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| -rw-r--r-- | include/canvas/elapsedtime.hxx | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/include/canvas/elapsedtime.hxx b/include/canvas/elapsedtime.hxx new file mode 100644 index 000000000..cf73af960 --- /dev/null +++ b/include/canvas/elapsedtime.hxx @@ -0,0 +1,163 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ + +#ifndef INCLUDED_CANVAS_ELAPSEDTIME_HXX +#define INCLUDED_CANVAS_ELAPSEDTIME_HXX + +#include <canvas/canvastoolsdllapi.h> +#include <memory> + +namespace canvas::tools +{ + /** Calculate elapsed time. + + This class provides several time-measurement and + -management functions. In its simplest use-case, it + measures the time from its creation. + */ + class CANVASTOOLS_DLLPUBLIC ElapsedTime + { + public: + /** Create a new ElapsedTime object + + The moment of construction starts the time + measurement. That means, a subsequent getElapsedTime() + call will return the time difference between object + creation and getElapsedTime() call. + */ + ElapsedTime(); + + /** Creates a new ElapsedTime object based on another + timer. + + The moment of construction starts the time + measurement. That means, a subsequent getElapsedTime() + call will return the time difference between object + creation and getElapsedTime() call. All time values + are not taken from the system's time base, but from + the provided timer. + */ + ElapsedTime( std::shared_ptr<ElapsedTime> xTimeBase ); + + /** Reset the time + + The instance of the reset() call starts the time + measurement from scratch. That means, a subsequent + getElapsedTime() call will return the time difference + between reset() and getElapsedTime() call. + */ + void reset(); + + /** Query the elapsed time + + This method returns the elapsed time in seconds + between either the construction of this object, or the + last reset() call, if any (but see the time modulation + methods below, for means to modify the otherwise + continuous flow of time). + + @return the elapsed time in seconds. + */ + double getElapsedTime() const; + + /** Pauses the running timer. + + This method stops the time, as returned by this + object, until continueTimer() is called. During this + period, getElapsedTime() will always return the same + time value (i.e. the instant when pauseTimer() was + called). + */ + void pauseTimer(); + + /** Continues the paused timer. + + This method re-enables the time flow, that is, time + starts running again for clients calling + getElapsedTime(). The (subtle) difference to the + holdTimer/releaseTimer() methods below is, that there + is no perceived time 'jump' between the pauseTimer() + call and the continueTimer() call, i.e. the time + starts over with the same value it has stopped on + pauseTimer(). + */ + void continueTimer(); + + /** Adjusts the timer, hold and pause times. + + This method modifies the time as returned by this + object by the specified amount. This affects the time + as returned by getElapsedTime(), regardless of the + mode (e.g. paused, or on hold). + + @param fOffset + This value will be added to the current time, i.e. the + next call to getElapsedTime() (when performed + immediately) will be adjusted by fOffset. + */ + void adjustTimer( double fOffset ); + + /** Holds the current time. + + This call makes the timer hold the current time + (e.g. getElapsedTime() will return the time when + holdTimer() was called), while the underlying time is + running on. When releaseTimer() is called, the time + will 'jump' to the then-current, underlying time. This + is equivalent to pressing the "interim time" button on + a stop watch, which shows this stopped time, while the + clock keeps running internally. + */ + void holdTimer(); + + /** Releases a held timer. + + After this call, the timer again returns the running + time on getElapsedTime(). + */ + void releaseTimer(); + + private: + static double getSystemTime(); + double getCurrentTime() const; + double getElapsedTimeImpl() const; // does not set m_fLastQueriedTime + + const std::shared_ptr<ElapsedTime> m_pTimeBase; + + /// To validate adjustTimer() calls with bLimitToLastQueriedTime=true + mutable double m_fLastQueriedTime; + + /// Start time, from which the difference to the time base is returned + double m_fStartTime; + + /// Instant, when last pause or hold started, relative to m_fStartTime + double m_fFrozenTime; + + /// True, when in pause mode + bool m_bInPauseMode; + + /// True, when in hold mode + bool m_bInHoldMode; + }; + +} + +#endif /* INCLUDED_CANVAS_ELAPSEDTIME_HXX */ + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |