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_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_TRAIT_SAFE 1 // include btraits.safe (rather expensive, unused)
  37 //#define BOARD_TRAIT_SAFE 2 // include btraits.safe based on full is_bad_selfatari()
  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 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 #ifdef BOARD_TRAIT_SAFE
 109         /* Whether it is SAFE to play here. This is essentially just
 110          * cached result of board_safe_to_play(). (Of course the concept
 111          * of "safety" is not perfect here, but it's the cheapest
 112          * reasonable thing we can do.) */
 113         bool safe:1;
 114 #endif
 115         /* Whether we need to re-compute this coordinate; used to
 116          * weed out duplicates. Maintained only for S_BLACK. */
 117         bool dirty:1;
 118 };
 119
 120
 121 /* You should treat this struct as read-only. Always call functions below if
 122  * you want to change it. */
 123
 124 struct board {
 125         int size; /* Including S_OFFBOARD margin - see below. */
 126         int size2; /* size^2 */
 127         int bits2; /* ceiling(log2(size2)) */
 128         int captures[S_MAX];
 129         floating_t komi;
 130         int handicap;
 131         /* The ruleset is currently almost never taken into account;
 132          * the board implementation is basically Chinese rules (handicap
 133          * stones compensation) w/ suicide (or you can look at it as
 134          * New Zealand w/o handi stones compensation), while the engine
 135          * enforces no-suicide, making for real Chinese rules. */
 136         enum {
 137                 RULES_CHINESE, /* default value */
 138                 RULES_AGA,
 139                 RULES_NEW_ZEALAND,
 140                 RULES_JAPANESE,
 141                 RULES_STONES_ONLY, /* do not count eyes */
 142         } rules;
 143
 144         char *fbookfile;
 145         struct fbook *fbook;
 146
 147         /* Iterator offsets for foreach_neighbor*() */
 148         int nei8[8], dnei[4];
 149
 150         int moves;
 151         struct move last_move;
 152         struct move last_move2; /* second-to-last move */
 153         struct move last_move3; /* just before last_move2, only set if last_move is pass */
 154         struct move last_move4; /* just before last_move3, only set if last_move & last_move2 are pass */
 155         /* Whether we tried to add a hash twice; board_play*() can
 156          * set this, but it will still carry out the move as well! */
 157         bool superko_violation;
 158
 159         /* The following two structures are goban maps and are indexed by
 160          * coord.pos. The map is surrounded by a one-point margin from
 161          * S_OFFBOARD stones in order to speed up some internal loops.
 162          * Some of the foreach iterators below might include these points;
 163          * you need to handle them yourselves, if you need to. */
 164
 165         /* Stones played on the board */
 166         enum stone *b; /* enum stone */
 167         /* Group id the stones are part of; 0 == no group */
 168         group_t *g;
 169         /* Positions of next stones in the stone group; 0 == last stone */
 170         coord_t *p;
 171         /* Neighboring colors; numbers of neighbors of index color */
 172         struct neighbor_colors *n;
 173         /* Zobrist hash for each position */
 174         hash_t *h;
 175 #ifdef BOARD_SPATHASH
 176         /* For spatial hashes, we use only 24 bits. */
 177         /* [0] is d==1, we don't keep hash for d==0. */
 178         /* We keep hashes for black-to-play ([][0]) and white-to-play
 179          * ([][1], reversed stone colors since we match all patterns as
 180          * black-to-play). */
 181         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 182 #endif
 183 #ifdef BOARD_PAT3
 184         /* 3x3 pattern code for each position; see pattern3.h for encoding
 185          * specification. The information is only valid for empty points. */
 186         hash3_t *pat3;
 187 #endif
 188 #ifdef BOARD_TRAITS
 189         /* Incrementally matched point traits information, black-to-play
 190          * ([][0]) and white-to-play ([][1]). */
 191         /* The information is only valid for empty points. */
 192         struct btraits (*t)[2];
 193 #endif
 194         /* Cached information on x-y coordinates so that we avoid division. */
 195         uint8_t (*coord)[2];
 196
 197         /* Group information - indexed by gid (which is coord of base group stone) */
 198         struct group *gi;
 199
 200         /* Positions of free positions - queue (not map) */
 201         /* Note that free position here is any valid move; including single-point eyes!
