GstUtils

GstUtils — Various utility functions

Synopsis

#include <gst/gst.h>

#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_UINT24_LE                  (data)
#define             GST_READ_UINT24_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)
gfloat              GST_READ_FLOAT_LE                   (const guint8 *data);
gfloat              GST_READ_FLOAT_BE                   (const guint8 *data);
gdouble             GST_READ_DOUBLE_LE                  (const guint8 *data);
gdouble             GST_READ_DOUBLE_BE                  (const guint8 *data);
#define             GST_WRITE_UINT8                     (data,
                                                         num)
#define             GST_WRITE_UINT16_LE                 (data,
                                                         num)
#define             GST_WRITE_UINT16_BE                 (data,
                                                         num)
#define             GST_WRITE_UINT24_LE                 (data,
                                                         num)
#define             GST_WRITE_UINT24_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)
void                GST_WRITE_FLOAT_LE                  (guint8 *data,
                                                         gfloat num);
void                GST_WRITE_FLOAT_BE                  (guint8 *data,
                                                         gfloat num);
void                GST_WRITE_DOUBLE_LE                 (guint8 *data,
                                                         gdouble num);
void                GST_WRITE_DOUBLE_BE                 (guint8 *data,
                                                         gdouble 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)
#define             GDOUBLE_FROM_BE                     (val)
#define             GDOUBLE_FROM_LE                     (val)
gdouble             GDOUBLE_SWAP_LE_BE                  (gdouble in);
#define             GDOUBLE_TO_BE                       (val)
#define             GDOUBLE_TO_LE                       (val)
#define             GFLOAT_FROM_BE                      (val)
#define             GFLOAT_FROM_LE                      (val)
gfloat              GFLOAT_SWAP_LE_BE                   (gfloat in);
#define             GFLOAT_TO_BE                        (val)
#define             GFLOAT_TO_LE                        (val)
#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_round         (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);
guint64             gst_util_uint64_scale_ceil          (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);
guint64             gst_util_uint64_scale_int           (guint64 val,
                                                         gint num,
                                                         gint denom);
guint64             gst_util_uint64_scale_int_round     (guint64 val,
                                                         gint num,
                                                         gint denom);
guint64             gst_util_uint64_scale_int_ceil      (guint64 val,
                                                         gint num,
                                                         gint denom);
gint                gst_util_greatest_common_divisor    (gint a,
                                                         gint b);
gint64              gst_util_greatest_common_divisor_int64
                                                        (gint64 a,
                                                         gint64 b);
void                gst_util_fraction_to_double         (gint src_n,
                                                         gint src_d,
                                                         gdouble *dest);
void                gst_util_double_to_fraction         (gdouble src,
                                                         gint *dest_n,
                                                         gint *dest_d);
gboolean            gst_util_fraction_multiply          (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d,
                                                         gint *res_n,
                                                         gint *res_d);
gboolean            gst_util_fraction_add               (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d,
                                                         gint *res_n,
                                                         gint *res_d);
gint                gst_util_fraction_compare           (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d);
guint32             gst_util_seqnum_next                (void);
gint32              gst_util_seqnum_compare             (guint32 s1,
                                                         guint32 s2);
guint               gst_util_group_id_next              (void);
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);
GstClockTime        gst_util_get_timestamp              (void);
enum                GstSearchMode;
gpointer            gst_util_array_binary_search        (gpointer array,
                                                         guint num_elements,
                                                         gsize element_size,
                                                         GCompareDataFunc search_func,
                                                         GstSearchMode mode,
                                                         gconstpointer search_data,
                                                         gpointer user_data);

Description

Details

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)            (_GST_GET (data, 0,  8,  0))

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

data :

 memory location

GST_READ_UINT16_LE()

#  define GST_READ_UINT16_LE(data)      _GST_FAST_READ_SWAP (16, 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)      _GST_FAST_READ (16, data)

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

data :

 memory location

GST_READ_UINT24_LE()

#define GST_READ_UINT24_LE(data) __gst_slow_read24_le((const guint8 *)(data))

Read a 24 bit unsigned integer value in little endian format from the memory buffer.

data :

 memory location

GST_READ_UINT24_BE()

#define GST_READ_UINT24_BE(data) __gst_slow_read24_be((const guint8 *)(data))

Read a 24 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)      _GST_FAST_READ_SWAP (32, 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)      _GST_FAST_READ (32, 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)      _GST_FAST_READ_SWAP (64, 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)      _GST_FAST_READ (64, data)

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

data :

 memory location

GST_READ_FLOAT_LE ()

gfloat              GST_READ_FLOAT_LE                   (const guint8 *data);

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

data :

 memory location

Returns :

