mq.h

   1 #ifndef PACHI_MQ_H
   2 #define PACHI_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         for (unsigned int i = 1; i < 4; i++) {
  65                 if (q->moves <= i)
  66                         return;
  67                 if (q->move[q->moves - 1 - i] == q->move[q->moves - 1]) {
  68                         q->tag[q->moves - 1 - i] |= q->tag[q->moves - 1];
  69                         q->moves--;
  70                         return;
  71                 }
  72         }
  73 }
  74
  75 static inline void
  76 mq_print(struct move_queue *q, struct board *b, char *label)
  77 {
  78         fprintf(stderr, "%s candidate moves: ", label);
  79         for (unsigned int i = 0; i < q->moves; i++) {
  80                 fprintf(stderr, "%s ", coord2sstr(q->move[i], b));
  81         }
  82         fprintf(stderr, "\n");
  83 }
  84
  85 #endif