board.h

   1 /* probdist.h must be included before the include goard since we require
   2  * proper including order. */
   3 #include "probdist.h"
   4
   5 #ifndef ZZGO_BOARD_H
   6 #define ZZGO_BOARD_H
   7
   8 #include <inttypes.h>
   9 #include <stdbool.h>
  10 #include <stdint.h>
  11
  12 #include "util.h"
  13 #include "stone.h"
  14 #include "move.h"
  15
  16 struct 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         /* Whether we tried to add a hash twice; board_play*() can
 146          * set this, but it will still carry out the move as well! */
 147         bool superko_violation;
 148
 149         /* The following two structures are goban maps and are indexed by
 150          * coord.pos. The map is surrounded by a one-point margin from
 151          * S_OFFBOARD stones in order to speed up some internal loops.
 152          * Some of the foreach iterators below might include these points;
 153          * you need to handle them yourselves, if you need to. */
 154
 155         /* Stones played on the board */
 156         enum stone *b; /* enum stone */
 157         /* Group id the stones are part of; 0 == no group */
 158         group_t *g;
 159         /* Positions of next stones in the stone group; 0 == last stone */
 160         coord_t *p;
 161         /* Neighboring colors; numbers of neighbors of index color */
 162         struct neighbor_colors *n;
 163         /* Zobrist hash for each position */
 164         hash_t *h;
 165 #ifdef BOARD_PAT3
 166         /* 3x3 pattern code for each position; see pattern3.h for encoding
 167          * specification. The information is only valid for empty points. */
 168         hash3_t *pat3;
 169 #endif
 170 #ifdef BOARD_TRAITS
 171         /* Incrementally matched point traits information, black-to-play
 172          * ([][0]) and white-to-play ([][1]). */
 173         /* The information is only valid for empty points. */
 174         struct btraits (*t)[2];
 175 #endif
 176         /* Cached information on x-y coordinates so that we avoid division. */
 177         uint8_t (*coord)[2];
 178
 179         /* Group information - indexed by gid (which is coord of base group stone) */
 180         struct group *gi;
 181
 182         /* Positions of free positions - queue (not map) */
 183         /* Note that free position here is any valid move; including single-point eyes!
 184          * However, pass is not included. */
 185         coord_t *f; int flen;
 186
 187 #ifdef WANT_BOARD_C
 188         /* Queue of capturable groups */
 189         group_t *c; int clen;
 190 #endif
 191
 192 #ifdef BOARD_TRAITS
 193         /* Queue of positions that need their traits updated */
 194         coord_t *tq; int tqlen;
 195 #endif
 196
 197         /* Symmetry information */
 198         struct board_symmetry symmetry;
 199
 200         /* Last ko played on the board. */
 201         struct move last_ko;
 202         int last_ko_age;
 203
 204         /* Basic ko check */
 205         struct move ko;
 206
 207         /* Engine-specific state; persistent through board development,
 208          * is reset only at clear_board. */
 209         void *es;
 210
 211         /* Playout-specific state; persistent through board development,
 212          * but its lifetime is maintained in play_random_game(); it should
 213          * not be set outside of it. */
 214         void *ps;
 215
 216
 217         /* --- PRIVATE DATA --- */
 218
 219         /* For superko check: */
 220
 221         /* Board "history" - hashes encountered. Size of the hash should be
 222          * >> board_size^2. */
 223 #define history_hash_bits 12
 224 #define history_hash_mask ((1 << history_hash_bits) - 1)
 225 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 226 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 227         hash_t history_hash[1 << history_hash_bits];
 228         /* Hash of current board position. */
 229         hash_t hash;
 230         /* Hash of current board position quadrants. */
 231         hash_t qhash[4];
 232 };
 233
 234 #ifdef BOARD_SIZE
 235 /* Avoid unused variable warnings */
 236 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 237 #define board_size2(b_) (board_size(b_) * board_size(b_))
 238 #else
 239 #define board_size(b_) ((b_)->size)
 240 #define board_size2(b_) ((b_)->size2)
 241 #endif
 242
 243 /* This is a shortcut for taking different action on smaller
 244  * and large boards (e.g. picking different variable defaults).
