b_, coord_) - 1 \
 104                   /* number of capturable enemy groups */ \
 105                   + trait_at(b_, coord_, color_).cap \
 106                   /* number of non-capturable friendly groups */ \
 107                   + neighbor_count_at(b_, coord_, color_) - trait_at(b_, coord_, stone_other(color_)).cap \
 108                  ) > 0)
 109 };
 110
 111
 112 /* You should treat this struct as read-only. Always call functions below if
 113  * you want to change it. */
 114
 115 struct board {
 116         int size; /* Including S_OFFBOARD margin - see below. */
 117         int size2; /* size^2 */
 118         int captures[S_MAX];
 119         float komi;
 120         int handicap;
 121
 122         /* Iterator offsets for foreach_neighbor*() */
 123         int nei8[8], dnei[4];
 124
 125         int moves;
 126         struct move last_move;
 127         struct move last_move2; /* second-to-last move */
 128         /* Whether we tried to add a hash twice; board_play*() can
 129          * set this, but it will still carry out the move as well! */
 130         bool superko_violation;
 131
 132         /* The following two structures are goban maps and are indexed by
 133          * coord.pos. The map is surrounded by a one-point margin from
 134          * S_OFFBOARD stones in order to speed up some internal loops.
 135          * Some of the foreach iterators below might include these points;
 136          * you need to handle them yourselves, if you need to. */
 137
 138         /* Stones played on the board */
 139         enum stone *b; /* enum stone */
 140         /* Group id the stones are part of; 0 == no group */
 141         group_t *g;
 142         /* Positions of next stones in the stone group; 0 == last stone */
 143         coord_t *p;
 144         /* Neighboring colors; numbers of neighbors of index color */
 145         struct neighbor_colors *n;
 146         /* Zobrist hash for each position */
 147         hash_t *h;
 148 #ifdef BOARD_SPATHASH
 149         /* For spatial hashes, we use only 24 bits. */
 150         /* [0] is d==1, we don't keep hash for d==0. */
 151         /* We keep hashes for black-to-play ([][0]) and white-to-play
 152          * ([][1], reversed stone colors since we match all patterns as
 153          * black-to-play). */
 154         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 155 #endif
 156 #ifdef BOARD_PAT3
 157         /* 3x3 pattern code for each position; see pattern3.h for encoding
 158          * specification. The information is only valid for empty points. */
 159         uint16_t *pat3;
 160 #endif
 161 #ifdef BOARD_TRAITS
 162         /* Incrementally matched point traits information, black-to-play
 163          * ([][0]) and white-to-play ([][1]). */
 164         /* The information is only valid for empty points. */
 165         struct btraits (*t)[2];
 166 #endif
 167 #ifdef BOARD_GAMMA
 168         /* Relative probabilities of moves being played next, computed by
 169          * multiplying gammas of the appropriate pattern features based on
 170          * pat3 and traits (see pattern.h). The probability distribution
 171          * is maintained over the full board grid. */
 172         /* - Always invalid moves might have non-zero probability. (TODO)
 173          * - Self-eye-filling moves might have non-zero probability. (TODO)
 174          * - Ko-prohibited moves might have non-zero probability.
