RingBuffer Class Reference

#include <RingBuffer.h>

Detailed Description

Implements a file/stream reader/writer.

This class, despite its name, no-longer provides a ring buffer. It can buffer reads and provide support for streaming files. It also provides a wrapper for the ThreadedFileWriter which makes sure that the file reader does not read past where the wrapped TFW has written new data.

Definition at line 23 of file RingBuffer.h.


Public Member Functions
	RingBuffer (const QString &lfilename, bool write, bool usereadahead=true, uint read_retries=12)
	Creates a RingBuffer instance.
	~RingBuffer ()
	Shuts down any threads and closes any files.
void	SetWriteBufferSize (int newSize)
	Calls ThreadedFileWriter::SetWriteBufferSize(int).
void	SetWriteBufferMinWriteSize (int newMinSize)
	Calls ThreadedFileWriter::SetWriteBufferMinWriteSize(int).
void	UpdateRawBitrate (uint rawbitrate)
	Set the raw bit rate, to allow RingBuffer adjust effective bitrate.
void	UpdatePlaySpeed (float playspeed)
	Set the play speed, to allow RingBuffer adjust effective bitrate.
QString	GetFilename (void) const
	Returns name of file used by this RingBuffer.
int	DataInReadAhead (void) const
	Returns ReadBufAvail(void).
bool	GetStopReads (void) const
	Returns value of stopreads.
bool	isPaused (void) const
	Returns false iff read-ahead is not running and read-ahead is not paused.
long long	GetReadPosition (void) const
	Returns how far into the file we have read.
long long	GetWritePosition (void) const
	Returns how far into a ThreadedFileWriter file we have written.
long long	GetRealFileSize (void) const
	Returns the size of the file we are reading/writing, or -1 if the query fails.
uint	GetBitrate (void) const
	Returns effective bits per second (in thousands).
uint	GetReadBlockSize (void) const
	Returns size of each disk read made by read ahead thread (in bytes).
bool	IsOpen (void) const
	Returns true if the file is open for either reading or writing.
void	OpenFile (const QString &lfilename, uint retryCount=12)
	Opens a file for reading.
int	Read (void *buf, int count)
	This is the public method for reading from a file, it calls the appropriate read method if the file is remote or buffered, or a DVD.
int	Peek (void *buf, int count)
void	Reset (bool full=false, bool toAdjust=false, bool resetInternal=false)
	Resets the read-ahead thread and our position in the file.
long long	Seek (long long pos, int whence)
	Seeks to a particular position in the file.
void	Pause (void)
	Pauses the read-ahead thread.
void	Unpause (void)
	Unpauses the read-ahead thread.
void	WaitForPause (void)
	Waits for Pause(void) to take effect.
void	Start (void)
	Starts the read-ahead thread.
void	StopReads (void)
	????
void	StartReads (void)
	????
bool	LiveMode (void) const
	Returns true if this RingBuffer has been assigned a LiveTVChain.
void	SetLiveMode (LiveTVChain *chain)
	Assigns a LiveTVChain to this RingBuffer.
void	IgnoreLiveEOF (bool ignore)
	Tells RingBuffer whether to igonre the end-of-file.
int	Write (const void *buf, uint count)
	Writes buffer to ThreadedFileWriter::Write(const void*,uint).
bool	IsIOBound (void) const
	Returns true if a RingBuffer::Read(void*,int) is likely to block.
void	WriterFlush (void)
	Calls ThreadedFileWriter::Flush(void) and ThreadedFileWriter::Sync(void).
void	Sync (void)
	Calls ThreadedFileWriter::Sync(void).
long long	WriterSeek (long long pos, int whence)
	Calls ThreadedFileWriter::Seek(long long,int).
bool	isDVD (void) const
	Returns true if this is a DVD backed RingBuffer.
DVDRingBufferPriv *	DVD ()
bool	InDVDMenuOrStillFrame (void)
long long	SetAdjustFilesize (void)
void	SetTimeout (bool fast)
Protected Member Functions
void	ReadAheadThread (void)
	Read-ahead run function.
Static Protected Member Functions
static void *	StartReader (void *type)
	Thunk that calls ReadAheadThread(void).
Private Member Functions
void	CalcReadAheadThresh (void)
	Calculates fill_min, fill_threshold, and readblocksize from the estimated effective bitrate of the stream.
int	safe_read_dvd (void *data, uint sz)
int	safe_read (int fd, void *data, uint sz)
	Reads data from the file-descriptor.
int	safe_read (RemoteFile rf, void data, uint sz)
	Reads data from the RemoteFile.
int	ReadFromBuf (void *buf, int count, bool peek=false)
	Reads from the read-ahead buffer, this is called by Read(void*, int) when the read-ahead thread is running.
int	ReadBufFree (void) const
	Returns number of bytes available for reading into buffer.
int	ReadBufAvail (void) const
	Returns number of bytes available for reading from buffer.
void	StartupReadAheadThread (void)
	Creates the read-ahead thread, and waits for it to start.
void	ResetReadAhead (long long newinternal)
	Restart the read-ahead threat at the 'newinternal' position.
void	KillReadAheadThread (void)
	Stops the read-ahead thread, and waits for it to stop.
Private Attributes
QString	filename
ThreadedFileWriter *	tfw
int	fd2
bool	writemode
long long	readpos
long long	writepos
bool	stopreads
pthread_rwlock_t	rwlock
int	recorder_num
RemoteEncoder *	remoteencoder
RemoteFile *	remotefile
QMutex	readAheadLock
pthread_t	reader
bool	startreadahead
char *	readAheadBuffer
bool	readaheadrunning
bool	readaheadpaused
bool	pausereadthread
int	rbrpos
int	rbwpos
long long	internalreadpos
bool	ateof
bool	readsallowed
volatile bool	wantseek
bool	setswitchtonext
QMutex	bitratelock
uint	rawbitrate
float	playspeed
int	fill_threshold
int	fill_min
int	readblocksize
QWaitCondition	pauseWait
int	wanttoread
QWaitCondition	availWait
QMutex	availWaitMutex
QWaitCondition	readsAllowedWait
int	numfailures
bool	commserror
DVDRingBufferPriv *	dvdPriv
bool	oldfile
LiveTVChain *	livetvchain
bool	ignoreliveeof
long long	readAdjust
QWaitCondition	readAheadRunningCond
	Condition to signal that the read ahead thread is running.
QMutex	readAheadRunningCondLock
Static Private Attributes
static const uint	kBufferSize = 3 * 1024 * 1024
static const uint	kReadTestSize = PNG_MIN_SIZE

