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;
 139
 140         char *fbookfile;
 141         struct fbook *fbook;
 142
 143         /* Iterator offsets for foreach_neighbor*() */
 144         int nei8[8], dnei[4];
 145
 146         int moves;
 147         struct move last_move;
 148         struct move last_move2; /* second-to-last move */
 149         struct move last_move3; /* just before last_move2, only set if last_move is pass */
 150         struct move last_move4; /* just before last_move3, only set if last_move & last_move2 are pass */
 151         /* Whether we tried to add a hash twice; board_play*() can
 152          * set this, but it will still carry out the move as well! */
 153         bool superko_violation;
 154
 155         /* The following two structures are goban maps and are indexed by
 156          * coord.pos. The map is surrounded by a one-point margin from
 157          * S_OFFBOARD stones in order to speed up some internal loops.
 158          * Some of the foreach iterators below might include these points;
 159          * you need to handle them yourselves, if you need to. */
 160
 161         /* Stones played on the board */
 162         enum stone *b; /* enum stone */
 163         /* Group id the stones are part of; 0 == no group */
 164         group_t *g;
 165         /* Positions of next stones in the stone group; 0 == last stone */
 166         coord_t *p;
 167         /* Neighboring colors; numbers of neighbors of index color */
 168         struct neighbor_colors *n;
 169         /* Zobrist hash for each position */
 170         hash_t *h;
 171 #ifdef BOARD_PAT3
 172         /* 3x3 pattern code for each position; see pattern3.h for encoding
 173          * specification. The information is only valid for empty points. */
 174         hash3_t *pat3;
 175 #endif
 176 #ifdef BOARD_TRAITS
 177         /* Incrementally matched point traits information, black-to-play
 178          * ([][0]) and white-to-play ([][1]). */
 179         /* The information is only valid for empty points. */
 180         struct btraits (*t)[2];
 181 #endif
 182         /* Cached information on x-y coordinates so that we avoid division. */
 183         uint8_t (*coord)[2];
 184
 185         /* Group information - indexed by gid (which is coord of base group stone) */
 186         struct group *gi;
 187
 188         /* Positions of free positions - queue (not map) */
 189         /* Note that free position here is any valid move; including single-point eyes!
 190          * However, pass is not included. */
 191         coord_t *f; int flen;
 192
 193 #ifdef WANT_BOARD_C
 194         /* Queue of capturable groups */
 195         group_t *c; int clen;
 196 #endif
 197
 198 #ifdef BOARD_TRAITS
 199         /* Queue of positions that need their traits updated */
 200         coord_t *tq; int tqlen;
 201 #endif
 202
 203         /* Symmetry information */
 204         struct board_symmetry symmetry;
 205
 206         /* Last ko played on the board. */
 207         struct move last_ko;
 208         int last_ko_age;
 209
 210         /* Basic ko check */
 211         struct move ko;
 212
 213         /* Engine-specific state; persistent through board development,
 214          * is reset only at clear_board. */
 215         void *es;
 216
 217         /* Playout-specific state; persistent through board development,
 218          * but its lifetime is maintained in play_random_game(); it should
 219          * not be set outside of it. */
 220         void *ps;
 221
 222
 223         /* --- PRIVATE DATA --- */
 224
 225         /* For superko check: */
 226
 227         /* Board "history" - hashes encountered. Size of the hash should be
 228          * >> board_size^2. */
 229 #define history_hash_bits 12
 230 #define history_hash_mask ((1 << history_hash_bits) - 1)
 231 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 232 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 233         hash_t history_hash[1 << history_hash_bits];
 234         /* Hash of current board position. */
 235         hash_t hash;
 236         /* Hash of current board position quadrants. */
 237         hash_t qhash[4];
 238 };
 239
 240 #ifdef BOARD_SIZE
 241 /* Avoid unused variable warnings */
 242 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 243 #define board_size2(b_) (board_size(b_) * board_size(b_))
 244 #else
 245 #define board_size(b_) ((b_)->size)
 246 #define board_size2(b_) ((b_)->size2)
 247 #endif
 248
 249 /* This is a shortcut for taking different action on smaller
 250  * and large boards (e.g. picking different variable defaults).
