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
  18
  19 /* Maximum supported board size. (Without the S_OFFBOARD edges.) */
  20 #define BOARD_MAX_SIZE 19
  21
  22
  23 /* The board implementation has bunch of optional features.
  24  * Turn them on below: */
  25
  26 #define WANT_BOARD_C // capturable groups queue
  27
  28 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  29
  30 //#define BOARD_SPATHASH // incremental patternsp.h hashes
  31 #define BOARD_SPATHASH_MAXD 3 // maximal diameter
  32
  33 #define BOARD_PAT3 // incremental 3x3 pattern codes
  34
  35 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  36 //#define BOARD_GAMMA 1 // incremental probability distribution (requires BOARD_TRAITS, BOARD_PAT3)
  37
  38
  39 #define BOARD_MAX_MOVES (BOARD_MAX_SIZE * BOARD_MAX_SIZE)
  40 #define BOARD_MAX_GROUPS (BOARD_MAX_SIZE * BOARD_MAX_SIZE / 2)
  41
  42
  43 /* Some engines might normalize their reading and skip symmetrical
  44  * moves. We will tell them how can they do it. */
  45 struct board_symmetry {
  46         /* Playground is in this rectangle. */
  47         int x1, x2, y1, y2;
  48         /* d ==  0: Full rectangle
  49          * d ==  1: Top triangle */
  50         int d;
  51         /* General symmetry type. */
  52         /* Note that the above is redundant to this, but just provided
  53          * for easier usage. */
  54         enum {
  55                 SYM_FULL,
  56                 SYM_DIAG_UP,
  57                 SYM_DIAG_DOWN,
  58                 SYM_HORIZ,
  59                 SYM_VERT,
  60                 SYM_NONE
  61         } type;
  62 };
  63
  64
  65 typedef uint64_t hash_t;
  66 #define PRIhash PRIx64
  67
  68 /* XXX: This really belongs in pattern3.h, unfortunately that would mean
  69  * a dependency hell. */
  70 typedef uint16_t hash3_t; // 3x3 pattern hash
  71
  72
  73 /* Note that "group" is only chain of stones that is solidly
  74  * connected for us. */
  75 typedef coord_t group_t;
  76
  77 struct group {
  78         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  79          * don't care. */
  80         /* _Combination_ of these two values can make some difference
  81          * in performance - fine-tune. */
  82 #define GROUP_KEEP_LIBS 10
  83         // refill lib[] only when we hit this; this must be at least 2!
  84         // Moggy requires at least 3 - see below for semantic impact.
  85 #define GROUP_REFILL_LIBS 5
  86         coord_t lib[GROUP_KEEP_LIBS];
  87         /* libs is only LOWER BOUND for the number of real liberties!!!
  88          * It denotes only number of items in lib[], thus you can rely
  89          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  90         int libs;
  91 };
  92
  93 struct neighbor_colors {
  94         char colors[S_MAX];
  95 };
  96
  97
  98 /* Point traits bitmap; we update this information incrementally,
  99  * it can be used e.g. for fast pattern.h features matching. */
 100 struct btraits {
 101         /* Number of neighbors we can capture. 0=this move is
 102          * not capturing, 1..4=this many neighbors we can capture
 103          * (can be multiple neighbors of same group). */
 104         unsigned cap:3;
 105         /* Number of 1-stone neighbors we can capture. */
 106         unsigned cap1:3;
 107         /* Whether it is SAFE to play here. This is essentially just
 108          * cached result of board_safe_to_play(). (Of course the concept
 109          * of "safety" is not perfect here, but it's the cheapest
 110          * reasonable thing we can do.) */
 111         bool safe:1;
 112         /* Whether we need to re-compute this coordinate; used to
 113          * weed out duplicates. Maintained only for S_BLACK. */
 114         bool dirty:1;
 115 };
 116
 117
 118 /* You should treat this struct as read-only. Always call functions below if
 119  * you want to change it. */
 120
 121 struct board {
 122         int size; /* Including S_OFFBOARD margin - see below. */
 123         int size2; /* size^2 */
 124         int bits2; /* ceiling(log2(size2)) */
 125         int captures[S_MAX];
 126         float komi;
 127         int handicap;
 128         /* The ruleset is currently almost never taken into account;
 129          * the board implementation is basically Chinese rules (handicap
 130          * stones compensation) w/ suicide (or you can look at it as
 131          * New Zealand w/o handi stones compensation), while the engine
 132          * enforces no-suicide, making for real Chinese rules. */
 133         enum {
 134                 RULES_CHINESE, /* default value */
 135                 RULES_AGA,
 136                 RULES_NEW_ZEALAND,
 137                 RULES_JAPANESE,
 138         } rules;
 139
 140         /* Iterator offsets for foreach_neighbor*() */
 141         int nei8[8], dnei[4];
 142
 143         int moves;
 144         struct move last_move;
 145         struct move last_move2; /* second-to-last move */
 146         /* Whether we tried to add a hash twice; board_play*() can
 147          * set this, but it will still carry out the move as well! */
 148         bool superko_violation;
 149
 150         /* The following two structures are goban maps and are indexed by
 151          * coord.pos. The map is surrounded by a one-point margin from
 152          * S_OFFBOARD stones in order to speed up some internal loops.
