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 PACHI_BOARD_H
   6 #define PACHI_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 fbook;
  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_PAT3 // incremental 3x3 pattern codes
  31
  32 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  33 //#define BOARD_TRAIT_SAFE 1 // include btraits.safe (rather expensive, unused)
  34 //#define BOARD_TRAIT_SAFE 2 // include btraits.safe based on full is_bad_selfatari()
  35
  36
  37 #define BOARD_MAX_MOVES (BOARD_MAX_SIZE * BOARD_MAX_SIZE)
  38 #define BOARD_MAX_GROUPS (BOARD_MAX_SIZE * BOARD_MAX_SIZE / 2)
  39
  40
  41 /* Some engines might normalize their reading and skip symmetrical
  42  * moves. We will tell them how can they do it. */
  43 struct board_symmetry {
  44         /* Playground is in this rectangle. */
  45         int x1, x2, y1, y2;
  46         /* d ==  0: Full rectangle
  47          * d ==  1: Top triangle */
  48         int d;
  49         /* General symmetry type. */
  50         /* Note that the above is redundant to this, but just provided
  51          * for easier usage. */
  52         enum {
  53                 SYM_FULL,
  54                 SYM_DIAG_UP,
  55                 SYM_DIAG_DOWN,
  56                 SYM_HORIZ,
  57                 SYM_VERT,
  58                 SYM_NONE
  59         } type;
  60 };
  61
  62
  63 typedef uint64_t hash_t;
  64 #define PRIhash PRIx64
  65
  66 /* XXX: This really belongs in pattern3.h, unfortunately that would mean
  67  * a dependency hell. */
  68 typedef uint32_t hash3_t; // 3x3 pattern hash
  69
  70
  71 /* Note that "group" is only chain of stones that is solidly
  72  * connected for us. */
  73 typedef coord_t group_t;
  74
  75 struct group {
  76         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  77          * don't care. */
  78         /* _Combination_ of these two values can make some difference
  79          * in performance - fine-tune. */
  80 #define GROUP_KEEP_LIBS 10
  81         // refill lib[] only when we hit this; this must be at least 2!
  82         // Moggy requires at least 3 - see below for semantic impact.
  83 #define GROUP_REFILL_LIBS 5
  84         coord_t lib[GROUP_KEEP_LIBS];
  85         /* libs is only LOWER BOUND for the number of real liberties!!!
  86          * It denotes only number of items in lib[], thus you can rely
  87          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  88         int libs;
  89 };
  90
  91 struct neighbor_colors {
  92         char colors[S_MAX];
  93 };
  94
  95
  96 /* Point traits bitmap; we update this information incrementally,
  97  * it can be used e.g. for fast pattern features matching. */
  98 struct btraits {
  99         /* Number of neighbors we can capture. 0=this move is
 100          * not capturing, 1..4=this many neighbors we can capture
 101          * (can be multiple neighbors of same group). */
 102         unsigned cap:3;
 103         /* Number of 1-stone neighbors we can capture. */
 104         unsigned cap1:3;
 105 #ifdef BOARD_TRAIT_SAFE
 106         /* Whether it is SAFE to play here. This is essentially just
 107          * cached result of board_safe_to_play(). (Of course the concept
 108          * of "safety" is not perfect here, but it's the cheapest
 109          * reasonable thing we can do.) */
 110         bool safe:1;
 111 #endif
 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         floating_t 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_STONES_ONLY, /* do not count eyes */
 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         struct move last_move3; /* just before last_move2, only set if last_move is pass */
 151         struct move last_move4; /* just before last_move3, only set if last_move & last_move2 are pass */
 152         /* Whether we tried to add a hash twice; board_play*() can
 153          * set this, but it will still carry out the move as well! */
 154         bool superko_violation;
 155
 156         /* The following two structures are goban maps and are indexed by
 157          * coord.pos. The map is surrounded by a one-point margin from
 158          * S_OFFBOARD stones in order to speed up some internal loops.