 245  * This is of course less optimal than fine-tuning dependency
 246  * function of values on board size, but that is difficult and
 247  * possibly not very rewarding if you are interested just in
 248  * 9x9 and 19x19. */
 249 #define board_large(b_) (board_size(b_)-2 >= 15)
 250
 251 #if BOARD_SIZE == 19
 252 #  define board_bits2(b_) 9
 253 #elif BOARD_SIZE == 13
 254 #  define board_bits2(b_) 8
 255 #elif BOARD_SIZE == 9
 256 #  define board_bits2(b_) 7
 257 #else
 258 #  define board_bits2(b_) ((b_)->bits2)
 259 #endif
 260
 261 #define board_at(b_, c) ((b_)->b[c])
 262 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 263
 264 #define group_at(b_, c) ((b_)->g[c])
 265 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 266
 267 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 268 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 269 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 270 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 271 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 272 #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))
 273
 274 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 275
 276 #define groupnext_at(b_, c) ((b_)->p[c])
 277 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 278
 279 #define group_base(g_) (g_)
 280 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 281 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 282 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 283 /* board_group_other_lib() makes sense only for groups with two liberties. */
 284 #define board_group_other_lib(b_, g_, l_) (board_group_info(b_, g_).lib[board_group_info(b_, g_).lib[0] != (l_) ? 0 : 1])
 285
 286 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 287
 288 struct board *board_init(char *fbookfile);
 289 struct board *board_copy(struct board *board2, struct board *board1);
 290 void board_done_noalloc(struct board *board);
 291 void board_done(struct board *board);
 292 /* size here is without the S_OFFBOARD margin. */
 293 void board_resize(struct board *board, int size);
 294 void board_clear(struct board *board);
 295
 296 struct FILE;
 297 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 298 void board_print(struct board *board, FILE *f);
 299 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 300
 301 /* Place given handicap on the board; coordinates are printed to f. */
 302 void board_handicap(struct board *board, int stones, FILE *f);
 303
 304 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 305 int board_play(struct board *board, struct move *m);
 306 /* Like above, but plays random move; the move coordinate is recorded
 307  * to *coord. This method will never fill your own eye. pass is played
 308  * when no move can be played. You can impose extra restrictions if you
 309  * supply your own permit function; the permit function can also modify
 310  * the move coordinate to redirect the move elsewhere. */
 311 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 312 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 313
 314 /* Returns true if given move can be played. */
 315 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 316 static bool board_is_valid_move(struct board *b, struct move *m);
 317 /* Returns true if ko was just taken. */
 318 static bool board_playing_ko_threat(struct board *b);
 319 /* Returns 0 or ID of neighboring group in atari. */
 320 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 321 /* Returns true if the move is not obvious self-atari. */
 322 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 323
 324 /* Determine number of stones in a group, up to @max stones. */
 325 static int group_stone_count(struct board *b, group_t group, int max);
 326
 327 /* Adjust symmetry information as if given coordinate has been played. */
 328 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 329
 330 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 331 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 332 /* Returns true if given coordinate could be a false eye; this check makes
 333  * sense only if you already know the coordinate is_eyelike(). */
 334 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 335 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 336  * at least tries to). */
 337 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 338 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 339 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 340
 341 /* board_official_score() is the scoring method for yielding score suitable
 342  * for external presentation. For fast scoring of entirely filled boards
 343  * (e.g. playouts), use board_fast_score(). */
 344 /* Positive: W wins */
 345 /* Compare number of stones + 1pt eyes. */
 346 floating_t board_fast_score(struct board *board);
 347 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 348 struct move_queue;
 349 floating_t board_official_score(struct board *board, struct move_queue *mq);
 350
 351 /** Iterators */
 352
 353 #define foreach_point(board_) \
 354         do { \
 355                 coord_t c = 0; \
 356                 for (; c < board_size(board_) * board_size(board_); c++)
 357 #define foreach_point_and_pass(board_) \
 358         do { \
 359                 coord_t c = pass; \
 360                 for (; c < board_size(board_) * board_size(board_); c++)
 361 #define foreach_point_end \
 362         } while (0)
 363
 364 #define foreach_free_point(board_) \
 365         do { \
 366                 int fmax__ = (board_)->flen; \
 367                 for (int f__ = 0; f__ < fmax__; f__++) { \
 368                         coord_t c = (board_)->f[f__];
 369 #define foreach_free_point_end \
 370                 } \
 371         } while (0)
 372
 373 #define foreach_in_group(board_, group_) \
 374         do { \
 375                 struct board *board__ = board_; \
