qt浮点数比较大小

###################
qFuzzyIsNull(float a); 或者 qFuzzyIsNull（double a);
#################
Q_REQUIRED_RESULT Q_DECL_CONSTEXPR static inline Q_DECL_UNUSED bool qFuzzyCompare(double p1, double p2)
{
    return (qAbs(p1 - p2) * 1000000000000. <= qMin(qAbs(p1), qAbs(p2)));
}

Q_REQUIRED_RESULT Q_DECL_CONSTEXPR static inline Q_DECL_UNUSED bool qFuzzyCompare(float p1, float p2)
{
    return (qAbs(p1 - p2) * 100000.f <= qMin(qAbs(p1), qAbs(p2)));
}

Q_REQUIRED_RESULT Q_DECL_CONSTEXPR static inline Q_DECL_UNUSED bool qFuzzyIsNull(double d)
{
    return qAbs(d) <= 0.000000000001;
}

Q_REQUIRED_RESULT Q_DECL_CONSTEXPR static inline Q_DECL_UNUSED  bool qFuzzyIsNull(float f)
{
    return qAbs(f) <= 0.00001f;
}