PAdaptiveDelay Class Reference

Class for implementing an "adaptive" delay. More...

#include <delaychan.h>

Inheritance diagram for PAdaptiveDelay:

Collaboration diagram for PAdaptiveDelay:

Public Member Functions
Construction
	PAdaptiveDelay (unsigned maximumSlip=0, unsigned minimumDelay=0)
	Create a new adaptive delay with the specified parameters. More...
Operating Parameters
void	SetMaximumSlip (unsigned maximumSlip)
	Set the number of milliseconds that the delay may "catch up" by using zero delays. More...
PTimeInterval	GetMaximumSlip () const
	Get the current slip time. More...
Functionality
PBoolean	Delay (int time)
	Wait until the specified number of milliseconds have elapsed from the previous call (on average). More...
void	Restart ()
	Invalidate the timer. More...
Public Member Functions inherited from PObject
unsigned	GetTraceContextIdentifier () const
	Get PTRACE context identifier. More...
void	SetTraceContextIdentifier (unsigned id)
void	GetTraceContextIdentifier (PObject &obj)
void	GetTraceContextIdentifier (PObject *obj)
void	SetTraceContextIdentifier (const PObject &obj)
void	SetTraceContextIdentifier (const PObject *obj)
virtual	~PObject ()
virtual PObject *	Clone () const
	Create a copy of the class on the heap. More...
template<class CLS >
CLS *	CloneAs () const
	As for Clone() but converts to specified type. More...
virtual PINDEX	HashFunction () const
	This function yields a hash value required by the PDictionary class. More...
virtual Comparison	Compare (const PObject &obj) const
	Compare the two objects and return their relative rank. More...
virtual Comparison	CompareObjectMemoryDirect (const PObject &obj) const
	Determine the byte wise comparison of two objects. More...
bool	operator== (const PObject &obj) const
	Compare the two objects. More...
bool	operator!= (const PObject &obj) const
	Compare the two objects. More...
bool	operator< (const PObject &obj) const
	Compare the two objects. More...
bool	operator> (const PObject &obj) const
	Compare the two objects. More...
bool	operator<= (const PObject &obj) const
	Compare the two objects. More...
bool	operator>= (const PObject &obj) const
	Compare the two objects. More...
virtual const char *	GetClass (unsigned ancestor=0) const
	Get the current dynamic type of the object instance. More...
PBoolean	IsClass (const char *cls) const
virtual PBoolean	InternalIsDescendant (const char *clsName) const
	Determine if the dynamic type of the current instance is a descendent of the specified class. More...
__inline const PObject *	PTraceObjectInstance () const
virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...
virtual void	ReadFrom (istream &strm)
	Input the contents of the object from the stream. More...

Protected Attributes
PTimeInterval	m_jitterLimit
PTimeInterval	m_minimumDelay
PTime	m_targetTime
bool	m_firstTime
Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

Additional Inherited Members
Public Types inherited from PObject
enum	Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
	Result of the comparison operation performed by the Compare() function. More...
Static Public Member Functions inherited from PObject
static Comparison	InternalCompareObjectMemoryDirect (const PObject *obj1, const PObject *obj2, PINDEX size)
	Internal function caled from CompareObjectMemoryDirect() More...
static const char *	Class ()
	Get the name of the class as a C string. More...
static __inline const PObject *	PTraceObjectInstance (const char *)
static __inline const PObject *	PTraceObjectInstance (const PObject *obj)
Protected Member Functions inherited from PObject
	PObject ()
	Constructor for PObject, made protected so cannot ever create one on its own. More...
Friends inherited from PObject

Detailed Description

Class for implementing an "adaptive" delay.

This class will cause the the caller to, on average, delay the specified number of milliseconds between calls. This can be used to simulate hardware timing for a sofwtare only device

Constructor & Destructor Documentation

PAdaptiveDelay::PAdaptiveDelay	(	unsigned	maximumSlip = 0,
		unsigned	minimumDelay = 0
	)

Create a new adaptive delay with the specified parameters.

The maximum slip time can also be set later using SetMaximumSlip.

Parameters

maximumSlip	Maximum slip time in milliseconds
minimumDelay	Minimum delay (usually OS time slice)

Member Function Documentation

PBoolean PAdaptiveDelay::Delay

(

int

time

)

Wait until the specified number of milliseconds have elapsed from the previous call (on average).

The first time the function is called, no delay occurs. If the maximum slip time is set and the caller is "too late", the timer is restarted automatically and no delay occurs.

If the calculated delay is less than the OS timer resolution specified on costruction, no delay occurs now ("better sooner than later" strategy).

Returns

true if we are "too late" of time milliseconds (unrelated to the maximum slip time).

PTimeInterval PAdaptiveDelay::GetMaximumSlip ( ) const

inline

Get the current slip time.

References m_jitterLimit.

void PAdaptiveDelay::Restart

(

)

Invalidate the timer.

The timing of this function call is not important, the timer will restart at the next call to Delay().

void PAdaptiveDelay::SetMaximumSlip ( unsigned  maximumSlip )

inline

Set the number of milliseconds that the delay may "catch up" by using zero delays.

This is caused by the Delay() function not being called for a time by external factors.

If maximumSlip is 0, this feature is disabled.

References m_jitterLimit.

Member Data Documentation

bool PAdaptiveDelay::m_firstTime

protected

PTimeInterval PAdaptiveDelay::m_jitterLimit

protected

Referenced by GetMaximumSlip(), and SetMaximumSlip().

PTimeInterval PAdaptiveDelay::m_minimumDelay

protected

PTime PAdaptiveDelay::m_targetTime

protected

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

• delaychan.h