 175          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 176         struct probdist prob[2];
 177 #endif
 178
 179         /* Group information - indexed by gid (which is coord of base group stone) */
 180         struct group *gi;
 181
 182         /* Positions of free positions - queue (not map) */
 183         /* Note that free position here is any valid move; including single-point eyes! */
 184         coord_t *f; int flen;
 185
 186 #ifdef WANT_BOARD_C
 187         /* Queue of capturable groups */
 188         group_t *c; int clen;
 189 #endif
 190
 191         /* Symmetry information */
 192         struct board_symmetry symmetry;
 193
 194         /* Last ko played on the board. */
 195         struct move last_ko;
 196         int last_ko_age;
 197
 198         /* Basic ko check */
 199         struct move ko;
 200
 201         /* Engine-specific state; persistent through board development,
 202          * is reset only at clear_board. */
 203         void *es;
 204
 205         /* Playout-specific state; persistent through board development,
 206          * but its lifetime is maintained in play_random_game(); it should
 207          * not be set outside of it. */
 208         void *ps;
 209
 210 #ifdef BOARD_GAMMA
 211         /* Gamma values for probability distribution; user must setup
 212          * this pointer before any move is played. */
 213         struct features_gamma *gamma;
 214 #endif
 215
 216
 217         /* --- PRIVATE DATA --- */
 218
 219         /* For superko check: */
 220
 221         /* Board "history" - hashes encountered. Size of the hash should be
 222          * >> board_size^2. */
 223 #define history_hash_bits 12
 224 #define history_hash_mask ((1 << history_hash_bits) - 1)
 225 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 226 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 227         hash_t history_hash[1 << history_hash_bits];
 228         /* Hash of current board position. */
 229         hash_t hash;
 230 };
 231
 232 #ifdef BOARD_SIZE
 233 /* Avoid unused variable warnings */
 234 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 235 #define board_size2(b_) (board_size(b_) * board_size(b_))
 236 #else
 237 #define board_size(b_) ((b_)->size)
 238 #define board_size2(b_) ((b_)->size2)
 239 #endif
 240
 241 #define board_at(b_, c) ((b_)->b[coord_raw(c)])
 242 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 243
 244 #define group_at(b_, c) ((b_)->g[coord_raw(c)])
 245 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 246
 247 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 248 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord_raw(coord)].colors[(enum stone) color])
 249 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 250 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 251 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 252 #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))
 253
 254 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 255
 256 #define groupnext_at(b_, c) ((b_)->p[coord_raw(c)])
 257 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 258
 259 #define group_base(g_) (g_)
 260 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 261 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 262 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 263
 264 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord_raw(coord)])
 265
 266 struct board *board_init(void);
 267 struct board *board_copy(struct board *board2, struct board *board1);
 268 void board_done_noalloc(struct board *board);
 269 void board_done(struct board *board);
 270 /* size here is without the S_OFFBOARD margin. */
 271 void board_resize(struct board *board, int size);
 272 void board_clear(struct board *board);
 273
 274 struct FILE;
 275 typedef void (*board_cprint)(struct board *b, coord_t c, FILE *f);
 276 void board_print(struct board *board, FILE *f);
 277 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 278
 279 /* Place given handicap on the board; coordinates are printed to f. */
 280 void board_handicap(struct board *board, int stones, FILE *f);
 281
 282 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 283 int board_play(struct board *board, struct move *m);
 284 /* Like above, but plays random move; the move coordinate is recorded
 285  * to *coord. This method will never fill your own eye. pass is played
 286  * when no move can be played. You can impose extra restrictions if you
 287  * supply your own permit function. */
 288 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 289 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 290
 291 /* Returns true if given move can be played. */
 292 static bool board_is_valid_move(struct board *b, struct move *m);
 293 /* Returns true if ko was just taken. */
 294 static bool board_playing_ko_threat(struct board *b);
 295 /* Returns 0 or ID of neighboring group in atari. */
 296 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 297
 298 /* Adjust symmetry information as if given coordinate has been played. */
 299 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 300 /* Force re-compute of a probability distribution item. */
 301 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 302
