MeterUpdateQueue Class Reference

Queue of MeterUpdateMsg used to feed the MeterPanel. More...

#include <MeterPanel.h>

Collaboration diagram for MeterUpdateQueue:

Public Member Functions
	MeterUpdateQueue (size_t maxLen)
	~MeterUpdateQueue ()
bool	Put (MeterUpdateMsg &msg)
bool	Get (MeterUpdateMsg &msg)
void	Clear ()

Private Attributes
NonInterfering< std::atomic< size_t > >	mStart { 0 }
NonInterfering< std::atomic< size_t > >	mEnd { 0 }
const size_t	mBufferSize
ArrayOf< MeterUpdateMsg >	mBuffer {mBufferSize}

Detailed Description

Queue of MeterUpdateMsg used to feed the MeterPanel.

Definition at line 75 of file MeterPanel.h.

Constructor & Destructor Documentation

MeterUpdateQueue()

MeterUpdateQueue::MeterUpdateQueue ( size_t  maxLen )

explicit

Definition at line 192 of file MeterPanel.cpp.

                                               :
   mBufferSize(maxLen)
{
   Clear();
}

References Clear().

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~MeterUpdateQueue()

MeterUpdateQueue::~MeterUpdateQueue

(

)

Definition at line 199 of file MeterPanel.cpp.

{
}

Member Function Documentation

Clear()

void MeterUpdateQueue::Clear

(

)

Definition at line 203 of file MeterPanel.cpp.

{
   mStart.store(0);
   mEnd.store(0);
}

References mEnd, and mStart.

Referenced by MeterPanel::Clear(), MeterUpdateQueue(), MeterPanel::OnMeterUpdate(), and MeterPanel::Reset().

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Get()

bool MeterUpdateQueue::Get

(

MeterUpdateMsg &

msg

)

Definition at line 234 of file MeterPanel.cpp.

{
   auto start = mStart.load(std::memory_order_relaxed);
   auto end = mEnd.load(std::memory_order_acquire);
   int len = (end + mBufferSize - start) % mBufferSize;
 
   if (len == 0)
      return false;
 
   msg = mBuffer[start];
   mStart.store((start + 1) % mBufferSize, std::memory_order_release);
 
   return true;
}

References PackedArray::end(), mBuffer, mBufferSize, mEnd, and mStart.

Referenced by MeterPanel::OnMeterUpdate().

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Put()

bool MeterUpdateQueue::Put

(

MeterUpdateMsg &

msg

)

Definition at line 211 of file MeterPanel.cpp.

{
   auto start = mStart.load(std::memory_order_acquire);
   auto end = mEnd.load(std::memory_order_relaxed);
   // mStart can be greater than mEnd because it is all mod mBufferSize
   assert( (end + mBufferSize - start) >= 0 );
   int len = (end + mBufferSize - start) % mBufferSize;
 
   // Never completely fill the queue, because then the
   // state is ambiguous (mStart==mEnd)
   if (len + 1 >= (int)(mBufferSize))
      return false;
 
   //wxLogDebug(wxT("Put: %s"), msg.toString());
 
   mBuffer[end] = msg;
   mEnd.store((end + 1) % mBufferSize, std::memory_order_release);
 
   return true;
}

References PackedArray::end(), mBuffer, mBufferSize, mEnd, and mStart.

Referenced by MeterPanel::UpdateDisplay().

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Member Data Documentation

mBuffer

ArrayOf<MeterUpdateMsg> MeterUpdateQueue::mBuffer {mBufferSize}

private

Definition at line 92 of file MeterPanel.h.

Referenced by Get(), and Put().

mBufferSize

const size_t MeterUpdateQueue::mBufferSize

private

Definition at line 91 of file MeterPanel.h.

Referenced by Get(), and Put().

mEnd

NonInterfering< std::atomic<size_t> > MeterUpdateQueue::mEnd { 0 }

private

Definition at line 89 of file MeterPanel.h.

Referenced by Clear(), Get(), and Put().

mStart

NonInterfering< std::atomic<size_t> > MeterUpdateQueue::mStart { 0 }

private

Definition at line 89 of file MeterPanel.h.

Referenced by Clear(), Get(), and Put().

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

• MeterPanel.h
• MeterPanel.cpp