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 /* 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 board_safe_to_play(). (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         /* Whether we need to re-compute this coordinate; used to
 101          * weed out duplicates. Maintained only for S_BLACK. */
 102         bool dirty:1;
 103 };
 104
 105
 106 /* You should treat this struct as read-only. Always call functions below if
 107  * you want to change it. */
 108
 109 struct board {
 110         int size; /* Including S_OFFBOARD margin - see below. */
 111         int size2; /* size^2 */
 112         int captures[S_MAX];
 113         float komi;
 114         int handicap;
 115         /* The ruleset is currently almost never taken into account;
 116          * the board implementation is basically Chinese rules (handicap
 117          * stones compensation) w/ suicide (or you can look at it as
 118          * New Zealand w/o handi stones compensation), while the engine
 119          * enforces no-suicide, making for real Chinese rules. */
 120         enum {
 121                 RULES_CHINESE, /* default value */
 122                 RULES_AGA,
 123                 RULES_NEW_ZEALAND,
 124                 RULES_JAPANESE,
 125         } rules;
 126
 127         /* Iterator offsets for foreach_neighbor*() */
 128         int nei8[8], dnei[4];
 129
 130         int moves;
 131         struct move last_move;
 132         struct move last_move2; /* second-to-last move */
 133         /* Whether we tried to add a hash twice; board_play*() can
 134          * set this, but it will still carry out the move as well! */
 135         bool superko_violation;
 136
 137         /* The following two structures are goban maps and are indexed by
 138          * coord.pos. The map is surrounded by a one-point margin from
 139          * S_OFFBOARD stones in order to speed up some internal loops.
 140          * Some of the foreach iterators below might include these points;
 141          * you need to handle them yourselves, if you need to. */
 142
 143         /* Stones played on the board */
 144         enum stone *b; /* enum stone */
 145         /* Group id the stones are part of; 0 == no group */
 146         group_t *g;
 147         /* Positions of next stones in the stone group; 0 == last stone */
 148         coord_t *p;
 149         /* Neighboring colors; numbers of neighbors of index color */
 150         struct neighbor_colors *n;
 151         /* Zobrist hash for each position */
 152         hash_t *h;
 153 #ifdef BOARD_SPATHASH
 154         /* For spatial hashes, we use only 24 bits. */
 155         /* [0] is d==1, we don't keep hash for d==0. */
 156         /* We keep hashes for black-to-play ([][0]) and white-to-play
 157          * ([][1], reversed stone colors since we match all patterns as
 158          * black-to-play). */
 159         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 160 #endif
 161 #ifdef BOARD_PAT3
 162         /* 3x3 pattern code for each position; see pattern3.h for encoding
 163          * specification. The information is only valid for empty points. */
 164         uint16_t *pat3;
 165 #endif
 166 #ifdef BOARD_TRAITS
 167         /* Incrementally matched point traits information, black-to-play
 168          * ([][0]) and white-to-play ([][1]). */
 169         /* The information is only valid for empty points. */
 170         struct btraits (*t)[2];
 171 #endif
 172 #ifdef BOARD_GAMMA
 173         /* Relative probabilities of moves being played next, computed by
 174          * multiplying gammas of the appropriate pattern features based on
 175          * pat3 and traits (see pattern.h). The probability distribution
 176          * is maintained over the full board grid. */
 177         /* - Always invalid moves are guaranteed to have zero probability.
 178          * - Self-eye-filling moves will always have zero probability.
 179          * - Ko-prohibited moves might have non-zero probability.
