board.h

   1 /* probdist.h must be included before the include goard since we require
   2  * proper including order. */
   3 #include "probdist.h"
   4
   5 #ifndef ZZGO_BOARD_H
   6 #define ZZGO_BOARD_H
   7
   8 #include <inttypes.h>
   9 #include <stdbool.h>
  10 #include <stdint.h>
  11
  12 #include "util.h"
  13 #include "stone.h"
  14 #include "move.h"
  15
  16 struct features_gamma;
  17 struct fbook;
  18
  19
  20 /* Maximum supported board size. (Without the S_OFFBOARD edges.) */
  21 #define BOARD_MAX_SIZE 19
  22
  23
  24 /* The board implementation has bunch of optional features.
  25  * Turn them on below: */
  26
  27 #define WANT_BOARD_C // capturable groups queue
  28
  29 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  30
  31 //#define BOARD_SPATHASH // incremental patternsp.h hashes
  32 #define BOARD_SPATHASH_MAXD 3 // maximal diameter
  33
  34 #define BOARD_PAT3 // incremental 3x3 pattern codes
  35
  36 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  37 //#define BOARD_GAMMA 1 // incremental probability distribution; either defined with BOARD_TRAITS, or keeping just pat3 stuff with BOARD_PAT3
  38
  39
  40 #define BOARD_MAX_MOVES (BOARD_MAX_SIZE * BOARD_MAX_SIZE)
  41 #define BOARD_MAX_GROUPS (BOARD_MAX_SIZE * BOARD_MAX_SIZE / 2)
  42
  43
  44 /* Some engines might normalize their reading and skip symmetrical
  45  * moves. We will tell them how can they do it. */
  46 struct board_symmetry {
  47         /* Playground is in this rectangle. */
  48         int x1, x2, y1, y2;
  49         /* d ==  0: Full rectangle
  50          * d ==  1: Top triangle */
  51         int d;
  52         /* General symmetry type. */
  53         /* Note that the above is redundant to this, but just provided
  54          * for easier usage. */
  55         enum {
  56                 SYM_FULL,
  57                 SYM_DIAG_UP,
  58                 SYM_DIAG_DOWN,
  59                 SYM_HORIZ,
  60                 SYM_VERT,
  61                 SYM_NONE
  62         } type;
  63 };
  64
  65
  66 typedef uint64_t hash_t;
  67 #define PRIhash PRIx64
  68
  69 /* XXX: This really belongs in pattern3.h, unfortunately that would mean
  70  * a dependency hell. */
  71 typedef uint32_t hash3_t; // 3x3 pattern hash
  72
  73
  74 /* Note that "group" is only chain of stones that is solidly
  75  * connected for us. */
  76 typedef coord_t group_t;
  77
  78 struct group {
  79         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  80          * don't care. */
  81         /* _Combination_ of these two values can make some difference
  82          * in performance - fine-tune. */
  83 #define GROUP_KEEP_LIBS 10
  84         // refill lib[] only when we hit this; this must be at least 2!
  85         // Moggy requires at least 3 - see below for semantic impact.
  86 #define GROUP_REFILL_LIBS 5
  87         coord_t lib[GROUP_KEEP_LIBS];
  88         /* libs is only LOWER BOUND for the number of real liberties!!!
  89          * It denotes only number of items in lib[], thus you can rely
  90          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  91         int libs;
  92 };
  93
  94 struct neighbor_colors {
  95         char colors[S_MAX];
  96 };
  97
  98
  99 /* Point traits bitmap; we update this information incrementally,
 100  * it can be used e.g. for fast pattern.h features matching. */
 101 struct btraits {
 102         /* Number of neighbors we can capture. 0=this move is
 103          * not capturing, 1..4=this many neighbors we can capture
 104          * (can be multiple neighbors of same group). */
 105         unsigned cap:3;
 106         /* Number of 1-stone neighbors we can capture. */
 107         unsigned cap1:3;
 108         /* Whether it is SAFE to play here. This is essentially just
 109          * cached result of board_safe_to_play(). (Of course the concept
 110          * of "safety" is not perfect here, but it's the cheapest
 111          * reasonable thing we can do.) */
 112         bool safe:1;
 113         /* Whether we need to re-compute this coordinate; used to
 114          * weed out duplicates. Maintained only for S_BLACK. */
 115         bool dirty:1;
 116 };
 117
 118
 119 /* You should treat this struct as read-only. Always call functions below if
 120  * you want to change it. */
 121
 122 struct board {
 123         int size; /* Including S_OFFBOARD margin - see below. */
 124         int size2; /* size^2 */
 125         int bits2; /* ceiling(log2(size2)) */
 126         int captures[S_MAX];
 127         float komi;
 128         int handicap;
 129         /* The ruleset is currently almost never taken into account;
 130          * the board implementation is basically Chinese rules (handicap
 131          * stones compensation) w/ suicide (or you can look at it as
 132          * New Zealand w/o handi stones compensation), while the engine
 133          * enforces no-suicide, making for real Chinese rules. */
 134         enum {
 135                 RULES_CHINESE, /* default value */
 136                 RULES_AGA,
 137                 RULES_NEW_ZEALAND,
 138                 RULES_JAPANESE,
 139         } rules;
 140
 141         char *fbookfile;
 142         struct fbook *fbook;
 143
 144         /* Iterator offsets for foreach_neighbor*() */
 145         int nei8[8], dnei[4];
 146
 147         int moves;
 148         struct move last_move;
 149         struct move last_move2; /* second-to-last move */
 150         /* Whether we tried to add a hash twice; board_play*() can
 151          * set this, but it will still carry out the move as well! */
 152         bool superko_violation;
 153
 154         /* The following two structures are goban maps and are indexed by
 155          * coord.pos. The map is surrounded by a one-point margin from
 156          * S_OFFBOARD stones in order to speed up some internal loops.
