qwt_algorithm.hpp

#ifndef QWT_ALGORITHM_HPP
#define QWT_ALGORITHM_HPP
#include <algorithm>  // std::find
#include <iterator>   // std::prev
 
template< typename Iter >
Iter qwtSelectNextIterator(Iter begin, Iter end, typename std::iterator_traits< Iter >::value_type current, bool forward)
{
    if (begin == end) {
        return end;
    }
 
    Iter ite = std::find(begin, end, current);
 
    if (ite == end) {
        ite = begin;
    }
 
    if (forward) {
        ++ite;
        if (ite == end) {
            ite = begin;
        }
    } else {
        if (ite != begin) {
            --ite;
        } else {
            ite = std::prev(end);
        }
    }
 
    return ite;
}
 
#endif  // QWT_ALGORITHM_HPP