 180          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 181         struct probdist prob[2];
 182 #endif
 183
 184         /* Group information - indexed by gid (which is coord of base group stone) */
 185         struct group *gi;
 186
 187         /* Positions of free positions - queue (not map) */
 188         /* Note that free position here is any valid move; including single-point eyes! */
 189         coord_t *f; int flen;
 190
 191 #ifdef WANT_BOARD_C
 192         /* Queue of capturable groups */
 193         group_t *c; int clen;
 194 #endif
 195
 196 #ifdef BOARD_TRAITS
 197         /* Queue of positions that need their traits updated */
 198         coord_t *tq; int tqlen;
 199 #endif
 200
 201         /* Symmetry information */
 202         struct board_symmetry symmetry;
 203
 204         /* Last ko played on the board. */
 205         struct move last_ko;
 206         int last_ko_age;
 207
 208         /* Basic ko check */
 209         struct move ko;
 210
 211         /* Engine-specific state; persistent through board development,
 212          * is reset only at clear_board. */
 213         void *es;
 214
 215         /* Playout-specific state; persistent through board development,
 216          * but its lifetime is maintained in play_random_game(); it should
 217          * not be set outside of it. */
 218         void *ps;
 219
 220 #ifdef BOARD_GAMMA
 221         /* Gamma values for probability distribution; user must setup
 222          * this pointer before any move is played, using board_gamma_set(). */
 223         struct features_gamma *gamma;
 224         /* Whether to compute the 'safe' trait using board_safe_to_play()
 225          * (false) or is_bad_selfatari() (true, much slower). */
 226         bool precise_selfatari;
 227 #endif
 228
 229
 230         /* --- PRIVATE DATA --- */
 231
 232         /* For superko check: */
 233
 234         /* Board "history" - hashes encountered. Size of the hash should be
 235          * >> board_size^2. */
 236 #define history_hash_bits 12
 237 #define history_hash_mask ((1 << history_hash_bits) - 1)
 238 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 239 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 240         hash_t history_hash[1 << history_hash_bits];
 241         /* Hash of current board position. */
 242         hash_t hash;
 243 };
 244
 245 #ifdef BOARD_SIZE
 246 /* Avoid unused variable warnings */
 247 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 248 #define board_size2(b_) (board_size(b_) * board_size(b_))
 249 #else
 250 #define board_size(b_) ((b_)->size)
 251 #define board_size2(b_) ((b_)->size2)
 252 #endif
 253
 254 #define board_at(b_, c) ((b_)->b[coord_raw(c)])
 255 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 256
 257 #define group_at(b_, c) ((b_)->g[coord_raw(c)])
 258 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 259
 260 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 261 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord_raw(coord)].colors[(enum stone) color])
 262 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 263 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 264 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 265 #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))
 266
 267 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 268
 269 #define groupnext_at(b_, c) ((b_)->p[coord_raw(c)])
 270 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 271
 272 #define group_base(g_) (g_)
 273 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 274 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 275 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 276
 277 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord_raw(coord)])
 278
 279 struct board *board_init(void);
 280 struct board *board_copy(struct board *board2, struct board *board1);
 281 void board_done_noalloc(struct board *board);
 282 void board_done(struct board *board);
 283 /* size here is without the S_OFFBOARD margin. */
 284 void board_resize(struct board *board, int size);
 285 void board_clear(struct board *board);
 286
 287 struct FILE;
 288 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 289 void board_print(struct board *board, FILE *f);
 290 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 291
 292 /* Place given handicap on the board; coordinates are printed to f. */
 293 void board_handicap(struct board *board, int stones, FILE *f);
 294
 295 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 296 int board_play(struct board *board, struct move *m);
 297 /* Like above, but plays random move; the move coordinate is recorded
 298  * to *coord. This method will never fill your own eye. pass is played
 299  * when no move can be played. You can impose extra restrictions if you
 300  * supply your own permit function. */
 301 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 302 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 303
 304 /* Returns true if given move can be played. */
 305 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 306 static bool board_is_valid_move(struct board *b, struct move *m);
 307 /* Returns true if ko was just taken. */
 308 static bool board_playing_ko_threat(struct board *b);
 309 /* Returns 0 or ID of neighboring group in atari. */
 310 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 311 /* Returns true if the move is not obvious self-atari. */
 312 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 313
 314 /* Adjust symmetry information as if given coordinate has been played. */
 315 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 316 /* Associate a set of feature gamma values (for pd building) with the board. */
 317 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 318 /* Force re-compute of a probability distribution item. */
 319 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 320
 321 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 322 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 323 /* Returns true if given coordinate could be a false eye; this check makes
 324  * sense only if you already know the coordinate is_eyelike(). */
 325 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 326 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 327  * at least tries to). */
 328 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 329 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 330 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 331
 332 /* board_official_score() is the scoring method for yielding score suitable
 333  * for external presentation. For fast scoring of entirely filled boards
 334  * (e.g. playouts), use board_fast_score(). */
 335 /* Positive: W wins */
 336 /* Compare number of stones + 1pt eyes. */