 303 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 304 static bool board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color);
 305 /* Returns true if given coordinate could be a false eye; this check makes
 306  * sense only if you already know the coordinate is_eyelike(). */
 307 bool board_is_false_eyelike(struct board *board, coord_t *coord, enum stone eye_color);
 308 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 309  * at least tries to). */
 310 bool board_is_one_point_eye(struct board *board, coord_t *c, enum stone eye_color);
 311 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 312 enum stone board_get_one_point_eye(struct board *board, coord_t *c);
 313
 314 /* board_official_score() is the scoring method for yielding score suitable
 315  * for external presentation. For fast scoring of entirely filled boards
 316  * (e.g. playouts), use board_fast_score(). */
 317 /* Positive: W wins */
 318 /* Compare number of stones + 1pt eyes. */
 319 float board_fast_score(struct board *board);
 320 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 321 struct move_queue;
 322 float board_official_score(struct board *board, struct move_queue *mq);
 323
 324 /** Iterators */
 325
 326 #define foreach_point(board_) \
 327         do { \
 328                 coord_t c; coord_pos(c, 0, (board_)); \
 329                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 330 #define foreach_point_and_pass(board_) \
 331         do { \
 332                 coord_t c; coord_pos(c, -1, (board_)); \
 333                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 334 #define foreach_point_end \
 335         } while (0)
 336
 337 #define foreach_in_group(board_, group_) \
 338         do { \
 339                 struct board *board__ = board_; \
 340                 coord_t c = group_base(group_); \
 341                 coord_t c2 = c; coord_raw(c2) = groupnext_at(board__, c2); \
 342                 do {
 343 #define foreach_in_group_end \
 344                         c = c2; coord_raw(c2) = groupnext_at(board__, c2); \
 345                 } while (coord_raw(c) != 0); \
 346         } while (0)
 347
 348 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 349  * on S_OFFBOARD coordinates. */
 350 #define foreach_neighbor(board_, coord_, loop_body) \
 351         do { \
 352                 struct board *board__ = board_; \
 353                 coord_t coord__ = coord_; \
 354                 coord_t c; \
 355                 coord_pos(c, coord_raw(coord__) - 1, (board__)); do { loop_body } while (0); \
 356                 coord_pos(c, coord_raw(coord__) - board_size(board__), (board__)); do { loop_body } while (0); \
 357                 coord_pos(c, coord_raw(coord__) + 1, (board__)); do { loop_body } while (0); \
 358                 coord_pos(c, coord_raw(coord__) + board_size(board__), (board__)); do { loop_body } while (0); \
 359         } while (0)
 360
 361 #define foreach_8neighbor(board_, coord_) \
 362         do { \
 363                 int fn__i; \
 364                 coord_t c = (coord_); \
 365                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 366                         c += (board_)->nei8[fn__i];
 367 #define foreach_8neighbor_end \
 368                 } \
 369         } while (0)
 370
 371 #define foreach_diag_neighbor(board_, coord_) \
 372         do { \
 373                 int fn__i; \
 374                 coord_t c = (coord_); \
 375                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 376                         c += (board_)->dnei[fn__i];
 377 #define foreach_diag_neighbor_end \
 378                 } \
 379         } while (0)
 380
 381
 382 static inline bool
 383 board_is_eyelike(struct board *board, coord_t *coord, enum stone eye_color)
 384 {
 385         return (neighbor_count_at(board, *coord, eye_color)
 386                 + neighbor_count_at(board, *coord, S_OFFBOARD)) == 4;
 387 }
 388
 389 static inline bool
 390 board_is_valid_move(struct board *board, struct move *m)
 391 {
 392         if (board_at(board, m->coord) != S_NONE)
 393                 return false;
 394         if (!board_is_eyelike(board, &m->coord, stone_other(m->color)))
 395                 return true;
 396         /* Play within {true,false} eye-ish formation */
 397         if (board->ko.coord == m->coord && board->ko.color == m->color)
 398                 return false;
 399         int groups_in_atari = 0;
 400         foreach_neighbor(board, m->coord, {
 401                 group_t g = group_at(board, c);
 402                 groups_in_atari += (board_group_info(board, g).libs == 1);
 403         });
 404         return !!groups_in_atari;
 405 }
 406
 407 static inline bool
 408 board_playing_ko_threat(struct board *b)
 409 {
 410         return !is_pass(b->ko.coord);
 411 }
 412
 413 static inline group_t
 414 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 415 {
 416 #ifdef BOARD_TRAITS
 417         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 418 #endif
 419         foreach_neighbor(b, coord, {
 420                 group_t g = group_at(b, c);
 421                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 422                         return g;
 423                 /* We return first match. */
 424         });
 425         return 0;
 426 }
 427
 428 #endif