mirror of https://github.com/ARMmbed/mbed-os.git
				
				
				
			
		
			
				
	
	
		
			128 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
			
		
		
	
	
			128 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
/* mbed Microcontroller Library
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 * Copyright (c) 2006-2019 ARM Limited
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 * SPDX-License-Identifier: Apache-2.0
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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#ifndef MBED_TIMEOUT_H
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#define MBED_TIMEOUT_H
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#include "drivers/HighResClock.h"
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#include "drivers/Ticker.h"
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namespace mbed {
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/**
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 * \defgroup drivers_Timeout Timeout class
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 * \ingroup drivers-public-api-ticker
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 * @{
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 */
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/** A Timeout is used to call a function at a point in the future
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 *
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 * You can use as many separate Timeout objects as you require.
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 *
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 * @note Synchronization level: Interrupt safe
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 *
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 * Example:
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 * @code
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 * // Blink until timeout.
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 *
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 * #include "mbed.h"
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 *
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 * Timeout timeout;
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 * DigitalOut led(LED1);
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 *
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 * int on = 1;
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 *
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 * void attimeout() {
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 *     on = 0;
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 * }
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 *
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 * int main() {
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 *     timeout.attach(&attimeout, 5);
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 *     while(on) {
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 *         led = !led;
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 *         ThisThread::sleep_for(200);
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 *     }
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 * }
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 * @endcode
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 */
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class TimeoutBase : public TickerBase {
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public:
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    /** Return time remaining until callback
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     *
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     * @return time remaining until callback is due
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     *
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     * @note if the callback is overdue, or has already run, the returned value will be negative
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     */
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    std::chrono::microseconds remaining_time() const
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    {
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        return scheduled_time() - _ticker_data.now();
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    }
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#if !defined(DOXYGEN_ONLY)
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protected:
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    using TickerBase::TickerBase;
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    ~TimeoutBase() = default;
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    void handler() final;
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    /** Return scheduled callback time
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     *
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     * @return scheduled callback time
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     *
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     * @note if the callback is overdue, or has already run, the returned value will be in the past
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     */
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    TickerDataClock::time_point scheduled_time() const
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    {
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        return get_time_point(event);
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    }
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#endif
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};
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class Timeout : public TimeoutBase {
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public:
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    Timeout();
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    /** Clock to use with attach_absolute, guaranteeing running only while attached or manually locked */
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    using clock = HighResClock;
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    /** @copydoc TimeoutBase::scheduled_time() */
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    HighResClock::time_point scheduled_time() const
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    {
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        /* Massage from virtual TickerDataClock::time_point used internally to true HighResClock::time_point */
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        return HighResClock::time_point{TimeoutBase::scheduled_time().time_since_epoch()};
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    }
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    /** Attach a function to be called by the Timeout, specifying the absolute time
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     *
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     *  @param func pointer to the function to be called
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     *  @param abs_time the absolute time for the call, referenced to HighResClock
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     *
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     *  @note setting @a abs_time to a time in the past means the event will be scheduled immediately
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     *  resulting in an instant call to the function.
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     */
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    template <class F>
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    void attach_absolute(F &&func, HighResClock::time_point abs_time)
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    {
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        /* Massage from true HighResClock::time_point to virtual TickerDataClock::time_point used internally */
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        TimeoutBase::attach_absolute(std::forward<F>(func), TickerDataClock::time_point{abs_time.time_since_epoch()});
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    }
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};
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/** @}*/
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} // namespace mbed
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#endif
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