GstMemory is a lightweight refcounted object that wraps a region of memory. More...

#include <gstreamermm/memory.h>

Inheritance diagram for Gst::Memory:

Public Member Functions
void	reference () const
	Increment the reference count for this object. More...

void	unreference () const
	Decrement the reference count for this object. More...

GstMemory*	gobj ()
	Provides access to the underlying C instance. More...

const GstMemory*	gobj () const
	Provides access to the underlying C instance. More...

GstMemory*	gobj_copy () const
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

	Memory ()=delete

	Memory (const Memory&)=delete

Memory&	operator= (const Memory&)=delete

gsize	get_maxsize () const
	Get the maximum size allocated. More...

gsize	get_align () const
	Get the alignment of the memory. More...

gsize	get_offset () const
	Get the offset where valid data starts. More...

gsize	get_size () const
	Get the size of valid data. More...

Glib::RefPtr< Gst::Memory >	get_parent ()
	Get parent memory block. More...

Glib::RefPtr< const Gst::Memory >	get_parent () const

Glib::RefPtr< Gst::Allocator >	get_allocator ()
	Get the Gst::Allocator. More...

Glib::RefPtr< const Gst::Allocator >	get_allocator () const

bool	is_type (const Glib::ustring& mem_type) const
	Check if mem if allocated with an allocator for mem_type. More...

Glib::RefPtr< Gst::Memory >	share (gssize offset, gssize size)
	Return a shared copy of size bytes from mem starting from offset. More...

void	resize (gssize offset, gsize size)
	Resize the memory region. More...

bool	is_span (const Glib::RefPtr< Gst::Memory >& mem2, gsize& offset)
	Check if mem1 and mem2 share the memory with a common parent memory object and that the memory is contiguous. More...

bool	map (Gst::MapInfo& info, Gst::MapFlags flags)
	Fill info with the pointer and sizes of the memory in mem that can be accessed according to flags. More...

void	unmap (Gst::MapInfo& info)
	Release the memory obtained with map() More...

Glib::RefPtr< Gst::Memory >	copy (gssize offset, gssize size)
	Return a copy of size bytes from mem starting from offset. More...

void	init (Gst::MemoryFlags flags, const Glib::RefPtr< Gst::Allocator >& allocator, const Glib::RefPtr< Gst::Memory >& parent, gsize maxsize, gsize align, gsize offset, gsize size)
	Initializes a newly allocated mem with the given parameters. More...

gsize	get_sizes (gsize& offset, gsize& maxsize)
	Get the current size, offset and maxsize of mem. More...

Glib::RefPtr< Gst::Memory >	make_mapped (Gst::MapInfo& info, Gst::MapFlags flags)
	Create a Gst::Memory object that is mapped with flags. More...

Public Member Functions inherited from Gst::MiniObject
void	reference () const
	Increment the reference count for this object. More...

void	unreference () const
	Decrement the reference count for this object. More...

GstMiniObject*	gobj ()
	Provides access to the underlying C instance. More...

const GstMiniObject*	gobj () const
	Provides access to the underlying C instance. More...

GstMiniObject*	gobj_copy () const
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

	MiniObject ()=delete

	MiniObject (const MiniObject&)=delete

MiniObject&	operator= (const MiniObject&)=delete

	~MiniObject ()

guint	get_flags () const

void	set_flags (const guint& value)

gint	get_refcount () const

gint	get_lockstate () const

bool	lock (LockFlags flags)
	Lock the mini-object with the specified access mode in flags. More...

void	unlock (LockFlags flags)
	Unlock the mini-object with the specified access mode in flags. More...

bool	is_writable () const
	If mini_object has the LOCKABLE flag set, check if the current EXCLUSIVE lock on object is the only one, this means that changes to the object will not be visible to any other object. More...

Glib::RefPtr< MiniObject >	create_writable ()
	Checks if a mini-object is writable. More...

void	set_qdata (GQuark quark, QuarkData* data)
	This sets an opaque, named pointer on a miniobject. More...

QuarkData*	get_qdata (GQuark quark) const
	This function gets back user data pointers stored via set_qdata(). More...

QuarkData*	steal_qdata (GQuark quark)
	This function gets back user data pointers stored via set_qdata() and removes the data from object without invoking its destroy() function (if any was set). More...

void	add_finalize_notifier (const SlotFinalizer& slot)
	Adds notifier when mini object is finalized. More...

void	remove_finalize_notifier ()
	Remove finalize notifier. More...