 337 float board_fast_score(struct board *board);
 338 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 339 struct move_queue;
 340 float board_official_score(struct board *board, struct move_queue *mq);
 341
 342 /** Iterators */
 343
 344 #define foreach_point(board_) \
 345         do { \
 346                 coord_t c; coord_pos(c, 0, (board_)); \
 347                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 348 #define foreach_point_and_pass(board_) \
 349         do { \
 350                 coord_t c; coord_pos(c, -1, (board_)); \
 351                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 352 #define foreach_point_end \
 353         } while (0)
 354
 355 #define foreach_in_group(board_, group_) \
 356         do { \
 357                 struct board *board__ = board_; \
 358                 coord_t c = group_base(group_); \
 359                 coord_t c2 = c; coord_raw(c2) = groupnext_at(board__, c2); \
 360                 do {
 361 #define foreach_in_group_end \
 362                         c = c2; coord_raw(c2) = groupnext_at(board__, c2); \
 363                 } while (coord_raw(c) != 0); \
 364         } while (0)
 365
 366 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 367  * on S_OFFBOARD coordinates. */
 368 #define foreach_neighbor(board_, coord_, loop_body) \
 369         do { \
 370                 struct board *board__ = board_; \
 371                 coord_t coord__ = coord_; \
 372                 coord_t c; \
 373                 coord_pos(c, coord_raw(coord__) - 1, (board__)); do { loop_body } while (0); \
 374                 coord_pos(c, coord_raw(coord__) - board_size(board__), (board__)); do { loop_body } while (0); \
 375                 coord_pos(c, coord_raw(coord__) + 1, (board__)); do { loop_body } while (0); \
 376                 coord_pos(c, coord_raw(coord__) + board_size(board__), (board__)); do { loop_body } while (0); \
 377         } while (0)
 378
 379 #define foreach_8neighbor(board_, coord_) \
 380         do { \
 381                 int fn__i; \
 382                 coord_t c = (coord_); \
 383                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 384                         c += (board_)->nei8[fn__i];
 385 #define foreach_8neighbor_end \
 386                 } \
 387         } while (0)
 388
 389 #define foreach_diag_neighbor(board_, coord_) \
 390         do { \
 391                 int fn__i; \
 392                 coord_t c = (coord_); \
 393                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 394                         c += (board_)->dnei[fn__i];
 395 #define foreach_diag_neighbor_end \
 396                 } \
 397         } while (0)
 398
 399
 400 static inline bool
 401 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 402 {
 403         return (neighbor_count_at(board, coord, eye_color)
 404                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 405 }
 406
 407 static inline bool
 408 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 409 {
 410         if (board_at(board, coord) != S_NONE)
 411                 return false;
 412         if (!board_is_eyelike(board, coord, stone_other(color)))
 413                 return true;
 414         /* Play within {true,false} eye-ish formation */
 415         if (board->ko.coord == coord && board->ko.color == color)
 416                 return false;
 417 #ifdef BOARD_TRAITS
 418         /* XXX: Disallows suicide. */
 419         return trait_at(board, coord, color).cap > 0;
 420 #else
 421         int groups_in_atari = 0;
 422         foreach_neighbor(board, coord, {
 423                 group_t g = group_at(board, c);
 424                 groups_in_atari += (board_group_info(board, g).libs == 1);
 425         });
 426         return !!groups_in_atari;
 427 #endif
 428 }
 429
 430 static inline bool
 431 board_is_valid_move(struct board *board, struct move *m)
 432 {
 433         return board_is_valid_play(board, m->color, m->coord);
 434 }
 435
 436 static inline bool
 437 board_playing_ko_threat(struct board *b)
 438 {
 439         return !is_pass(b->ko.coord);
 440 }
 441
 442 static inline group_t
 443 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 444 {
 445 #ifdef BOARD_TRAITS
 446         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 447 #endif
 448         foreach_neighbor(b, coord, {
 449                 group_t g = group_at(b, c);
 450                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 451                         return g;
 452                 /* We return first match. */
 453         });
 454         return 0;
 455 }
 456
 457 static inline bool
 458 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 459 {
 460         /* number of free neighbors */
 461         int libs = immediate_liberty_count(b, coord);
 462         if (libs > 1)
 463                 return true;
 464
 465 #ifdef BOARD_TRAITS
 466         /* number of capturable enemy groups */
 467         if (trait_at(b, coord, color).cap > 0)
 468                 return true; // XXX: We don't account for snapback.
 469         /* number of non-capturable friendly groups */
 470         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 471         if (noncap_ours < 1)
 472                 return false;
 473 /*#else see below */
 474 #endif
 475
 476         /* ok, but we need to check if they don't have just two libs. */
 477         coord_t onelib = -1;
 478         foreach_neighbor(b, coord, {
 479 #ifndef BOARD_TRAITS
 480                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 481                         return true; // can capture; no snapback check
 482 #endif
 483                 if (board_at(b, c) != color) continue;
 484                 group_t g = group_at(b, c);
 485                 if (board_group_info(b, g).libs == 1) continue; // in atari
 486                 if (board_group_info(b, g).libs == 2) { // two liberties
 487                         if (libs > 0) return true; // we already have one real liberty
 488                         // get the other liberty
 489                         coord_t lib = board_group_info(b, g).lib[0];
 490                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 491                         /* we might be connecting two 2-lib groups, which is ok;
 492                          * so remember the other liberty and just make sure it's
 493                          * not the same one */
 494                         if (onelib >= 0 && lib != onelib) return true;
 495                         onelib = lib;
 496                         continue;
 497                 }
 498                 // many liberties
 499                 return true;
 500         });
 501         // no good support group
 502         return false;
 503 }
 504
 505 #endif