+ reverse_iterator_impl operator+(int n) const
+ { return reverse_iterator_impl(m_cur - n); }
+ reverse_iterator_impl operator+(size_t n) const
+ { return reverse_iterator_impl(m_cur - n); }
+ reverse_iterator_impl operator-(int n) const
+ { return reverse_iterator_impl(m_cur + n); }
+ reverse_iterator_impl operator-(size_t n) const
+ { return reverse_iterator_impl(m_cur + n); }
+ reverse_iterator_impl operator+=(int n)
+ { m_cur -= n; return *this; }
+ reverse_iterator_impl operator+=(size_t n)
+ { m_cur -= n; return *this; }
+ reverse_iterator_impl operator-=(int n)
+ { m_cur += n; return *this; }
+ reverse_iterator_impl operator-=(size_t n)
+ { m_cur += n; return *this; }
+
+ unsigned operator-(const reverse_iterator_impl& i) const
+ { return i.m_cur - m_cur; }
+