 202          * However, pass is not included. */
 203         coord_t *f; int flen;
 204
 205 #ifdef WANT_BOARD_C
 206         /* Queue of capturable groups */
 207         group_t *c; int clen;
 208 #endif
 209
 210 #ifdef BOARD_TRAITS
 211         /* Queue of positions that need their traits updated */
 212         coord_t *tq; int tqlen;
 213 #endif
 214
 215         /* Symmetry information */
 216         struct board_symmetry symmetry;
 217
 218         /* Last ko played on the board. */
 219         struct move last_ko;
 220         int last_ko_age;
 221
 222         /* Basic ko check */
 223         struct move ko;
 224
 225         /* Engine-specific state; persistent through board development,
 226          * is reset only at clear_board. */
 227         void *es;
 228
 229         /* Playout-specific state; persistent through board development,
 230          * but its lifetime is maintained in play_random_game(); it should
 231          * not be set outside of it. */
 232         void *ps;
 233
 234
 235         /* --- PRIVATE DATA --- */
 236
 237         /* For superko check: */
 238
 239         /* Board "history" - hashes encountered. Size of the hash should be
 240          * >> board_size^2. */
 241 #define history_hash_bits 12
 242 #define history_hash_mask ((1 << history_hash_bits) - 1)
 243 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 244 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 245         hash_t history_hash[1 << history_hash_bits];
 246         /* Hash of current board position. */
 247         hash_t hash;
 248         /* Hash of current board position quadrants. */
 249         hash_t qhash[4];
 250 };
 251
 252 #ifdef BOARD_SIZE
 253 /* Avoid unused variable warnings */
 254 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 255 #define board_size2(b_) (board_size(b_) * board_size(b_))
 256 #else
 257 #define board_size(b_) ((b_)->size)
 258 #define board_size2(b_) ((b_)->size2)
 259 #endif
 260
 261 /* This is a shortcut for taking different action on smaller
 262  * and large boards (e.g. picking different variable defaults).
 263  * This is of course less optimal than fine-tuning dependency
 264  * function of values on board size, but that is difficult and
 265  * possibly not very rewarding if you are interested just in
 266  * 9x9 and 19x19. */
 267 #define board_large(b_) (board_size(b_)-2 >= 15)
 268
 269 #if BOARD_SIZE == 19
 270 #  define board_bits2(b_) 9
 271 #elif BOARD_SIZE == 13
 272 #  define board_bits2(b_) 8
 273 #elif BOARD_SIZE == 9
 274 #  define board_bits2(b_) 7
 275 #else
 276 #  define board_bits2(b_) ((b_)->bits2)
 277 #endif
 278
 279 #define board_at(b_, c) ((b_)->b[c])
 280 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 281
 282 #define group_at(b_, c) ((b_)->g[c])
 283 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 284
 285 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 286 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 287 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 288 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 289 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 290 #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))
 291
 292 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 293
 294 #define groupnext_at(b_, c) ((b_)->p[c])
 295 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 296
 297 #define group_base(g_) (g_)
 298 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 299 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 300 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 301 /* board_group_other_lib() makes sense only for groups with two liberties. */
 302 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 303
 304 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 305
 306 struct board *board_init(char *fbookfile);
 307 struct board *board_copy(struct board *board2, struct board *board1);
 308 void board_done_noalloc(struct board *board);
 309 void board_done(struct board *board);
 310 /* size here is without the S_OFFBOARD margin. */
 311 void board_resize(struct board *board, int size);
 312 void board_clear(struct board *board);
 313
 314 struct FILE;
 315 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 316 void board_print(struct board *board, FILE *f);
 317 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 318
 319 /* Place given handicap on the board; coordinates are printed to f. */
 320 void board_handicap(struct board *board, int stones, FILE *f);
 321
 322 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 323 int board_play(struct board *board, struct move *m);
 324 /* Like above, but plays random move; the move coordinate is recorded
 325  * to *coord. This method will never fill your own eye. pass is played
