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
  34
  35 #define BOARD_MAX_MOVES (BOARD_MAX_SIZE * BOARD_MAX_SIZE)
  36 #define BOARD_MAX_GROUPS (BOARD_MAX_SIZE * BOARD_MAX_SIZE / 2)
  37
  38
  39 /* Some engines might normalize their reading and skip symmetrical
  40  * moves. We will tell them how can they do it. */
  41 struct board_symmetry {
  42         /* Playground is in this rectangle. */
  43         int x1, x2, y1, y2;
  44         /* d ==  0: Full rectangle
  45          * d ==  1: Top triangle */
  46         int d;
  47         /* General symmetry type. */
  48         /* Note that the above is redundant to this, but just provided
  49          * for easier usage. */
  50         enum {
  51                 SYM_FULL,
  52                 SYM_DIAG_UP,
  53                 SYM_DIAG_DOWN,
  54                 SYM_HORIZ,
  55                 SYM_VERT,
  56                 SYM_NONE
  57         } type;
  58 };
  59
  60
  61 typedef uint64_t hash_t;
  62 #define PRIhash PRIx64
  63
  64 /* XXX: This really belongs in pattern3.h, unfortunately that would mean
  65  * a dependency hell. */
  66 typedef uint32_t hash3_t; // 3x3 pattern hash
  67
  68
  69 /* Note that "group" is only chain of stones that is solidly
  70  * connected for us. */
  71 typedef coord_t group_t;
  72
  73 struct group {
  74         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  75          * don't care. */
  76         /* _Combination_ of these two values can make some difference
  77          * in performance - fine-tune. */
  78 #define GROUP_KEEP_LIBS 10
  79         // refill lib[] only when we hit this; this must be at least 2!
  80         // Moggy requires at least 3 - see below for semantic impact.
  81 #define GROUP_REFILL_LIBS 5
  82         coord_t lib[GROUP_KEEP_LIBS];
  83         /* libs is only LOWER BOUND for the number of real liberties!!!
  84          * It denotes only number of items in lib[], thus you can rely
  85          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  86         int libs;
  87 };
  88
  89 struct neighbor_colors {
  90         char colors[S_MAX];
  91 };
  92
  93
  94 /* Point traits bitmap; we update this information incrementally,
  95  * it can be used e.g. for fast pattern features matching. */
  96 struct btraits {
  97         /* Number of neighbors we can capture. 0=this move is
  98          * not capturing, 1..4=this many neighbors we can capture
  99          * (can be multiple neighbors of same group). */
 100         unsigned cap:3;
 101         /* Number of 1-stone neighbors we can capture. */
 102         unsigned cap1:3;
 103         /* Whether it is SAFE to play here. This is essentially just
 104          * cached result of board_safe_to_play(). (Of course the concept
 105          * of "safety" is not perfect here, but it's the cheapest
 106          * reasonable thing we can do.) */
 107         bool safe:1;
 108         /* Whether we need to re-compute this coordinate; used to
 109          * weed out duplicates. Maintained only for S_BLACK. */
 110         bool dirty:1;
 111 };
 112
 113
 114 /* You should treat this struct as read-only. Always call functions below if
 115  * you want to change it. */
 116
 117 struct board {
 118         int size; /* Including S_OFFBOARD margin - see below. */
 119         int size2; /* size^2 */
 120         int bits2; /* ceiling(log2(size2)) */
 121         int captures[S_MAX];
 122         floating_t komi;
 123         int handicap;
 124         /* The ruleset is currently almost never taken into account;
 125          * the board implementation is basically Chinese rules (handicap
 126          * stones compensation) w/ suicide (or you can look at it as
 127          * New Zealand w/o handi stones compensation), while the engine
 128          * enforces no-suicide, making for real Chinese rules. */
 129         enum {
 130                 RULES_CHINESE, /* default value */
 131                 RULES_AGA,
 132                 RULES_NEW_ZEALAND,
 133                 RULES_JAPANESE,
 134         } rules;
 135
 136         char *fbookfile;
 137         struct fbook *fbook;
 138
 139         /* Iterator offsets for foreach_neighbor*() */
 140         int nei8[8], dnei[4];
 141
 142         int moves;
 143         struct move last_move;
 144         struct move last_move2; /* second-to-last move */
 145         struct move last_move3; /* just before last_move2, only set if last_move is pass */
 146         struct move last_move4; /* just before last_move3, only set if last_move & last_move2 are pass */
 147         /* Whether we tried to add a hash twice; board_play*() can
 148          * set this, but it will still carry out the move as well! */
 149         bool superko_violation;
 150
 151         /* The following two structures are goban maps and are indexed by
 152          * coord.pos. The map is surrounded by a one-point margin from
 153          * S_OFFBOARD stones in order to speed up some internal loops.