 157          * Some of the foreach iterators below might include these points;
 158          * you need to handle them yourselves, if you need to. */
 159
 160         /* Stones played on the board */
 161         enum stone *b; /* enum stone */
 162         /* Group id the stones are part of; 0 == no group */
 163         group_t *g;
 164         /* Positions of next stones in the stone group; 0 == last stone */
 165         coord_t *p;
 166         /* Neighboring colors; numbers of neighbors of index color */
 167         struct neighbor_colors *n;
 168         /* Zobrist hash for each position */
 169         hash_t *h;
 170 #ifdef BOARD_SPATHASH
 171         /* For spatial hashes, we use only 24 bits. */
 172         /* [0] is d==1, we don't keep hash for d==0. */
 173         /* We keep hashes for black-to-play ([][0]) and white-to-play
 174          * ([][1], reversed stone colors since we match all patterns as
 175          * black-to-play). */
 176         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 177 #endif
 178 #ifdef BOARD_PAT3
 179         /* 3x3 pattern code for each position; see pattern3.h for encoding
 180          * specification. The information is only valid for empty points. */
 181         hash3_t *pat3;
 182 #endif
 183 #ifdef BOARD_TRAITS
 184         /* Incrementally matched point traits information, black-to-play
 185          * ([][0]) and white-to-play ([][1]). */
 186         /* The information is only valid for empty points. */
 187         struct btraits (*t)[2];
 188 #endif
 189 #ifdef BOARD_GAMMA
 190         /* Relative probabilities of moves being played next, computed by
 191          * multiplying gammas of the appropriate pattern features based on
 192          * pat3 and traits (see pattern.h). The probability distribution
 193          * is maintained over the full board grid. */
 194         /* - Always invalid moves are guaranteed to have zero probability.
 195          * - Self-eye-filling moves will always have zero probability.
 196          * - Ko-prohibited moves might have non-zero probability.
 197          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 198         struct probdist prob[2];
 199 #endif
 200         /* Cached information on x-y coordinates so that we avoid division. */
 201         uint8_t (*coord)[2];
 202
 203         /* Group information - indexed by gid (which is coord of base group stone) */
 204         struct group *gi;
 205
 206         /* Positions of free positions - queue (not map) */
 207         /* Note that free position here is any valid move; including single-point eyes!
