123 lines
2.6 KiB
C++
123 lines
2.6 KiB
C++
#ifndef headerfilestopcalculating
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#define headerfilestopcalculating
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/*!
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\file stopcalculating.h
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\brief it tells us whether there was a stop signal or not
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*/
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#include <ttmath/ttmathtypes.h>
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#include <windows.h>
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/*!
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\brief it tells us whether there was a stop signal or not
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we can pass a pointer to the object of this class to the certain
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calculating methods especially for the method which calculates the
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Factorial (1*2*3*4....), such methods as the Factorial takes a lot of time
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and sometimes we want to break the calculations for example when we've got
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a new input string
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those methods which take a lot of time check the object of type NewStopCalculating
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and if there was a stop signal they stop and return immediately without returning
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a correct result
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the stop signal can be caused by another thread in our case by the first (gui) thread
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there'll be only one object of this class
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(it'll be as an variable of ThreadController class)
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*/
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class NewStopCalculating : public ttmath::StopCalculating
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{
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public:
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/*!
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the constructor
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*/
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NewStopCalculating()
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{
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stop = 0;
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}
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/*!
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the destructor
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*/
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~NewStopCalculating()
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{
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if(stop) CloseHandle(stop);
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}
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/*!
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it initializes an object of this class
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this method will be called from Init() of the ThreadController object
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*/
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bool Init() volatile
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{
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char buffer[80];
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// with 'GetTickCount()' we're generating an unique identifier of our event
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// (there can be another window of ttcalc)
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sprintf(buffer,"TTCalcStopEventForStoppingCalculations7756%u",
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(unsigned int)GetTickCount());
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// 'stop' will be manual-reseted and initialized as non-signaled
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if( (stop = CreateEvent(0,true,false,buffer))==NULL)
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return false;
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return true;
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}
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/*!
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when we want to stop the calculations for example when the user changed somewhat
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we call the Stop() method from the first (gui) thread
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*/
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void Stop() volatile
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{
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SetEvent(stop);
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}
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/*!
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when we start the calculations we call this method
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(we call it from WaitForCalculatingAndBlockForStop() method of
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ThreadController class)
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*/
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void Start() volatile
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{
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ResetEvent(stop);
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}
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/*!
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it returns 'true' if there was a stop signal
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it's useful for the second thread and functions which take plenty of time
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for calculating, when this method returns 'true' those methods break the
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calculations and return without returning a correct value
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*/
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virtual bool WasStopSignal() const volatile
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{
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if( WaitForSingleObject(stop,0) == WAIT_OBJECT_0 )
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return true;
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return false;
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}
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private:
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// manual-reset, initialized as non-signaled
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HANDLE stop;
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};
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#endif
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