 154          * Some of the foreach iterators below might include these points;
 155          * you need to handle them yourselves, if you need to. */
 156
 157         /* Stones played on the board */
 158         enum stone *b; /* enum stone */
 159         /* Group id the stones are part of; 0 == no group */
 160         group_t *g;
 161         /* Positions of next stones in the stone group; 0 == last stone */
 162         coord_t *p;
 163         /* Neighboring colors; numbers of neighbors of index color */
 164         struct neighbor_colors *n;
 165         /* Zobrist hash for each position */
 166         hash_t *h;
 167 #ifdef BOARD_PAT3
 168         /* 3x3 pattern code for each position; see pattern3.h for encoding
 169          * specification. The information is only valid for empty points. */
 170         hash3_t *pat3;
 171 #endif
 172 #ifdef BOARD_TRAITS
 173         /* Incrementally matched point traits information, black-to-play
 174          * ([][0]) and white-to-play ([][1]). */
 175         /* The information is only valid for empty points. */
 176         struct btraits (*t)[2];
 177 #endif
 178         /* Cached information on x-y coordinates so that we avoid division. */
 179         uint8_t (*coord)[2];
 180
 181         /* Group information - indexed by gid (which is coord of base group stone) */
 182         struct group *gi;
 183
 184         /* Positions of free positions - queue (not map) */
 185         /* Note that free position here is any valid move; including single-point eyes!
 186          * However, pass is not included. */
 187         coord_t *f; int flen;
 188
 189 #ifdef WANT_BOARD_C
 190         /* Queue of capturable groups */
 191         group_t *c; int clen;
 192 #endif
 193
 194 #ifdef BOARD_TRAITS
 195         /* Queue of positions that need their traits updated */
 196         coord_t *tq; int tqlen;
 197 #endif
 198
 199         /* Symmetry information */
 200         struct board_symmetry symmetry;
 201
 202         /* Last ko played on the board. */
 203         struct move last_ko;
 204         int last_ko_age;
 205
 206         /* Basic ko check */
 207         struct move ko;
 208
 209         /* Engine-specific state; persistent through board development,
 210          * is reset only at clear_board. */
 211         void *es;
 212
 213         /* Playout-specific state; persistent through board development,
 214          * but its lifetime is maintained in play_random_game(); it should
 215          * not be set outside of it. */
 216         void *ps;
 217
 218
 219         /* --- PRIVATE DATA --- */
 220
 221         /* For superko check: */
 222
 223         /* Board "history" - hashes encountered. Size of the hash should be
 224          * >> board_size^2. */
 225 #define history_hash_bits 12
 226 #define history_hash_mask ((1 << history_hash_bits) - 1)
 227 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 228 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 229         hash_t history_hash[1 << history_hash_bits];
 230         /* Hash of current board position. */
 231         hash_t hash;
 232         /* Hash of current board position quadrants. */
 233         hash_t qhash[4];
 234 };
 235
 236 #ifdef BOARD_SIZE
 237 /* Avoid unused variable warnings */
 238 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 239 #define board_size2(b_) (board_size(b_) * board_size(b_))
 240 #else
 241 #define board_size(b_) ((b_)->size)
 242 #define board_size2(b_) ((b_)->size2)
 243 #endif
 244
 245 /* This is a shortcut for taking different action on smaller
 246  * and large boards (e.g. picking different variable defaults).
