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         /* Each move can have an optional tag or set of tags.
  17          * The usage of these is user-dependent. */
  18         unsigned char tag[MQL];
  19 };
  20
  21 /* Pick a random move from the queue. */
  22 static coord_t mq_pick(struct move_queue *q);
  23
  24 /* Add a move to the queue. */
  25 static void mq_add(struct move_queue *q, coord_t c, unsigned char tag);
  26
  27 /* Cat two queues together. */
  28 static void mq_append(struct move_queue *qd, struct move_queue *qs);
  29
  30 /* Check if the last move in queue is not a dupe, and remove it
  31  * in that case. */
  32 static void mq_nodup(struct move_queue *q);
  33
  34 /* Print queue contents on stderr. */
  35 static void mq_print(struct move_queue *q, struct board *b, char *label);
  36
  37
  38 static inline coord_t
  39 mq_pick(struct move_queue *q)
  40 {
  41         return q->moves ? q->move[fast_random(q->moves)] : pass;
  42 }
  43
  44 static inline void
  45 mq_add(struct move_queue *q, coord_t c, unsigned char tag)
  46 {
  47         assert(q->moves < MQL);
  48         q->tag[q->moves] = tag;
  49         q->move[q->moves++] = c;
  50 }
  51
  52 static inline void
  53 mq_append(struct move_queue *qd, struct move_queue *qs)
  54 {
  55         assert(qd->moves + qs->moves < MQL);
  56         memcpy(&qd->tag[qd->moves], qs->tag, qs->moves * sizeof(*qs->tag));
  57         memcpy(&qd->move[qd->moves], qs->move, qs->moves * sizeof(*qs->move));
  58         qd->moves += qs->moves;
  59 }
  60
  61 static inline void
  62 mq_nodup(struct move_queue *q)
  63 {
  64         if ((q->moves > 1 && q->move[q->moves - 2] == q->move[q->moves - 1])
  65             || (q->moves > 2 && q->move[q->moves - 3] == q->move[q->moves - 1])
  66             || (q->moves > 3 && q->move[q->moves - 4] == q->move[q->moves - 1]))
  67                 q->moves--;
  68 }
  69
  70 static inline void
  71 mq_print(struct move_queue *q, struct board *b, char *label)
  72 {
  73         fprintf(stderr, "%s candidate moves: ", label);
  74         for (unsigned int i = 0; i < q->moves; i++) {
  75                 fprintf(stderr, "%s ", coord2sstr(q->move[i], b));
  76         }
  77         fprintf(stderr, "\n");
  78 }
  79
  80 #endif