Constructor & Destructor Documentation

RingBuffer::RingBuffer	(	const QString &	lfilename,
		bool	write,
		bool	usereadahead = `true`,
		uint	read_retries = `12`
	)

Creates a RingBuffer instance.

You can explicitly disable the readahead thread by setting readahead to false, or by just not calling Start(void).

Parameters:

	lfilename	Name of file to read or write.
	write	If true an encapsulated writer is created
	readahead	If false a call to Start(void) will not a pre-buffering thread, otherwise Start(void) will start a pre-buffering thread.
	read_retries	How often to retry reading the file before giving up.

Definition at line 86 of file RingBuffer.cpp.

RingBuffer::~RingBuffer ( void )

Shuts down any threads and closes any files.

Definition at line 311 of file RingBuffer.cpp.

Member Function Documentation

void RingBuffer::SetWriteBufferSize ( int newSize )

Calls ThreadedFileWriter::SetWriteBufferSize(int).

Definition at line 1269 of file RingBuffer.cpp.

Referenced by TVRec::SetupRecorder().

void RingBuffer::SetWriteBufferMinWriteSize ( int newMinSize )

Calls ThreadedFileWriter::SetWriteBufferMinWriteSize(int).

Definition at line 1277 of file RingBuffer.cpp.

void RingBuffer::UpdateRawBitrate ( uint rawbitrate )

Set the raw bit rate, to allow RingBuffer adjust effective bitrate.

Parameters:

raw_bitrate

Streams average number of kilobits per second when playspeed is 1.0

Definition at line 485 of file RingBuffer.cpp.

