Structure

A #GstStructure is a collection of key/value pairs. The keys are expressed as GQuarks and the values can be of any GType.

In addition to the key/value pairs, a #GstStructure also has a name. The name starts with a letter and can be filled by letters, numbers and any of "/-_.:".

#GstStructure is used by various GStreamer subsystems to store information in a flexible and extensible way. A #GstStructure does not have a refcount because it usually is part of a higher level object such as #GstCaps, #GstMessage, #GstEvent, #GstQuery. It provides a means to enforce mutability using the refcount of the parent with the gst_structure_set_parent_refcount() method.

A #GstStructure can be created with gst_structure_new_empty() or gst_structure_new(), which both take a name and an optional set of key/value pairs along with the types of the values.

Field values can be changed with gst_structure_set_value() or gst_structure_set().

Field values can be retrieved with gst_structure_get_value() or the more convenient gst_structure_get_*() functions.

Fields can be removed with gst_structure_remove_field() or gst_structure_remove_fields().

Strings in structures must be ASCII or UTF-8 encoded. Other encodings are not allowed. Strings may be %NULL however.

Be aware that the current #GstCaps / #GstStructure serialization into string has limited support for nested #GstCaps / #GstStructure fields. It can only support one level of nesting. Using more levels will lead to unexpected behavior when using serialization features, such as gst_caps_to_string() or gst_value_serialize() and their counterparts.

class Structure {

GstStructure* gstStructure;

GstStructure* getStructureStruct();

void* getStruct();

this(GstStructure* gstStructure);

static Structure fromString(string name);

static GType getType();

this(string name);

this(GQuark quark);

this(string name, string firstfield, void* varargs);

bool canIntersect(Structure struct2);

Structure copy();

void fixate();

bool fixateField(string fieldName);

bool fixateFieldBoolean(string fieldName, bool target);

bool fixateFieldNearestDouble(string fieldName, double target);

bool fixateFieldNearestFraction(string fieldName, int targetNumerator, int targetDenominator);

bool fixateFieldNearestInt(string fieldName, int target);

bool fixateFieldString(string fieldName, string target);

bool foreac(GstStructureForeachFunc func, void* userData);

bool getBoolean(string fieldname, bool value);

bool getClockTime(string fieldname, GstClockTime value);

bool getDate(string fieldname, Date value);

bool getDateTime(string fieldname, DateTime value);

bool getDouble(string fieldname, double value);

bool getEnum(string fieldname, GType enumtype, int value);

GType getFieldType(string fieldname);

bool getFraction(string fieldname, int valueNumerator, int valueDenominator);

bool getInt(string fieldname, int value);

bool getInt64(string fieldname, long value);

string getName();

GQuark getNameId();

string getString(string fieldname);

bool getUint(string fieldname, uint value);

bool getUint64(string fieldname, ulong value);

bool getValist(string firstFieldname, void* args);

Value getValue(string fieldname);

bool hasField(string fieldname);

bool hasFieldTyped(string fieldname, GType type);

bool hasName(string name);

bool idGetValist(GQuark firstFieldId, void* args);

Value idGetValue(GQuark field);

bool idHasField(GQuark field);

bool idHasFieldTyped(GQuark field, GType type);

void idSetValist(GQuark fieldname, void* varargs);

void idSetValue(GQuark field, Value value);

void idTakeValue(GQuark field, Value value);

Structure intersect(Structure struct2);

bool isEqual(Structure structure2);

bool isSubset(Structure superset);

bool mapInPlace(GstStructureMapFunc func, void* userData);

int nFields();

string nthFieldName(uint index);

void removeAllFields();

void removeField(string fieldname);

void removeFieldsValist(string fieldname, void* varargs);

void setName(string name);

bool setParentRefcount(int* refcount);

void setValist(string fieldname, void* varargs);

void setValue(string fieldname, Value value);

void takeValue(string fieldname, Value value);

string toString();

static Structure fromString(string str, string end);

}

Constructors

this this(GstStructure* gstStructure): Sets our main struct and passes it to the parent class.
this this(string name): Creates a new, empty #GstStructure with the given @name.
this this(GQuark quark): Creates a new, empty #GstStructure with the given name as a GQuark.
this this(string name, string firstfield, void* varargs): Creates a new #GstStructure with the given @name. Structure fields are set according to the varargs in a manner similar to gst_structure_new().

