edit_distance.hpp

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#ifndef EAGINE_EDIT_DISTANCE_HPP
#define EAGINE_EDIT_DISTANCE_HPP
 
#include "flat_map.hpp"
#include "math/tvec.hpp"
#include "string_span.hpp"
 
namespace eagine {
 
class default_keyboard_layout {
public:
    using coord_type = math::tvec<float, 3, true>;
 
    default_keyboard_layout(const float shift = 1.F);
 
    auto get_coord(char c) noexcept -> coord_type {
        const auto pos = _key_coord.find(c);
        if(pos != _key_coord.end()) {
            return pos->second;
        }
        return {6.F, 3.F, 0.5F};
    }
 
    template <typename Function>
    auto for_each_char_coord(Function function) const noexcept {
        for(const auto& [kchr, coord] : _key_coord) {
            function(kchr, coord);
        }
    }
 
protected:
    void add_key_coord(char key, math::tvec<float, 3, true> coord) {
        _key_coord[key] = coord;
    }
 
private:
    flat_map<char, math::tvec<float, 3, true>> _key_coord;
};
//------------------------------------------------------------------------------
class keyboard_distance {
public:
    template <typename Layout>
    keyboard_distance(const Layout& layout, float multiplier = 1.F) {
        layout.for_each_char_coord([&](char lc, auto lp) {
            layout.for_each_char_coord([&](char rc, auto rp) {
                if(lc != rc) {
                    _key_dist[{lc, rc}] = multiplier * math::distance(lp, rp);
                }
            });
        });
    }
 
    auto operator()(string_view ls, string_view rs) const -> float;
 
private:
    flat_map<std::pair<char, char>, float> _key_dist;
};
 
} // namespace eagine
 
#if !EAGINE_LINK_LIBRARY || defined(EAGINE_IMPLEMENTING_LIBRARY)
#include <eagine/edit_distance.inl>
#endif
 
#endif // EAGINE_EDIT_DISTANCE_HPP