board.h

   1 #ifndef ZZGO_BOARD_H
   2 #define ZZGO_BOARD_H
   3
   4 #include <inttypes.h>
   5 #include <stdbool.h>
   6 #include <stdint.h>
   7
   8 #include "stone.h"
   9 #include "move.h"
  10 #include "probdist.h"
  11 #include "util.h"
  12
  13 struct features_gamma;
  14
  15
  16 /* The board implementation has bunch of optional features.
  17  * Turn them on below: */
  18
  19 #define WANT_BOARD_C // capturable groups queue
  20
  21 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  22
  23 //#define BOARD_SPATHASH // incremental patternsp.h hashes
  24 #define BOARD_SPATHASH_MAXD 3 // maximal diameter
  25
  26 #define BOARD_PAT3 // incremental 3x3 pattern codes
  27
  28 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  29 //#define BOARD_GAMMA 1 // incremental probability distribution (requires BOARD_TRAITS, BOARD_PAT3)
  30
  31
  32 /* Allow board_play_random_move() to return pass even when
  33  * there are other moves available. */
  34 extern bool random_pass;
  35
  36
  37 /* Some engines might normalize their reading and skip symmetrical
  38  * moves. We will tell them how can they do it. */
  39 struct board_symmetry {
  40         /* Playground is in this rectangle. */
  41         int x1, x2, y1, y2;
  42         /* d ==  0: Full rectangle
  43          * d ==  1: Top triangle */
  44         int d;
  45         /* General symmetry type. */
  46         /* Note that the above is redundant to this, but just provided
  47          * for easier usage. */
  48         enum {
  49                 SYM_FULL,
  50                 SYM_DIAG_UP,
  51                 SYM_DIAG_DOWN,
  52                 SYM_HORIZ,
  53                 SYM_VERT,
  54                 SYM_NONE
  55         } type;
  56 };
  57
  58
  59 typedef uint64_t hash_t;
  60 #define PRIhash PRIx64
  61
  62
  63 /* Note that "group" is only chain of stones that is solidly
  64  * connected for us. */
  65 typedef coord_t group_t;
  66
  67 struct group {
  68         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  69          * don't care. */
  70         /* _Combination_ of these two values can make some difference
  71          * in performance - fine-tune. */
  72 #define GROUP_KEEP_LIBS 10
  73         // refill lib[] only when we hit this; this must be at least 2!
  74         // Moggy requires at least 3 - see below for semantic impact.
  75 #define GROUP_REFILL_LIBS 5
  76         coord_t lib[GROUP_KEEP_LIBS];
  77         /* libs is only LOWER BOUND for the number of real liberties!!!
  78          * It denotes only number of items in lib[], thus you can rely
  79          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  80         int libs;
  81 };
  82
  83 struct neighbor_colors {
  84         char colors[S_MAX];
  85 };
  86
  87
  88 /* Point traits bitmap; we update this information incrementally,
  89  * it can be used e.g. for fast pattern.h features matching. */
  90 struct btraits {
  91         /* Number of neighbors we can capture. 0=this move is
  92          * not capturing, 1..4=this many neighbors we can capture
  93          * (can be multiple neighbors of same group). */
  94         unsigned cap:3;
  95         /* Whether it is SAFE to play here. This is essentially just
  96          * cached result of board_safe_to_play(). (Of course the concept
  97          * of "safety" is not perfect here, but it's the cheapest
  98          * reasonable thing we can do.) */
  99         bool safe:1;
 100         /* Whether we need to re-compute this coordinate; used to
 101          * weed out duplicates. Maintained only for S_BLACK. */
 102         bool dirty:1;
 103 };
 104
 105
 106 /* You should treat this struct as read-only. Always call functions below if
 107  * you want to change it. */
 108
 109 struct board {
 110         int size; /* Including S_OFFBOARD margin - see below. */
 111         int size2; /* size^2 */
 112         int captures[S_MAX];
 113         float komi;
 114         int handicap;
 115
 116         /* Iterator offsets for foreach_neighbor*() */
 117         int nei8[8], dnei[4];
 118
 119         int moves;
 120         struct move last_move;
 121         struct move last_move2; /* second-to-last move */
 122         /* Whether we tried to add a hash twice; board_play*() can
 123          * set this, but it will still carry out the move as well! */
 124         bool superko_violation;
 125
 126         /* The following two structures are goban maps and are indexed by
 127          * coord.pos. The map is surrounded by a one-point margin from
 128          * S_OFFBOARD stones in order to speed up some internal loops.