 251  * This is of course less optimal than fine-tuning dependency
 252  * function of values on board size, but that is difficult and
 253  * possibly not very rewarding if you are interested just in
 254  * 9x9 and 19x19. */
 255 #define board_large(b_) (board_size(b_)-2 >= 15)
 256
 257 #if BOARD_SIZE == 19
 258 #  define board_bits2(b_) 9
 259 #elif BOARD_SIZE == 13
 260 #  define board_bits2(b_) 8
 261 #elif BOARD_SIZE == 9
 262 #  define board_bits2(b_) 7
 263 #else
 264 #  define board_bits2(b_) ((b_)->bits2)
 265 #endif
 266
 267 #define board_at(b_, c) ((b_)->b[c])
 268 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 269
 270 #define group_at(b_, c) ((b_)->g[c])
 271 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 272
 273 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 274 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 275 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 276 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 277 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 278 #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))
 279
 280 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 281
 282 #define groupnext_at(b_, c) ((b_)->p[c])
 283 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 284
 285 #define group_base(g_) (g_)
 286 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 287 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 288 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 289 /* board_group_other_lib() makes sense only for groups with two liberties. */
 290 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 291
 292 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 293
 294 struct board *board_init(char *fbookfile);
 295 struct board *board_copy(struct board *board2, struct board *board1);
 296 void board_done_noalloc(struct board *board);
 297 void board_done(struct board *board);
 298 /* size here is without the S_OFFBOARD margin. */
 299 void board_resize(struct board *board, int size);
 300 void board_clear(struct board *board);
 301
 302 struct FILE;
 303 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 304 void board_print(struct board *board, FILE *f);
 305 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 306
 307 /* Place given handicap on the board; coordinates are printed to f. */
 308 void board_handicap(struct board *board, int stones, FILE *f);
 309
 310 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 311 int board_play(struct board *board, struct move *m);
 312 /* Like above, but plays random move; the move coordinate is recorded
 313  * to *coord. This method will never fill your own eye. pass is played
 314  * when no move can be played. You can impose extra restrictions if you
 315  * supply your own permit function; the permit function can also modify
 316  * the move coordinate to redirect the move elsewhere. */
 317 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 318 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 319
 320 /*Undo, supported only for pass moves. Returns -1 on error, 0 otherwise. */
 321 int board_undo(struct board *board);
 322
 323 /* Returns true if given move can be played. */
 324 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 325 static bool board_is_valid_move(struct board *b, struct move *m);
 326 /* Returns true if ko was just taken. */
 327 static bool board_playing_ko_threat(struct board *b);
 328 /* Returns 0 or ID of neighboring group in atari. */
 329 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 330 /* Returns true if the move is not obvious self-atari. */
 331 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 332
 333 /* Determine number of stones in a group, up to @max stones. */
 334 static int group_stone_count(struct board *b, group_t group, int max);
 335
 336 /* Adjust symmetry information as if given coordinate has been played. */
 337 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 338 /* Check if coordinates are within symmetry base. (If false, they can
 339  * be derived from the base.) */
 340 static bool board_coord_in_symmetry(struct board *b, coord_t c);
 341
 342 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 343 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 344 /* Returns true if given coordinate could be a false eye; this check makes
 345  * sense only if you already know the coordinate is_eyelike(). */
 346 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 347 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 348  * at least tries to). */
 349 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 350 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 351 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 352
 353 /* board_official_score() is the scoring method for yielding score suitable
 354  * for external presentation. For fast scoring of entirely filled boards
 355  * (e.g. playouts), use board_fast_score(). */
 356 /* Positive: W wins */
 357 /* Compare number of stones + 1pt eyes. */
 358 floating_t board_fast_score(struct board *board);
 359 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 360 struct move_queue;
 361 floating_t board_official_score(struct board *board, struct move_queue *mq);
 362
 363 /** Iterators */
 364
 365 #define foreach_point(board_) \
 366         do { \
 367                 coord_t c = 0; \
 368                 for (; c < board_size(board_) * board_size(board_); c++)
 369 #define foreach_point_and_pass(board_) \
 370         do { \
 371                 coord_t c = pass; \
 372                 for (; c < board_size(board_) * board_size(board_); c++)
 373 #define foreach_point_end \
 374         } while (0)
 375
 376 #define foreach_free_point(board_) \
 377         do { \
 378                 int fmax__ = (board_)->flen; \
 379                 for (int f__ = 0; f__ < fmax__; f__++) { \
 380                         coord_t c = (board_)->f[f__];
 381 #define foreach_free_point_end \
 382                 } \
 383         } while (0)
 384
 385 #define foreach_in_group(board_, group_) \
 386         do { \
 387                 struct board *board__ = board_; \
 388                 coord_t c = group_base(group_); \
 389                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 390                 do {
 391 #define foreach_in_group_end \
 392                         c = c2; c2 = groupnext_at(board__, c2); \
