A TS packet buffer for time shift. More...

#include <tsTimeShiftBuffer.h>

Inheritance diagram for ts::TimeShiftBuffer:

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Collaboration diagram for ts::TimeShiftBuffer:

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Public Member Functions
	TimeShiftBuffer (Report *report, size_t count=DEFAULT_TOTAL_PACKETS)
	Constructor.

	TimeShiftBuffer (ReporterBase *delegate, size_t count=DEFAULT_TOTAL_PACKETS)
	Constructor.

virtual	~TimeShiftBuffer () override
	Destructor.

bool	close (bool silent=false)
	Close the buffer.

size_t	count () const
	Get the current number of packets in the time-shift buffer.

bool	empty () const
	Check if the buffer is empty.

bool	full () const
	Check if the buffer is full.

bool	isOpen () const
	Check if the buffer is open.

bool	memoryResident () const
	Check if the buffer is completely memory resident.

bool	muteReport (bool mute)
	Temporarily mute the associated report.

bool	open ()
	Open the buffer.

virtual Report &	report () const override
	Access the Report which is associated with this object.

bool	setBackupDirectory (const fs::path &directory)
	Set the directory for the backup file on disk.

bool	setMemoryPackets (size_t count)
	Set the maximum number of cached packets to be held in memory.

Report *	setReport (Report *report)
	Associate this object with another Report to log errors.

ReporterBase *	setReport (ReporterBase *delegate)
	Associate this object with another ReporterBase to log errors.

bool	setTotalPackets (size_t count)
	Set the total size of the time shift buffer in packets.

bool	shift (TSPacket &packet, TSPacketMetadata &metadata)
	Push a packet in the time-shift buffer and pull the oldest one.

size_t	size () const
	Get the total size in packets of the time-shift buffer.

Static Public Member Functions
static int	SilentLevel (bool silent, int default_severity=Severity::Error)
	Compute a log severity level from a "silent" parameter.

Static Public Attributes
static constexpr size_t	DEFAULT_MEMORY_PACKETS = 128
	Default number of cached packets in memory.

static constexpr size_t	DEFAULT_TOTAL_PACKETS = 128
	Default size in packets of a time shift buffer.

static constexpr size_t	MIN_MEMORY_PACKETS = 2
	Minimum number of cached packets in memory.

static constexpr size_t	MIN_TOTAL_PACKETS = 2
	Minimum size in packets of a time shift buffer.

Detailed Description

A TS packet buffer for time shift.

The buffer is partly implemented in virtual memory and partly on disk.

Constructor & Destructor Documentation

◆ TimeShiftBuffer() [1/2]

ts::TimeShiftBuffer::TimeShiftBuffer	(	Report *	report,
		size_t	count = `DEFAULT_TOTAL_PACKETS`
	)

explicit

Constructor.

Parameters

[in]	report	Where to report errors. The report object must remain valid as long as this object exists or setReport() is used with another Report object. If report is null, log messages are discarded.
[in]	count	Max number of packets in the buffer.

◆ TimeShiftBuffer() [2/2]

ts::TimeShiftBuffer::TimeShiftBuffer	(	ReporterBase *	delegate,
		size_t	count = `DEFAULT_TOTAL_PACKETS`
	)

explicit

Constructor.

Parameters

[in]	delegate	Use the report of another ReporterBase. If delegate is null, log messages are discarded.
[in]	count	Max number of packets in the buffer.

Member Function Documentation

◆ setTotalPackets()

bool ts::TimeShiftBuffer::setTotalPackets ( size_t count )

Set the total size of the time shift buffer in packets.

Must be called before open().

Parameters

[in] count Max number of packets in the buffer.

Returns: True on success, false if already open.

◆ setMemoryPackets()

bool ts::TimeShiftBuffer::setMemoryPackets ( size_t count )

Set the maximum number of cached packets to be held in memory.

Must be called before open().

Parameters

[in] count Max number of cached packets in memory.

Returns: True on success, false if already open.

◆ setBackupDirectory()

bool ts::TimeShiftBuffer::setBackupDirectory ( const fs::path & directory )

Set the directory for the backup file on disk.

Must be called before open(). By default, the file is created in the system-dependent temporary directory. When the maximum number of cached packets in memory is larger than the buffer size, the buffer is entirely resident in memory and no file is created. The back file is automatically deleted when the time-shift buffer is closed.

Parameters

[in] directory Directory name.

Returns: True on success, false if already open or too small.

◆ open()

bool ts::TimeShiftBuffer::open ( )

Open the buffer.