Members

Functions

canIntersect bool canIntersect(Structure struct2): Tries intersecting @struct1 and @struct2 and reports whether the result would not be empty.
copy Structure copy(): Duplicates a #GstStructure and all its fields and values.
fixate void fixate(): Fixate all values in @structure using gst_value_fixate(). @structure will be modified in-place and should be writable.
fixateField bool fixateField(string fieldName): Fixates a #GstStructure by changing the given field with its fixated value.
fixateFieldBoolean bool fixateFieldBoolean(string fieldName, bool target): Fixates a #GstStructure by changing the given @field_name field to the given @target boolean if that field is not fixed yet.
fixateFieldNearestDouble bool fixateFieldNearestDouble(string fieldName, double target): Fixates a #GstStructure by changing the given field to the nearest double to @target that is a subset of the existing field.
fixateFieldNearestFraction bool fixateFieldNearestFraction(string fieldName, int targetNumerator, int targetDenominator): Fixates a #GstStructure by changing the given field to the nearest fraction to @target_numerator/@target_denominator that is a subset of the existing field.
fixateFieldNearestInt bool fixateFieldNearestInt(string fieldName, int target): Fixates a #GstStructure by changing the given field to the nearest integer to @target that is a subset of the existing field.
fixateFieldString bool fixateFieldString(string fieldName, string target): Fixates a #GstStructure by changing the given @field_name field to the given @target string if that field is not fixed yet.
foreac bool foreac(GstStructureForeachFunc func, void* userData): Calls the provided function once for each field in the #GstStructure. The function must not modify the fields. Also see gst_structure_map_in_place().
free void free(): Frees a #GstStructure and all its fields and values. The structure must not have a parent when this function is called.
getBoolean bool getBoolean(string fieldname, bool value): Sets the boolean pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getClockTime bool getClockTime(string fieldname, GstClockTime value): Sets the clock time pointed to by @value corresponding to the clock time of the given field. Caller is responsible for making sure the field exists and has the correct type.
getDate bool getDate(string fieldname, Date value): Sets the date pointed to by @value corresponding to the date of the given field. Caller is responsible for making sure the field exists and has the correct type.
getDateTime bool getDateTime(string fieldname, DateTime value): Sets the datetime pointed to by @value corresponding to the datetime of the given field. Caller is responsible for making sure the field exists and has the correct type.
getDouble bool getDouble(string fieldname, double value): Sets the double pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getEnum bool getEnum(string fieldname, GType enumtype, int value): Sets the int pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists, has the correct type and that the enumtype is correct.
getFieldType GType getFieldType(string fieldname): Finds the field with the given name, and returns the type of the value it contains. If the field is not found, G_TYPE_INVALID is returned.
getFraction bool getFraction(string fieldname, int valueNumerator, int valueDenominator): Sets the integers pointed to by @value_numerator and @value_denominator corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getInt bool getInt(string fieldname, int value): Sets the int pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getInt64 bool getInt64(string fieldname, long value): Sets the #gint64 pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getName string getName(): Get the name of @structure as a string.
getNameId GQuark getNameId(): Get the name of @structure as a GQuark.
getString string getString(string fieldname): Finds the field corresponding to @fieldname, and returns the string contained in the field's value. Caller is responsible for making sure the field exists and has the correct type.
getStruct void* getStruct(): the main Gtk struct as a void*
getStructureStruct GstStructure* getStructureStruct(): Get the main Gtk struct
getUint bool getUint(string fieldname, uint value): Sets the uint pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getUint64 bool getUint64(string fieldname, ulong value): Sets the #guint64 pointed to by @value corresponding to the value of the given field. Caller is responsible for making sure the field exists and has the correct type.
