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Service loop
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Implemented event manager and text transmission loop.
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@peterkvt80
peterkvt80 committed Aug 20, 2017
1 parent eaadd3c commit a0db713
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Showing 2 changed files with 100 additions and 107 deletions.
189 changes: 85 additions & 104 deletions service.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,10 @@ Service::Service()
}

Service::Service(Configure *configure, PageList *pageList) :
_configure(configure),_pageList(pageList)
_configure(configure),
_pageList(pageList),
_lineCounter(0),
_fieldCounter(0)
{
// @todo Put priority into config and add commands to allow updates.
uint8_t priority[8]={5,3,3,6,3,3,5,9}; // 1=High priority,9=low. Note: priority[0] is mag 8
Expand Down Expand Up @@ -38,119 +41,97 @@ void Service::_register(PacketSource *src)
int Service::run()
{
std::cerr << "[Service::worker]This is the worker process" << std::endl;
uint8_t nmag=1;
vbit::Mag **mag; // Pointer to magazines array
vbit::Mag *pMag; // Pointer to the magazine that we are working on
uint8_t priorityCount[STREAMS]; // Will be handled by the packet sources themselves.

uint8_t hold[STREAMS]; /// If hold is set then the magazine can not be sent until the next field
std::list<vbit::PacketSource*>::const_iterator iterator=_Sources.begin(); // Iterator for packet sources

vbit::Packet* pkt=new vbit::Packet(8,25," "); // This just allocates storage.

uint8_t rowCounter=0; // Counts 16 rows to a field

static vbit::Packet* filler=new vbit::Packet(8,25," "); // @todo Again, we should have a pre-prepared quiet packet to avoid eating the heap


// Initialise the priority counts
/*
for (uint8_t i=0;i<STREAMS-1;i++)
{
hold[i]=0;
priorityCount[i]=priority[i];
}
*/

// Get the magazines
// mag=_pageList->GetMagazines();

std::cerr << "[Service::worker]Loop starts" << std::endl;
while(1) // normal
{
// If counters (or other trigger) causes an event then send the events
// Iterate through the packet sources
// Check if there is a packet available
// If there is then send it
// update the counters.

// Find the next magazine to put out.
// We decrement the priority count for each magazine until one reaches 0.
for (;priorityCount[nmag]>0;nmag=(nmag+1)%(STREAMS-1)) /// @todo Subtitles need stream 8. But we can't access magazine 9
{
priorityCount[nmag]--;
}
pMag=mag[nmag];

// If the magazine has no pages it can be put into hold.
// @todo Subtitles are an exception. They should not have a page but they could be skipped.
if (pMag->GetPageCount()<1)
{
hold[nmag]=true;
priorityCount[nmag]=127; // Slow down this empty stream
}
else
{
if (!hold[nmag]) // Not in hold
{
pMag->GetPacket(pkt); // YEAH. Don't do this!!!!
bool isHeader=false;
if (pkt!=NULL) // How could this be NULL? After the last packet of a page has been sent.
{
isHeader=pMag->GetHeaderFlag(); // pkt->IsHeader();

std::cout.write(pkt->tx(), 42); // Transmit the packet - using cout.write to ensure writing 42 bytes even if it contains a null.

// Was the last packet a header? If so we need to go into hold
if (isHeader)
{
hold[nmag]=true;
// std::cerr << "Header wait mode mag=" << (int) nmag << std::endl;
}
rowCounter++;
if (rowCounter>=16)
{
rowCounter=0;
for (uint8_t i=0;i<STREAMS-1;i++) hold[i]=0; // Any holds are released now
// Should put packet 8/30 stuff here as in vbit stream.c
}
} // not a null packet
else
{
// After a GetPacket returns NULL (after the page runs out of packets)
}
} // not in hold
else
{
// To avoid a deadlock, we check if everything is in hold
bool blocked=true;
for (uint8_t i=0;i<STREAMS-1;i++) // Hold does not include stream 9 (subtitles)
{
if (hold[i]==false)
{
blocked=false;
break;
}
}
if (blocked)
{
std::cout << filler->tx();
// Step the row counter
rowCounter++;
if (rowCounter>=16)
{
rowCounter=0;
for (uint8_t i=0;i<STREAMS;i++) hold[i]=0; // Any holds are released now
}
} // blocked
}
} // page count is positive

