GstUtils

GstUtils — Various utility functions

Synopsis


#include <gst/gst.h>


#define             GST_BOILERPLATE_WITH_INTERFACE      (type, type_as_function,		
                                                         parent_type, parent_type_as_macro, interface_type,			
                                                         interface_type_as_macro, interface_as_function)
#define             GST_BOILERPLATE_FULL                (type, type_as_function, parent_type, parent_type_macro, additional_initializations)
#define             GST_BOILERPLATE                     (type,type_as_function,parent_type,parent_type_macro)
#define             GST_CALL_PARENT                     (parent_class_cast, name, args)
#define             GST_CALL_PARENT_WITH_DEFAULT        (parent_class_cast, name, args, def_return)
#define             GST_READ_UINT8                      (data)
#define             GST_READ_UINT16_LE                  (data)
#define             GST_READ_UINT16_BE                  (data)
#define             GST_READ_UINT32_LE                  (data)
#define             GST_READ_UINT32_BE                  (data)
#define             GST_READ_UINT64_LE                  (data)
#define             GST_READ_UINT64_BE                  (data)
#define             GST_WRITE_UINT8                     (data, num)
#define             GST_WRITE_UINT16_LE                 (data, num)
#define             GST_WRITE_UINT16_BE                 (data, num)
#define             GST_WRITE_UINT32_LE                 (data, num)
#define             GST_WRITE_UINT32_BE                 (data, num)
#define             GST_WRITE_UINT64_LE                 (data, num)
#define             GST_WRITE_UINT64_BE                 (data, num)
#define             GST_ROUND_UP_2                      (num)
#define             GST_ROUND_UP_4                      (num)
#define             GST_ROUND_UP_8                      (num)
#define             GST_ROUND_UP_16                     (num)
#define             GST_ROUND_UP_32                     (num)
#define             GST_ROUND_UP_64                     (num)
#define             GST_ROUND_DOWN_2                    (num)
#define             GST_ROUND_DOWN_4                    (num)
#define             GST_ROUND_DOWN_8                    (num)
#define             GST_ROUND_DOWN_16                   (num)
#define             GST_ROUND_DOWN_32                   (num)
#define             GST_ROUND_DOWN_64                   (num)
void                gst_atomic_int_set                  (gint *atomic_int,
                                                         gint value);
const gchar*        gst_flow_get_name                   (GstFlowReturn ret);
GQuark              gst_flow_to_quark                   (GstFlowReturn ret);
void                gst_print_element_args              (GString *buf,
                                                         gint indent,
                                                         GstElement *element);
void                gst_print_pad_caps                  (GString *buf,
                                                         gint indent,
                                                         GstPad *pad);
#define             gst_guint64_to_gdouble              (value)
#define             gst_gdouble_to_guint64              (value)
void                gst_util_dump_mem                   (const guchar *mem,
                                                         guint size);
guint64             gst_util_uint64_scale               (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);
guint64             gst_util_uint64_scale_int           (guint64 val,
                                                         gint num,
                                                         gint denom);
void                gst_util_set_object_arg             (GObject *object,
                                                         const gchar *name,
                                                         const gchar *value);
void                gst_util_set_value_from_string      (GValue *value,
                                                         const gchar *value_str);

Description

When defining own plugins, use the GST_BOILERPLATE ease gobject creation.

Details

GST_BOILERPLATE_WITH_INTERFACE()

#define             GST_BOILERPLATE_WITH_INTERFACE(type, type_as_function,		\
                parent_type, parent_type_as_macro, interface_type,			\
                interface_type_as_macro, interface_as_function)

Like GST_BOILERPLATE, but makes the type 1) implement an interface, and 2) implement GstImplementsInterface for that type.

After this you will need to implement interface_as_function ## _supported and interface_as_function ## _interface_init

type :

 the name of the type struct

type_as_function :

 the prefix for the functions

parent_type :

 the parent type struct name

parent_type_as_macro :

 the parent type macro

interface_type :

 the name of the interface type struct

interface_type_as_macro :

 the interface type macro

interface_as_function :

 the interface function name prefix

GST_BOILERPLATE_FULL()

#define             GST_BOILERPLATE_FULL(type, type_as_function, parent_type, parent_type_macro, additional_initializations)

Define the boilerplate type stuff to reduce typos and code size. Defines the get_type method and the parent_class static variable. 

  GST_BOILERPLATE_FULL (GstFdSink, gst_fdsink, GstElement, GST_TYPE_ELEMENT, _do_init);

type :

 the name of the type struct

type_as_function :

 the prefix for the functions

parent_type :

 the parent type struct name

parent_type_macro :

 the parent type macro

additional_initializations :

 function pointer in the form of void additional_initializations (GType type) that can be used for initializing interfaces and the like

GST_BOILERPLATE()

#define             GST_BOILERPLATE(type,type_as_function,parent_type,parent_type_macro)

Define the boilerplate type stuff to reduce typos and code size. Defines the get_type method and the parent_class static variable. 

