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 /* Warning: move_queue is further specialized upon in libmap_mq.
  10  * Take care of that when doing any changes here. */
  11
  12 #include "move.h"
  13 #include "random.h"
  14
  15 #define MQL 512 /* XXX: On larger board this might not be enough. */
  16 struct move_queue {
  17         unsigned int moves;
  18         coord_t move[MQL];
  19         /* Each move can have an optional tag or set of tags.
  20          * The usage of these is user-dependent. */
  21         unsigned char tag[MQL];
  22 };
  23
  24 /* Pick a random move from the queue. */
  25 static coord_t mq_pick(struct move_queue *q);
  26
  27 /* Add a move to the queue. */
  28 static void mq_add(struct move_queue *q, coord_t c, unsigned char tag);
  29
  30 /* Cat two queues together. */
  31 static void mq_append(struct move_queue *qd, struct move_queue *qs);
  32
  33 /* Check if the last move in queue is not a dupe, and remove it
  34  * in that case. */
  35 static void mq_nodup(struct move_queue *q);
  36
  37 /* Print queue contents on stderr. */
  38 static void mq_print(struct move_queue *q, struct board *b, char *label);
  39
  40
  41 static inline coord_t
  42 mq_pick(struct move_queue *q)
  43 {
  44         return q->moves ? q->move[fast_random(q->moves)] : pass;
  45 }
  46
  47 static inline void
  48 mq_add(struct move_queue *q, coord_t c, unsigned char tag)
  49 {
  50         assert(q->moves < MQL);
  51         q->tag[q->moves] = tag;
  52         q->move[q->moves++] = c;
  53 }
  54
  55 static inline void
  56 mq_append(struct move_queue *qd, struct move_queue *qs)
  57 {
  58         assert(qd->moves + qs->moves < MQL);
  59         memcpy(&qd->tag[qd->moves], qs->tag, qs->moves * sizeof(*qs->tag));
  60         memcpy(&qd->move[qd->moves], qs->move, qs->moves * sizeof(*qs->move));
  61         qd->moves += qs->moves;
  62 }
  63
  64 static inline void
  65 mq_nodup(struct move_queue *q)
  66 {
  67         for (unsigned int i = 1; i < 4; i++) {
  68                 if (q->moves <= i)
  69                         return;
  70                 if (q->move[q->moves - 1 - i] == q->move[q->moves - 1]) {
  71                         q->tag[q->moves - 1 - i] |= q->tag[q->moves - 1];
  72                         q->moves--;
  73                         return;
  74                 }
  75         }
  76 }
  77
  78 static inline void
  79 mq_print(struct move_queue *q, struct board *b, char *label)
  80 {
  81         fprintf(stderr, "%s candidate moves: ", label);
  82         for (unsigned int i = 0; i < q->moves; i++) {
  83                 fprintf(stderr, "%s ", coord2sstr(q->move[i], b));
  84         }
  85         fprintf(stderr, "\n");
  86 }
  87
  88 #endif