ocarina/include/core/queue.h

142 lines
4.2 KiB
C

/*
* Copyright 2013 (c) Anna Schumaker.
*
* Queues are lists of tracks that the user has requested to play next.
* Users of queues are expected to implement their own save and load functions,
* and to provide a filled out queue_ops structure during initialization.
*/
#ifndef OCARINA_CORE_QUEUE_H
#define OCARINA_CORE_QUEUE_H
#include <core/file.h>
#include <core/tags/track.h>
struct queue;
struct queue_ops {
/* Called to tell a higher layer that a queue has been initialized. */
void *(*qop_init)(struct queue *, void *);
/* Called to tell a higher layer that a queue is deinitializing. */
void (*qop_deinit)(struct queue *);
/* Called to tell a higher layer that a track has been added. */
void (*qop_added)(struct queue *, unsigned int);
/* Called to tell a higher layer that a track has been removed. */
void (*qop_removed)(struct queue *, unsigned int);
/* Called to tell a higher layer that the queue has been cleared. */
void (*qop_cleared)(struct queue *, unsigned int);
/* Called to tell a higher layer that a track has been updated. */
void (*qop_updated)(struct queue *, unsigned int);
};
struct queue_iter {
GList *it_iter; /* The current link in the GQueue. */
guint it_pos; /* The current index into the queue. */
};
struct queue {
unsigned int q_length; /* The queue's total runtime (in seconds). */
GQueue q_tracks; /* The queue's list of tracks. */
GSList *q_sort; /* The queue's sort order. */
void *q_private; /* The queue's private data. */
struct queue_iter q_cur; /* The queue's last-played position. */
const struct queue_ops *q_ops; /* The queue's operations vector. */
};
/* Called to initialize a queue iterator. */
static inline void queue_iter_init(struct queue *queue, struct queue_iter *it)
{
it->it_iter = g_queue_peek_head_link(&queue->q_tracks);
it->it_pos = g_queue_link_index(&queue->q_tracks, it->it_iter);
}
/* Called to advance a queue iterator by one step. */
static inline void queue_iter_next(struct queue_iter *it)
{
it->it_iter = g_list_next(it->it_iter);
it->it_pos++;
}
/* Called to rewind a queue iterator by one step. */
static inline void queue_iter_prev(struct queue_iter *it)
{
it->it_iter = g_list_previous(it->it_iter);
it->it_pos--;
}
/* Called to set a queue iterator to a specific position. */
static inline void queue_iter_set(struct queue *queue, struct queue_iter *it,
unsigned int pos)
{
it->it_iter = g_queue_peek_nth_link(&queue->q_tracks, pos);
it->it_pos = pos;
}
/* Called to access the value of a queue iterator. */
static inline struct track *queue_iter_val(struct queue_iter *it)
{
return (it->it_iter) ? it->it_iter->data : NULL;
}
#define queue_for_each(queue, it) \
for (queue_iter_init(queue, it); (it)->it_iter; queue_iter_next(it))
/* Called to initialize a queue. */
void queue_init(struct queue *, const struct queue_ops *, void *);
/* Called to deinitialize a queue. */
void queue_deinit(struct queue *);
/* Called to find the size of the queue. */
static inline unsigned int queue_size(struct queue *queue)
{
return g_queue_get_length(&queue->q_tracks);
}
/* Called to access the queued track at a given index. */
static inline struct track *queue_at(struct queue *queue, unsigned int index)
{
return (struct track *)g_queue_peek_nth(&queue->q_tracks, index);
}
/* Called to add a track to the queue. */
unsigned int queue_add(struct queue *, struct track *);
/* Called to add a track to the front of the queue. */
unsigned int queue_add_front(struct queue *, struct track *);
/* Called to remove a track from the queue by index. */
void queue_remove(struct queue *, unsigned int);
/* Called to remove all instances of the track from the queue. */
unsigned int queue_remove_all(struct queue *, struct track *);
/* Called to remove all tracks from the queue. */
void queue_clear(struct queue *);
/* Called to check if a queue has a track. */
bool queue_has(struct queue *, struct track *);
/* Called to tell the queue that a track has been updated. */
void queue_updated(struct queue *, struct track *);
/* Called to tell the queue that a specific index has been selected. */
struct track *queue_selected(struct queue *, unsigned int);
#endif /* OCARINA_CORE_QUEUE_H */