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#pragma once
#include <array>
#include <string_view>
namespace kel {
namespace lbm {
/**
* Helper object which creates a templated string from the provided string
* literal. It guarantees compile time uniqueness and thus allows using strings
* in template parameters.
*/
template <class CharT, size_t N> class string_literal {
public:
static_assert(N > 0, "string_literal needs a null terminator");
constexpr string_literal(const CharT (&input)[N]) noexcept {
for (size_t i = 0; i < N; ++i) {
data[i] = input[i];
}
}
std::array<CharT, N> data{};
constexpr std::string_view view() const noexcept {
return std::string_view{data.data()};
}
constexpr bool
operator==(const string_literal<CharT, N> &) const noexcept = default;
template <class CharTR, size_t NR>
constexpr bool
operator==(const string_literal<CharTR, NR> &) const noexcept {
return false;
}
template<size_t NR>
constexpr string_literal<CharT, N+NR-1> operator+(const string_literal<CharT, NR>& rhs) const noexcept {
CharT sum[N+NR-1];
// The weird i+1 happens due to needing to skip the '\0' terminator
for(size_t i = 0; (i+1) < N; ++i){
sum[i] = data[i];
}
for(size_t i = 0; i < NR; ++i){
sum[i+N-1] = rhs.data[i];
}
return string_literal<CharT, N+NR-1>{sum};
}
};
template <typename T, T... Chars>
constexpr string_literal<T, sizeof...(Chars) + 1u> operator""_sl() {
return string_literal<T, sizeof...(Chars) + 1u>{{Chars..., '\0'}};
}
}
}
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