 326  * when no move can be played. You can impose extra restrictions if you
 327  * supply your own permit function; the permit function can also modify
 328  * the move coordinate to redirect the move elsewhere. */
 329 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 330 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 331
 332 /*Undo, supported only for pass moves. Returns -1 on error, 0 otherwise. */
 333 int board_undo(struct board *board);
 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 /* Determine number of stones in a group, up to @max stones. */
 346 static int group_stone_count(struct board *b, group_t group, int max);
 347
 348 /* Adjust symmetry information as if given coordinate has been played. */
 349 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 350 /* Check if coordinates are within symmetry base. (If false, they can
 351  * be derived from the base.) */
 352 static bool board_coord_in_symmetry(struct board *b, coord_t c);
 353
 354 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 355 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 356 /* Returns true if given coordinate could be a false eye; this check makes
 357  * sense only if you already know the coordinate is_eyelike(). */
 358 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 359 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 360  * at least tries to). */
 361 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 362 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 363 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 364
 365 /* board_official_score() is the scoring method for yielding score suitable
 366  * for external presentation. For fast scoring of entirely filled boards
 367  * (e.g. playouts), use board_fast_score(). */
 368 /* Positive: W wins */
 369 /* Compare number of stones + 1pt eyes. */
 370 floating_t board_fast_score(struct board *board);
 371 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 372 struct move_queue;
 373 floating_t board_official_score(struct board *board, struct move_queue *mq);
 374
 375 /** Iterators */
 376
 377 #define foreach_point(board_) \
 378         do { \
 379                 coord_t c = 0; \
 380                 for (; c < board_size(board_) * board_size(board_); c++)
 381 #define foreach_point_and_pass(board_) \
 382         do { \
 383                 coord_t c = pass; \
 384                 for (; c < board_size(board_) * board_size(board_); c++)
 385 #define foreach_point_end \
 386         } while (0)
 387
 388 #define foreach_free_point(board_) \
 389         do { \
 390                 int fmax__ = (board_)->flen; \
 391                 for (int f__ = 0; f__ < fmax__; f__++) { \
 392                         coord_t c = (board_)->f[f__];
 393 #define foreach_free_point_end \
 394                 } \
 395         } while (0)
 396
 397 #define foreach_in_group(board_, group_) \
 398         do { \
 399                 struct board *board__ = board_; \
 400                 coord_t c = group_base(group_); \
 401                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 402                 do {
 403 #define foreach_in_group_end \
 404                         c = c2; c2 = groupnext_at(board__, c2); \
 405                 } while (c != 0); \
 406         } while (0)
 407
 408 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 409  * on S_OFFBOARD coordinates. */
 410 #define foreach_neighbor(board_, coord_, loop_body) \
 411         do { \
 412                 struct board *board__ = board_; \
 413                 coord_t coord__ = coord_; \
 414                 coord_t c; \
 415                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 416                 c = coord__ - 1; do { loop_body } while (0); \
 417                 c = coord__ + 1; do { loop_body } while (0); \
 418                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 419         } while (0)
 420
 421 #define foreach_8neighbor(board_, coord_) \
 422         do { \
 423                 int fn__i; \
 424                 coord_t c = (coord_); \
 425                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 426                         c += (board_)->nei8[fn__i];
 427 #define foreach_8neighbor_end \
 428                 } \
 429         } while (0)
 430
 431 #define foreach_diag_neighbor(board_, coord_) \
 432         do { \
 433                 int fn__i; \
 434                 coord_t c = (coord_); \
 435                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 436                         c += (board_)->dnei[fn__i];
 437 #define foreach_diag_neighbor_end \
 438                 } \
 439         } while (0)
 440
 441
 442 static inline bool
 443 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 444 {
