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 bits2; /* ceiling(log2(size2)) */
 108         int captures[S_MAX];
 109         float komi;
 110         int handicap;
 111         /* The ruleset is currently almost never taken into account;
 112          * the board implementation is basically Chinese rules (handicap
 113          * stones compensation) w/ suicide (or you can look at it as
 114          * New Zealand w/o handi stones compensation), while the engine
 115          * enforces no-suicide, making for real Chinese rules. */
 116         enum {
 117                 RULES_CHINESE, /* default value */
 118                 RULES_AGA,
 119                 RULES_NEW_ZEALAND,
 120                 RULES_JAPANESE,
 121         } rules;
 122
 123         /* Iterator offsets for foreach_neighbor*() */
 124         int nei8[8], dnei[4];
 125
 126         int moves;
 127         struct move last_move;
 128         struct move last_move2; /* second-to-last move */
 129         /* Whether we tried to add a hash twice; board_play*() can
 130          * set this, but it will still carry out the move as well! */
 131         bool superko_violation;
 132
 133         /* The following two structures are goban maps and are indexed by
 134          * coord.pos. The map is surrounded by a one-point margin from
 135          * S_OFFBOARD stones in order to speed up some internal loops.
 136          * Some of the foreach iterators below might include these points;
 137          * you need to handle them yourselves, if you need to. */
 138
 139         /* Stones played on the board */
 140         enum stone *b; /* enum stone */
 141         /* Group id the stones are part of; 0 == no group */
 142         group_t *g;
 143         /* Positions of next stones in the stone group; 0 == last stone */
 144         coord_t *p;
 145         /* Neighboring colors; numbers of neighbors of index color */
 146         struct neighbor_colors *n;
 147         /* Zobrist hash for each position */
 148         hash_t *h;
 149 #ifdef BOARD_SPATHASH
 150         /* For spatial hashes, we use only 24 bits. */
 151         /* [0] is d==1, we don't keep hash for d==0. */
 152         /* We keep hashes for black-to-play ([][0]) and white-to-play
 153          * ([][1], reversed stone colors since we match all patterns as
 154          * black-to-play). */
 155         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 156 #endif
 157 #ifdef BOARD_PAT3
 158         /* 3x3 pattern code for each position; see pattern3.h for encoding
 159          * specification. The information is only valid for empty points. */
 160         uint16_t *pat3;
 161 #endif
 162 #ifdef BOARD_TRAITS
 163         /* Incrementally matched point traits information, black-to-play
 164          * ([][0]) and white-to-play ([][1]). */
 165         /* The information is only valid for empty points. */
 166         struct btraits (*t)[2];
 167 #endif
 168 #ifdef BOARD_GAMMA
 169         /* Relative probabilities of moves being played next, computed by
 170          * multiplying gammas of the appropriate pattern features based on
 171          * pat3 and traits (see pattern.h). The probability distribution
 172          * is maintained over the full board grid. */
 173         /* - Always invalid moves are guaranteed to have zero probability.
 174          * - Self-eye-filling moves will always have zero probability.
 175          * - Ko-prohibited moves might have non-zero probability.
 176          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 177         struct probdist prob[2];
 178 #endif
 179         /* Cached information on x-y coordinates so that we avoid division. */
 180         uint8_t (*coord)[2];
 181
 182         /* Group information - indexed by gid (which is coord of base group stone) */
 183         struct group *gi;
 184
 185         /* Positions of free positions - queue (not map) */
 186         /* Note that free position here is any valid move; including single-point eyes!