Referenced by NuppelDecoder::GetFrame(), NuppelVideoPlayer::JumpToProgram(), NuppelDecoder::OpenFile(), IvtvDecoder::OpenFile(), AvFormatDecoder::ScanStreams(), and NuppelVideoPlayer::SwitchToProgram().

void RingBuffer::UpdatePlaySpeed ( float playspeed )

Set the play speed, to allow RingBuffer adjust effective bitrate.

Parameters:

play_speed

Speed to set. (1.0 for normal speed)

Definition at line 518 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::StartPlaying().

QString RingBuffer::GetFilename ( void ) const [inline]

Returns name of file used by this RingBuffer.

Definition at line 38 of file RingBuffer.h.

Referenced by FileTransfer::GetFileSize(), NuppelVideoPlayer::OpenFile(), NuppelDecoder::OpenFile(), AvFormatDecoder::OpenFile(), TV::ProcessNetworkControlCommand(), AvFormatDecoder::Reset(), RecorderBase::SetRingBuffer(), TV::SetupPlayer(), and NuppelVideoRecorder::StartRecording().

int RingBuffer::DataInReadAhead ( void ) const [inline]

Returns ReadBufAvail(void).

Definition at line 40 of file RingBuffer.h.

Referenced by NuppelVideoPlayer::IsReallyNearEnd().

bool RingBuffer::GetStopReads ( void ) const [inline]

Returns value of stopreads.

See also:: StartReads(void), StopReads(void)

Definition at line 43 of file RingBuffer.h.

Referenced by FileTransfer::RequestBlock().

bool RingBuffer::isPaused ( void ) const [inline]

Returns false iff read-ahead is not running and read-ahead is not paused.

Definition at line 46 of file RingBuffer.h.

Referenced by NuppelVideoPlayer::IsPaused(), and TV::TogglePIPView().

long long RingBuffer::GetReadPosition ( void ) const

Returns how far into the file we have read.

Definition at line 1285 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::calcSliderPos(), NuppelDecoder::GetFrame(), NuppelDecoder::OpenFile(), IvtvDecoder::ReadWrite(), FileTransfer::Seek(), and AvFormatDecoder::SeekReset().

long long RingBuffer::GetWritePosition ( void ) const

Returns how far into a ThreadedFileWriter file we have written.

Definition at line 1298 of file RingBuffer.cpp.

Referenced by DTVRecorder::FindH264Keyframes(), TVRec::GetFilePosition(), DTVRecorder::HandleKeyframe(), DVBRecorder::HandleSingleProgramPAT(), DVBRecorder::HandleSingleProgramPMT(), MpegRecorder::ProcessData(), RecorderBase::SavePositionMap(), NuppelVideoRecorder::UpdateSeekTable(), NuppelVideoRecorder::WriteHeader(), NuppelVideoRecorder::WriteKeyFrameAdjustTable(), and NuppelVideoRecorder::WriteSeekTable().

long long RingBuffer::GetRealFileSize ( void ) const

Returns the size of the file we are reading/writing, or -1 if the query fails.

Definition at line 1307 of file RingBuffer.cpp.

Referenced by AVF_Seek(), NuppelVideoRecorder::FinishRecording(), MpegRecorder::FinishRecording(), DTVRecorder::FinishRecording(), AvFormatDecoder::HandleGopStart(), IvtvDecoder::MpegPreProcessPkt(), IvtvDecoder::OpenFile(), AvFormatDecoder::OpenFile(), NuppelVideoRecorder::SetNextRecording(), MpegRecorder::SetNextRecording(), and DTVRecorder::SetNextRecording().

uint RingBuffer::GetBitrate ( void ) const

Returns effective bits per second (in thousands).

NOTE: This is reported in telecom kilobytes, to get the bits per second multiply by 1000, not 1024.

Definition at line 498 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::IsReallyNearEnd().

uint RingBuffer::GetReadBlockSize ( void ) const

Returns size of each disk read made by read ahead thread (in bytes).

Definition at line 508 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::IsReallyNearEnd().

bool RingBuffer::IsOpen ( void ) const

Returns true if the file is open for either reading or writing.

