GstIndex

Name

GstIndex -- Generate indexes on objects

Synopsis


#include <gst/gst.h>


struct      GstIndexEntry;
struct      GstIndexGroup;
enum        GstIndexCertainty;
enum        GstIndexEntryType;
enum        GstIndexLookupMethod;
#define     GST_INDEX_NASSOCS               (entry)
#define     GST_INDEX_ASSOC_FLAGS           (entry)
#define     GST_INDEX_ASSOC_FORMAT          (entry,i)
#define     GST_INDEX_ASSOC_VALUE           (entry,i)
struct      GstIndexAssociation;
enum        GstAssocFlags;
#define     GST_INDEX_FORMAT_FORMAT         (entry)
#define     GST_INDEX_FORMAT_KEY            (entry)
#define     GST_INDEX_ID_DESCRIPTION        (entry)
gboolean    (*GstIndexFilter)               (GstIndex *index,
                                             GstIndexEntry *entry);
gboolean    (*GstIndexResolver)             (GstIndex *index,
                                             GstObject *writer,
                                             gchar **writer_string,
                                             gpointer user_data);
struct      GstIndex;
GstIndex*   gst_index_new                   (void);
gint        gst_index_get_group             (GstIndex *index);
gint        gst_index_new_group             (GstIndex *index);
gboolean    gst_index_set_group             (GstIndex *index,
                                             gint groupnum);
void        gst_index_set_certainty         (GstIndex *index,
                                             GstIndexCertainty certainty);
GstIndexCertainty gst_index_get_certainty   (GstIndex *index);
void        gst_index_set_filter            (GstIndex *index,
                                             GstIndexFilter filter,
                                             gpointer user_data);
void        gst_index_set_resolver          (GstIndex *index,
                                             GstIndexResolver resolver,
                                             gpointer user_data);
gboolean    gst_index_get_writer_id         (GstIndex *index,
                                             GstObject *writer,
                                             gint *id);
GstIndexEntry* gst_index_add_format         (GstIndex *index,
                                             gint id,
                                             GstFormat format);
GstIndexEntry* gst_index_add_association    (GstIndex *index,
                                             gint id,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value,
                                             ...);
GstIndexEntry* gst_index_add_object         (GstIndex *index,
                                             gint id,
                                             gchar *key,
                                             GType type,
                                             gpointer object);
GstIndexEntry* gst_index_add_id             (GstIndex *index,
                                             gint id,
                                             gchar *description);
GstIndexEntry* gst_index_get_assoc_entry    (GstIndex *index,
                                             gint id,
                                             GstIndexLookupMethod method,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value);
GstIndexEntry* gst_index_get_assoc_entry_full
                                            (GstIndex *index,
                                             gint id,
                                             GstIndexLookupMethod method,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value,
                                             GCompareDataFunc func,
                                             gpointer user_data);
void        gst_index_entry_free            (GstIndexEntry *entry);
gboolean    gst_index_entry_assoc_map       (GstIndexEntry *entry,
                                             GstFormat format,
                                             gint64 *value);

Object Hierarchy


  GObject
   +----GstObject
         +----GstIndex

Properties


  "resolver"             GstIndexResolver     : Read / Write

Signal Prototypes


"entry-added"
            void        user_function      (GstIndex *gstindex,
                                            gpointer arg1,
                                            gpointer user_data);

Description

GstIndex is used to generate a stream index of one or more elements in a pipeline.

Details

struct GstIndexEntry

struct GstIndexEntry {

  GstIndexEntryType	 type;
  gint			 id;

  union {
    struct {
      gchar		*description;
    } id;
    struct {
      gint		 nassocs;
      GstIndexAssociation 
	      		*assocs;
      GstAssocFlags	 flags;
    } assoc;
    struct {
      gchar		*key;
      GType		 type;
      gpointer		 object;
    } object;
    struct {
      GstFormat		 format;
      gchar		*key;
    } format;
  } data;
};

The basic element of an index.


struct GstIndexGroup

struct GstIndexGroup {

  /* unique ID of group in index */
  gint groupnum;

  /* list of entries */
  GList *entries;

  /* the certainty level of the group */
  GstIndexCertainty certainty;

  /* peer group that contains more certain entries */
  gint peergroup;
};

A group of related entries in an index.


enum GstIndexCertainty

typedef enum {
  GST_INDEX_UNKNOWN,
  GST_INDEX_CERTAIN,
  GST_INDEX_FUZZY
} GstIndexCertainty;

The certainty of a group in the index.

GST_INDEX_UNKNOWN

accuracy is not known

GST_INDEX_CERTAIN

accuracy is perfect

GST_INDEX_FUZZY

accuracy is fuzzy


enum GstIndexEntryType

typedef enum {
  GST_INDEX_ENTRY_ID,
  GST_INDEX_ENTRY_ASSOCIATION,
  GST_INDEX_ENTRY_OBJECT,
  GST_INDEX_ENTRY_FORMAT,
} GstIndexEntryType;

The different types of entries in the index.