 187          * However, pass is not included. */
 188         coord_t *f; int flen;
 189
 190 #ifdef WANT_BOARD_C
 191         /* Queue of capturable groups */
 192         group_t *c; int clen;
 193 #endif
 194
 195 #ifdef BOARD_TRAITS
 196         /* Queue of positions that need their traits updated */
 197         coord_t *tq; int tqlen;
 198 #endif
 199
 200         /* Symmetry information */
 201         struct board_symmetry symmetry;
 202
 203         /* Last ko played on the board. */
 204         struct move last_ko;
 205         int last_ko_age;
 206
 207         /* Basic ko check */
 208         struct move ko;
 209
 210         /* Engine-specific state; persistent through board development,
 211          * is reset only at clear_board. */
 212         void *es;
 213
 214         /* Playout-specific state; persistent through board development,
 215          * but its lifetime is maintained in play_random_game(); it should
 216          * not be set outside of it. */
 217         void *ps;
 218
 219 #ifdef BOARD_GAMMA
 220         /* Gamma values for probability distribution; user must setup
 221          * this pointer before any move is played, using board_gamma_set(). */
 222         struct features_gamma *gamma;
 223         /* Whether to compute the 'safe' trait using board_safe_to_play()
 224          * (false) or is_bad_selfatari() (true, much slower). */
 225         bool precise_selfatari;
 226 #endif
 227
 228
 229         /* --- PRIVATE DATA --- */
 230
 231         /* For superko check: */
 232
 233         /* Board "history" - hashes encountered. Size of the hash should be
 234          * >> board_size^2. */
 235 #define history_hash_bits 12
 236 #define history_hash_mask ((1 << history_hash_bits) - 1)
 237 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 238 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 239         hash_t history_hash[1 << history_hash_bits];
 240         /* Hash of current board position. */
 241         hash_t hash;
 242 };
 243
 244 #ifdef BOARD_SIZE
 245 /* Avoid unused variable warnings */
 246 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 247 #define board_size2(b_) (board_size(b_) * board_size(b_))
 248 #else
 249 #define board_size(b_) ((b_)->size)
 250 #define board_size2(b_) ((b_)->size2)
 251 #endif
 252
 253 #if BOARD_SIZE == 19
 254 #  define board_bits2(b_) 9
 255 #elif BOARD_SIZE == 13
 256 #  define board_bits2(b_) 8
 257 #elif BOARD_SIZE == 9
 258 #  define board_bits2(b_) 7
 259 #else
 260 #  define board_bits2(b_) ((b_)->bits2)
 261 #endif
 262
 263 #define board_at(b_, c) ((b_)->b[c])
 264 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 265
 266 #define group_at(b_, c) ((b_)->g[c])
 267 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 268
 269 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 270 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 271 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 272 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 273 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 274 #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))
 275
 276 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 277
 278 #define groupnext_at(b_, c) ((b_)->p[c])
 279 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 280
 281 #define group_base(g_) (g_)
 282 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 283 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 284 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 285
 286 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 287
 288 struct board *board_init(void);
 289 struct board *board_copy(struct board *board2, struct board *board1);
 290 void board_done_noalloc(struct board *board);
 291 void board_done(struct board *board);
 292 /* size here is without the S_OFFBOARD margin. */
 293 void board_resize(struct board *board, int size);
 294 void board_clear(struct board *board);
 295
 296 struct FILE;
 297 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 298 void board_print(struct board *board, FILE *f);
 299 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 300
 301 /* Place given handicap on the board; coordinates are printed to f. */
 302 void board_handicap(struct board *board, int stones, FILE *f);
 303
 304 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 305 int board_play(struct board *board, struct move *m);
 306 /* Like above, but plays random move; the move coordinate is recorded
 307  * to *coord. This method will never fill your own eye. pass is played
 308  * when no move can be played. You can impose extra restrictions if you
 309  * supply your own permit function. */
 310 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 311 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 312
 313 /* Returns true if given move can be played. */
 314 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 315 static bool board_is_valid_move(struct board *b, struct move *m);
 316 /* Returns true if ko was just taken. */
 317 static bool board_playing_ko_threat(struct board *b);
 318 /* Returns 0 or ID of neighboring group in atari. */
 319 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 320 /* Returns true if the move is not obvious self-atari. */
 321 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 322
 323 /* Adjust symmetry information as if given coordinate has been played. */
 324 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 325 /* Associate a set of feature gamma values (for pd building) with the board. */
 326 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 327 /* Force re-compute of a probability distribution item. */
 328 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 329
 330 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 331 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 332 /* Returns true if given coordinate could be a false eye; this check makes
 333  * sense only if you already know the coordinate is_eyelike(). */
 334 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 335 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 336  * at least tries to). */
 337 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 338 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 339 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 340
 341 /* board_official_score() is the scoring method for yielding score suitable
 342  * for external presentation. For fast scoring of entirely filled boards
 343  * (e.g. playouts), use board_fast_score(). */
 344 /* Positive: W wins */
 345 /* Compare number of stones + 1pt eyes. */