 208          * However, pass is not included. */
 209         coord_t *f; int flen;
 210
 211 #ifdef WANT_BOARD_C
 212         /* Queue of capturable groups */
 213         group_t *c; int clen;
 214 #endif
 215
 216 #ifdef BOARD_TRAITS
 217         /* Queue of positions that need their traits updated */
 218         coord_t *tq; int tqlen;
 219 #endif
 220
 221         /* Symmetry information */
 222         struct board_symmetry symmetry;
 223
 224         /* Last ko played on the board. */
 225         struct move last_ko;
 226         int last_ko_age;
 227
 228         /* Basic ko check */
 229         struct move ko;
 230
 231         /* Engine-specific state; persistent through board development,
 232          * is reset only at clear_board. */
 233         void *es;
 234
 235         /* Playout-specific state; persistent through board development,
 236          * but its lifetime is maintained in play_random_game(); it should
 237          * not be set outside of it. */
 238         void *ps;
 239
 240 #ifdef BOARD_GAMMA
 241         /* Gamma values for probability distribution; user must setup
 242          * this pointer before any move is played, using board_gamma_set(). */
 243         struct features_gamma *gamma;
 244         /* Whether to compute the 'safe' trait using board_safe_to_play()
 245          * (false) or is_bad_selfatari() (true, much slower). */
 246         bool precise_selfatari;
 247 #endif
 248
 249
 250         /* --- PRIVATE DATA --- */
 251
 252         /* For superko check: */
 253
 254         /* Board "history" - hashes encountered. Size of the hash should be
 255          * >> board_size^2. */
 256 #define history_hash_bits 12
 257 #define history_hash_mask ((1 << history_hash_bits) - 1)
 258 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 259 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 260         hash_t history_hash[1 << history_hash_bits];
 261         /* Hash of current board position. */
 262         hash_t hash;
 263         /* Hash of current board position quadrants. */
 264         hash_t qhash[4];
 265 };
 266
 267 #ifdef BOARD_SIZE
 268 /* Avoid unused variable warnings */
 269 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 270 #define board_size2(b_) (board_size(b_) * board_size(b_))
 271 #else
 272 #define board_size(b_) ((b_)->size)
 273 #define board_size2(b_) ((b_)->size2)
 274 #endif
 275
 276 #if BOARD_SIZE == 19
 277 #  define board_bits2(b_) 9
 278 #elif BOARD_SIZE == 13
 279 #  define board_bits2(b_) 8
 280 #elif BOARD_SIZE == 9
 281 #  define board_bits2(b_) 7
 282 #else
 283 #  define board_bits2(b_) ((b_)->bits2)
 284 #endif
 285
 286 #define board_at(b_, c) ((b_)->b[c])
 287 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 288
 289 #define group_at(b_, c) ((b_)->g[c])
 290 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 291
 292 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 293 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 294 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 295 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 296 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 297 #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))
 298
 299 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 300
 301 #define groupnext_at(b_, c) ((b_)->p[c])
 302 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 303
 304 #define group_base(g_) (g_)
 305 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 306 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 307 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 308 /* board_group_other_lib() makes sense only for groups with two liberties. */
 309 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 310
 311 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 312
 313 struct board *board_init(char *fbookfile);
 314 struct board *board_copy(struct board *board2, struct board *board1);
 315 void board_done_noalloc(struct board *board);
 316 void board_done(struct board *board);
 317 /* size here is without the S_OFFBOARD margin. */
 318 void board_resize(struct board *board, int size);
 319 void board_clear(struct board *board);
 320
 321 struct FILE;
 322 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 323 void board_print(struct board *board, FILE *f);
 324 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 325
 326 /* Place given handicap on the board; coordinates are printed to f. */
 327 void board_handicap(struct board *board, int stones, FILE *f);
 328
 329 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 330 int board_play(struct board *board, struct move *m);
 331 /* Like above, but plays random move; the move coordinate is recorded
 332  * to *coord. This method will never fill your own eye. pass is played
 333  * when no move can be played. You can impose extra restrictions if you
 334  * supply your own permit function; the permit function can also modify
 335  * the move coordinate to redirect the move elsewhere. */
 336 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 337 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 338
 339 /* Returns true if given move can be played. */
 340 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 341 static bool board_is_valid_move(struct board *b, struct move *m);
 342 /* Returns true if ko was just taken. */
 343 static bool board_playing_ko_threat(struct board *b);
 344 /* Returns 0 or ID of neighboring group in atari. */
 345 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 346 /* Returns true if the move is not obvious self-atari. */
 347 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 348
 349 /* Adjust symmetry information as if given coordinate has been played. */
 350 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 351 /* Associate a set of feature gamma values (for pd building) with the board. */
 352 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 353 /* Force re-compute of a probability distribution item. */
 354 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 355
 356 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 357 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 358 /* Returns true if given coordinate could be a false eye; this check makes
 359  * sense only if you already know the coordinate is_eyelike(). */
 360 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 361 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 362  * at least tries to). */
 363 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 364 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 365 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 366
 367 /* board_official_score() is the scoring method for yielding score suitable
 368  * for external presentation. For fast scoring of entirely filled boards
 369  * (e.g. playouts), use board_fast_score(). */