 376                 coord_t c = group_base(group_); \
 377                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 378                 do {
 379 #define foreach_in_group_end \
 380                         c = c2; c2 = groupnext_at(board__, c2); \
 381                 } while (c != 0); \
 382         } while (0)
 383
 384 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 385  * on S_OFFBOARD coordinates. */
 386 #define foreach_neighbor(board_, coord_, loop_body) \
 387         do { \
 388                 struct board *board__ = board_; \
 389                 coord_t coord__ = coord_; \
 390                 coord_t c; \
 391                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 392                 c = coord__ - 1; do { loop_body } while (0); \
 393                 c = coord__ + 1; do { loop_body } while (0); \
 394                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 395         } while (0)
 396
 397 #define foreach_8neighbor(board_, coord_) \
 398         do { \
 399                 int fn__i; \
 400                 coord_t c = (coord_); \
 401                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 402                         c += (board_)->nei8[fn__i];
 403 #define foreach_8neighbor_end \
 404                 } \
 405         } while (0)
 406
 407 #define foreach_diag_neighbor(board_, coord_) \
 408         do { \
 409                 int fn__i; \
 410                 coord_t c = (coord_); \
 411                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 412                         c += (board_)->dnei[fn__i];
 413 #define foreach_diag_neighbor_end \
 414                 } \
 415         } while (0)
 416
 417
 418 static inline bool
 419 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 420 {
 421         return (neighbor_count_at(board, coord, eye_color)
 422                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 423 }
 424
 425 static inline bool
 426 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 427 {
 428         if (board_at(board, coord) != S_NONE)
 429                 return false;
 430         if (!board_is_eyelike(board, coord, stone_other(color)))
 431                 return true;
 432         /* Play within {true,false} eye-ish formation */
 433         if (board->ko.coord == coord && board->ko.color == color)
 434                 return false;
 435 #ifdef BOARD_TRAITS
 436         /* XXX: Disallows suicide. */
 437         return trait_at(board, coord, color).cap > 0;
 438 #else
 439         int groups_in_atari = 0;
 440         foreach_neighbor(board, coord, {
 441                 group_t g = group_at(board, c);
 442                 groups_in_atari += (board_group_info(board, g).libs == 1);
 443         });
 444         return !!groups_in_atari;
 445 #endif
 446 }
 447
 448 static inline bool
 449 board_is_valid_move(struct board *board, struct move *m)
 450 {
 451         return board_is_valid_play(board, m->color, m->coord);
 452 }
 453
 454 static inline bool
 455 board_playing_ko_threat(struct board *b)
 456 {
 457         return !is_pass(b->ko.coord);
 458 }
 459
 460 static inline group_t
 461 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 462 {
 463 #ifdef BOARD_TRAITS
 464         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 465 #endif
 466         foreach_neighbor(b, coord, {
 467                 group_t g = group_at(b, c);
 468                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 469                         return g;
 470                 /* We return first match. */
 471         });
 472         return 0;
 473 }
 474
 475 static inline bool
 476 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 477 {
 478         /* number of free neighbors */
 479         int libs = immediate_liberty_count(b, coord);
 480         if (libs > 1)
 481                 return true;
 482
 483 #ifdef BOARD_TRAITS
 484         /* number of capturable enemy groups */
 485         if (trait_at(b, coord, color).cap > 0)
 486                 return true; // XXX: We don't account for snapback.
 487         /* number of non-capturable friendly groups */
 488         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 489         if (noncap_ours < 1)
 490                 return false;
 491 /*#else see below */
 492 #endif
 493
 494         /* ok, but we need to check if they don't have just two libs. */
 495         coord_t onelib = -1;
 496         foreach_neighbor(b, coord, {
 497 #ifndef BOARD_TRAITS
 498                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 499                         return true; // can capture; no snapback check
 500 #endif
 501                 if (board_at(b, c) != color) continue;
 502                 group_t g = group_at(b, c);
 503                 if (board_group_info(b, g).libs == 1) continue; // in atari
 504                 if (board_group_info(b, g).libs == 2) { // two liberties
 505                         if (libs > 0) return true; // we already have one real liberty
 506                         /* we might be connecting two 2-lib groups, which is ok;
 507                          * so remember the other liberty and just make sure it's
 508                          * not the same one */
 509                         if (onelib >= 0 && c != onelib) return true;
 510                         onelib = board_group_other_lib(b, g, c);
 511                         continue;
 512                 }
 513                 // many liberties
 514                 return true;
 515         });
 516         // no good support group
 517         return false;
 518 }
 519
 520 static inline int
 521 group_stone_count(struct board *b, group_t group, int max)
 522 {
 523         int n = 0;
 524         foreach_in_group(b, group) {
 525                 n++;
 526                 if (n >= max) return max;
 527         } foreach_in_group_end;
 528         return n;
 529 }
 530
 531 #endif