find_extremes.hpp

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#ifndef RITSUKO_FIND_EXTREMES_HPP
#define RITSUKO_FIND_EXTREMES_HPP
 
#include "choose_missing_placeholder.hpp"
#include <limits>
 
namespace ritsuko {
 
struct IntegerExtremes {
    bool has_lowest = false;
 
    bool has_highest = false;
 
    bool has_zero = false;
};
 
template<class Iterator, class Mask, class Type_ = typename std::remove_cv<typename std::remove_reference<decltype(*(std::declval<Iterator>()))>::type>::type>
IntegerExtremes find_integer_extremes(Iterator start, Iterator end, Mask mask) {
    static_assert(std::numeric_limits<Type_>::is_integer);
 
    IntegerExtremes output;
    output.has_zero = found(start, end, mask, 0);
    output.has_highest = found(start, end, mask, std::numeric_limits<Type_>::max());
 
    if constexpr(std::numeric_limits<Type_>::is_signed) {
        output.has_lowest = found(start, end, mask, std::numeric_limits<Type_>::min());
    } else {
        output.has_lowest = output.has_zero;
    }
 
    return output;
}
 
template<class Iterator, class Type_ = typename std::remove_cv<typename std::remove_reference<decltype(*(std::declval<Iterator>()))>::type>::type>
IntegerExtremes find_integer_extremes(Iterator start, Iterator end) {
    return find_integer_extremes(start, end, false);
}
 
struct FloatExtremes {
    bool has_nan = false;
 
    bool has_positive_inf = false;
 
    bool has_negative_inf = false;
 
    bool has_lowest = false;
 
    bool has_highest = false;
 
    bool has_zero = false;
};
 
template<class Iterator, class Mask, class Type_ = typename std::remove_cv<typename std::remove_reference<decltype(*(std::declval<Iterator>()))>::type>::type>
FloatExtremes find_float_extremes(Iterator start, Iterator end, Mask mask, bool skip_nan) {
    FloatExtremes output;
 
    if constexpr(std::numeric_limits<Type_>::is_iec559) {
        if (!skip_nan) {
            output.has_nan = check_for_nan(start, end, mask);
        }
 
        auto inf = std::numeric_limits<Type_>::infinity();
        output.has_positive_inf = found(start, end, mask, inf);
        output.has_negative_inf = found(start, end, mask, -inf);
    }
 
    output.has_lowest = found(start, end, mask, std::numeric_limits<Type_>::lowest());
    output.has_highest = found(start, end, mask, std::numeric_limits<Type_>::max());
    output.has_zero = found(start, end, mask, 0);
 
    return output;
}
 
template<class Iterator, class Type_ = typename std::remove_cv<typename std::remove_reference<decltype(*(std::declval<Iterator>()))>::type>::type>
FloatExtremes find_float_extremes(Iterator start, Iterator end, bool skip_nan = false) {
    return find_float_extremes(start, end, false, skip_nan);
}
 
}
 
#endif