 393                 } while (c != 0); \
 394         } while (0)
 395
 396 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 397  * on S_OFFBOARD coordinates. */
 398 #define foreach_neighbor(board_, coord_, loop_body) \
 399         do { \
 400                 struct board *board__ = board_; \
 401                 coord_t coord__ = coord_; \
 402                 coord_t c; \
 403                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 404                 c = coord__ - 1; do { loop_body } while (0); \
 405                 c = coord__ + 1; do { loop_body } while (0); \
 406                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 407         } while (0)
 408
 409 #define foreach_8neighbor(board_, coord_) \
 410         do { \
 411                 int fn__i; \
 412                 coord_t c = (coord_); \
 413                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 414                         c += (board_)->nei8[fn__i];
 415 #define foreach_8neighbor_end \
 416                 } \
 417         } while (0)
 418
 419 #define foreach_diag_neighbor(board_, coord_) \
 420         do { \
 421                 int fn__i; \
 422                 coord_t c = (coord_); \
 423                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 424                         c += (board_)->dnei[fn__i];
 425 #define foreach_diag_neighbor_end \
 426                 } \
 427         } while (0)
 428
 429
 430 static inline bool
 431 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 432 {
 433         return (neighbor_count_at(board, coord, eye_color)
 434                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 435 }
 436
 437 static inline bool
 438 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 439 {
 440         if (board_at(board, coord) != S_NONE)
 441                 return false;
 442         if (!board_is_eyelike(board, coord, stone_other(color)))
 443                 return true;
 444         /* Play within {true,false} eye-ish formation */
 445         if (board->ko.coord == coord && board->ko.color == color)
 446                 return false;
 447 #ifdef BOARD_TRAITS
 448         /* XXX: Disallows suicide. */
 449         return trait_at(board, coord, color).cap > 0;
 450 #else
 451         int groups_in_atari = 0;
 452         foreach_neighbor(board, coord, {
 453                 group_t g = group_at(board, c);
 454                 groups_in_atari += (board_group_info(board, g).libs == 1);
 455         });
 456         return !!groups_in_atari;
 457 #endif
 458 }
 459
 460 static inline bool
 461 board_is_valid_move(struct board *board, struct move *m)
 462 {
 463         return board_is_valid_play(board, m->color, m->coord);
 464 }
 465
 466 static inline bool
 467 board_playing_ko_threat(struct board *b)
 468 {
 469         return !is_pass(b->ko.coord);
 470 }
 471
 472 static inline group_t
 473 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 474 {
 475 #ifdef BOARD_TRAITS
 476         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 477 #endif
 478         foreach_neighbor(b, coord, {
 479                 group_t g = group_at(b, c);
 480                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 481                         return g;
 482                 /* We return first match. */
 483         });
 484         return 0;
 485 }
 486
 487 static inline bool
 488 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 489 {
 490         /* number of free neighbors */
 491         int libs = immediate_liberty_count(b, coord);
 492         if (libs > 1)
 493                 return true;
 494
 495 #ifdef BOARD_TRAITS
 496         /* number of capturable enemy groups */
 497         if (trait_at(b, coord, color).cap > 0)
 498                 return true; // XXX: We don't account for snapback.
 499         /* number of non-capturable friendly groups */
 500         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 501         if (noncap_ours < 1)
 502                 return false;
 503 /*#else see below */
 504 #endif
 505
 506         /* ok, but we need to check if they don't have just two libs. */
 507         coord_t onelib = -1;
 508         foreach_neighbor(b, coord, {
 509 #ifndef BOARD_TRAITS
 510                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 511                         return true; // can capture; no snapback check
 512 #endif
 513                 if (board_at(b, c) != color) continue;
 514                 group_t g = group_at(b, c);
 515                 if (board_group_info(b, g).libs == 1) continue; // in atari
 516                 if (board_group_info(b, g).libs == 2) { // two liberties
 517                         if (libs > 0) return true; // we already have one real liberty
 518                         /* we might be connecting two 2-lib groups, which is ok;
 519                          * so remember the other liberty and just make sure it's
 520                          * not the same one */
 521                         if (onelib >= 0 && c != onelib) return true;
 522                         onelib = board_group_other_lib(b, g, c);
 523                         continue;
 524                 }
 525                 // many liberties
 526                 return true;
 527         });
 528         // no good support group
 529         return false;
 530 }
 531
 532 static inline int
 533 group_stone_count(struct board *b, group_t group, int max)
 534 {
 535         int n = 0;
 536         foreach_in_group(b, group) {
 537                 n++;
 538                 if (n >= max) return max;
 539         } foreach_in_group_end;
 540         return n;
 541 }
 542
 543 static inline bool
 544 board_coord_in_symmetry(struct board *b, coord_t c)
 545 {
 546         if (coord_y(c, b) < b->symmetry.y1 || coord_y(c, b) > b->symmetry.y2)
 547                 return false;
 548         if (coord_x(c, b) < b->symmetry.x1 || coord_x(c, b) > b->symmetry.x2)
 549                 return false;
 550         if (b->symmetry.d) {
 551                 int x = coord_x(c, b);
 552                 if (b->symmetry.type == SYM_DIAG_DOWN)
 553                         x = board_size(b) - 1 - x;
 554                 if (x > coord_y(c, b))
 555                         return false;
 556         }
 557         return true;
 558
 559 }
 560
 561 #endif