Definition at line 299 of file RingBuffer.cpp.

Referenced by NuppelVideoRecorder::CreateNuppelFile(), PreviewGenerator::GetScreenGrab(), TV::HandleStateChange(), NuppelVideoRecorder::Initialize(), FileTransfer::isOpen(), NuppelVideoPlayer::JumpToProgram(), NuppelVideoPlayer::OpenFile(), PlaybackBox::startPlayer(), NuppelVideoPlayer::SwitchToProgram(), and TVRec::TuningNewRecorder().

void RingBuffer::OpenFile	(	const QString &	lfilename,
		uint	retryCount = `12`
	)

Opens a file for reading.

Parameters:

	lfilename	Name of file to read
	retryCount	How often to retry reading the file before giving up

Definition at line 151 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::JumpToProgram(), RingBuffer(), and NuppelVideoPlayer::SwitchToProgram().

int RingBuffer::Read	(	void *	buf,
		int	count
	)

This is the public method for reading from a file, it calls the appropriate read method if the file is remote or buffered, or a DVD.

Parameters:

	buf	Pointer to where data will be written
	count	Number of bytes to read

Returns:: Returns number of bytes read

Definition at line 1077 of file RingBuffer.cpp.

Referenced by AVF_Read(), NuppelDecoder::GetFrame(), NuppelDecoder::OpenFile(), Peek(), NuppelDecoder::ReadFileheader(), NuppelDecoder::ReadFrameheader(), IvtvDecoder::ReadWrite(), and FileTransfer::RequestBlock().

int RingBuffer::Peek	(	void *	buf,
		int	count
	)

Definition at line 911 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::OpenFile().

void RingBuffer::Reset	(	bool	full = `false`,
		bool	toAdjust = `false`,
		bool	resetInternal = `false`
	)

Resets the read-ahead thread and our position in the file.

Definition at line 361 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::FileChangedCallback(), NuppelVideoPlayer::JumpToProgram(), and NuppelVideoPlayer::SwitchToProgram().

long long RingBuffer::Seek	(	long long	pos,
		int	whence
	)

Seeks to a particular position in the file.

Definition at line 1180 of file RingBuffer.cpp.

Referenced by AVF_Seek(), DecoderBase::DoFastForwardSeek(), DecoderBase::DoRewindSeek(), NuppelDecoder::GetFrame(), NuppelDecoder::OpenFile(), AvFormatDecoder::OpenFile(), Peek(), FileTransfer::Seek(), and TV::SwapPIP().

void RingBuffer::Pause ( void )

Pauses the read-ahead thread.

Calls StopReads(void).

See also:: Unpause(void), WaitForPause(void)

Definition at line 671 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::FileChangedCallback(), NuppelVideoPlayer::JumpToProgram(), PlaybackBox::killPlayer(), NuppelVideoPlayer::Pause(), ReadFromBuf(), TV::StopStuff(), TV::SwapPIP(), TV::SwitchCards(), NuppelVideoPlayer::SwitchToProgram(), and TV::TogglePIPView().

void RingBuffer::Unpause ( void )

Unpauses the read-ahead thread.

Calls StartReads(void).

See also:: Pause(void)

Definition at line 681 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::FileChangedCallback(), NuppelVideoPlayer::JumpToProgram(), NuppelVideoPlayer::OpenFile(), NuppelVideoPlayer::Play(), ReadFromBuf(), TV::SwapPIP(), and NuppelVideoPlayer::SwitchToProgram().

void RingBuffer::WaitForPause ( void )

Waits for Pause(void) to take effect.

Definition at line 690 of file RingBuffer.cpp.

Referenced by TV::DoPause(), NuppelVideoPlayer::FileChangedCallback(), NuppelVideoPlayer::JumpToProgram(), ReadFromBuf(), TV::StopStuff(), TV::SwapPIP(), TV::SwitchCards(), and NuppelVideoPlayer::SwitchToProgram().

void RingBuffer::Start ( void )

Starts the read-ahead thread.

If this RingBuffer is not in write-mode, the RingBuffer constructor was called with a usereadahead of true, and the read-ahead thread is not already running.

