rb-history

rb-history — sequence data structure useful for implementing play orders

Synopsis

                    RBHistory;
                    RBHistoryClass;
RBHistory*          rb_history_new                      (gboolean truncate_on_play,
                                                         GFunc destroyer,
                                                         gpointer destroy_userdata);
void                rb_history_set_destroy_notify       (RBHistory *hist,
                                                         GFunc destroyer,
                                                         gpointer destroy_userdata);
void                rb_history_set_truncate_on_play     (RBHistory *hist,
                                                         gboolean truncate_on_play);
void                rb_history_set_maximum_size         (RBHistory *hist,
                                                         guint maximum_size);
guint               rb_history_length                   (RBHistory *hist);
RhythmDBEntry*      rb_history_first                    (RBHistory *hist);
RhythmDBEntry*      rb_history_previous                 (RBHistory *hist);
RhythmDBEntry*      rb_history_current                  (RBHistory *hist);
RhythmDBEntry*      rb_history_next                     (RBHistory *hist);
RhythmDBEntry*      rb_history_last                     (RBHistory *hist);
void                rb_history_go_first                 (RBHistory *hist);
void                rb_history_go_previous              (RBHistory *hist);
void                rb_history_go_next                  (RBHistory *hist);
void                rb_history_go_last                  (RBHistory *hist);
void                rb_history_set_playing              (RBHistory *hist,
                                                         RhythmDBEntry *entry);
void                rb_history_append                   (RBHistory *hist,
                                                         RhythmDBEntry *entry);
gint                rb_history_get_current_index        (RBHistory *hist);
void                rb_history_insert_at_index          (RBHistory *hist,
                                                         RhythmDBEntry *entry,
                                                         guint index);
void                rb_history_remove_entry             (RBHistory *hist,
                                                         RhythmDBEntry *entry);
void                rb_history_clear                    (RBHistory *hist);
GPtrArray*          rb_history_dump                     (RBHistory *hist);
gboolean            rb_history_contains_entry           (RBHistory *hist,
                                                         RhythmDBEntry *entry);

Object Hierarchy

  GObject
   +----RBHistory

Properties

  "maximum-size"             guint                 : Read / Write
  "truncate-on-play"         gboolean              : Read / Write / Construct

Description

RBHistory is a GSequence that maintains a "current" pointer and can delete an arbitrary element in amortized O(log(N)) time. It can call a deletion callback when it removes one of its entries.

All operations take amortized O(log(N)) (worst-case O(N)) time unless noted otherwise.

Details

RBHistory

typedef struct _RBHistory RBHistory;


RBHistoryClass

typedef struct {
	GObjectClass parent_class;
} RBHistoryClass;


rb_history_new ()

RBHistory*          rb_history_new                      (gboolean truncate_on_play,
                                                         GFunc destroyer,
                                                         gpointer destroy_userdata);

truncate_on_play :

Whether rb_history_set_playing() should truncate the history

destroyer :

function to call when removing an entry from the history

destroy_userdata :

data to pass to destroyer

Returns :

a new RBHistory

rb_history_set_destroy_notify ()

void                rb_history_set_destroy_notify       (RBHistory *hist,
                                                         GFunc destroyer,
                                                         gpointer destroy_userdata);

Sets a new function to call when removing entries from the history.

hist :

a RBHistory

destroyer :

function to call when removing an entry from the history

destroy_userdata :

data to pass to destroyer

rb_history_set_truncate_on_play ()

void                rb_history_set_truncate_on_play     (RBHistory *hist,
                                                         gboolean truncate_on_play);

Sets the 'truncate-on-play' property.

hist :

a RBHistory

truncate_on_play :

Whether rb_history_set_playing() should truncate the history

rb_history_set_maximum_size ()

void                rb_history_set_maximum_size         (RBHistory *hist,
                                                         guint maximum_size);

Sets the maximum-size property

hist :

a RBHistory

maximum_size :

new maximum size of the history (or 0 for no limit)

rb_history_length ()

guint               rb_history_length                   (RBHistory *hist);

hist :

a RBHistory

Returns :

the number of entries in the history

rb_history_first ()

