static_string_view.hh

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#ifndef STATIC_STRING_VIEW_HH
#define STATIC_STRING_VIEW_HH
 
#include "StringStorage.hh"
#include <cassert>
#include <cstring>
#include <string_view>
#include <utility>
 
class static_string_view
{
public:
        // Disallow construction from non-const char array.
        template<size_t N>
        constexpr static_string_view(char (&buf)[N]) = delete;
 
        // Construct from string-literal (a const char array).
        template<size_t N>
        constexpr static_string_view(const char (&buf)[N])
                : s(buf, N-1)
        {
                assert(buf[N - 1] == '\0');
        }
 
        // Used by make_string_storage().
        struct lifetime_ok_tag {};
        constexpr static_string_view(lifetime_ok_tag, std::string_view v)
                : s(v) {}
 
        // Allow (implicit) conversion to std::string_view.
        constexpr operator std::string_view() const { return s; }
 
private:
        const std::string_view s;
};
 
inline auto make_string_storage(std::string_view sv)
{
        auto size = sv.size();
        auto storage = allocate_string_storage(size);
        char* p = storage.get();
        memcpy(p, sv.data(), size);
        return std::pair{std::move(storage),
                         static_string_view(static_string_view::lifetime_ok_tag{},
                                            std::string_view(p, size))};
}
 
#endif