 370 /* Positive: W wins */
 371 /* Compare number of stones + 1pt eyes. */
 372 float board_fast_score(struct board *board);
 373 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 374 struct move_queue;
 375 float board_official_score(struct board *board, struct move_queue *mq);
 376
 377 /** Iterators */
 378
 379 #define foreach_point(board_) \
 380         do { \
 381                 coord_t c = 0; \
 382                 for (; c < board_size(board_) * board_size(board_); c++)
 383 #define foreach_point_and_pass(board_) \
 384         do { \
 385                 coord_t c = pass; \
 386                 for (; c < board_size(board_) * board_size(board_); c++)
 387 #define foreach_point_end \
 388         } while (0)
 389
 390 #define foreach_free_point(board_) \
 391         do { \
 392                 int fmax__ = (board_)->flen; \
 393                 for (int f__ = 0; f__ < fmax__; f__++) { \
 394                         coord_t c = (board_)->f[f__];
 395 #define foreach_free_point_end \
 396                 } \
 397         } while (0)
 398
 399 #define foreach_in_group(board_, group_) \
 400         do { \
 401                 struct board *board__ = board_; \
 402                 coord_t c = group_base(group_); \
 403                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 404                 do {
 405 #define foreach_in_group_end \
 406                         c = c2; c2 = groupnext_at(board__, c2); \
 407                 } while (c != 0); \
 408         } while (0)
 409
 410 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 411  * on S_OFFBOARD coordinates. */
 412 #define foreach_neighbor(board_, coord_, loop_body) \
 413         do { \
 414                 struct board *board__ = board_; \
 415                 coord_t coord__ = coord_; \
 416                 coord_t c; \
 417                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 418                 c = coord__ - 1; do { loop_body } while (0); \
 419                 c = coord__ + 1; do { loop_body } while (0); \
 420                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 421         } while (0)
 422
 423 #define foreach_8neighbor(board_, coord_) \
 424         do { \
 425                 int fn__i; \
 426                 coord_t c = (coord_); \
 427                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 428                         c += (board_)->nei8[fn__i];
 429 #define foreach_8neighbor_end \
 430                 } \
 431         } while (0)
 432
 433 #define foreach_diag_neighbor(board_, coord_) \
 434         do { \
 435                 int fn__i; \
 436                 coord_t c = (coord_); \
 437                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 438                         c += (board_)->dnei[fn__i];
 439 #define foreach_diag_neighbor_end \
 440                 } \
 441         } while (0)
 442
 443
 444 static inline bool
 445 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 446 {
 447         return (neighbor_count_at(board, coord, eye_color)
 448                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 449 }
 450
 451 static inline bool
 452 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 453 {
 454         if (board_at(board, coord) != S_NONE)
 455                 return false;
 456         if (!board_is_eyelike(board, coord, stone_other(color)))
 457                 return true;
 458         /* Play within {true,false} eye-ish formation */
 459         if (board->ko.coord == coord && board->ko.color == color)
 460                 return false;
 461 #ifdef BOARD_TRAITS
 462         /* XXX: Disallows suicide. */
 463         return trait_at(board, coord, color).cap > 0;
 464 #else
 465         int groups_in_atari = 0;
 466         foreach_neighbor(board, coord, {
 467                 group_t g = group_at(board, c);
 468                 groups_in_atari += (board_group_info(board, g).libs == 1);
 469         });
 470         return !!groups_in_atari;
 471 #endif
 472 }
 473
 474 static inline bool
 475 board_is_valid_move(struct board *board, struct move *m)
 476 {
 477         return board_is_valid_play(board, m->color, m->coord);
 478 }
 479
 480 static inline bool
 481 board_playing_ko_threat(struct board *b)
 482 {
 483         return !is_pass(b->ko.coord);
 484 }
 485
 486 static inline group_t
 487 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 488 {
 489 #ifdef BOARD_TRAITS
 490         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 491 #endif
 492         foreach_neighbor(b, coord, {
 493                 group_t g = group_at(b, c);
 494                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 495                         return g;
 496                 /* We return first match. */
 497         });
 498         return 0;
 499 }
 500
 501 static inline bool
 502 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 503 {
 504         /* number of free neighbors */
 505         int libs = immediate_liberty_count(b, coord);
 506         if (libs > 1)
 507                 return true;
 508
 509 #ifdef BOARD_TRAITS
 510         /* number of capturable enemy groups */
 511         if (trait_at(b, coord, color).cap > 0)
 512                 return true; // XXX: We don't account for snapback.
 513         /* number of non-capturable friendly groups */
 514         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 515         if (noncap_ours < 1)
 516                 return false;
 517 /*#else see below */
 518 #endif
 519
 520         /* ok, but we need to check if they don't have just two libs. */
 521         coord_t onelib = -1;
 522         foreach_neighbor(b, coord, {
 523 #ifndef BOARD_TRAITS
 524                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 525                         return true; // can capture; no snapback check
 526 #endif
 527                 if (board_at(b, c) != color) continue;
 528                 group_t g = group_at(b, c);
 529                 if (board_group_info(b, g).libs == 1) continue; // in atari
 530                 if (board_group_info(b, g).libs == 2) { // two liberties
 531                         if (libs > 0) return true; // we already have one real liberty
 532                         /* we might be connecting two 2-lib groups, which is ok;
 533                          * so remember the other liberty and just make sure it's
 534                          * not the same one */
 535                         if (onelib >= 0 && c != onelib) return true;
 536                         onelib = board_group_other_lib(b, g, c);
 537                         continue;
 538                 }
 539                 // many liberties
 540                 return true;
 541         });
 542         // no good support group
 543         return false;
 544 }
 545
 546 #endif