fixed_string.hpp

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#pragma once
 
#include <algorithm>
#include <array>
#include <cstddef>
#include <ostream>
#include <string_view>
 
namespace relx {
namespace schema {
 
template <std::size_t N>
struct fixed_string {
  constexpr fixed_string(const char (&str)[N]) : value{} { std::copy_n(str, N, value); }
 
  constexpr fixed_string(const fixed_string&) = default;
 
  char value[N];
 
  constexpr operator std::string_view() const {
    return std::string_view(value, N - 1);  // exclude null terminator
  }
 
  constexpr const char* c_str() const { return value; }
 
  constexpr std::size_t size() const {
    return N - 1;  // exclude null terminator
  }
 
  constexpr bool empty() const { return size() == 0; }
 
  template <std::size_t M>
  constexpr bool operator==(const fixed_string<M>& other) const {
    return std::string_view(*this) == std::string_view(other);
  }
 
  template <std::size_t M>
  constexpr bool operator!=(const fixed_string<M>& other) const {
    return !(*this == other);
  }
};
 
// Output stream operator
template <std::size_t N>
std::ostream& operator<<(std::ostream& os, const fixed_string<N>& str) {
  return os << std::string_view(str);
}
}  // namespace schema
namespace literals {
// Standard C++11 user-defined literal syntax
template <char... Chars>
constexpr auto operator""_fs() {
  constexpr char str[] = {Chars..., '\0'};
  return schema::fixed_string<sizeof...(Chars) + 1>(str);
}
}  // namespace literals
 
}  // namespace relx