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 "util.h"
   9 #include "stone.h"
  10 #include "move.h"
  11 #include "probdist.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 /* Some engines might normalize their reading and skip symmetrical
  33  * moves. We will tell them how can they do it. */
  34 struct board_symmetry {
  35         /* Playground is in this rectangle. */
  36         int x1, x2, y1, y2;
  37         /* d ==  0: Full rectangle
  38          * d ==  1: Top triangle */
  39         int d;
  40         /* General symmetry type. */
  41         /* Note that the above is redundant to this, but just provided
  42          * for easier usage. */
  43         enum {
  44                 SYM_FULL,
  45                 SYM_DIAG_UP,
  46                 SYM_DIAG_DOWN,
  47                 SYM_HORIZ,
  48                 SYM_VERT,
  49                 SYM_NONE
  50         } type;
  51 };
  52
  53
  54 typedef uint64_t hash_t;
  55 #define PRIhash PRIx64
  56
  57
  58 /* Note that "group" is only chain of stones that is solidly
  59  * connected for us. */
  60 typedef coord_t group_t;
  61
  62 struct group {
  63         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  64          * don't care. */
  65         /* _Combination_ of these two values can make some difference
  66          * in performance - fine-tune. */
  67 #define GROUP_KEEP_LIBS 10
  68         // refill lib[] only when we hit this; this must be at least 2!
  69         // Moggy requires at least 3 - see below for semantic impact.
  70 #define GROUP_REFILL_LIBS 5
  71         coord_t lib[GROUP_KEEP_LIBS];
  72         /* libs is only LOWER BOUND for the number of real liberties!!!
  73          * It denotes only number of items in lib[], thus you can rely
  74          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  75         int libs;
  76 };
  77
  78 struct neighbor_colors {
  79         char colors[S_MAX];
  80 };
  81
  82
  83 /* Point traits bitmap; we update this information incrementally,
  84  * it can be used e.g. for fast pattern.h features matching. */
  85 struct btraits {
  86         /* Number of neighbors we can capture. 0=this move is
  87          * not capturing, 1..4=this many neighbors we can capture
  88          * (can be multiple neighbors of same group). */
  89         unsigned cap:3;
  90         /* Whether it is SAFE to play here. This is essentially just
  91          * cached result of board_safe_to_play(). (Of course the concept
  92          * of "safety" is not perfect here, but it's the cheapest
  93          * reasonable thing we can do.) */
  94         bool safe:1;
  95         /* Whether we need to re-compute this coordinate; used to
  96          * weed out duplicates. Maintained only for S_BLACK. */
  97         bool dirty:1;
  98 };
  99
 100
 101 /* You should treat this struct as read-only. Always call functions below if
 102  * you want to change it. */
 103
 104 struct board {
 105         int size; /* Including S_OFFBOARD margin - see below. */
 106         int size2; /* size^2 */
 107         int captures[S_MAX];
 108         float komi;
 109         int handicap;
 110         /* The ruleset is currently almost never taken into account;
 111          * the board implementation is basically Chinese rules (handicap
 112          * stones compensation) w/ suicide (or you can look at it as
 113          * New Zealand w/o handi stones compensation), while the engine
 114          * enforces no-suicide, making for real Chinese rules. */
 115         enum {
 116                 RULES_CHINESE, /* default value */
 117                 RULES_AGA,
 118                 RULES_NEW_ZEALAND,
 119                 RULES_JAPANESE,
 120         } rules;
 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 are guaranteed to have zero probability.
 173          * - Self-eye-filling moves will always have zero probability.
 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         /* Cached information on x-y coordinates so that we avoid division. */
 179         uint8_t (*coord)[2];
 180
 181         /* Group information - indexed by gid (which is coord of base group stone) */
 182         struct group *gi;
 183
 184         /* Positions of free positions - queue (not map) */
 185         /* Note that free position here is any valid move; including single-point eyes!