GST_INDEX_ENTRY_ID

This entry is an id that maps an index id to its owner object

GST_INDEX_ENTRY_ASSOCIATION

This entry is an association between formats

GST_INDEX_ENTRY_OBJECT

An object

GST_INDEX_ENTRY_FORMAT

A format definition


enum GstIndexLookupMethod

typedef enum {
  GST_INDEX_LOOKUP_EXACT,
  GST_INDEX_LOOKUP_BEFORE,
  GST_INDEX_LOOKUP_AFTER,
} GstIndexLookupMethod;

Specify the method to find an index entry in the index.

GST_INDEX_LOOKUP_EXACT

There has to be an exact indexentry with the given format/value

GST_INDEX_LOOKUP_BEFORE

The exact entry or the one before it

GST_INDEX_LOOKUP_AFTER

The exact entry or the one after it


GST_INDEX_NASSOCS()

#define GST_INDEX_NASSOCS(entry)		((entry)->data.assoc.nassocs)

Get the number of associations in the entry.

entry :

The entry to query


GST_INDEX_ASSOC_FLAGS()

#define GST_INDEX_ASSOC_FLAGS(entry)		((entry)->data.assoc.flags)

Get the flags for this entry

entry :

The entry to query


GST_INDEX_ASSOC_FORMAT()

#define GST_INDEX_ASSOC_FORMAT(entry,i)		((entry)->data.assoc.assocs[(i)].format)

Get the i-th format of the entry.

entry :

The entry to query

i :

The format index


GST_INDEX_ASSOC_VALUE()

#define GST_INDEX_ASSOC_VALUE(entry,i)		((entry)->data.assoc.assocs[(i)].value)

Get the i-th value of the entry.

entry :

The entry to query

i :

The value index


struct GstIndexAssociation

struct GstIndexAssociation {

  GstFormat 	format;
  gint64 	value;
};

An association in an entry.

GstFormat format

the format of the association

gint64 value

the value of the association


enum GstAssocFlags

typedef enum {
  GST_ASSOCIATION_FLAG_NONE 	= 0,
  GST_ASSOCIATION_FLAG_KEY_UNIT = (1 << 0),

  /* new flags should start here */
  GST_ASSOCIATION_FLAG_LAST	= (1 << 8),
} GstAssocFlags;

flags for an association entry

GST_ASSOCIATION_FLAG_NONE

no extra flags

GST_ASSOCIATION_FLAG_KEY_UNIT

the entry marks a key unit, a key unit is one that marks a place where one can randomly seek to.

GST_ASSOCIATION_FLAG_LAST

extra user defined flags should start here.


GST_INDEX_FORMAT_FORMAT()

#define GST_INDEX_FORMAT_FORMAT(entry)		((entry)->data.format.format)

Get the format of the format entry

entry :

The entry to query


GST_INDEX_FORMAT_KEY()

#define GST_INDEX_FORMAT_KEY(entry)		((entry)->data.format.key)

Get the key of the format entry

entry :

The entry to query


GST_INDEX_ID_DESCRIPTION()

#define GST_INDEX_ID_DESCRIPTION(entry)		((entry)->data.id.description)

Get the description of the id entry

entry :

The entry to query


GstIndexFilter ()

gboolean    (*GstIndexFilter)               (GstIndex *index,
                                             GstIndexEntry *entry);

Function to filter out entries in the index.

index :

The index being queried

entry :

The entry to be added.

Returns :

This function should return TRUE if the entry is to be added to the index, FALSE otherwise.


GstIndexResolver ()

gboolean    (*GstIndexResolver)             (GstIndex *index,
                                             GstObject *writer,
                                             gchar **writer_string,
                                             gpointer user_data);

Function to resolve ids to writer descriptions.

index :

the index being queried.

writer :

The object that wants to write

writer_string :

A description of the writer.

user_data :

user_data as registered

Returns :

TRUE if an id could be assigned to the writer.


struct GstIndex

struct GstIndex;

The GstIndex object


gst_index_new ()

GstIndex*   gst_index_new                   (void);

Create a new tileindex object

Returns :

a new index object


gst_index_get_group ()

gint        gst_index_get_group             (GstIndex *index);

Get the id of the current group.

index :

the index to get the current group from

Returns :

the id of the current group.


gst_index_new_group ()

gint        gst_index_new_group             (GstIndex *index);

Create a new group for the given index. It will be set as the current group.

index :

the index to create the new group in

Returns :

the id of the newly created group.


gst_index_set_group ()

gboolean    gst_index_set_group             (GstIndex *index,
                                             gint groupnum);

Set the current groupnumber to the given argument.

index :

the index to set the new group in

groupnum :

the groupnumber to set

Returns :

TRUE if the operation succeeded, FALSE if the group did not exist.


gst_index_set_certainty ()

void        gst_index_set_certainty         (GstIndex *index,
                                             GstIndexCertainty certainty);

Set the certainty of the given index.

index :

the index to set the certainty on

certainty :

the certainty to set


gst_index_get_certainty ()