 129          * Some of the foreach iterators below might include these points;
 130          * you need to handle them yourselves, if you need to. */
 131
 132         /* Stones played on the board */
 133         enum stone *b; /* enum stone */
 134         /* Group id the stones are part of; 0 == no group */
 135         group_t *g;
 136         /* Positions of next stones in the stone group; 0 == last stone */
 137         coord_t *p;
 138         /* Neighboring colors; numbers of neighbors of index color */
 139         struct neighbor_colors *n;
 140         /* Zobrist hash for each position */
 141         hash_t *h;
 142 #ifdef BOARD_SPATHASH
 143         /* For spatial hashes, we use only 24 bits. */
 144         /* [0] is d==1, we don't keep hash for d==0. */
 145         /* We keep hashes for black-to-play ([][0]) and white-to-play
 146          * ([][1], reversed stone colors since we match all patterns as
 147          * black-to-play). */
 148         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 149 #endif
 150 #ifdef BOARD_PAT3
 151         /* 3x3 pattern code for each position; see pattern3.h for encoding
 152          * specification. The information is only valid for empty points. */
 153         uint16_t *pat3;
 154 #endif
 155 #ifdef BOARD_TRAITS
 156         /* Incrementally matched point traits information, black-to-play
 157          * ([][0]) and white-to-play ([][1]). */
 158         /* The information is only valid for empty points. */
 159         struct btraits (*t)[2];
 160 #endif
 161 #ifdef BOARD_GAMMA
 162         /* Relative probabilities of moves being played next, computed by
 163          * multiplying gammas of the appropriate pattern features based on
 164          * pat3 and traits (see pattern.h). The probability distribution
 165          * is maintained over the full board grid. */
 166         /* - Always invalid moves are guaranteed to have zero probability.
 167          * - Self-eye-filling moves will always have zero probability.
 168          * - Ko-prohibited moves might have non-zero probability.
 169          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 170         struct probdist prob[2];
 171 #endif
 172
 173         /* Group information - indexed by gid (which is coord of base group stone) */
 174         struct group *gi;
 175
 176         /* Positions of free positions - queue (not map) */
 177         /* Note that free position here is any valid move; including single-point eyes! */
 178         coord_t *f; int flen;
 179
 180 #ifdef WANT_BOARD_C
 181         /* Queue of capturable groups */
 182         group_t *c; int clen;
 183 #endif
 184
 185 #ifdef BOARD_TRAITS
 186         /* Queue of positions that need their traits updated */
 187         coord_t *tq; int tqlen;
 188 #endif
 189
 190         /* Symmetry information */
 191         struct board_symmetry symmetry;
 192
 193         /* Last ko played on the board. */
 194         struct move last_ko;
 195         int last_ko_age;
 196
 197         /* Basic ko check */
 198         struct move ko;
 199
 200         /* Engine-specific state; persistent through board development,
 201          * is reset only at clear_board. */
 202         void *es;
 203
 204         /* Playout-specific state; persistent through board development,
 205          * but its lifetime is maintained in play_random_game(); it should
 206          * not be set outside of it. */
 207         void *ps;
 208
 209 #ifdef BOARD_GAMMA
 210         /* Gamma values for probability distribution; user must setup
 211          * this pointer before any move is played, using board_gamma_set(). */
 212         struct features_gamma *gamma;
 213         /* Whether to compute the 'safe' trait using board_safe_to_play()
 214          * (false) or is_bad_selfatari() (true, much slower). */
 215         bool precise_selfatari;
 216 #endif
 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 };
 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 #define board_at(b_, c) ((b_)->b[coord_raw(c)])
 244 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 245
 246 #define group_at(b_, c) ((b_)->g[coord_raw(c)])
 247 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 248
 249 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 250 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord_raw(coord)].colors[(enum stone) color])
 251 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 252 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 253 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 254 #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))
 255
 256 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 257
 258 #define groupnext_at(b_, c) ((b_)->p[coord_raw(c)])
 259 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 260
 261 #define group_base(g_) (g_)
 262 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 263 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 264 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 265