 The floating point value read from data

GST_READ_FLOAT_BE ()

gfloat              GST_READ_FLOAT_BE                   (const guint8 *data);

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

data :

 memory location

Returns :

 The floating point value read from data

GST_READ_DOUBLE_LE ()

gdouble             GST_READ_DOUBLE_LE                  (const guint8 *data);

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

data :

 memory location

Returns :

 The double-precision floating point value read from data

GST_READ_DOUBLE_BE ()

gdouble             GST_READ_DOUBLE_BE                  (const guint8 *data);

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

data :

 memory location

Returns :

 The double-precision floating point value read from data

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_UINT24_LE()

#define             GST_WRITE_UINT24_LE(data, num)

Store a 24 bit unsigned integer value in little endian format into the memory buffer.

data :

 memory location

num :

 value to store

GST_WRITE_UINT24_BE()

#define             GST_WRITE_UINT24_BE(data, num)

Store a 24 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_WRITE_FLOAT_LE ()

void                GST_WRITE_FLOAT_LE                  (guint8 *data,
                                                         gfloat num);

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

data :

 memory location

num :

 value to store

GST_WRITE_FLOAT_BE ()

void                GST_WRITE_FLOAT_BE                  (guint8 *data,
                                                         gfloat num);

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

data :

 memory location

num :

 value to store

GST_WRITE_DOUBLE_LE ()

void                GST_WRITE_DOUBLE_LE                 (guint8 *data,
                                                         gdouble num);

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

data :

 memory location

num :

 value to store

GST_WRITE_DOUBLE_BE ()

void                GST_WRITE_DOUBLE_BE                 (guint8 *data,
                                                         gdouble num);

Store a 64 bit double 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

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

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

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

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

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

GDOUBLE_FROM_BE()

#define GDOUBLE_FROM_BE(val) (GDOUBLE_TO_BE (val))

Convert 64-bit floating point value (double) from big endian byte order into native byte order.

val :

 value

GDOUBLE_FROM_LE()

#define GDOUBLE_FROM_LE(val) (GDOUBLE_TO_LE (val))

Convert 64-bit floating point value (double) from little endian byte order into native byte order.

val :

 value

GDOUBLE_SWAP_LE_BE ()

gdouble             GDOUBLE_SWAP_LE_BE                  (gdouble in);

Swap byte order of a 64-bit floating point value (double).

in :

 input value

Returns :

 in byte-swapped.

GDOUBLE_TO_BE()

#define GDOUBLE_TO_BE(val)   (GDOUBLE_SWAP_LE_BE (val))

Convert 64-bit floating point value (double) from native byte order into big endian byte order.

val :

 value

GDOUBLE_TO_LE()

#define GDOUBLE_TO_LE(val)   ((gdouble) (val))

Convert 64-bit floating point value (double) from native byte order into little endian byte order.

val :

 value

GFLOAT_FROM_BE()

#define GFLOAT_FROM_BE(val)  (GFLOAT_TO_BE (val))

Convert 32-bit floating point value (float) from big endian byte order into native byte order.

val :

 value

GFLOAT_FROM_LE()

#define GFLOAT_FROM_LE(val)  (GFLOAT_TO_LE (val))

Convert 32-bit floating point value (float) from little endian byte order into native byte order.

val :

 value

GFLOAT_SWAP_LE_BE ()

gfloat              GFLOAT_SWAP_LE_BE                   (gfloat in);

Swap byte order of a 32-bit floating point value (float).

in :

 input value

Returns :

 in byte-swapped.

GFLOAT_TO_BE()

#define GFLOAT_TO_BE(val)    (GFLOAT_SWAP_LE_BE (val))

Convert 32-bit floating point value (float) from native byte order into big endian byte order.

val :

 value

GFLOAT_TO_LE()

#define GFLOAT_TO_LE(val)    ((gfloat) (val))

Convert 32-bit floating point value (float) from native byte order into little endian byte order.

val :

 value

gst_guint64_to_gdouble()

#define         gst_guint64_to_gdouble(value)   gst_util_guint64_to_gdouble(value)

Convert value to a gdouble.

value :

 the guint64 value to convert

Returns :

 value converted to a gdouble.

gst_gdouble_to_guint64()

#define         gst_gdouble_to_guint64(value)   gst_util_gdouble_to_guint64(value)

Convert value to a guint64.

value :

 the gdouble value to convert

Returns :

 value converted to a guint64.

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 the rational number num / denom, avoiding overflows and underflows and without loss of precision.