// Reset the priority of this magazine
if (priority[nmag]==0)
priority[nmag]=1; // Can't be 0 or that mag will take all the packets
priorityCount[nmag]=priority[nmag]; // Reset the priority for the mag that just went out
_updateEvents(); // Must only call this ONCE per transmitted row

// Iterate through the packet sources until we get a packet to transmit

vbit::PacketSource* p;
do
{
if (iterator==_Sources.end())
{
iterator=_Sources.begin();
// @todo Count iterations here and break out with a filler to prevent a deadlock
}
p=(*iterator);
++iterator;
}
while (!p->IsReady());

p->GetPacket(pkt); // @todo Don't annoy Alistair by putting this bug back in


// Transmit the packet
// @todo Does this code make sense?
if (pkt!=NULL) // How could this be NULL? After the last packet of a page has been sent.
{
std::cout.write(pkt->tx(), 42); // Transmit the packet - using cout.write to ensure writing 42 bytes even if it contains a null.
}
else
{
std::cout << filler->tx();
} // blocked

} // while
return 99; // don't really want to return anything
} // worker


void Service::_updateEvents()
{
// Step the counters
_lineCounter++;
if (_lineCounter%LINESPERFIELD==0)
{
_lineCounter=0;
_fieldCounter++;
if (_fieldCounter>=50)
{
_fieldCounter=0;
// Could implement a seconds counter here if we needed it
}
// New field, so set the FIELD event in all the sources.
for (std::list<vbit::PacketSource*>::const_iterator iterator = _Sources.begin(), end = _Sources.end(); iterator != end; ++iterator)
{
(*iterator)->SetEvent(EVENT_FIELD);
}
// Packet 830?
if (_fieldCounter%10==0)
{
Event ev;
switch (_fieldCounter/10)
{
case 0:
ev=EVENT_P830_FORMAT_1;
break;
case 1:
ev=EVENT_P830_FORMAT_2_LABEL_0;
break;
case 2:
ev=EVENT_P830_FORMAT_2_LABEL_1;
break;
case 3:
ev=EVENT_P830_FORMAT_2_LABEL_2;
break;
case 4:
ev=EVENT_P830_FORMAT_2_LABEL_3;
break;
}
for (std::list<vbit::PacketSource*>::const_iterator iterator = _Sources.begin(), end = _Sources.end(); iterator != end; ++iterator)
{
(*iterator)->SetEvent(ev);
}
}
}
// @todo Subtitle events. Flag when a subtitle is ready to go up
// @todo Databroadcast events. Flag when there is data in the buffer.
}
18 changes: 15 additions & 3 deletions service.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@

/// Eight magazines and subtitles (maybe other packets too)
#define STREAMS 9
/// Strictly these should ODD/EVEN VBI line counts as in general they would be different.
#define LINESPERFIELD 16

namespace ttx
{
Expand Down Expand Up @@ -45,13 +47,23 @@ class Service
*/
int run();
private:
// Member variables
// Member variables that define the service
Configure* _configure; /// Member reference to the configuration settings
PageList* _pageList; /// Member reference to the pages list

// Member variables for event management
uint8_t _lineCounter; // Which VBI line are we on? Used to signal a new field.
uint8_t _fieldCounter; // Which field? Used to time packet 8/30
std::list<vbit::PacketSource*> _Sources; /// A list of packet sources

// Member functions
std::list<vbit::PacketSource*> _Sources;
void _register(vbit::PacketSource *src);
void _register(vbit::PacketSource *src); /// Register packet sources

/**
* @brief Check if anything changed, and if so signal the event to the packet sources.
* Must be called once per transmitted row so that it can maintain a field count
*/
void _updateEvents();

};

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