  GST_BOILERPLATE (GstFdSink, gst_fdsink, GstElement, GST_TYPE_ELEMENT);

type :

 the name of the type struct

type_as_function :

 the prefix for the functions

parent_type :

 the parent type struct name

parent_type_macro :

 the parent type macro

GST_CALL_PARENT()

#define             GST_CALL_PARENT(parent_class_cast, name, args)

Just call the parent handler. This assumes that there is a variable named parent_class that points to the (duh!) parent class. Note that this macro is not to be used with things that return something, use the _WITH_DEFAULT version for that

parent_class_cast :

 the name of the class cast macro for the parent type

name :

 name of the function to call

args :

 arguments enclosed in '( )'

GST_CALL_PARENT_WITH_DEFAULT()

#define             GST_CALL_PARENT_WITH_DEFAULT(parent_class_cast, name, args, def_return)

Same as GST_CALL_PARENT(), but in case there is no implementation, it evaluates to def_return.

parent_class_cast :

 the name of the class cast macro for the parent type

name :

 name of the function to call

args :

 arguments enclosed in '( )'

def_return :

 default result

GST_READ_UINT8()

#define             GST_READ_UINT8(data)

Read an 8 bit unsigned integer value from the memory buffer.

data :

 memory location

GST_READ_UINT16_LE()

#define             GST_READ_UINT16_LE(data)

Read a 16 bit unsigned integer value in little endian format from the memory buffer.

data :

 memory location

GST_READ_UINT16_BE()

#define             GST_READ_UINT16_BE(data)

Read a 16 bit unsigned integer value in big endian format from the memory buffer.

data :

 memory location

GST_READ_UINT32_LE()

#define             GST_READ_UINT32_LE(data)

Read a 32 bit unsigned integer value in little endian format from the memory buffer.

data :

 memory location

GST_READ_UINT32_BE()

#define             GST_READ_UINT32_BE(data)

Read a 32 bit unsigned integer value in big endian format from the memory buffer.

data :

 memory location

GST_READ_UINT64_LE()

#define             GST_READ_UINT64_LE(data)

Read a 64 bit unsigned integer value in little endian format from the memory buffer.

data :

 memory location

GST_READ_UINT64_BE()

#define             GST_READ_UINT64_BE(data)

Read a 64 bit unsigned integer value in big endian format from the memory buffer.

data :

 memory location

GST_WRITE_UINT8()

#define             GST_WRITE_UINT8(data, num)

Store an 8 bit unsigned integer value into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT16_LE()

#define             GST_WRITE_UINT16_LE(data, num)

Store a 16 bit unsigned integer value in little endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT16_BE()

#define             GST_WRITE_UINT16_BE(data, num)

Store a 16 bit unsigned integer value in big endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT32_LE()

#define             GST_WRITE_UINT32_LE(data, num)

Store a 32 bit unsigned integer value in little endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT32_BE()

#define             GST_WRITE_UINT32_BE(data, num)

Store a 32 bit unsigned integer value in big endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT64_LE()

#define             GST_WRITE_UINT64_LE(data, num)

Store a 64 bit unsigned integer value in little endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT64_BE()

#define             GST_WRITE_UINT64_BE(data, num)

Store a 64 bit unsigned integer value in big endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_ROUND_UP_2()

#define GST_ROUND_UP_2(num)  (((num)+1)&~1)

Rounds an integer value up to the next multiple of 2.

num :

 integer value to round up

GST_ROUND_UP_4()

#define GST_ROUND_UP_4(num)  (((num)+3)&~3)

Rounds an integer value up to the next multiple of 4.

num :

 integer value to round up

GST_ROUND_UP_8()

#define GST_ROUND_UP_8(num)  (((num)+7)&~7)

Rounds an integer value up to the next multiple of 8.

num :

 integer value to round up

GST_ROUND_UP_16()

#define GST_ROUND_UP_16(num) (((num)+15)&~15)

Rounds an integer value up to the next multiple of 16.

num :

 integer value to round up

GST_ROUND_UP_32()

#define GST_ROUND_UP_32(num) (((num)+31)&~31)

Rounds an integer value up to the next multiple of 32.

num :

 integer value to round up

GST_ROUND_UP_64()

#define GST_ROUND_UP_64(num) (((num)+63)&~63)

Rounds an integer value up to the next multiple of 64.

num :

 integer value to round up

GST_ROUND_DOWN_2()

