Function code_point_index

source/extern/fmt/format.h:743–746

template <typename Char>
inline auto code_point_index(basic_string_view<Char> s, size_t n) -> size_t {
  size_t size = s.size();
  return n < size ? n : size;
}

// Calculates the index of the nth code point in a UTF-8 string.
inline auto code_point_index(string_view s, size_t n) -> size_t {