110 lines
1.9 KiB
C++
110 lines
1.9 KiB
C++
/*++
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Copyright (C) 1996-1999 Microsoft Corporation
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Module Name:
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stepper.cpp
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Abstract:
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Implements time keeping and display in the graph window.
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--*/
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#include "polyline.h"
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CStepper::CStepper()
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{
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m_iPos = 0;
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m_iStepNum = 0;
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m_iStepCnt = 1;
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}
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void CStepper::Init(INT iLength, INT iStepCnt)
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{
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m_iStepCnt = iStepCnt ? iStepCnt : 1;
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m_iStepSize = iLength / m_iStepCnt;
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m_iRemainder = iLength - m_iStepCnt * m_iStepSize;
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m_iState = m_iStepCnt;
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m_iPos = 0;
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m_iStepNum = 0;
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}
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void CStepper::Reset()
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{
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m_iPos = 0;
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m_iStepNum = 0;
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m_iState = m_iStepCnt;
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}
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INT CStepper::NextPosition()
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{
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m_iPos += m_iStepSize;
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m_iState -= m_iRemainder;
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if (m_iState <= 0)
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{
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m_iState += m_iStepCnt;
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m_iPos++;
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}
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m_iStepNum++;
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return m_iPos;
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}
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INT CStepper::PrevPosition()
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{
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m_iPos -= m_iStepSize;
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m_iState += m_iRemainder;
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if (m_iState > m_iStepCnt)
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{
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m_iState -= m_iStepCnt;
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m_iPos--;
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}
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m_iStepNum--;
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return m_iPos;
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}
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INT CStepper::StepTo(INT nSteps)
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{
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INT iDiff;
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iDiff = (nSteps * m_iRemainder) / m_iStepCnt;
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m_iState = (iDiff + 1) * m_iStepCnt - (nSteps * m_iRemainder);
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m_iPos = (nSteps * m_iStepSize) + iDiff;
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m_iStepNum = nSteps;
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return m_iPos;
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}
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INT CStepper::PrevStepNum( INT iPosition )
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{
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INT iStepNum = -1;
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INT iLength;
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// Floating point conversion to integer truncates,
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// so this method returns the step previous to the position.
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iLength = m_iStepCnt * m_iStepSize + m_iRemainder;
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if ( iPosition <= iLength ) {
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// Calculation is (iPosition/iLength) * m_iStepCnt.
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iStepNum = iPosition * m_iStepCnt;
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iStepNum = iStepNum / iLength;
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}
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return iStepNum;
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}
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