 153          * Some of the foreach iterators below might include these points;
 154          * you need to handle them yourselves, if you need to. */
 155
 156         /* Stones played on the board */
 157         enum stone *b; /* enum stone */
 158         /* Group id the stones are part of; 0 == no group */
 159         group_t *g;
 160         /* Positions of next stones in the stone group; 0 == last stone */
 161         coord_t *p;
 162         /* Neighboring colors; numbers of neighbors of index color */
 163         struct neighbor_colors *n;
 164         /* Zobrist hash for each position */
 165         hash_t *h;
 166 #ifdef BOARD_SPATHASH
 167         /* For spatial hashes, we use only 24 bits. */
 168         /* [0] is d==1, we don't keep hash for d==0. */
 169         /* We keep hashes for black-to-play ([][0]) and white-to-play
 170          * ([][1], reversed stone colors since we match all patterns as
 171          * black-to-play). */
 172         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 173 #endif
 174 #ifdef BOARD_PAT3
 175         /* 3x3 pattern code for each position; see pattern3.h for encoding
 176          * specification. The information is only valid for empty points. */
 177         hash3_t *pat3;
 178 #endif
 179 #ifdef BOARD_TRAITS
 180         /* Incrementally matched point traits information, black-to-play
 181          * ([][0]) and white-to-play ([][1]). */
 182         /* The information is only valid for empty points. */
 183         struct btraits (*t)[2];
 184 #endif
 185 #ifdef BOARD_GAMMA
 186         /* Relative probabilities of moves being played next, computed by
 187          * multiplying gammas of the appropriate pattern features based on
 188          * pat3 and traits (see pattern.h). The probability distribution
 189          * is maintained over the full board grid. */
 190         /* - Always invalid moves are guaranteed to have zero probability.
 191          * - Self-eye-filling moves will always have zero probability.
 192          * - Ko-prohibited moves might have non-zero probability.
 193          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 194         struct probdist prob[2];
 195 #endif
 196         /* Cached information on x-y coordinates so that we avoid division. */
 197         uint8_t (*coord)[2];
 198
 199         /* Group information - indexed by gid (which is coord of base group stone) */
 200         struct group *gi;
 201
 202         /* Positions of free positions - queue (not map) */
 203         /* Note that free position here is any valid move; including single-point eyes!
 204          * However, pass is not included. */
 205         coord_t *f; int flen;
 206
 207 #ifdef WANT_BOARD_C
 208         /* Queue of capturable groups */
 209         group_t *c; int clen;
 210 #endif
 211
 212 #ifdef BOARD_TRAITS
 213         /* Queue of positions that need their traits updated */
 214         coord_t *tq; int tqlen;
 215 #endif
 216
 217         /* Symmetry information */
 218         struct board_symmetry symmetry;
 219
 220         /* Last ko played on the board. */
 221         struct move last_ko;
 222         int last_ko_age;
 223
 224         /* Basic ko check */
 225         struct move ko;
 226
 227         /* Engine-specific state; persistent through board development,
 228          * is reset only at clear_board. */
 229         void *es;
 230
 231         /* Playout-specific state; persistent through board development,
 232          * but its lifetime is maintained in play_random_game(); it should
 233          * not be set outside of it. */
 234         void *ps;
 235
 236 #ifdef BOARD_GAMMA
 237         /* Gamma values for probability distribution; user must setup
 238          * this pointer before any move is played, using board_gamma_set(). */
 239         struct features_gamma *gamma;
 240         /* Whether to compute the 'safe' trait using board_safe_to_play()
 241          * (false) or is_bad_selfatari() (true, much slower). */
 242         bool precise_selfatari;
 243 #endif
 244
 245
 246         /* --- PRIVATE DATA --- */
 247
 248         /* For superko check: */
 249
 250         /* Board "history" - hashes encountered. Size of the hash should be
 251          * >> board_size^2. */
 252 #define history_hash_bits 12
 253 #define history_hash_mask ((1 << history_hash_bits) - 1)
 254 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 255 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 256         hash_t history_hash[1 << history_hash_bits];
 257         /* Hash of current board position. */
 258         hash_t hash;
 259         /* Hash of current board position quadrants. */
 260         hash_t qhash[4];
 261 };
 262
 263 #ifdef BOARD_SIZE
 264 /* Avoid unused variable warnings */
 265 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 266 #define board_size2(b_) (board_size(b_) * board_size(b_))
 267 #else
 268 #define board_size(b_) ((b_)->size)
 269 #define board_size2(b_) ((b_)->size2)
 270 #endif
 271
 272 #if BOARD_SIZE == 19
 273 #  define board_bits2(b_) 9
 274 #elif BOARD_SIZE == 13
 275 #  define board_bits2(b_) 8
 276 #elif BOARD_SIZE == 9
 277 #  define board_bits2(b_) 7
 278 #else
 279 #  define board_bits2(b_) ((b_)->bits2)
 280 #endif
 281
 282 #define board_at(b_, c) ((b_)->b[c])
 283 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 284
 285 #define group_at(b_, c) ((b_)->g[c])
