86 lines
1.8 KiB
C++
86 lines
1.8 KiB
C++
#ifndef __CPP_TIMER_H_
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#define __CPP_TIMER_H_
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/**
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* GNU GENERAL PUBLIC LICENSE
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* Version 3, 29 June 2007
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*
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* (C) 2020, Bernd Porr <mail@bernporr.me.uk>
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*
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* This is inspired by the timer_create man page.
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**/
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <signal.h>
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#include <time.h>
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#include <functional>
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#include <atomic>
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#define CLOCKID CLOCK_MONOTONIC
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#define SIG SIGRTMIN
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/**
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* Timer class which repeatedly fires. It's wrapper around the
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* POSIX per-process timer.
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**/
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class CppTimer {
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public:
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static constexpr int PERIODIC = 0;
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static constexpr int ONESHOT = 1;
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static constexpr long MS_TO_NS = 1000000;
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/**
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* Creates an instance of the timer and connects the
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* signal handler to the timer.
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**/
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CppTimer();
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/**
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* Starts the timer. The timer fires first after
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* the specified time in nanoseconds and then at
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* that interval in PERIODIC mode. In ONESHOT mode
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* the timer fires once after the specified time in
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* nanoseconds.
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**/
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virtual void start(long nanosecs, std::function<void()> callbackIn, int type = PERIODIC);
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/**
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* Stops the timer by disarming it. It can be re-started
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* with start().
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**/
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virtual void stop();
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/**
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* Destructor disarms the timer, deletes it and
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* disconnect the signal handler.
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**/
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virtual ~CppTimer();
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bool isRunning();
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void block();
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private:
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timer_t timerid = 0;
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struct sigevent sev;
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struct sigaction sa;
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struct itimerspec its;
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int pipeFd[2];
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std::atomic<bool> running = false;
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std::function<void()> callback;
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void discardPipe();
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static void handler(int sig, siginfo_t *si, void *uc ) {
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CppTimer *timer = reinterpret_cast<CppTimer *> (si->si_value.sival_ptr);
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timer->callback();
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char buf = '\n';
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write(timer->pipeFd[1], &buf, 1);
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timer->running = false;
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}
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};
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#endif
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