mq.h

   1 #ifndef ZZGO_MQ_H
   2 #define ZZGO_MQ_H
   3
   4 /* Move queues; in fact, they are more like move lists, usually used
   5  * to accumulate equally good move candidates, then choosing from them
   6  * randomly. But they are also used to juggle group lists (using the
   7  * fact that coord_t == group_t). */
   8
   9 #include "move.h"
  10 #include "random.h"
  11
  12 #define MQL 512 /* XXX: On larger board this might not be enough. */
  13 struct move_queue {
  14         unsigned int moves;
  15         coord_t move[MQL];
  16 };
  17
  18 /* Pick a random move from the queue. */
  19 static coord_t mq_pick(struct move_queue *q);
  20
  21 /* Add a move to the queue. */
  22 static void mq_add(struct move_queue *q, coord_t c);
  23
  24 /* Cat two queues together. */
  25 static void mq_append(struct move_queue *qd, struct move_queue *qs);
  26
  27 /* Check if the last move in queue is not a dupe, and remove it
  28  * in that case. */
  29 static void mq_nodup(struct move_queue *q);
  30
  31 /* Print queue contents on stderr. */
  32 static void mq_print(struct move_queue *q, struct board *b, char *label);
  33
  34
  35 static inline coord_t
  36 mq_pick(struct move_queue *q)
  37 {
  38         return q->moves ? q->move[fast_random(q->moves)] : pass;
  39 }
  40
  41 static inline void
  42 mq_add(struct move_queue *q, coord_t c)
  43 {
  44         assert(q->moves < MQL);
  45         q->move[q->moves++] = c;
  46 }
  47
  48 static inline void
  49 mq_append(struct move_queue *qd, struct move_queue *qs)
  50 {
  51         assert(qd->moves + qs->moves < MQL);
  52         memcpy(&qd->move[qd->moves], qs->move, qs->moves * sizeof(*qs->move));
  53         qd->moves += qs->moves;
  54 }
  55
  56 static inline void
  57 mq_nodup(struct move_queue *q)
  58 {
  59         if ((q->moves > 1 && q->move[q->moves - 2] == q->move[q->moves - 1])
  60             || (q->moves > 2 && q->move[q->moves - 3] == q->move[q->moves - 1])
  61             || (q->moves > 3 && q->move[q->moves - 4] == q->move[q->moves - 1]))
  62                 q->moves--;
  63 }
  64
  65 static inline void
  66 mq_print(struct move_queue *q, struct board *b, char *label)
  67 {
  68         fprintf(stderr, "%s candidate moves: ", label);
  69         for (unsigned int i = 0; i < q->moves; i++) {
  70                 fprintf(stderr, "%s ", coord2sstr(q->move[i], b));
  71         }
  72         fprintf(stderr, "\n");
  73 }
  74
  75 #endif