#define GST_ROUND_DOWN_2(num)  ((num)&(~1))

Rounds an integer value down to the next multiple of 2.

num :

 integer value to round down

Since 0.10.12

GST_ROUND_DOWN_4()

#define GST_ROUND_DOWN_4(num)  ((num)&(~3))

Rounds an integer value down to the next multiple of 4.

num :

 integer value to round down

Since 0.10.12

GST_ROUND_DOWN_8()

#define GST_ROUND_DOWN_8(num)  ((num)&(~7))

Rounds an integer value down to the next multiple of 8.

num :

 integer value to round down

Since 0.10.12

GST_ROUND_DOWN_16()

#define GST_ROUND_DOWN_16(num) ((num)&(~15))

Rounds an integer value down to the next multiple of 16.

num :

 integer value to round down

Since 0.10.12

GST_ROUND_DOWN_32()

#define GST_ROUND_DOWN_32(num) ((num)&(~31))

Rounds an integer value down to the next multiple of 32.

num :

 integer value to round down

Since 0.10.12

GST_ROUND_DOWN_64()

#define GST_ROUND_DOWN_64(num) ((num)&(~63))

Rounds an integer value down to the next multiple of 64.

num :

 integer value to round down

Since 0.10.12

gst_atomic_int_set ()

void                gst_atomic_int_set                  (gint *atomic_int,
                                                         gint value);

Unconditionally sets the atomic integer to value.

atomic_int :

 pointer to an atomic integer

value :

 value to set

gst_flow_get_name ()

const gchar*        gst_flow_get_name                   (GstFlowReturn ret);

Gets a string representing the given flow return.

ret :

 a GstFlowReturn to get the name of.

Returns :

 a static string with the name of the flow return.

gst_flow_to_quark ()

GQuark              gst_flow_to_quark                   (GstFlowReturn ret);

Get the unique quark for the given GstFlowReturn.

ret :

 a GstFlowReturn to get the quark of.

Returns :

 the quark associated with the flow return or 0 if an invalid return was specified.

gst_print_element_args ()

void                gst_print_element_args              (GString *buf,
                                                         gint indent,
                                                         GstElement *element);

Print the element argument in a human readable format in the given GString.

buf :

 the buffer to print the args in

indent :

 initial indentation

element :

 the element to print the args of

gst_print_pad_caps ()

void                gst_print_pad_caps                  (GString *buf,
                                                         gint indent,
                                                         GstPad *pad);

Write the pad capabilities in a human readable format into the given GString.

buf :

 the buffer to print the caps in

indent :

 initial indentation

pad :

 the pad to print the caps from

gst_guint64_to_gdouble()

#define             gst_guint64_to_gdouble(value)

Convert value to a gdouble.

value :

 the guint64 value to convert

gst_gdouble_to_guint64()

#define             gst_gdouble_to_guint64(value)

Convert value to a guint64.

value :

 the gdouble value to convert

gst_util_dump_mem ()

void                gst_util_dump_mem                   (const guchar *mem,
                                                         guint size);

Dumps the memory block into a hex representation. Useful for debugging.

mem :

 a pointer to the memory to dump

size :

 the size of the memory block to dump

gst_util_uint64_scale ()

guint64             gst_util_uint64_scale               (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);

Scale val by num / denom, trying to avoid overflows.

This function can potentially be very slow if denom > G_MAXUINT32.

val :

 the number to scale

num :

 the numerator of the scale ratio

denom :

 the denominator of the scale ratio

Returns :

 val * num / denom, trying to avoid overflows. In the case of an overflow, this function returns G_MAXUINT64.

gst_util_uint64_scale_int ()

guint64             gst_util_uint64_scale_int           (guint64 val,
                                                         gint num,
                                                         gint denom);

Scale a guint64 by a factor expressed as a fraction (num/denom), avoiding overflows and loss of precision.

num and denom must be positive integers. denom cannot be 0.

val :

 guint64 (such as a GstClockTime) to scale.

num :

 numerator of the scale factor.

denom :

 denominator of the scale factor.

Returns :

 val * num / denom, avoiding overflow and loss of precision. In the case of an overflow, this function returns G_MAXUINT64.

gst_util_set_object_arg ()

void                gst_util_set_object_arg             (GObject *object,
                                                         const gchar *name,
                                                         const gchar *value);

Convertes the string value to the type of the objects argument and sets the argument with it.

object :

 the object to set the argument of

name :

 the name of the argument to set

value :

 the string value to set

gst_util_set_value_from_string ()

void                gst_util_set_value_from_string      (GValue *value,
                                                         const gchar *value_str);

Converts the string to the type of the value and sets the value with it.

value :

 the value to set

value_str :

 the string to get the value from