 186          * However, pass is not included. */
 187         coord_t *f; int flen;
 188
 189 #ifdef WANT_BOARD_C
 190         /* Queue of capturable groups */
 191         group_t *c; int clen;
 192 #endif
 193
 194 #ifdef BOARD_TRAITS
 195         /* Queue of positions that need their traits updated */
 196         coord_t *tq; int tqlen;
 197 #endif
 198
 199         /* Symmetry information */
 200         struct board_symmetry symmetry;
 201
 202         /* Last ko played on the board. */
 203         struct move last_ko;
 204         int last_ko_age;
 205
 206         /* Basic ko check */
 207         struct move ko;
 208
 209         /* Engine-specific state; persistent through board development,
 210          * is reset only at clear_board. */
 211         void *es;
 212
 213         /* Playout-specific state; persistent through board development,
 214          * but its lifetime is maintained in play_random_game(); it should
 215          * not be set outside of it. */
 216         void *ps;
 217
 218 #ifdef BOARD_GAMMA
 219         /* Gamma values for probability distribution; user must setup
 220          * this pointer before any move is played, using board_gamma_set(). */
 221         struct features_gamma *gamma;
 222         /* Whether to compute the 'safe' trait using board_safe_to_play()
 223          * (false) or is_bad_selfatari() (true, much slower). */
 224         bool precise_selfatari;
 225 #endif
 226
 227
 228         /* --- PRIVATE DATA --- */
 229
 230         /* For superko check: */
 231
 232         /* Board "history" - hashes encountered. Size of the hash should be
 233          * >> board_size^2. */
 234 #define history_hash_bits 12
 235 #define history_hash_mask ((1 << history_hash_bits) - 1)
 236 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 237 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 238         hash_t history_hash[1 << history_hash_bits];
 239         /* Hash of current board position. */
 240         hash_t hash;
 241 };
 242
 243 #ifdef BOARD_SIZE
 244 /* Avoid unused variable warnings */
 245 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 246 #define board_size2(b_) (board_size(b_) * board_size(b_))
 247 #else
 248 #define board_size(b_) ((b_)->size)
 249 #define board_size2(b_) ((b_)->size2)
 250 #endif
 251
 252 #define board_at(b_, c) ((b_)->b[c])
 253 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 254
 255 #define group_at(b_, c) ((b_)->g[c])
 256 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 257
 258 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 259 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 260 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 261 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 262 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 263 #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))
 264
 265 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 266
 267 #define groupnext_at(b_, c) ((b_)->p[c])
 268 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 269
 270 #define group_base(g_) (g_)
 271 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 272 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 273 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 274
 275 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 276
 277 struct board *board_init(void);
 278 struct board *board_copy(struct board *board2, struct board *board1);
 279 void board_done_noalloc(struct board *board);
 280 void board_done(struct board *board);
 281 /* size here is without the S_OFFBOARD margin. */
 282 void board_resize(struct board *board, int size);
 283 void board_clear(struct board *board);
 284
 285 struct FILE;
 286 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 287 void board_print(struct board *board, FILE *f);
 288 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 289
 290 /* Place given handicap on the board; coordinates are printed to f. */
 291 void board_handicap(struct board *board, int stones, FILE *f);
 292
 293 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 294 int board_play(struct board *board, struct move *m);
 295 /* Like above, but plays random move; the move coordinate is recorded
 296  * to *coord. This method will never fill your own eye. pass is played
 297  * when no move can be played. You can impose extra restrictions if you
 298  * supply your own permit function. */
 299 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 300 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 301
 302 /* Returns true if given move can be played. */
 303 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 304 static bool board_is_valid_move(struct board *b, struct move *m);
 305 /* Returns true if ko was just taken. */
 306 static bool board_playing_ko_threat(struct board *b);
 307 /* Returns 0 or ID of neighboring group in atari. */
 308 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 309 /* Returns true if the move is not obvious self-atari. */
 310 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 311
 312 /* Adjust symmetry information as if given coordinate has been played. */
 313 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 314 /* Associate a set of feature gamma values (for pd building) with the board. */
 315 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 316 /* Force re-compute of a probability distribution item. */
 317 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 318
 319 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 320 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 321 /* Returns true if given coordinate could be a false eye; this check makes
 322  * sense only if you already know the coordinate is_eyelike(). */
 323 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 324 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 325  * at least tries to). */
 326 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 327 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 328 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 329
 330 /* board_official_score() is the scoring method for yielding score suitable
 331  * for external presentation. For fast scoring of entirely filled boards
 332  * (e.g. playouts), use board_fast_score(). */
 333 /* Positive: W wins */
 334 /* Compare number of stones + 1pt eyes. */
 335 float board_fast_score(struct board *board);
 336 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 337 struct move_queue;
