mq.h

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