RhythmDBEntry*      rb_history_first                    (RBHistory *hist);

hist :

a RBHistory

Returns :

the first entry in the history

rb_history_previous ()

RhythmDBEntry*      rb_history_previous                 (RBHistory *hist);

hist :

a RBHistory

Returns :

the RhythmDBEntry before the current position

rb_history_current ()

RhythmDBEntry*      rb_history_current                  (RBHistory *hist);

hist :

a RBHistory

Returns :

the current RhythmDBEntry, or NULL if there is no current position

rb_history_next ()

RhythmDBEntry*      rb_history_next                     (RBHistory *hist);

hist :

a RBHistory

Returns :

the RhythmDBEntry after the current position

rb_history_last ()

RhythmDBEntry*      rb_history_last                     (RBHistory *hist);

hist :

a RBHistory

Returns :

the last RhythmDBEntry in the history

rb_history_go_first ()

void                rb_history_go_first                 (RBHistory *hist);

Moves the current position to the first entry in the history

hist :

a RBHistory

rb_history_go_previous ()

void                rb_history_go_previous              (RBHistory *hist);

Moves the current position to the previous entry. If the current position is already at the start of the history, nothing happens.

hist :

a RBHistory

rb_history_go_next ()

void                rb_history_go_next                  (RBHistory *hist);

Moves the current position to the next entry. If the current position is already at the end of the history, nothing happens.

hist :

a RBHistory

rb_history_go_last ()

void                rb_history_go_last                  (RBHistory *hist);

Moves the current position to the last entry in the history

hist :

a RBHistory

rb_history_set_playing ()

void                rb_history_set_playing              (RBHistory *hist,
                                                         RhythmDBEntry *entry);

Updates the current position to point to the specified entry. If the truncate-on-play property is set, this will remove all entries after that.

hist :

a RBHistory

entry :

the new playing RhythmDBEntry

rb_history_append ()

void                rb_history_append                   (RBHistory *hist,
                                                         RhythmDBEntry *entry);

Adds a new entry to the end of the history list. If a size limit is set, an entry may be removed from the start to keep the history list within the limit.

hist :

a RBHistory

entry :

a RhythmDBEntry to append

rb_history_get_current_index ()

gint                rb_history_get_current_index        (RBHistory *hist);

Gets the index of the current entry. This is guaranteed to be < the history's size, so if the history is empty, it returns -1.

hist :

a RBHistory

Returns :

index of the current entry

rb_history_insert_at_index ()

void                rb_history_insert_at_index          (RBHistory *hist,
                                                         RhythmDBEntry *entry,
                                                         guint index);

Inserts entry at index within the history list. 0<=index<=size

hist :

a RBHistory

entry :

a RhythmDBEntry to insert

index :

position at which to insert entry

rb_history_remove_entry ()

void                rb_history_remove_entry             (RBHistory *hist,
                                                         RhythmDBEntry *entry);

Removes the specified entry from the history list.

hist :

a RBHistory

entry :

the RhythmDBEntry to remove

rb_history_clear ()

void                rb_history_clear                    (RBHistory *hist);

Empties the history list.

hist :

a RBHistory

rb_history_dump ()

GPtrArray*          rb_history_dump                     (RBHistory *hist);

Constructs a copy of the whole history in order. Caller must free the result. The caller does not own any references on the entries in the returned array. Takes O(Nlog(N)) time.

hist :

a RBHistory

Returns :

a copy of the history list

rb_history_contains_entry ()

gboolean            rb_history_contains_entry           (RBHistory *hist,
                                                         RhythmDBEntry *entry);

hist :

a RBHistory

entry :

a RhythmDBEntry to check for

Returns :

TRUE if the entry is present in the history list.

Property Details

The "maximum-size" property

  "maximum-size"             guint                 : Read / Write

Maximum number of entries to store in the history. If 0, no limit is applied.

Default value: 0


The "truncate-on-play" property

  "truncate-on-play"         gboolean              : Read / Write / Construct

If set, rb_history_set_playing() truncates the rest of the history

Default value: FALSE