 346 float board_fast_score(struct board *board);
 347 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 348 struct move_queue;
 349 float board_official_score(struct board *board, struct move_queue *mq);
 350
 351 /** Iterators */
 352
 353 #define foreach_point(board_) \
 354         do { \
 355                 coord_t c = 0; \
 356                 for (; c < board_size(board_) * board_size(board_); c++)
 357 #define foreach_point_and_pass(board_) \
 358         do { \
 359                 coord_t c = pass; \
 360                 for (; c < board_size(board_) * board_size(board_); c++)
 361 #define foreach_point_end \
 362         } while (0)
 363
 364 #define foreach_in_group(board_, group_) \
 365         do { \
 366                 struct board *board__ = board_; \
 367                 coord_t c = group_base(group_); \
 368                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 369                 do {
 370 #define foreach_in_group_end \
 371                         c = c2; c2 = groupnext_at(board__, c2); \
 372                 } while (c != 0); \
 373         } while (0)
 374
 375 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 376  * on S_OFFBOARD coordinates. */
 377 #define foreach_neighbor(board_, coord_, loop_body) \
 378         do { \
 379                 struct board *board__ = board_; \
 380                 coord_t coord__ = coord_; \
 381                 coord_t c; \
 382                 c = coord__ - 1; do { loop_body } while (0); \
 383                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 384                 c = coord__ + 1; do { loop_body } while (0); \
 385                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 386         } while (0)
 387
 388 #define foreach_8neighbor(board_, coord_) \
 389         do { \
 390                 int fn__i; \
 391                 coord_t c = (coord_); \
 392                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 393                         c += (board_)->nei8[fn__i];
 394 #define foreach_8neighbor_end \
 395                 } \
 396         } while (0)
 397
 398 #define foreach_diag_neighbor(board_, coord_) \
 399         do { \
 400                 int fn__i; \
 401                 coord_t c = (coord_); \
 402                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 403                         c += (board_)->dnei[fn__i];
 404 #define foreach_diag_neighbor_end \
 405                 } \
 406         } while (0)
 407
 408
 409 static inline bool
 410 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 411 {
 412         return (neighbor_count_at(board, coord, eye_color)
 413                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 414 }
 415
 416 static inline bool
 417 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 418 {
 419         if (board_at(board, coord) != S_NONE)
 420                 return false;
 421         if (!board_is_eyelike(board, coord, stone_other(color)))
 422                 return true;
 423         /* Play within {true,false} eye-ish formation */
 424         if (board->ko.coord == coord && board->ko.color == color)
 425                 return false;
 426 #ifdef BOARD_TRAITS
 427         /* XXX: Disallows suicide. */
 428         return trait_at(board, coord, color).cap > 0;
 429 #else
 430         int groups_in_atari = 0;
 431         foreach_neighbor(board, coord, {
 432                 group_t g = group_at(board, c);
 433                 groups_in_atari += (board_group_info(board, g).libs == 1);
 434         });
 435         return !!groups_in_atari;
 436 #endif
 437 }
 438
 439 static inline bool
 440 board_is_valid_move(struct board *board, struct move *m)
 441 {
 442         return board_is_valid_play(board, m->color, m->coord);
 443 }
 444
 445 static inline bool
 446 board_playing_ko_threat(struct board *b)
 447 {
 448         return !is_pass(b->ko.coord);
 449 }
 450
 451 static inline group_t
 452 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 453 {
 454 #ifdef BOARD_TRAITS
 455         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 456 #endif
 457         foreach_neighbor(b, coord, {
 458                 group_t g = group_at(b, c);
 459                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 460                         return g;
 461                 /* We return first match. */
 462         });
 463         return 0;
 464 }
 465
 466 static inline bool
 467 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 468 {
 469         /* number of free neighbors */
 470         int libs = immediate_liberty_count(b, coord);
 471         if (libs > 1)
 472                 return true;
 473
 474 #ifdef BOARD_TRAITS
 475         /* number of capturable enemy groups */
 476         if (trait_at(b, coord, color).cap > 0)
 477                 return true; // XXX: We don't account for snapback.
 478         /* number of non-capturable friendly groups */
 479         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 480         if (noncap_ours < 1)
 481                 return false;
 482 /*#else see below */
 483 #endif
 484
 485         /* ok, but we need to check if they don't have just two libs. */
 486         coord_t onelib = -1;
 487         foreach_neighbor(b, coord, {
 488 #ifndef BOARD_TRAITS
 489                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 490                         return true; // can capture; no snapback check
 491 #endif
 492                 if (board_at(b, c) != color) continue;
 493                 group_t g = group_at(b, c);
 494                 if (board_group_info(b, g).libs == 1) continue; // in atari
 495                 if (board_group_info(b, g).libs == 2) { // two liberties
 496                         if (libs > 0) return true; // we already have one real liberty
 497                         // get the other liberty
 498                         coord_t lib = board_group_info(b, g).lib[0];
 499                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 500                         /* we might be connecting two 2-lib groups, which is ok;
 501                          * so remember the other liberty and just make sure it's
 502                          * not the same one */
 503                         if (onelib >= 0 && lib != onelib) return true;
 504                         onelib = lib;
 505                         continue;
 506                 }
 507                 // many liberties
 508                 return true;
 509         });
 510         // no good support group
 511         return false;
 512 }
 513
 514 #endif