 338 float board_official_score(struct board *board, struct move_queue *mq);
 339
 340 /** Iterators */
 341
 342 #define foreach_point(board_) \
 343         do { \
 344                 coord_t c = 0; \
 345                 for (; c < board_size(board_) * board_size(board_); c++)
 346 #define foreach_point_and_pass(board_) \
 347         do { \
 348                 coord_t c = pass; \
 349                 for (; c < board_size(board_) * board_size(board_); c++)
 350 #define foreach_point_end \
 351         } while (0)
 352
 353 #define foreach_in_group(board_, group_) \
 354         do { \
 355                 struct board *board__ = board_; \
 356                 coord_t c = group_base(group_); \
 357                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 358                 do {
 359 #define foreach_in_group_end \
 360                         c = c2; c2 = groupnext_at(board__, c2); \
 361                 } while (c != 0); \
 362         } while (0)
 363
 364 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 365  * on S_OFFBOARD coordinates. */
 366 #define foreach_neighbor(board_, coord_, loop_body) \
 367         do { \
 368                 struct board *board__ = board_; \
 369                 coord_t coord__ = coord_; \
 370                 coord_t c; \
 371                 c = coord__ - 1; do { loop_body } while (0); \
 372                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 373                 c = coord__ + 1; do { loop_body } while (0); \
 374                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 375         } while (0)
 376
 377 #define foreach_8neighbor(board_, coord_) \
 378         do { \
 379                 int fn__i; \
 380                 coord_t c = (coord_); \
 381                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 382                         c += (board_)->nei8[fn__i];
 383 #define foreach_8neighbor_end \
 384                 } \
 385         } while (0)
 386
 387 #define foreach_diag_neighbor(board_, coord_) \
 388         do { \
 389                 int fn__i; \
 390                 coord_t c = (coord_); \
 391                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 392                         c += (board_)->dnei[fn__i];
 393 #define foreach_diag_neighbor_end \
 394                 } \
 395         } while (0)
 396
 397
 398 static inline bool
 399 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 400 {
 401         return (neighbor_count_at(board, coord, eye_color)
 402                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 403 }
 404
 405 static inline bool
 406 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 407 {
 408         if (board_at(board, coord) != S_NONE)
 409                 return false;
 410         if (!board_is_eyelike(board, coord, stone_other(color)))
 411                 return true;
 412         /* Play within {true,false} eye-ish formation */
 413         if (board->ko.coord == coord && board->ko.color == color)
 414                 return false;
 415 #ifdef BOARD_TRAITS
 416         /* XXX: Disallows suicide. */
 417         return trait_at(board, coord, color).cap > 0;
 418 #else
 419         int groups_in_atari = 0;
 420         foreach_neighbor(board, coord, {
 421                 group_t g = group_at(board, c);
 422                 groups_in_atari += (board_group_info(board, g).libs == 1);
 423         });
 424         return !!groups_in_atari;
 425 #endif
 426 }
 427
 428 static inline bool
 429 board_is_valid_move(struct board *board, struct move *m)
 430 {
 431         return board_is_valid_play(board, m->color, m->coord);
 432 }
 433
 434 static inline bool
 435 board_playing_ko_threat(struct board *b)
 436 {
 437         return !is_pass(b->ko.coord);
 438 }
 439
 440 static inline group_t
 441 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 442 {
 443 #ifdef BOARD_TRAITS
 444         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 445 #endif
 446         foreach_neighbor(b, coord, {
 447                 group_t g = group_at(b, c);
 448                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 449                         return g;
 450                 /* We return first match. */
 451         });
 452         return 0;
 453 }
 454
 455 static inline bool
 456 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 457 {
 458         /* number of free neighbors */
 459         int libs = immediate_liberty_count(b, coord);
 460         if (libs > 1)
 461                 return true;
 462
 463 #ifdef BOARD_TRAITS
 464         /* number of capturable enemy groups */
 465         if (trait_at(b, coord, color).cap > 0)
 466                 return true; // XXX: We don't account for snapback.
 467         /* number of non-capturable friendly groups */
 468         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 469         if (noncap_ours < 1)
 470                 return false;
 471 /*#else see below */
 472 #endif
 473
 474         /* ok, but we need to check if they don't have just two libs. */
 475         coord_t onelib = -1;
 476         foreach_neighbor(b, coord, {
 477 #ifndef BOARD_TRAITS
 478                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 479                         return true; // can capture; no snapback check
 480 #endif
 481                 if (board_at(b, c) != color) continue;
 482                 group_t g = group_at(b, c);
 483                 if (board_group_info(b, g).libs == 1) continue; // in atari
 484                 if (board_group_info(b, g).libs == 2) { // two liberties
 485                         if (libs > 0) return true; // we already have one real liberty
 486                         // get the other liberty
 487                         coord_t lib = board_group_info(b, g).lib[0];
 488                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 489                         /* we might be connecting two 2-lib groups, which is ok;
 490                          * so remember the other liberty and just make sure it's
 491                          * not the same one */
 492                         if (onelib >= 0 && lib != onelib) return true;
 493                         onelib = lib;
 494                         continue;
 495                 }
 496                 // many liberties
 497                 return true;
 498         });
 499         // no good support group
 500         return false;
 501 }
 502
 503 #endif