 159          * Some of the foreach iterators below might include these points;
 160          * you need to handle them yourselves, if you need to. */
 161
 162         /* Stones played on the board */
 163         enum stone *b; /* enum stone */
 164         /* Group id the stones are part of; 0 == no group */
 165         group_t *g;
 166         /* Positions of next stones in the stone group; 0 == last stone */
 167         coord_t *p;
 168         /* Neighboring colors; numbers of neighbors of index color */
 169         struct neighbor_colors *n;
 170         /* Zobrist hash for each position */
 171         hash_t *h;
 172 #ifdef BOARD_PAT3
 173         /* 3x3 pattern code for each position; see pattern3.h for encoding
 174          * specification. The information is only valid for empty points. */
 175         hash3_t *pat3;
 176 #endif
 177 #ifdef BOARD_TRAITS
 178         /* Incrementally matched point traits information, black-to-play
 179          * ([][0]) and white-to-play ([][1]). */
 180         /* The information is only valid for empty points. */
 181         struct btraits (*t)[2];
 182 #endif
 183         /* Cached information on x-y coordinates so that we avoid division. */
 184         uint8_t (*coord)[2];
 185
 186         /* Group information - indexed by gid (which is coord of base group stone) */
 187         struct group *gi;
 188
 189         /* Positions of free positions - queue (not map) */
 190         /* Note that free position here is any valid move; including single-point eyes!
 191          * However, pass is not included. */
 192         coord_t *f; int flen;
 193
 194 #ifdef WANT_BOARD_C
 195         /* Queue of capturable groups */
 196         group_t *c; int clen;
 197 #endif
 198
 199 #ifdef BOARD_TRAITS
 200         /* Queue of positions that need their traits updated */
 201         coord_t *tq; int tqlen;
 202 #endif
 203
 204         /* Symmetry information */
 205         struct board_symmetry symmetry;
 206
 207         /* Last ko played on the board. */
 208         struct move last_ko;
 209         int last_ko_age;
 210
 211         /* Basic ko check */
 212         struct move ko;
 213
 214         /* Engine-specific state; persistent through board development,
 215          * is reset only at clear_board. */
 216         void *es;
 217
 218         /* Playout-specific state; persistent through board development,
 219          * but its lifetime is maintained in play_random_game(); it should
 220          * not be set outside of it. */
 221         void *ps;
 222
 223
 224         /* --- PRIVATE DATA --- */
 225
 226         /* For superko check: */
 227
 228         /* Board "history" - hashes encountered. Size of the hash should be
 229          * >> board_size^2. */
 230 #define history_hash_bits 12
 231 #define history_hash_mask ((1 << history_hash_bits) - 1)
 232 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 233 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 234         hash_t history_hash[1 << history_hash_bits];
 235         /* Hash of current board position. */
 236         hash_t hash;
 237         /* Hash of current board position quadrants. */
 238         hash_t qhash[4];
 239 };
 240
 241 #ifdef BOARD_SIZE
 242 /* Avoid unused variable warnings */
 243 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 244 #define board_size2(b_) (board_size(b_) * board_size(b_))
 245 #else
 246 #define board_size(b_) ((b_)->size)
 247 #define board_size2(b_) ((b_)->size2)
 248 #endif
 249
 250 /* This is a shortcut for taking different action on smaller
 251  * and large boards (e.g. picking different variable defaults).
 252  * This is of course less optimal than fine-tuning dependency
 253  * function of values on board size, but that is difficult and
 254  * possibly not very rewarding if you are interested just in
 255  * 9x9 and 19x19. */
 256 #define board_large(b_) (board_size(b_)-2 >= 15)
 257
 258 #if BOARD_SIZE == 19
 259 #  define board_bits2(b_) 9
 260 #elif BOARD_SIZE == 13
 261 #  define board_bits2(b_) 8
 262 #elif BOARD_SIZE == 9
 263 #  define board_bits2(b_) 7
 264 #else
 265 #  define board_bits2(b_) ((b_)->bits2)
 266 #endif
 267
 268 #define board_at(b_, c) ((b_)->b[c])
 269 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 270
 271 #define group_at(b_, c) ((b_)->g[c])
 272 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 273
 274 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 275 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 276 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 277 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 278 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 279 #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))
 280
 281 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 282
 283 #define groupnext_at(b_, c) ((b_)->p[c])
 284 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 285
 286 #define group_base(g_) (g_)
 287 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 288 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 289 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 290 /* board_group_other_lib() makes sense only for groups with two liberties. */
 291 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 292
 293 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 294
 295 struct board *board_init(char *fbookfile);
 296 struct board *board_copy(struct board *board2, struct board *board1);
