ocarina/include/core/playlists/iterator.h

/*
 * Copyright 2016 (c) Anna Schumaker.
 */
#ifndef OCARINA_CORE_PLAYLISTS_ITERATOR_H
#define OCARINA_CORE_PLAYLISTS_ITERATOR_H
#include <core/playlists/playlist.h>
#include <core/queue.h>

/* Called to set the playlist iterator to a specific position. */
static inline bool playlist_iter_set(struct playlist   *playlist,
				     struct queue_iter *iter,
				     unsigned int       n)
{
	if (!playlist || !iter)
		return false;
	iter->it_iter = g_queue_peek_nth_link(&playlist->pl_queue.q_tracks, n);
	iter->it_pos  = n;
	return iter->it_iter != NULL;
}

/* Called to advance the requested playlist iterator. */
static inline bool playlist_iter_next(struct queue_iter *iter)
{
	if (!iter)
		return false;
	iter->it_iter = g_list_next(iter->it_iter);
	iter->it_pos++;
	return iter->it_iter != NULL;
}

/* Called to get a pointer to the track at the requested iterator. */
static inline struct track *playlist_iter_track(struct queue_iter *iter)
{
	return (iter && iter->it_iter) ? iter->it_iter->data : NULL;
}

/* Called to iterate over the entire playlist. */
#define playlist_for_each(playlist, it)				\
	for (playlist_iter_set(playlist, it, 0); (it)->it_iter; \
	     playlist_iter_next(it))


/* Called to set the index of the current track. */
static inline bool playlist_current_set(struct playlist *playlist,
					unsigned int     n)
{
	if (!playlist)
		return false;
	return playlist_iter_set(playlist, &playlist->pl_current, n);
}

/* Called to advance the current track. */
static inline bool playlist_current_next(struct playlist *playlist)
{
	if (!playlist)
		return false;
	return playlist_iter_next(&playlist->pl_current);
}

/* Called to rewind the current track. */
static inline bool playlist_current_previous(struct playlist *playlist)
{
	if (!playlist)
		return false;
	playlist->pl_current.it_iter = g_list_previous(playlist->pl_current.it_iter);
	playlist->pl_current.it_pos--;
	return playlist->pl_current.it_iter != NULL;
}

/* Called to get a pointer to the current track. */
static inline struct track *playlist_current_track(struct playlist *playlist)
{
	return playlist ? playlist_iter_track(&playlist->pl_current) : NULL;
}

#endif /* OCARINA_CORE_PLAYLISTS_ITERATOR_H */