 266 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord_raw(coord)])
 267
 268 struct board *board_init(void);
 269 struct board *board_copy(struct board *board2, struct board *board1);
 270 void board_done_noalloc(struct board *board);
 271 void board_done(struct board *board);
 272 /* size here is without the S_OFFBOARD margin. */
 273 void board_resize(struct board *board, int size);
 274 void board_clear(struct board *board);
 275
 276 struct FILE;
 277 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 278 void board_print(struct board *board, FILE *f);
 279 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 280
 281 /* Place given handicap on the board; coordinates are printed to f. */
 282 void board_handicap(struct board *board, int stones, FILE *f);
 283
 284 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 285 int board_play(struct board *board, struct move *m);
 286 /* Like above, but plays random move; the move coordinate is recorded
 287  * to *coord. This method will never fill your own eye. pass is played
 288  * when no move can be played. You can impose extra restrictions if you
 289  * supply your own permit function. */
 290 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 291 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 292
 293 /* Returns true if given move can be played. */
 294 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 295 static bool board_is_valid_move(struct board *b, struct move *m);
 296 /* Returns true if ko was just taken. */
 297 static bool board_playing_ko_threat(struct board *b);
 298 /* Returns 0 or ID of neighboring group in atari. */
 299 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 300 /* Returns true if the move is not obvious self-atari. */
 301 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 302
 303 /* Adjust symmetry information as if given coordinate has been played. */
 304 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 305 /* Associate a set of feature gamma values (for pd building) with the board. */
 306 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 307 /* Force re-compute of a probability distribution item. */
 308 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 309
 310 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 311 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 312 /* Returns true if given coordinate could be a false eye; this check makes
 313  * sense only if you already know the coordinate is_eyelike(). */
 314 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 315 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 316  * at least tries to). */
 317 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 318 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 319 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 320
 321 /* board_official_score() is the scoring method for yielding score suitable
 322  * for external presentation. For fast scoring of entirely filled boards
 323  * (e.g. playouts), use board_fast_score(). */
 324 /* Positive: W wins */
 325 /* Compare number of stones + 1pt eyes. */
 326 float board_fast_score(struct board *board);
 327 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 328 struct move_queue;
 329 float board_official_score(struct board *board, struct move_queue *mq);
 330
 331 /** Iterators */
 332
 333 #define foreach_point(board_) \
 334         do { \
 335                 coord_t c; coord_pos(c, 0, (board_)); \
 336                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 337 #define foreach_point_and_pass(board_) \
 338         do { \
 339                 coord_t c; coord_pos(c, -1, (board_)); \
 340                 for (; coord_raw(c) < board_size(board_) * board_size(board_); coord_raw(c)++)
 341 #define foreach_point_end \
 342         } while (0)
 343
 344 #define foreach_in_group(board_, group_) \
 345         do { \
 346                 struct board *board__ = board_; \
 347                 coord_t c = group_base(group_); \
 348                 coord_t c2 = c; coord_raw(c2) = groupnext_at(board__, c2); \
 349                 do {
 350 #define foreach_in_group_end \
 351                         c = c2; coord_raw(c2) = groupnext_at(board__, c2); \
 352                 } while (coord_raw(c) != 0); \
 353         } while (0)
 354
 355 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 356  * on S_OFFBOARD coordinates. */
 357 #define foreach_neighbor(board_, coord_, loop_body) \
 358         do { \
 359                 struct board *board__ = board_; \
 360                 coord_t coord__ = coord_; \
 361                 coord_t c; \
 362                 coord_pos(c, coord_raw(coord__) - 1, (board__)); do { loop_body } while (0); \
 363                 coord_pos(c, coord_raw(coord__) - board_size(board__), (board__)); do { loop_body } while (0); \
 364                 coord_pos(c, coord_raw(coord__) + 1, (board__)); do { loop_body } while (0); \