 297 void board_done_noalloc(struct board *board);
 298 void board_done(struct board *board);
 299 /* size here is without the S_OFFBOARD margin. */
 300 void board_resize(struct board *board, int size);
 301 void board_clear(struct board *board);
 302
 303 struct FILE;
 304 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 305 void board_print(struct board *board, FILE *f);
 306 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 307
 308 /* Place given handicap on the board; coordinates are printed to f. */
 309 void board_handicap(struct board *board, int stones, FILE *f);
 310
 311 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 312 int board_play(struct board *board, struct move *m);
 313 /* Like above, but plays random move; the move coordinate is recorded
 314  * to *coord. This method will never fill your own eye. pass is played
 315  * when no move can be played. You can impose extra restrictions if you
 316  * supply your own permit function; the permit function can also modify
 317  * the move coordinate to redirect the move elsewhere. */
 318 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 319 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 320
 321 /*Undo, supported only for pass moves. Returns -1 on error, 0 otherwise. */
 322 int board_undo(struct board *board);
 323
 324 /* Returns true if given move can be played. */
 325 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 326 static bool board_is_valid_move(struct board *b, struct move *m);
 327 /* Returns true if ko was just taken. */
 328 static bool board_playing_ko_threat(struct board *b);
 329 /* Returns 0 or ID of neighboring group in atari. */
 330 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 331 /* Returns true if the move is not obvious self-atari. */
 332 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 333
 334 /* Determine number of stones in a group, up to @max stones. */
 335 static int group_stone_count(struct board *b, group_t group, int max);
 336
 337 /* Adjust symmetry information as if given coordinate has been played. */
 338 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 339 /* Check if coordinates are within symmetry base. (If false, they can
 340  * be derived from the base.) */
 341 static bool board_coord_in_symmetry(struct board *b, coord_t c);
 342
 343 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 344 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 345 /* Returns true if given coordinate could be a false eye; this check makes
 346  * sense only if you already know the coordinate is_eyelike(). */
 347 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 348 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 349  * at least tries to). */
 350 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 351 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 352 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 353
 354 /* board_official_score() is the scoring method for yielding score suitable
 355  * for external presentation. For fast scoring of entirely filled boards
 356  * (e.g. playouts), use board_fast_score(). */
 357 /* Positive: W wins */
 358 /* Compare number of stones + 1pt eyes. */
 359 floating_t board_fast_score(struct board *board);
 360 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 361 struct move_queue;
 362 floating_t board_official_score(struct board *board, struct move_queue *mq);
 363
 364 /** Iterators */
 365
 366 #define foreach_point(board_) \
 367         do { \
 368                 coord_t c = 0; \
 369                 for (; c < board_size(board_) * board_size(board_); c++)
 370 #define foreach_point_and_pass(board_) \
 371         do { \
 372                 coord_t c = pass; \
 373                 for (; c < board_size(board_) * board_size(board_); c++)
 374 #define foreach_point_end \
 375         } while (0)
 376
 377 #define foreach_free_point(board_) \
 378         do { \
 379                 int fmax__ = (board_)->flen; \
 380                 for (int f__ = 0; f__ < fmax__; f__++) { \
 381                         coord_t c = (board_)->f[f__];
 382 #define foreach_free_point_end \
 383                 } \
 384         } while (0)
 385
 386 #define foreach_in_group(board_, group_) \
 387         do { \
 388                 struct board *board__ = board_; \
 389                 coord_t c = group_base(group_); \
 390                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 391                 do {
 392 #define foreach_in_group_end \
 393                         c = c2; c2 = groupnext_at(board__, c2); \
 394                 } while (c != 0); \
 395         } while (0)
 396
 397 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 398  * on S_OFFBOARD coordinates. */
 399 #define foreach_neighbor(board_, coord_, loop_body) \
 400         do { \
 401                 struct board *board__ = board_; \
 402                 coord_t coord__ = coord_; \
 403                 coord_t c; \
 404                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 405                 c = coord__ - 1; do { loop_body } while (0); \
 406                 c = coord__ + 1; do { loop_body } while (0); \
 407                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 408         } while (0)
 409
 410 #define foreach_8neighbor(board_, coord_) \
 411         do { \
 412                 int fn__i; \
 413                 coord_t c = (coord_); \