 286 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 287
 288 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 289 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 290 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 291 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 292 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 293 #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))
 294
 295 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 296
 297 #define groupnext_at(b_, c) ((b_)->p[c])
 298 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 299
 300 #define group_base(g_) (g_)
 301 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 302 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 303 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 304 /* board_group_other_lib() makes sense only for groups with two liberties. */
 305 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 306
 307 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 308
 309 struct board *board_init(void);
 310 struct board *board_copy(struct board *board2, struct board *board1);
 311 void board_done_noalloc(struct board *board);
 312 void board_done(struct board *board);
 313 /* size here is without the S_OFFBOARD margin. */
 314 void board_resize(struct board *board, int size);
 315 void board_clear(struct board *board);
 316
 317 struct FILE;
 318 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 319 void board_print(struct board *board, FILE *f);
 320 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 321
 322 /* Place given handicap on the board; coordinates are printed to f. */
 323 void board_handicap(struct board *board, int stones, FILE *f);
 324
 325 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 326 int board_play(struct board *board, struct move *m);
 327 /* Like above, but plays random move; the move coordinate is recorded
 328  * to *coord. This method will never fill your own eye. pass is played
 329  * when no move can be played. You can impose extra restrictions if you
 330  * supply your own permit function; the permit function can also modify
 331  * the move coordinate to redirect the move elsewhere. */
 332 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 333 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 334
 335 /* Returns true if given move can be played. */
 336 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 337 static bool board_is_valid_move(struct board *b, struct move *m);
 338 /* Returns true if ko was just taken. */
 339 static bool board_playing_ko_threat(struct board *b);
 340 /* Returns 0 or ID of neighboring group in atari. */
 341 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 342 /* Returns true if the move is not obvious self-atari. */
 343 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 344
 345 /* Adjust symmetry information as if given coordinate has been played. */
 346 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 347 /* Associate a set of feature gamma values (for pd building) with the board. */
 348 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 349 /* Force re-compute of a probability distribution item. */
 350 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 351
 352 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 353 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 354 /* Returns true if given coordinate could be a false eye; this check makes
 355  * sense only if you already know the coordinate is_eyelike(). */
 356 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 357 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 358  * at least tries to). */
 359 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 360 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 361 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 362
 363 /* board_official_score() is the scoring method for yielding score suitable
 364  * for external presentation. For fast scoring of entirely filled boards
 365  * (e.g. playouts), use board_fast_score(). */
 366 /* Positive: W wins */
 367 /* Compare number of stones + 1pt eyes. */
 368 float board_fast_score(struct board *board);
 369 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 370 struct move_queue;
 371 float board_official_score(struct board *board, struct move_queue *mq);
 372
 373 /** Iterators */
 374
 375 #define foreach_point(board_) \
 376         do { \
 377                 coord_t c = 0; \
 378                 for (; c < board_size(board_) * board_size(board_); c++)
 379 #define foreach_point_and_pass(board_) \
 380         do { \
 381                 coord_t c = pass; \
 382                 for (; c < board_size(board_) * board_size(board_); c++)
 383 #define foreach_point_end \
 384         } while (0)
 385
 386 #define foreach_free_point(board_) \
 387         do { \
 388                 int fmax__ = (board_)->flen; \
 389                 for (int f__ = 0; f__ < fmax__; f__++) { \
 390                         coord_t c = (board_)->f[f__];
 391 #define foreach_free_point_end \
 392                 } \
 393         } while (0)
 394
 395 #define foreach_in_group(board_, group_) \
 396         do { \
 397                 struct board *board__ = board_; \
 398                 coord_t c = group_base(group_); \
 399                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 400                 do {
 401 #define foreach_in_group_end \
