queue.h

#ifndef _queue_h_INCLUDED
#define _queue_h_INCLUDED

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>

struct link {
  struct link *prev, *next;
  uint64_t stamp;
};

struct queue {
  struct link *links;
  struct link *first, *last;
  struct link *search;
  uint64_t stamp;
};

/*------------------------------------------------------------------------*/

void enqueue (struct queue *queue, struct link *link, bool update);
void dequeue (struct queue *queue, struct link *link);

/*------------------------------------------------------------------------*/

static inline void update_queue_search (struct queue *queue,
                                        struct link *link) {
  struct link *search = queue->search;
  assert (search);
  if (search->stamp < link->stamp)
    queue->search = link;
}

static inline void reset_queue_search (struct queue *queue) {
  queue->search = queue->last;
}

#endif