Definition at line 352 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::OpenFile().

void RingBuffer::StopReads ( void )

????

See also:: StartReads(void), Pause(void)

Definition at line 652 of file RingBuffer.cpp.

Referenced by Pause(), FileTransfer::Pause(), TV::PauseLiveTV(), FileTransfer::Stop(), TV::StopStuff(), TV::SwitchCards(), TVRec::TeardownRecorder(), and TV::TogglePIPView().

void RingBuffer::StartReads ( void )

????

See also:: StopReads(void), Unpause(void)

Definition at line 662 of file RingBuffer.cpp.

Referenced by TV::PauseLiveTV(), Unpause(), and FileTransfer::Unpause().

bool RingBuffer::LiveMode ( void ) const

Returns true if this RingBuffer has been assigned a LiveTVChain.

See also:: SetLiveMode(LiveTVChain*)

Definition at line 1322 of file RingBuffer.cpp.

Referenced by NuppelDecoder::GetFrame(), AvFormatDecoder::InitByteContext(), NuppelVideoRecorder::Initialize(), and NuppelVideoPlayer::OpenFile().

void RingBuffer::SetLiveMode ( LiveTVChain * chain )

Assigns a LiveTVChain to this RingBuffer.

See also:: LiveMode(void)

Definition at line 1331 of file RingBuffer.cpp.

Referenced by TV::HandleStateChange(), TV::SwitchCards(), and TV::TogglePIPView().

void RingBuffer::IgnoreLiveEOF ( bool ignore ) [inline]

Tells RingBuffer whether to igonre the end-of-file.

Definition at line 81 of file RingBuffer.h.

Referenced by NuppelVideoPlayer::JumpToProgram(), TV::PauseLiveTV(), TV::SwitchCards(), and TV::UnpauseLiveTV().

int RingBuffer::Write	(	const void *	buf,
		uint	count
	)

Writes buffer to ThreadedFileWriter::Write(const void*,uint).

Returns:: Bytes written, or -1 on error.

Definition at line 1147 of file RingBuffer.cpp.

Referenced by AVF_Write(), DVBRecorder::BufferedWrite(), DTVRecorder::BufferedWrite(), DTVRecorder::FinishRecording(), MpegRecorder::ProcessData(), NuppelVideoRecorder::WriteAudio(), NuppelVideoRecorder::WriteFileHeader(), NuppelVideoRecorder::WriteFrameheader(), NuppelVideoRecorder::WriteHeader(), NuppelVideoRecorder::WriteKeyFrameAdjustTable(), NuppelVideoRecorder::WriteSeekTable(), NuppelDecoder::WriteStoredData(), NuppelVideoRecorder::WriteText(), and NuppelVideoRecorder::WriteVideo().

bool RingBuffer::IsIOBound ( void ) const

Returns true if a RingBuffer::Read(void*,int) is likely to block.

Definition at line 1122 of file RingBuffer.cpp.

Referenced by NuppelVideoRecorder::WriteVideo().

void RingBuffer::WriterFlush ( void )

Calls ThreadedFileWriter::Flush(void) and ThreadedFileWriter::Sync(void).

Definition at line 1257 of file RingBuffer.cpp.

Referenced by NuppelVideoRecorder::FinishRecording(), MpegRecorder::FinishRecording(), DTVRecorder::FinishRecording(), NuppelVideoRecorder::SetNextRecording(), MpegRecorder::SetNextRecording(), and DTVRecorder::SetNextRecording().

void RingBuffer::Sync ( void )

Calls ThreadedFileWriter::Sync(void).

Definition at line 1171 of file RingBuffer.cpp.

long long RingBuffer::WriterSeek	(	long long	pos,
		int	whence
	)

Calls ThreadedFileWriter::Seek(long long,int).

Definition at line 1240 of file RingBuffer.cpp.

Referenced by NuppelVideoRecorder::WriteKeyFrameAdjustTable(), and NuppelVideoRecorder::WriteSeekTable().

bool RingBuffer::isDVD ( void ) const [inline]

Returns true if this is a DVD backed RingBuffer.

Definition at line 92 of file RingBuffer.h.