 365                 coord_pos(c, coord_raw(coord__) + board_size(board__), (board__)); do { loop_body } while (0); \
 366         } while (0)
 367
 368 #define foreach_8neighbor(board_, coord_) \
 369         do { \
 370                 int fn__i; \
 371                 coord_t c = (coord_); \
 372                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 373                         c += (board_)->nei8[fn__i];
 374 #define foreach_8neighbor_end \
 375                 } \
 376         } while (0)
 377
 378 #define foreach_diag_neighbor(board_, coord_) \
 379         do { \
 380                 int fn__i; \
 381                 coord_t c = (coord_); \
 382                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 383                         c += (board_)->dnei[fn__i];
 384 #define foreach_diag_neighbor_end \
 385                 } \
 386         } while (0)
 387
 388
 389 static inline bool
 390 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 391 {
 392         return (neighbor_count_at(board, coord, eye_color)
 393                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 394 }
 395
 396 static inline bool
 397 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 398 {
 399         if (board_at(board, coord) != S_NONE)
 400                 return false;
 401         if (!board_is_eyelike(board, coord, stone_other(color)))
 402                 return true;
 403         /* Play within {true,false} eye-ish formation */
 404         if (board->ko.coord == coord && board->ko.color == color)
 405                 return false;
 406 #ifdef BOARD_TRAITS
 407         /* XXX: Disallows suicide. */
 408         return trait_at(board, coord, color).cap > 0;
 409 #else
 410         int groups_in_atari = 0;
 411         foreach_neighbor(board, coord, {
 412                 group_t g = group_at(board, c);
 413                 groups_in_atari += (board_group_info(board, g).libs == 1);
 414         });
 415         return !!groups_in_atari;
 416 #endif
 417 }
 418
 419 static inline bool
 420 board_is_valid_move(struct board *board, struct move *m)
 421 {
 422         return board_is_valid_play(board, m->color, m->coord);
 423 }
 424
 425 static inline bool
 426 board_playing_ko_threat(struct board *b)
 427 {
 428         return !is_pass(b->ko.coord);
 429 }
 430
 431 static inline group_t
 432 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 433 {
 434 #ifdef BOARD_TRAITS
 435         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 436 #endif
 437         foreach_neighbor(b, coord, {
 438                 group_t g = group_at(b, c);
 439                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 440                         return g;
 441                 /* We return first match. */
 442         });
 443         return 0;
 444 }
 445
 446 static inline bool
 447 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 448 {
 449         /* number of free neighbors */
 450         int libs = immediate_liberty_count(b, coord);
 451         if (libs > 1)
 452                 return true;
 453
 454 #ifdef BOARD_TRAITS
 455         /* number of capturable enemy groups */
 456         if (trait_at(b, coord, color).cap > 0)
 457                 return true; // XXX: We don't account for snapback.
 458         /* number of non-capturable friendly groups */
 459         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 460         if (noncap_ours < 1)
 461                 return false;
 462 /*#else see below */
 463 #endif
 464
 465         /* ok, but we need to check if they don't have just two libs. */
 466         coord_t onelib = -1;
 467         foreach_neighbor(b, coord, {
 468 #ifndef BOARD_TRAITS
 469                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 470                         return true; // can capture; no snapback check
 471 #endif
 472                 if (board_at(b, c) != color) continue;
 473                 group_t g = group_at(b, c);
 474                 if (board_group_info(b, g).libs == 1) continue; // in atari
 475                 if (board_group_info(b, g).libs == 2) { // two liberties
 476                         if (libs > 0) return true; // we already have one real liberty
 477                         // get the other liberty
 478                         coord_t lib = board_group_info(b, g).lib[0];
 479                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 480                         /* we might be connecting two 2-lib groups, which is ok;
 481                          * so remember the other liberty and just make sure it's
 482                          * not the same one */
 483                         if (onelib >= 0 && lib != onelib) return true;
 484                         onelib = lib;
 485                         continue;
 486                 }
 487                 // many liberties
 488                 return true;
 489         });
 490         // no good support group
 491         return false;
 492 }
 493
 494 #endif