getValist bool getValist(string firstFieldname, void* args): Parses the variable arguments and reads fields from @structure accordingly. valist-variant of gst_structure_get(). Look at the documentation of gst_structure_get() for more details.
getValue Value getValue(string fieldname): Get the value of the field with name @fieldname.
hasField bool hasField(string fieldname): Check if @structure contains a field named @fieldname.
hasFieldTyped bool hasFieldTyped(string fieldname, GType type): Check if @structure contains a field named @fieldname and with GType @type.
hasName bool hasName(string name): Checks if the structure has the given name
idGetValist bool idGetValist(GQuark firstFieldId, void* args): Parses the variable arguments and reads fields from @structure accordingly. valist-variant of gst_structure_id_get(). Look at the documentation of gst_structure_id_get() for more details.
idGetValue Value idGetValue(GQuark field): Get the value of the field with GQuark @field.
idHasField bool idHasField(GQuark field): Check if @structure contains a field named @field.
idHasFieldTyped bool idHasFieldTyped(GQuark field, GType type): Check if @structure contains a field named @field and with GType @type.
idSetValist void idSetValist(GQuark fieldname, void* varargs): va_list form of gst_structure_id_set().
idSetValue void idSetValue(GQuark field, Value value): Sets the field with the given GQuark @field to @value. If the field does not exist, it is created. If the field exists, the previous value is replaced and freed.
idTakeValue void idTakeValue(GQuark field, Value value): Sets the field with the given GQuark @field to @value. If the field does not exist, it is created. If the field exists, the previous value is replaced and freed.
intersect Structure intersect(Structure struct2): Intersects @struct1 and @struct2 and returns the intersection.
isEqual bool isEqual(Structure structure2): Tests if the two #GstStructure are equal.
isSubset bool isSubset(Structure superset): Checks if @subset is a subset of @superset, i.e. has the same structure name and for all fields that are existing in @superset, @subset has a value that is a subset of the value in @superset.
mapInPlace bool mapInPlace(GstStructureMapFunc func, void* userData): Calls the provided function once for each field in the #GstStructure. In contrast to gst_structure_foreach(), the function may modify but not delete the fields. The structure must be mutable.
nFields int nFields(): Get the number of fields in the structure.
nthFieldName string nthFieldName(uint index): Get the name of the given field number, counting from 0 onwards.
removeAllFields void removeAllFields(): Removes all fields in a GstStructure.
removeField void removeField(string fieldname): Removes the field with the given name. If the field with the given name does not exist, the structure is unchanged.
removeFieldsValist void removeFieldsValist(string fieldname, void* varargs): va_list form of gst_structure_remove_fields().
setName void setName(string name): Sets the name of the structure to the given @name. The string provided is copied before being used. It must not be empty, start with a letter and can be followed by letters, numbers and any of "/-_.:".
setParentRefcount bool setParentRefcount(int* refcount): Sets the parent_refcount field of #GstStructure. This field is used to determine whether a structure is mutable or not. This function should only be called by code implementing parent objects of #GstStructure, as described in the MT Refcounting section of the design documents.
setValist void setValist(string fieldname, void* varargs): va_list form of gst_structure_set().
setValue void setValue(string fieldname, Value value): Sets the field with the given name @field to @value. If the field does not exist, it is created. If the field exists, the previous value is replaced and freed.
takeValue void takeValue(string fieldname, Value value): Sets the field with the given name @field to @value. If the field does not exist, it is created. If the field exists, the previous value is replaced and freed. The function will take ownership of @value.
toString string toString(): Converts @structure to a human-readable string representation.

Static functions

fromString Structure fromString(string name): Undocumented in source. Be warned that the author may not have intended to support it.
fromString Structure fromString(string str, string end): Creates a #GstStructure from a string representation. If end is not %NULL, a pointer to the place inside the given string where parsing ended will be returned.
getType GType getType()

Variables

gstStructure GstStructure* gstStructure;: the main Gtk struct

Meta

Source

See Implementation

gstreamer Structure classes

Structure