GstIndexCertainty gst_index_get_certainty   (GstIndex *index);

Get the certainty of the given index.

index :

the index to get the certainty of

Returns :

the certainty of the index.


gst_index_set_filter ()

void        gst_index_set_filter            (GstIndex *index,
                                             GstIndexFilter filter,
                                             gpointer user_data);

Lets the app register a custom filter function so that it can select what entries should be stored in the index.

index :

the index to register the filter on

filter :

the filter to register

user_data :

data passed to the filter function


gst_index_set_resolver ()

void        gst_index_set_resolver          (GstIndex *index,
                                             GstIndexResolver resolver,
                                             gpointer user_data);

Lets the app register a custom function to map index ids to writer descriptions.

index :

the index to register the resolver on

resolver :

the resolver to register

user_data :

data passed to the resolver function


gst_index_get_writer_id ()

gboolean    gst_index_get_writer_id         (GstIndex *index,
                                             GstObject *writer,
                                             gint *id);

Before entries can be added to the index, a writer should obtain a unique id. The methods to add new entries to the index require this id as an argument.

The application can implement a custom function to map the writer object to a string. That string will be used to register or look up an id in the index.

index :

the index to get a unique write id for

writer :

the GstObject to allocate an id for

id :

a pointer to a gint to hold the id

Returns :

TRUE if the writer would be mapped to an id.


gst_index_add_format ()

GstIndexEntry* gst_index_add_format         (GstIndex *index,
                                             gint id,
                                             GstFormat format);

Adds a format entry into the index. This function is used to map dynamic GstFormat ids to their original format key.

index :

the index to add the entry to

id :

the id of the index writer

format :

the format to add to the index

Returns :

a pointer to the newly added entry in the index.


gst_index_add_association ()

GstIndexEntry* gst_index_add_association    (GstIndex *index,
                                             gint id,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value,
                                             ...);

Associate given format/value pairs with eachother. Be sure to pass gint64 values to this functions varargs, you might want to use a gint64 cast to be sure.

index :

the index to add the entry to

id :

the id of the index writer

flags :

optinal flags for this entry

format :

the format of the value

value :

the value

... :

other format/value pairs or 0 to end the list

Returns :

a pointer to the newly added entry in the index.


gst_index_add_object ()

GstIndexEntry* gst_index_add_object         (GstIndex *index,
                                             gint id,
                                             gchar *key,
                                             GType type,
                                             gpointer object);

Add the given object to the index with the given key.

index :

the index to add the object to

id :

the id of the index writer

key :

a key for the object

type :

the GType of the object

object :

a pointer to the object to add

Returns :

a pointer to the newly added entry in the index.


gst_index_add_id ()

GstIndexEntry* gst_index_add_id             (GstIndex *index,
                                             gint id,
                                             gchar *description);

Add an id entry into the index.

index :

the index to add the entry to

id :

the id of the index writer

description :

the description of the index writer

Returns :

a pointer to the newly added entry in the index.


gst_index_get_assoc_entry ()

GstIndexEntry* gst_index_get_assoc_entry    (GstIndex *index,
                                             gint id,
                                             GstIndexLookupMethod method,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value);

Finds the given format/value in the index

index :

the index to search

id :

the id of the index writer

method :

The lookup method to use

flags :

Flags for the entry

format :

the format of the value

value :

the value to find

Returns :

the entry associated with the value or NULL if the value was not found.


gst_index_get_assoc_entry_full ()

GstIndexEntry* gst_index_get_assoc_entry_full
                                            (GstIndex *index,
                                             gint id,
                                             GstIndexLookupMethod method,
                                             GstAssocFlags flags,
                                             GstFormat format,
                                             gint64 value,
                                             GCompareDataFunc func,
                                             gpointer user_data);

Finds the given format/value in the index with the given compare function and user_data.

index :

the index to search

id :

the id of the index writer

method :

The lookup method to use

flags :

Flags for the entry

format :

the format of the value

value :

the value to find

func :

the function used to compare entries

user_data :

user data passed to the compare function

Returns :

the entry associated with the value or NULL if the value was not found.


gst_index_entry_free ()

void        gst_index_entry_free            (GstIndexEntry *entry);

Free the memory used by the given entry.

entry :

the entry to free


gst_index_entry_assoc_map ()

gboolean    gst_index_entry_assoc_map       (GstIndexEntry *entry,
                                             GstFormat format,
                                             gint64 *value);

Gets alternative formats associated with the indexentry.

entry :

the index to search

format :

the format of the value the find

value :

a pointer to store the value

Returns :

TRUE if there was a value associated with the given format.

Properties

"resolver" (GstIndexResolver : Read / Write)

Signals

The "entry-added" signal

void        user_function                  (GstIndex *gstindex,
                                            gpointer arg1,
                                            gpointer user_data);

Is emited when a new entry is added to the index.

gstindex :

the object which received the signal.

arg1 :

The entry added to the index.

user_data :

user data set when the signal handler was connected.

See Also

GstIndexFactory