This function can potentially be very slow if val and num are both greater than 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. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer it is truncated. See also gst_util_uint64_scale_round(), gst_util_uint64_scale_ceil(), gst_util_uint64_scale_int(), gst_util_uint64_scale_int_round(), gst_util_uint64_scale_int_ceil().

gst_util_uint64_scale_round ()

guint64             gst_util_uint64_scale_round         (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);

Scale val by the rational number num / denom, avoiding overflows and underflows and without loss of precision.

This function can potentially be very slow if val and num are both greater than 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. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer, it is rounded to the nearest integer (half-way cases are rounded up). See also gst_util_uint64_scale(), gst_util_uint64_scale_ceil(), gst_util_uint64_scale_int(), gst_util_uint64_scale_int_round(), gst_util_uint64_scale_int_ceil().

gst_util_uint64_scale_ceil ()

guint64             gst_util_uint64_scale_ceil          (guint64 val,
                                                         guint64 num,
                                                         guint64 denom);

Scale val by the rational number num / denom, avoiding overflows and underflows and without loss of precision.

This function can potentially be very slow if val and num are both greater than 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. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer, it is rounded up. See also gst_util_uint64_scale(), gst_util_uint64_scale_round(), gst_util_uint64_scale_int(), gst_util_uint64_scale_int_round(), gst_util_uint64_scale_int_ceil().

gst_util_uint64_scale_int ()

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

Scale val by the rational number num / denom, avoiding overflows and underflows and without loss of precision. num must be non-negative and denom must be positive.

val :

 guint64 (such as a GstClockTime) to scale.

num :

 numerator of the scale factor.

denom :

 denominator of the scale factor.

Returns :

 val * num / denom. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer, it is truncated. See also gst_util_uint64_scale_int_round(), gst_util_uint64_scale_int_ceil(), gst_util_uint64_scale(), gst_util_uint64_scale_round(), gst_util_uint64_scale_ceil().

gst_util_uint64_scale_int_round ()

guint64             gst_util_uint64_scale_int_round     (guint64 val,
                                                         gint num,
                                                         gint denom);

Scale val by the rational number num / denom, avoiding overflows and underflows and without loss of precision. num must be non-negative and denom must be positive.

val :

 guint64 (such as a GstClockTime) to scale.

num :

 numerator of the scale factor.

denom :

 denominator of the scale factor.

Returns :

 val * num / denom. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer, it is rounded to the nearest integer (half-way cases are rounded up). See also gst_util_uint64_scale_int(), gst_util_uint64_scale_int_ceil(), gst_util_uint64_scale(), gst_util_uint64_scale_round(), gst_util_uint64_scale_ceil().

gst_util_uint64_scale_int_ceil ()

guint64             gst_util_uint64_scale_int_ceil      (guint64 val,
                                                         gint num,
                                                         gint denom);

Scale val by the rational number num / denom, avoiding overflows and underflows and without loss of precision. num must be non-negative and denom must be positive.

val :

 guint64 (such as a GstClockTime) to scale.

num :

 numerator of the scale factor.

denom :

 denominator of the scale factor.

Returns :

 val * num / denom. In the case of an overflow, this function returns G_MAXUINT64. If the result is not exactly representable as an integer, it is rounded up. See also gst_util_uint64_scale_int(), gst_util_uint64_scale_int_round(), gst_util_uint64_scale(), gst_util_uint64_scale_round(), gst_util_uint64_scale_ceil().

gst_util_greatest_common_divisor ()

gint                gst_util_greatest_common_divisor    (gint a,
                                                         gint b);

Calculates the greatest common divisor of a and b.

a :

 First value as gint

b :

 Second value as gint

Returns :

 Greatest common divisor of a and b

gst_util_greatest_common_divisor_int64 ()

gint64              gst_util_greatest_common_divisor_int64
                                                        (gint64 a,
                                                         gint64 b);

Calculates the greatest common divisor of a and b.

a :

 First value as gint64

b :

 Second value as gint64

Returns :

 Greatest common divisor of a and b

gst_util_fraction_to_double ()

void                gst_util_fraction_to_double         (gint src_n,
                                                         gint src_d,
                                                         gdouble *dest);

Transforms a fraction to a gdouble.

src_n :

 Fraction numerator as gint

src_d :

 Fraction denominator gint

dest :

 pointer to a gdouble for the result. [out]

gst_util_double_to_fraction ()

void                gst_util_double_to_fraction         (gdouble src,
                                                         gint *dest_n,
                                                         gint *dest_d);

Transforms a gdouble to a fraction and simplifies the result.

src :

 gdouble to transform

dest_n :

 pointer to a gint to hold the result numerator. [out]

dest_d :

 pointer to a gint to hold the result denominator. [out]

gst_util_fraction_multiply ()

gboolean            gst_util_fraction_multiply          (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d,
                                                         gint *res_n,
                                                         gint *res_d);