Static Public Member Functions
static Glib::RefPtr< Memory >	create (Gst::MemoryFlags flags, gpointer data, gsize maxsize, gsize offset, gsize size)

Protected Member Functions
void	operator delete (void*, std::size_t)

Protected Member Functions inherited from Gst::MiniObject
void	operator delete (void*, std::size_t)

Related Functions
(Note that these are not member functions.)
Glib::RefPtr< Gst::Memory >	wrap (GstMemory* object, bool take_copy=false)
	A Glib::wrap() method for this object. More...

Related Functions inherited from Gst::MiniObject
Glib::RefPtr< Gst::MiniObject >	wrap (GstMiniObject* object, bool take_copy=false)
	A Glib::wrap() method for this object. More...

Additional Inherited Members
Public Types inherited from Gst::MiniObject
typedef sigc::slot< void >	SlotFinalizer

Detailed Description

GstMemory is a lightweight refcounted object that wraps a region of memory.

They are typically used to manage the data of a Gst::Buffer.

A GstMemory object has an allocated region of memory of maxsize. The maximum size does not change during the lifetime of the memory object. The memory also has an offset and size property that specifies the valid range of memory in the allocated region.

Memory is usually created by allocators with a Gst::Allocator::alloc() method call.

New memory can be created with Gst::Memory::create() that wraps the memory allocated elsewhere.

The size of the memory can be retrieved and changed with get_sizes() and resize() respectively.

Getting access to the data of the memory is performed with map(). The call will return a pointer to offset bytes into the region of memory. After the memory access is completed, unmap() should be called.

Memory can be copied with copy(), which will return a writable copy. share() will create a new memory block that shares the memory with an existing memory block at a custom offset and with a custom size.

Memory can be efficiently merged when is_span() returns TRUE.

Last reviewed on 2016-06-05 (1.8.0)

Constructor & Destructor Documentation

◆ Memory() [1/2]

Gst::Memory::Memory ( )

delete

◆ Memory() [2/2]

Gst::Memory::Memory ( const Memory& )

delete

Member Function Documentation

◆ copy()

Glib::RefPtr<Gst::Memory> Gst::Memory::copy	(	gssize	offset,
		gssize	size
	)

Return a copy of size bytes from mem starting from offset.

This copy is guaranteed to be writable. size can be set to -1 to return a copy from offset to the end of the memory region.

Parameters

offset	Offset to copy from.
size	Size to copy, or -1 to copy to the end of the memory region.

Returns: A new Gst::Memory.

◆ create()

static Glib::RefPtr<Memory> Gst::Memory::create	(	Gst::MemoryFlags	flags,
		gpointer	data,
		gsize	maxsize,
		gsize	offset,
		gsize	size
	)

static

◆ get_align()

gsize Gst::Memory::get_align ( ) const

Get the alignment of the memory.

◆ get_allocator() [1/2]

Glib::RefPtr<Gst::Allocator> Gst::Memory::get_allocator ( )

Get the Gst::Allocator.

◆ get_allocator() [2/2]

Glib::RefPtr<const Gst::Allocator> Gst::Memory::get_allocator ( ) const

◆ get_maxsize()

gsize Gst::Memory::get_maxsize ( ) const

Get the maximum size allocated.

◆ get_offset()

gsize Gst::Memory::get_offset ( ) const

Get the offset where valid data starts.

◆ get_parent() [1/2]

Glib::RefPtr<Gst::Memory> Gst::Memory::get_parent ( )

Get parent memory block.

◆ get_parent() [2/2]

Glib::RefPtr<const Gst::Memory> Gst::Memory::get_parent ( ) const

◆ get_size()

gsize Gst::Memory::get_size ( ) const

Get the size of valid data.

◆ get_sizes()

gsize Gst::Memory::get_sizes	(	gsize &	offset,
		gsize &	maxsize
	)

Get the current size, offset and maxsize of mem.

Parameters

offset	Pointer to offset.
maxsize	Pointer to maxsize.

Returns: The current sizes of mem.

◆ gobj() [1/2]

GstMemory* Gst::Memory::gobj ( )

Provides access to the underlying C instance.

◆ gobj() [2/2]

const GstMemory* Gst::Memory::gobj ( ) const

Provides access to the underlying C instance.

◆ gobj_copy()

GstMemory* Gst::Memory::gobj_copy ( ) const

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ init()

void Gst::Memory::init	(	Gst::MemoryFlags	flags,
		const Glib::RefPtr< Gst::Allocator >&	allocator,
		const Glib::RefPtr< Gst::Memory >&	parent,
		gsize	maxsize,
		gsize	align,
		gsize	offset,
		gsize	size
	)

Initializes a newly allocated mem with the given parameters.