Returns: True on success, false on error.

◆ close()

bool ts::TimeShiftBuffer::close ( bool silent = false )

Close the buffer.

The memory is freed and the disk backup file is deleted.

Parameters

[in] silent If true, do not report errors. This is typically useful when the object is in some error condition and closing it is necessary although it may generate additional meaningless errors.

Returns: True on success, false on error.

◆ isOpen()

bool ts::TimeShiftBuffer::isOpen ( ) const

inline

Check if the buffer is open.

Returns: True if the buffer is open.

◆ size()

size_t ts::TimeShiftBuffer::size ( ) const

inline

Get the total size in packets of the time-shift buffer.

Returns: The total size in packets of the time-shift buffer.

◆ count()

size_t ts::TimeShiftBuffer::count ( ) const

inline

Get the current number of packets in the time-shift buffer.

Returns: The current number of packets in the time-shift buffer.

◆ empty()

bool ts::TimeShiftBuffer::empty ( ) const

inline

Check if the buffer is empty.

Returns: True when the buffer is empty, false otherwise.

◆ full()

bool ts::TimeShiftBuffer::full ( ) const

inline

Check if the buffer is full.

Returns: True when the buffer is full, false otherwise.

◆ memoryResident()

bool ts::TimeShiftBuffer::memoryResident ( ) const

inline

Check if the buffer is completely memory resident.

Returns: True when the buffer is memory resident, false when it is backup by a file.

◆ shift()

bool ts::TimeShiftBuffer::shift	(	TSPacket &	packet,
		TSPacketMetadata &	metadata
	)

Push a packet in the time-shift buffer and pull the oldest one.

As long as the buffer is not full, a null packet is returned. When the buffer is full, the oldest packet is returned and removed from the buffer. Initial null packets which are generated while the time-shift buffer is filling can be recognized as they are marked as "input stuffing" in their metadata, after returning from shift().

Parameters

[in,out]	packet	On input, contains the packet to push. On output, contains the time-shifted packet.
[in,out]	metadata	Packet metadata.

Returns: True on success, false on error.

◆ report()

virtual Report & ts::ReporterBase::report ( ) const

overridevirtualinherited

Access the Report which is associated with this object.

Can be called from another thread only if the Report object is thread-safe.

Returns: A reference to the associated report.

Implements ts::ReporterInterface.

◆ setReport() [1/2]

Report * ts::ReporterBase::setReport ( Report * report )

inherited

Associate this object with another Report to log errors.

Parameters

[in] report Where to report errors. The report object must remain valid as long as this object exists or setReport() is used with another Report object. If report is null, log messages are discarded.

Returns: The address of the previous Report object or a null pointer if there was none.

◆ setReport() [2/2]

ReporterBase * ts::ReporterBase::setReport ( ReporterBase * delegate )

inherited

Associate this object with another ReporterBase to log errors.

Parameters

[in] delegate Use the report of another ReporterBase. If delegate is null, the previous explicit Report is used..

Returns: The address of the previous ReporterBase object or a null pointer if there was none.

◆ muteReport()

bool ts::ReporterBase::muteReport ( bool mute )

inherited

Temporarily mute the associated report.

Parameters

[in] mute It true, report() will return a null report (log messages are discarded), until muteReport() is invoked again with mute set to false.

Returns: Previous state of the mute field.

◆ SilentLevel()

static int ts::ReporterBase::SilentLevel	(	bool	silent,
		int	default_severity = `Severity::Error`
	)

inlinestaticinherited

Compute a log severity level from a "silent" parameter.

Some subclass methods have a "silent" parameter to avoid reporting errors which may be insignificant, typically when closing a device after an error, in which case the close operation may produce other errors if the previous error left the device in an inconsistent state. While those errors should not be displayed as errors, we still display them at debug level.

Parameters

[in]	silent	If true, do not report errors, report debug messages instead.
[in]	default_severity	Default severity, in non-silent mode (error by default).

Returns: Error when silent is false, Debug otherwise.

The documentation for this class was generated from the following file:

tsTimeShiftBuffer.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ TimeShiftBuffer() [1/2]

◆ TimeShiftBuffer() [2/2]

Member Function Documentation

◆ setTotalPackets()

◆ setMemoryPackets()

◆ setBackupDirectory()

◆ open()

◆ close()

◆ isOpen()

◆ size()

◆ count()

◆ empty()

◆ full()

◆ memoryResident()

◆ shift()

◆ report()

◆ setReport() [1/2]

◆ setReport() [2/2]

◆ muteReport()

◆ SilentLevel()