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Use ring buffer and semaphore #87

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1bee723
Use ring buffer and semaphore to eliminate busy wait in sniffer tool.
Locke Oct 2, 2016
63a7dcf
add RCSwitchEnableBlockingReceive flag
Locke Oct 2, 2016
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41 changes: 41 additions & 0 deletions RCSwitch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,13 @@ const unsigned int RCSwitch::nSeparationLimit = 4600;
// according to discussion on issue #14 it might be more suitable to set the separation
// limit to the same time as the 'low' part of the sync signal for the current protocol.
unsigned int RCSwitch::timings[RCSWITCH_MAX_CHANGES];

#if defined( RCSwitchEnableBlockingReceive )
unsigned long RCSwitch::events[RCSWITCH_MAX_EVENTS];
int RCSwitch::eventsHead = 0;
int RCSwitch::eventsTail = 0;
sem_t RCSwitch::eventSem;
#endif
#endif

RCSwitch::RCSwitch() {
Expand All @@ -106,6 +113,10 @@ RCSwitch::RCSwitch() {
this->nReceiverInterrupt = -1;
this->setReceiveTolerance(60);
RCSwitch::nReceivedValue = 0;

#if defined( RCSwitchEnableBlockingReceive )
::sem_init(&eventSem, 0, 0);
#endif
#endif
}

Expand Down Expand Up @@ -647,6 +658,10 @@ bool RECEIVE_ATTR RCSwitch::receiveProtocol(const int p, unsigned int changeCoun
RCSwitch::nReceivedBitlength = (changeCount - 1) / 2;
RCSwitch::nReceivedDelay = delay;
RCSwitch::nReceivedProtocol = p;

#if defined( RCSwitchEnableBlockingReceive )
RCSwitch::pushEvent(code);
#endif
}

return true;
Expand Down Expand Up @@ -693,4 +708,30 @@ void RECEIVE_ATTR RCSwitch::handleInterrupt() {
RCSwitch::timings[changeCount++] = duration;
lastTime = time;
}

#if defined( RCSwitchEnableBlockingReceive )
/**
* Pushes an event onto the end of the events ring.
*/
void RCSwitch::pushEvent(unsigned long event) {
RCSwitch::events[RCSwitch::eventsTail++] = event;
if (RCSwitch::eventsTail >= RCSWITCH_MAX_EVENTS) {
RCSwitch::eventsTail = 0;
}
::sem_post(&eventSem);
}

/**
* Blocks until the events ring contains at least one event then pops
* an event from the head of the events ring and returns it.
*/
unsigned long RCSwitch::popEvent() {
::sem_wait(&eventSem);
unsigned long event = RCSwitch::events[RCSwitch::eventsHead++];
if (RCSwitch::eventsHead >= RCSWITCH_MAX_EVENTS) {
RCSwitch::eventsHead = 0;
}
return event;
}
#endif
#endif
24 changes: 23 additions & 1 deletion RCSwitch.h
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,11 @@
#include <string.h> /* memcpy */
#include <stdlib.h> /* abs */
#include <wiringPi.h>

#if not defined ( RCSwitchDisableReceiving )
#define RCSwitchEnableBlockingReceive
#include <semaphore.h>
#endif
#else
#include "WProgram.h"
#endif
Expand All @@ -51,13 +56,17 @@
// At least for the ATTiny X4/X5, receiving has to be disabled due to
// missing libm depencies (udivmodhi4)
#if defined( __AVR_ATtinyX5__ ) or defined ( __AVR_ATtinyX4__ )
#define RCSwitchDisableReceiving
#define RCSwitchDisableReceiving
#endif

// Number of maximum High/Low changes per packet.
// We can handle up to (unsigned long) => 32 bit * 2 H/L changes per bit + 2 for sync
#define RCSWITCH_MAX_CHANGES 67

#if defined( RCSwitchEnableBlockingReceive )
#define RCSWITCH_MAX_EVENTS 100
#endif

class RCSwitch {

public:
Expand Down Expand Up @@ -85,6 +94,10 @@ class RCSwitch {
bool available();
void resetAvailable();

#if defined( RCSwitchEnableBlockingReceive )
unsigned long popEvent();
#endif

unsigned long getReceivedValue();
unsigned int getReceivedBitlength();
unsigned int getReceivedDelay();
Expand Down Expand Up @@ -146,6 +159,15 @@ class RCSwitch {
* timings[0] contains sync timing, followed by a number of bits
*/
static unsigned int timings[RCSWITCH_MAX_CHANGES];

#if defined( RCSwitchEnableBlockingReceive )
static void pushEvent(unsigned long);

static unsigned long events[RCSWITCH_MAX_EVENTS];
static int eventsHead;
static int eventsTail;
static sem_t eventSem;
#endif
#endif


Expand Down