Multiplies the fractions a_n/a_d and b_n/b_d and stores the result in res_n and res_d.

a_n :

 Numerator of first value

a_d :

 Denominator of first value

b_n :

 Numerator of second value

b_d :

 Denominator of second value

res_n :

 Pointer to gint to hold the result numerator. [out]

res_d :

 Pointer to gint to hold the result denominator. [out]

Returns :

 FALSE on overflow, TRUE otherwise.

gst_util_fraction_add ()

gboolean            gst_util_fraction_add               (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d,
                                                         gint *res_n,
                                                         gint *res_d);

Adds the fractions a_n/a_d and b_n/b_d and stores the result in res_n and res_d.

a_n :

 Numerator of first value

a_d :

 Denominator of first value

b_n :

 Numerator of second value

b_d :

 Denominator of second value

res_n :

 Pointer to gint to hold the result numerator. [out]

res_d :

 Pointer to gint to hold the result denominator. [out]

Returns :

 FALSE on overflow, TRUE otherwise.

gst_util_fraction_compare ()

gint                gst_util_fraction_compare           (gint a_n,
                                                         gint a_d,
                                                         gint b_n,
                                                         gint b_d);

Compares the fractions a_n/a_d and b_n/b_d and returns -1 if a < b, 0 if a = b and 1 if a > b.

a_n :

 Numerator of first value

a_d :

 Denominator of first value

b_n :

 Numerator of second value

b_d :

 Denominator of second value

Returns :

 -1 if a < b; 0 if a = b; 1 if a > b.

gst_util_seqnum_next ()

guint32             gst_util_seqnum_next                (void);

Return a constantly incrementing sequence number.

This function is used internally to GStreamer to be able to determine which events and messages are "the same". For example, elements may set the seqnum on a segment-done message to be the same as that of the last seek event, to indicate that event and the message correspond to the same segment.

Returns :

 A constantly incrementing 32-bit unsigned integer, which might overflow back to 0 at some point. Use gst_util_seqnum_compare() to make sure you handle wraparound correctly.

gst_util_seqnum_compare ()

gint32              gst_util_seqnum_compare             (guint32 s1,
                                                         guint32 s2);

Compare two sequence numbers, handling wraparound.

The current implementation just returns (gint32)(s1 - s2).

s1 :

 A sequence number.

s2 :

 Another sequence number.

Returns :

 A negative number if s1 is before s2, 0 if they are equal, or a positive number if s1 is after s2.

gst_util_group_id_next ()

guint               gst_util_group_id_next              (void);

Return a constantly incrementing group id.

This function is used to generate a new group-id for the stream-start event.

Returns :

 A constantly incrementing unsigned integer, which might overflow back to 0 at some point.

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.

Note that this function silently returns if object has no property named name or when value cannot be converted to the type of the property.

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.

Note that this function is dangerous as it does not return any indication if the conversion worked or not.

value :

 the value to set. [out caller-allocates]

value_str :

 the string to get the value from

gst_util_get_timestamp ()

GstClockTime        gst_util_get_timestamp              (void);

Get a timestamp as GstClockTime to be used for interval measurements. The timestamp should not be interpreted in any other way.

Returns :

 the timestamp

enum GstSearchMode

typedef enum {
  GST_SEARCH_MODE_EXACT = 0,
  GST_SEARCH_MODE_BEFORE,
  GST_SEARCH_MODE_AFTER
} GstSearchMode;

The different search modes.

GST_SEARCH_MODE_EXACT

 Only search for exact matches.

GST_SEARCH_MODE_BEFORE

 Search for an exact match or the element just before.

GST_SEARCH_MODE_AFTER

 Search for an exact match or the element just after.

gst_util_array_binary_search ()

gpointer            gst_util_array_binary_search        (gpointer array,
                                                         guint num_elements,
                                                         gsize element_size,
                                                         GCompareDataFunc search_func,
                                                         GstSearchMode mode,
                                                         gconstpointer search_data,
                                                         gpointer user_data);

Searches inside array for search_data by using the comparison function search_func. array must be sorted ascending.

As search_data is always passed as second argument to search_func it's not required that search_data has the same type as the array elements.

The complexity of this search function is O(log (num_elements)).

array :

 the sorted input array

num_elements :

 number of elements in the array

element_size :

 size of every element in bytes

search_func :

 function to compare two elements, search_data will always be passed as second argument. [scope call]

mode :

 search mode that should be used

search_data :

 element that should be found

user_data :

 data to pass to search_func. [closure]

Returns :

 The address of the found element or NULL if nothing was found. [transfer none]
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