Listing 1: Partial listing of delta.h

struct deltacontrol{
    int current;
    int delta;
    int len;
    int togo;
};

class DeltaControl
{
public:
    DeltaControl();
    virtual void SetFrom(int Major, int Minor);
    virtual void SetTo(int Major, int Minor);
    virtual BOOL Next();
    int GetMajor() {return m_Major.current;};
    int GetMinor() {return m_Minor.current;};
    virtual int GetLength() {return m_Minor.len + m_Major.len;};
protected:
    virtual void OnMajorChange(int Current) {};
    virtual void OnMinorChange(int Current) {};
    deltacontrl m_Major;
    deltacontrl m_Minor;
    int m_ErrorTerm;
    virtual void SetTo(int In, deltacontrol *Out);
    BOOL m_MinorLast;
};
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