 402                         c = c2; c2 = groupnext_at(board__, c2); \
 403                 } while (c != 0); \
 404         } while (0)
 405
 406 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 407  * on S_OFFBOARD coordinates. */
 408 #define foreach_neighbor(board_, coord_, loop_body) \
 409         do { \
 410                 struct board *board__ = board_; \
 411                 coord_t coord__ = coord_; \
 412                 coord_t c; \
 413                 c = coord__ - 1; do { loop_body } while (0); \
 414                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 415                 c = coord__ + 1; do { loop_body } while (0); \
 416                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 417         } while (0)
 418
 419 #define foreach_8neighbor(board_, coord_) \
 420         do { \
 421                 int fn__i; \
 422                 coord_t c = (coord_); \
 423                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 424                         c += (board_)->nei8[fn__i];
 425 #define foreach_8neighbor_end \
 426                 } \
 427         } while (0)
 428
 429 #define foreach_diag_neighbor(board_, coord_) \
 430         do { \
 431                 int fn__i; \
 432                 coord_t c = (coord_); \
 433                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 434                         c += (board_)->dnei[fn__i];
 435 #define foreach_diag_neighbor_end \
 436                 } \
 437         } while (0)
 438
 439
 440 static inline bool
 441 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 442 {
 443         return (neighbor_count_at(board, coord, eye_color)
 444                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 445 }
 446
 447 static inline bool
 448 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 449 {
 450         if (board_at(board, coord) != S_NONE)
 451                 return false;
 452         if (!board_is_eyelike(board, coord, stone_other(color)))
 453                 return true;
 454         /* Play within {true,false} eye-ish formation */
 455         if (board->ko.coord == coord && board->ko.color == color)
 456                 return false;
 457 #ifdef BOARD_TRAITS
 458         /* XXX: Disallows suicide. */
 459         return trait_at(board, coord, color).cap > 0;
 460 #else
 461         int groups_in_atari = 0;
 462         foreach_neighbor(board, coord, {
 463                 group_t g = group_at(board, c);
 464                 groups_in_atari += (board_group_info(board, g).libs == 1);
 465         });
 466         return !!groups_in_atari;
 467 #endif
 468 }
 469
 470 static inline bool
 471 board_is_valid_move(struct board *board, struct move *m)
 472 {
 473         return board_is_valid_play(board, m->color, m->coord);
 474 }
 475
 476 static inline bool
 477 board_playing_ko_threat(struct board *b)
 478 {
 479         return !is_pass(b->ko.coord);
 480 }
 481
 482 static inline group_t
 483 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 484 {
 485 #ifdef BOARD_TRAITS
 486         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 487 #endif
 488         foreach_neighbor(b, coord, {
 489                 group_t g = group_at(b, c);
 490                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 491                         return g;
 492                 /* We return first match. */
 493         });
 494         return 0;
 495 }
 496
 497 static inline bool
 498 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 499 {
 500         /* number of free neighbors */
 501         int libs = immediate_liberty_count(b, coord);
 502         if (libs > 1)
 503                 return true;
 504
 505 #ifdef BOARD_TRAITS
 506         /* number of capturable enemy groups */
 507         if (trait_at(b, coord, color).cap > 0)
 508                 return true; // XXX: We don't account for snapback.
 509         /* number of non-capturable friendly groups */
 510         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 511         if (noncap_ours < 1)
 512                 return false;
 513 /*#else see below */
 514 #endif
 515
 516         /* ok, but we need to check if they don't have just two libs. */
 517         coord_t onelib = -1;
 518         foreach_neighbor(b, coord, {
 519 #ifndef BOARD_TRAITS
 520                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 521                         return true; // can capture; no snapback check
 522 #endif
 523                 if (board_at(b, c) != color) continue;
 524                 group_t g = group_at(b, c);
 525                 if (board_group_info(b, g).libs == 1) continue; // in atari
 526                 if (board_group_info(b, g).libs == 2) { // two liberties
 527                         if (libs > 0) return true; // we already have one real liberty
 528                         /* we might be connecting two 2-lib groups, which is ok;
 529                          * so remember the other liberty and just make sure it's
 530                          * not the same one */
 531                         if (onelib >= 0 && c != onelib) return true;
 532                         onelib = board_group_other_lib(b, g, c);
 533                         continue;
 534                 }
 535                 // many liberties
 536                 return true;
 537         });
 538         // no good support group
 539         return false;
 540 }
 541
 542 #endif