DVDRingBufferPriv* RingBuffer::DVD ( ) [inline]

Definition at line 93 of file RingBuffer.h.

bool RingBuffer::InDVDMenuOrStillFrame ( void )

long long RingBuffer::SetAdjustFilesize ( void )

Definition at line 905 of file RingBuffer.cpp.

Referenced by NuppelVideoPlayer::SwitchToProgram().

void RingBuffer::SetTimeout ( bool fast ) [inline]

Definition at line 97 of file RingBuffer.h.

Referenced by FileTransfer::SetTimeout().

void * RingBuffer::StartReader ( void * type ) [static, protected]

Thunk that calls ReadAheadThread(void).

Definition at line 706 of file RingBuffer.cpp.

Referenced by StartupReadAheadThread().

void RingBuffer::ReadAheadThread ( void ) [protected]

Read-ahead run function.

Definition at line 716 of file RingBuffer.cpp.

Referenced by StartReader().

void RingBuffer::CalcReadAheadThresh ( void ) [private]

Calculates fill_min, fill_threshold, and readblocksize from the estimated effective bitrate of the stream.

Definition at line 529 of file RingBuffer.cpp.

Referenced by OpenFile(), UpdatePlaySpeed(), and UpdateRawBitrate().

int RingBuffer::safe_read_dvd	(	void *	data,
		uint	sz
	)			`[private]`

int RingBuffer::safe_read	(	int	fd,
		void *	data,
		uint	sz
	)			`[private]`

Reads data from the file-descriptor.

This will re-read the file forever until the end-of-file is reached or the buffer is full.

Parameters:

	fd	File descriptor to read from
	data	Pointer to where data will be written
	sz	Number of bytes to read

Returns:: Returns number of bytes read

Definition at line 394 of file RingBuffer.cpp.

Referenced by Read(), and ReadAheadThread().

int RingBuffer::safe_read	(	RemoteFile *	rf,
		void *	data,
		uint	sz
	)			`[private]`

Reads data from the RemoteFile.

Parameters:

	rf	RemoteFile to read from
	data	Pointer to where data will be written
	sz	Number of bytes to read

Returns:: Returns number of bytes read

Definition at line 462 of file RingBuffer.cpp.

int RingBuffer::ReadFromBuf	(	void *	buf,
		int	count,
		bool	peek = `false`
	)			`[private]`

Reads from the read-ahead buffer, this is called by Read(void*, int) when the read-ahead thread is running.

Parameters:

	buf	Pointer to where data will be written
	count	Number of bytes to read
	peek	If true, don't increment read count

Returns:: Returns number of bytes read

Definition at line 932 of file RingBuffer.cpp.

Referenced by Peek(), and Read().

int RingBuffer::ReadBufFree ( void ) const [private]

Returns number of bytes available for reading into buffer.

Definition at line 581 of file RingBuffer.cpp.

Referenced by ReadAheadThread().

int RingBuffer::ReadBufAvail ( void ) const [private]

Returns number of bytes available for reading from buffer.

Definition at line 590 of file RingBuffer.cpp.

Referenced by ReadFromBuf().

void RingBuffer::StartupReadAheadThread ( void ) [private]

Creates the read-ahead thread, and waits for it to start.

See also:: Start(void).

Definition at line 626 of file RingBuffer.cpp.

Referenced by ReadFromBuf(), and Start().

void RingBuffer::ResetReadAhead ( long long newinternal ) [private]

Restart the read-ahead threat at the 'newinternal' position.

This is called after a Seek(long long, int) so that the read-ahead buffer doesn't contain any stale data, and so that it will read any new data from the new position in the file.

WARNING: Must be called with rwlock in write lock state.

Parameters:

newinternal

Position in file to start reading data from

Definition at line 608 of file RingBuffer.cpp.

Referenced by ReadAheadThread(), Reset(), and Seek().

void RingBuffer::KillReadAheadThread ( void ) [private]

Stops the read-ahead thread, and waits for it to stop.

Definition at line 639 of file RingBuffer.cpp.

Referenced by ReadFromBuf(), and ~RingBuffer().