 247  * This is of course less optimal than fine-tuning dependency
 248  * function of values on board size, but that is difficult and
 249  * possibly not very rewarding if you are interested just in
 250  * 9x9 and 19x19. */
 251 #define board_large(b_) (board_size(b_)-2 >= 15)
 252
 253 #if BOARD_SIZE == 19
 254 #  define board_bits2(b_) 9
 255 #elif BOARD_SIZE == 13
 256 #  define board_bits2(b_) 8
 257 #elif BOARD_SIZE == 9
 258 #  define board_bits2(b_) 7
 259 #else
 260 #  define board_bits2(b_) ((b_)->bits2)
 261 #endif
 262
 263 #define board_at(b_, c) ((b_)->b[c])
 264 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 265
 266 #define group_at(b_, c) ((b_)->g[c])
 267 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 268
 269 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 270 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 271 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 272 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 273 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 274 #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))
 275
 276 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 277
 278 #define groupnext_at(b_, c) ((b_)->p[c])
 279 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 280
 281 #define group_base(g_) (g_)
 282 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 283 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 284 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 285 /* board_group_other_lib() makes sense only for groups with two liberties. */
 286 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 287
 288 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 289
 290 struct board *board_init(char *fbookfile);
 291 struct board *board_copy(struct board *board2, struct board *board1);
 292 void board_done_noalloc(struct board *board);
 293 void board_done(struct board *board);
 294 /* size here is without the S_OFFBOARD margin. */
 295 void board_resize(struct board *board, int size);
 296 void board_clear(struct board *board);
 297
 298 struct FILE;
 299 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 300 void board_print(struct board *board, FILE *f);
 301 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 302
 303 /* Place given handicap on the board; coordinates are printed to f. */
 304 void board_handicap(struct board *board, int stones, FILE *f);
 305
 306 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 307 int board_play(struct board *board, struct move *m);
 308 /* Like above, but plays random move; the move coordinate is recorded
 309  * to *coord. This method will never fill your own eye. pass is played
 310  * when no move can be played. You can impose extra restrictions if you
 311  * supply your own permit function; the permit function can also modify
 312  * the move coordinate to redirect the move elsewhere. */
 313 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 314 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 315
 316 /*Undo, supported only for pass moves. Returns -1 on error, 0 otherwise. */
 317 int board_undo(struct board *board);
 318
 319 /* Returns true if given move can be played. */
 320 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 321 static bool board_is_valid_move(struct board *b, struct move *m);
 322 /* Returns true if ko was just taken. */
 323 static bool board_playing_ko_threat(struct board *b);
 324 /* Returns 0 or ID of neighboring group in atari. */
 325 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 326 /* Returns true if the move is not obvious self-atari. */
 327 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 328
 329 /* Determine number of stones in a group, up to @max stones. */
 330 static int group_stone_count(struct board *b, group_t group, int max);
 331
 332 /* Adjust symmetry information as if given coordinate has been played. */
 333 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 334 /* Check if coordinates are within symmetry base. (If false, they can
 335  * be derived from the base.) */
 336 static bool board_coord_in_symmetry(struct board *b, coord_t c);
 337
 338 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 339 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 340 /* Returns true if given coordinate could be a false eye; this check makes
 341  * sense only if you already know the coordinate is_eyelike(). */
 342 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 343 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 344  * at least tries to). */
 345 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 346 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 347 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 348
 349 /* board_official_score() is the scoring method for yielding score suitable
 350  * for external presentation. For fast scoring of entirely filled boards
 351  * (e.g. playouts), use board_fast_score(). */
 352 /* Positive: W wins */
 353 /* Compare number of stones + 1pt eyes. */
 354 floating_t board_fast_score(struct board *board);
 355 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 356 struct move_queue;
 357 floating_t board_official_score(struct board *board, struct move_queue *mq);
 358
 359 /** Iterators */
 360
 361 #define foreach_point(board_) \
 362         do { \
 363                 coord_t c = 0; \
 364                 for (; c < board_size(board_) * board_size(board_); c++)
 365 #define foreach_point_and_pass(board_) \
 366         do { \
 367                 coord_t c = pass; \
 368                 for (; c < board_size(board_) * board_size(board_); c++)
 369 #define foreach_point_end \
 370         } while (0)
 371
 372 #define foreach_free_point(board_) \
 373         do { \
 374                 int fmax__ = (board_)->flen; \
 375                 for (int f__ = 0; f__ < fmax__; f__++) { \
 376                         coord_t c = (board_)->f[f__];
 377 #define foreach_free_point_end \
 378                 } \
 379         } while (0)
 380
 381 #define foreach_in_group(board_, group_) \
 382         do { \
 383                 struct board *board__ = board_; \
 384                 coord_t c = group_base(group_); \
 385                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 386                 do {
 387 #define foreach_in_group_end \
 388                         c = c2; c2 = groupnext_at(board__, c2); \