 414                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 415                         c += (board_)->nei8[fn__i];
 416 #define foreach_8neighbor_end \
 417                 } \
 418         } while (0)
 419
 420 #define foreach_diag_neighbor(board_, coord_) \
 421         do { \
 422                 int fn__i; \
 423                 coord_t c = (coord_); \
 424                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 425                         c += (board_)->dnei[fn__i];
 426 #define foreach_diag_neighbor_end \
 427                 } \
 428         } while (0)
 429
 430
 431 static inline bool
 432 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 433 {
 434         return (neighbor_count_at(board, coord, eye_color)
 435                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 436 }
 437
 438 static inline bool
 439 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 440 {
 441         if (board_at(board, coord) != S_NONE)
 442                 return false;
 443         if (!board_is_eyelike(board, coord, stone_other(color)))
 444                 return true;
 445         /* Play within {true,false} eye-ish formation */
 446         if (board->ko.coord == coord && board->ko.color == color)
 447                 return false;
 448 #ifdef BOARD_TRAITS
 449         /* XXX: Disallows suicide. */
 450         return trait_at(board, coord, color).cap > 0;
 451 #else
 452         int groups_in_atari = 0;
 453         foreach_neighbor(board, coord, {
 454                 group_t g = group_at(board, c);
 455                 groups_in_atari += (board_group_info(board, g).libs == 1);
 456         });
 457         return !!groups_in_atari;
 458 #endif
 459 }
 460
 461 static inline bool
 462 board_is_valid_move(struct board *board, struct move *m)
 463 {
 464         return board_is_valid_play(board, m->color, m->coord);
 465 }
 466
 467 static inline bool
 468 board_playing_ko_threat(struct board *b)
 469 {
 470         return !is_pass(b->ko.coord);
 471 }
 472
 473 static inline group_t
 474 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 475 {
 476 #ifdef BOARD_TRAITS
 477         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 478 #endif
 479         foreach_neighbor(b, coord, {
 480                 group_t g = group_at(b, c);
 481                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 482                         return g;
 483                 /* We return first match. */
 484         });
 485         return 0;
 486 }
 487
 488 static inline bool
 489 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 490 {
 491         /* number of free neighbors */
 492         int libs = immediate_liberty_count(b, coord);
 493         if (libs > 1)
 494                 return true;
 495
 496 #ifdef BOARD_TRAITS
 497         /* number of capturable enemy groups */
 498         if (trait_at(b, coord, color).cap > 0)
 499                 return true; // XXX: We don't account for snapback.
 500         /* number of non-capturable friendly groups */
 501         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 502         if (noncap_ours < 1)
 503                 return false;
 504 /*#else see below */
 505 #endif
 506
 507         /* ok, but we need to check if they don't have just two libs. */
 508         coord_t onelib = -1;
 509         foreach_neighbor(b, coord, {
 510 #ifndef BOARD_TRAITS
 511                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 512                         return true; // can capture; no snapback check
 513 #endif
 514                 if (board_at(b, c) != color) continue;
 515                 group_t g = group_at(b, c);
 516                 if (board_group_info(b, g).libs == 1) continue; // in atari
 517                 if (board_group_info(b, g).libs == 2) { // two liberties
 518                         if (libs > 0) return true; // we already have one real liberty
 519                         /* we might be connecting two 2-lib groups, which is ok;
 520                          * so remember the other liberty and just make sure it's
 521                          * not the same one */
 522                         if (onelib >= 0 && c != onelib) return true;
 523                         onelib = board_group_other_lib(b, g, c);
 524                         continue;
 525                 }
 526                 // many liberties
 527                 return true;
 528         });
 529         // no good support group
 530         return false;
 531 }
 532
 533 static inline int
 534 group_stone_count(struct board *b, group_t group, int max)
 535 {
 536         int n = 0;
 537         foreach_in_group(b, group) {
 538                 n++;
 539                 if (n >= max) return max;
 540         } foreach_in_group_end;
 541         return n;
 542 }
 543
 544 static inline bool
 545 board_coord_in_symmetry(struct board *b, coord_t c)
 546 {
 547         if (coord_y(c, b) < b->symmetry.y1 || coord_y(c, b) > b->symmetry.y2)
 548                 return false;
 549         if (coord_x(c, b) < b->symmetry.x1 || coord_x(c, b) > b->symmetry.x2)
 550                 return false;
 551         if (b->symmetry.d) {
 552                 int x = coord_x(c, b);
 553                 if (b->symmetry.type == SYM_DIAG_DOWN)
 554                         x = board_size(b) - 1 - x;
 555                 if (x > coord_y(c, b))
 556                         return false;
 557         }
 558         return true;
 559
 560 }
 561
 562 #endif