This function will call Gst::MiniObject::init() with the default memory parameters.

Parameters

flags	Gst::MemoryFlags.
allocator	The Gst::Allocator.
parent	The parent of mem.
maxsize	The total size of the memory.
align	The alignment of the memory.
offset	The offset in the memory.
size	The size of valid data in the memory.

◆ is_span()

bool Gst::Memory::is_span	(	const Glib::RefPtr< Gst::Memory >&	mem2,
		gsize &	offset
	)

Check if mem1 and mem2 share the memory with a common parent memory object and that the memory is contiguous.

If this is the case, the memory of mem1 and mem2 can be merged efficiently by performing share() on the parent object from the returned offset.

Parameters

mem2	A Gst::Memory.
offset	A pointer to a result offset.

Returns: true if the memory is contiguous and of a common parent.

◆ is_type()

bool Gst::Memory::is_type ( const Glib::ustring & mem_type ) const

Check if mem if allocated with an allocator for mem_type.

Parameters

mem_type A memory type.

Returns: true if mem was allocated from an allocator for mem_type.

◆ make_mapped()

Glib::RefPtr<Gst::Memory> Gst::Memory::make_mapped	(	Gst::MapInfo&	info,
		Gst::MapFlags	flags
	)

Create a Gst::Memory object that is mapped with flags.

If mem is mappable with flags, this function returns the mapped mem directly. Otherwise a mapped copy of mem is returned.

Parameters

info	Pointer for info.
flags	Mapping flags.

Returns: a Gst::Memory object mapped.

◆ map()

bool Gst::Memory::map	(	Gst::MapInfo&	info,
		Gst::MapFlags	flags
	)

Fill info with the pointer and sizes of the memory in mem that can be accessed according to flags.

This function can return false for various reasons:

the memory backed by mem is not accessible with the given flags.
the memory was already mapped with a different mapping.

info and its contents remain valid for as long as mem is valid and until unmap() is called.

For each map() call, a corresponding unmap() call should be done.

Parameters

info	Pointer for info.
flags	Mapping flags.

Returns: true if the map operation was successful.

◆ operator delete()

void Gst::Memory::operator delete	(	void *	,
		std::size_t
	)

protected

◆ operator=()

Memory& Gst::Memory::operator= ( const Memory& )

delete

◆ reference()

void Gst::Memory::reference ( ) const

Increment the reference count for this object.

You should never need to do this manually - use the object via a RefPtr instead.

◆ resize()

void Gst::Memory::resize	(	gssize	offset,
		gsize	size
	)

Resize the memory region.

mem should be writable and offset + size should be less than the maxsize of mem.

Gst::MEMORY_FLAG_ZERO_PREFIXED and Gst::MEMORY_FLAG_ZERO_PADDED will be cleared when offset or padding is increased respectively.

Parameters

offset	A new offset.
size	A new size.

◆ share()

Glib::RefPtr<Gst::Memory> Gst::Memory::share	(	gssize	offset,
		gssize	size
	)

Return a shared copy of size bytes from mem starting from offset.

No memory copy is performed and the memory region is simply shared. The result is guaranteed to be non-writable. size can be set to -1 to return a shared copy from offset to the end of the memory region.

Parameters

offset	Offset to share from.
size	Size to share, or -1 to share to the end of the memory region.

Returns: A new Gst::Memory.

◆ unmap()

void Gst::Memory::unmap ( Gst::MapInfo& info )

Release the memory obtained with map()

Parameters

info	A Gst::MapInfo.

◆ unreference()

void Gst::Memory::unreference ( ) const

Decrement the reference count for this object.

You should never need to do this manually - use the object via a RefPtr instead.

Friends And Related Function Documentation

◆ wrap()

Glib::RefPtr< Gst::Memory > wrap	(	GstMemory *	object,
		bool	take_copy = `false`
	)

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

Public Member Functions

Static Public Member Functions

Protected Member Functions

Related Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Memory() [1/2]

◆ Memory() [2/2]

Member Function Documentation

◆ copy()

◆ create()

◆ get_align()

◆ get_allocator() [1/2]

◆ get_allocator() [2/2]

◆ get_maxsize()

◆ get_offset()

◆ get_parent() [1/2]

◆ get_parent() [2/2]

◆ get_size()

◆ get_sizes()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ init()

◆ is_span()

◆ is_type()

◆ make_mapped()

◆ map()

◆ operator delete()

◆ operator=()

◆ reference()

◆ resize()

◆ share()

◆ unmap()

◆ unreference()

Friends And Related Function Documentation

◆ wrap()