pattern3.h

   1 #ifndef ZZGO_PATTERN3_H
   2 #define ZZGO_PATTERN3_H
   3
   4 /* Fast matching of simple 3x3 patterns. */
   5
   6 #include "tactics.h"
   7
   8 /* (Note that this is completely independent from the general pattern
   9  * matching infrastructure in pattern.[ch]. This is fast and simple.) */
  10
  11 struct board;
  12 struct move;
  13
  14 struct pattern3s {
  15         /* Hashtable: 2*8 bits (ignore middle point, 2 bits per intersection) */
  16         /* Value: 0: no pattern, 1: black pattern,
  17          * 2: white pattern, 3: both patterns */
  18         char hash[65536];
  19 };
  20
  21 /* Source pattern encoding:
  22  * X: black;  O: white;  .: empty;  #: edge
  23  * x: !black; o: !white; ?: any
  24  *
  25  * extra X: pattern valid only for one side;
  26  * middle point ignored. */
  27
  28 void pattern3s_init(struct pattern3s *p, char src[][11], int src_n);
  29
  30 /* Check if we match any pattern centered on given move. */
  31 static bool test_pattern3_here(struct pattern3s *p, struct board *b, struct move *m);
  32
  33
  34 /* TODO: Make use of the incremental spatial matching infrastructure
  35  * in board.h? */
  36 static inline bool
  37 test_pattern3_here(struct pattern3s *p, struct board *b, struct move *m)
  38 {
  39         int pat = 0;
  40         int x = coord_x(m->coord, b), y = coord_y(m->coord, b);
  41         pat |= (board_atxy(b, x - 1, y - 1) << 14)
  42                 | (board_atxy(b, x, y - 1) << 12)
  43                 | (board_atxy(b, x + 1, y - 1) << 10);
  44         pat |= (board_atxy(b, x - 1, y) << 8)
  45                 | (board_atxy(b, x + 1, y) << 6);
  46         pat |= (board_atxy(b, x - 1, y + 1) << 4)
  47                 | (board_atxy(b, x, y + 1) << 2)
  48                 | (board_atxy(b, x + 1, y + 1));
  49         //fprintf(stderr, "(%d,%d) hashtable[%04x] = %d\n", x, y, pat, p->hash[pat]);
  50         return (p->hash[pat] & m->color) && !is_bad_selfatari(b, m->color, m->coord);
  51 }
  52
  53 #endif