 389                 } while (c != 0); \
 390         } while (0)
 391
 392 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 393  * on S_OFFBOARD coordinates. */
 394 #define foreach_neighbor(board_, coord_, loop_body) \
 395         do { \
 396                 struct board *board__ = board_; \
 397                 coord_t coord__ = coord_; \
 398                 coord_t c; \
 399                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 400                 c = coord__ - 1; do { loop_body } while (0); \
 401                 c = coord__ + 1; do { loop_body } while (0); \
 402                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 403         } while (0)
 404
 405 #define foreach_8neighbor(board_, coord_) \
 406         do { \
 407                 int fn__i; \
 408                 coord_t c = (coord_); \
 409                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 410                         c += (board_)->nei8[fn__i];
 411 #define foreach_8neighbor_end \
 412                 } \
 413         } while (0)
 414
 415 #define foreach_diag_neighbor(board_, coord_) \
 416         do { \
 417                 int fn__i; \
 418                 coord_t c = (coord_); \
 419                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 420                         c += (board_)->dnei[fn__i];
 421 #define foreach_diag_neighbor_end \
 422                 } \
 423         } while (0)
 424
 425
 426 static inline bool
 427 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 428 {
 429         return (neighbor_count_at(board, coord, eye_color)
 430                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 431 }
 432
 433 static inline bool
 434 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 435 {
 436         if (board_at(board, coord) != S_NONE)
 437                 return false;
 438         if (!board_is_eyelike(board, coord, stone_other(color)))
 439                 return true;
 440         /* Play within {true,false} eye-ish formation */
 441         if (board->ko.coord == coord && board->ko.color == color)
 442                 return false;
 443 #ifdef BOARD_TRAITS
 444         /* XXX: Disallows suicide. */
 445         return trait_at(board, coord, color).cap > 0;
 446 #else
 447         int groups_in_atari = 0;
 448         foreach_neighbor(board, coord, {
 449                 group_t g = group_at(board, c);
 450                 groups_in_atari += (board_group_info(board, g).libs == 1);
 451         });
 452         return !!groups_in_atari;
 453 #endif
 454 }
 455
 456 static inline bool
 457 board_is_valid_move(struct board *board, struct move *m)
 458 {
 459         return board_is_valid_play(board, m->color, m->coord);
 460 }
 461
 462 static inline bool
 463 board_playing_ko_threat(struct board *b)
 464 {
 465         return !is_pass(b->ko.coord);
 466 }
 467
 468 static inline group_t
 469 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 470 {
 471 #ifdef BOARD_TRAITS
 472         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 473 #endif
 474         foreach_neighbor(b, coord, {
 475                 group_t g = group_at(b, c);
 476                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 477                         return g;
 478                 /* We return first match. */
 479         });
 480         return 0;
 481 }
 482
 483 static inline bool
 484 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 485 {
 486         /* number of free neighbors */
 487         int libs = immediate_liberty_count(b, coord);
 488         if (libs > 1)
 489                 return true;
 490
 491 #ifdef BOARD_TRAITS
 492         /* number of capturable enemy groups */
 493         if (trait_at(b, coord, color).cap > 0)
 494                 return true; // XXX: We don't account for snapback.
 495         /* number of non-capturable friendly groups */
 496         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 497         if (noncap_ours < 1)
 498                 return false;
 499 /*#else see below */
 500 #endif
 501
 502         /* ok, but we need to check if they don't have just two libs. */
 503         coord_t onelib = -1;
 504         foreach_neighbor(b, coord, {
 505 #ifndef BOARD_TRAITS
 506                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 507                         return true; // can capture; no snapback check
 508 #endif
 509                 if (board_at(b, c) != color) continue;
 510                 group_t g = group_at(b, c);
 511                 if (board_group_info(b, g).libs == 1) continue; // in atari
 512                 if (board_group_info(b, g).libs == 2) { // two liberties
 513                         if (libs > 0) return true; // we already have one real liberty
 514                         /* we might be connecting two 2-lib groups, which is ok;
 515                          * so remember the other liberty and just make sure it's
 516                          * not the same one */
 517                         if (onelib >= 0 && c != onelib) return true;
 518                         onelib = board_group_other_lib(b, g, c);
 519                         continue;
 520                 }
 521                 // many liberties
 522                 return true;
 523         });
 524         // no good support group
 525         return false;
 526 }
 527
 528 static inline int
 529 group_stone_count(struct board *b, group_t group, int max)
 530 {
 531         int n = 0;
 532         foreach_in_group(b, group) {
 533                 n++;
 534                 if (n >= max) return max;
 535         } foreach_in_group_end;
 536         return n;
 537 }
 538
 539 static inline bool
 540 board_coord_in_symmetry(struct board *b, coord_t c)
 541 {
 542         if (coord_y(c, b) < b->symmetry.y1 || coord_y(c, b) > b->symmetry.y2)
 543                 return false;
 544         if (coord_x(c, b) < b->symmetry.x1 || coord_x(c, b) > b->symmetry.x2)
 545                 return false;
 546         if (b->symmetry.d) {
 547                 int x = coord_x(c, b);
 548                 if (b->symmetry.type == SYM_DIAG_DOWN)
 549                         x = board_size(b) - 1 - x;
 550                 if (x > coord_y(c, b))
 551                         return false;
 552         }
 553         return true;
 554
 555 }
 556
 557 #endif