 445         return (neighbor_count_at(board, coord, eye_color)
 446                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 447 }
 448
 449 static inline bool
 450 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 451 {
 452         if (board_at(board, coord) != S_NONE)
 453                 return false;
 454         if (!board_is_eyelike(board, coord, stone_other(color)))
 455                 return true;
 456         /* Play within {true,false} eye-ish formation */
 457         if (board->ko.coord == coord && board->ko.color == color)
 458                 return false;
 459 #ifdef BOARD_TRAITS
 460         /* XXX: Disallows suicide. */
 461         return trait_at(board, coord, color).cap > 0;
 462 #else
 463         int groups_in_atari = 0;
 464         foreach_neighbor(board, coord, {
 465                 group_t g = group_at(board, c);
 466                 groups_in_atari += (board_group_info(board, g).libs == 1);
 467         });
 468         return !!groups_in_atari;
 469 #endif
 470 }
 471
 472 static inline bool
 473 board_is_valid_move(struct board *board, struct move *m)
 474 {
 475         return board_is_valid_play(board, m->color, m->coord);
 476 }
 477
 478 static inline bool
 479 board_playing_ko_threat(struct board *b)
 480 {
 481         return !is_pass(b->ko.coord);
 482 }
 483
 484 static inline group_t
 485 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 486 {
 487 #ifdef BOARD_TRAITS
 488         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 489 #endif
 490         foreach_neighbor(b, coord, {
 491                 group_t g = group_at(b, c);
 492                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 493                         return g;
 494                 /* We return first match. */
 495         });
 496         return 0;
 497 }
 498
 499 static inline bool
 500 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 501 {
 502         /* number of free neighbors */
 503         int libs = immediate_liberty_count(b, coord);
 504         if (libs > 1)
 505                 return true;
 506
 507 #ifdef BOARD_TRAITS
 508         /* number of capturable enemy groups */
 509         if (trait_at(b, coord, color).cap > 0)
 510                 return true; // XXX: We don't account for snapback.
 511         /* number of non-capturable friendly groups */
 512         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 513         if (noncap_ours < 1)
 514                 return false;
 515 /*#else see below */
 516 #endif
 517
 518         /* ok, but we need to check if they don't have just two libs. */
 519         coord_t onelib = -1;
 520         foreach_neighbor(b, coord, {
 521 #ifndef BOARD_TRAITS
 522                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 523                         return true; // can capture; no snapback check
 524 #endif
 525                 if (board_at(b, c) != color) continue;
 526                 group_t g = group_at(b, c);
 527                 if (board_group_info(b, g).libs == 1) continue; // in atari
 528                 if (board_group_info(b, g).libs == 2) { // two liberties
 529                         if (libs > 0) return true; // we already have one real liberty
 530                         /* we might be connecting two 2-lib groups, which is ok;
 531                          * so remember the other liberty and just make sure it's
 532                          * not the same one */
 533                         if (onelib >= 0 && c != onelib) return true;
 534                         onelib = board_group_other_lib(b, g, c);
 535                         continue;
 536                 }
 537                 // many liberties
 538                 return true;
 539         });
 540         // no good support group
 541         return false;
 542 }
 543
 544 static inline int
 545 group_stone_count(struct board *b, group_t group, int max)
 546 {
 547         int n = 0;
 548         foreach_in_group(b, group) {
 549                 n++;
 550                 if (n >= max) return max;
 551         } foreach_in_group_end;
 552         return n;
 553 }
 554
 555 static inline bool
 556 board_coord_in_symmetry(struct board *b, coord_t c)
 557 {
 558         if (coord_y(c, b) < b->symmetry.y1 || coord_y(c, b) > b->symmetry.y2)
 559                 return false;
 560         if (coord_x(c, b) < b->symmetry.x1 || coord_x(c, b) > b->symmetry.x2)
 561                 return false;
 562         if (b->symmetry.d) {
 563                 int x = coord_x(c, b);
 564                 if (b->symmetry.type == SYM_DIAG_DOWN)
 565                         x = board_size(b) - 1 - x;
 566                 if (x > coord_y(c, b))
 567                         return false;
 568         }
 569         return true;
 570
 571 }
 572
 573 #endif