Function split

dependencies/json/json.hpp:12348–12408

! @brief split the string input to reference tokens @note This function is only called by the json_pointer constructor. All exceptions below are documented there. @throw parse_error.107 if the pointer is not empty or begins with '/' @throw parse_error.108 if character '~' is not followed by '0' or '1' */

    @throw parse_error.108  if character '~' is not followed by '0' or '1'
    */
    static std::vector<std::string> split(const std::string& reference_string)
    {
        std::vector<std::string> result;

        // special case: empty reference string -> no reference tokens
        if (reference_string.empty())
        {
            return result;
        }

        // check if nonempty reference string begins with slash
        if (JSON_HEDLEY_UNLIKELY(reference_string[0] != '/'))
        {
            JSON_THROW(detail::parse_error::create(107, 1,
                                                   "JSON pointer must be empty or begin with '/' - was: '" +
                                                   reference_string + "'"));
        }

        // extract the reference tokens:
        // - slash: position of the last read slash (or end of string)
        // - start: position after the previous slash
        for (
            // search for the first slash after the first character
            std::size_t slash = reference_string.find_first_of('/', 1),
            // set the beginning of the first reference token
            start = 1;
            // we can stop if start == 0 (if slash == std::string::npos)
            start != 0;
            // set the beginning of the next reference token
            // (will eventually be 0 if slash == std::string::npos)
            start = (slash == std::string::npos) ? 0 : slash + 1,
            // find next slash
            slash = reference_string.find_first_of('/', start))
        {
            // use the text between the beginning of the reference token
            // (start) and the last slash (slash).
            auto reference_token = reference_string.substr(start, slash - start);

            // check reference tokens are properly escaped
            for (std::size_t pos = reference_token.find_first_of('~');
                    pos != std::string::npos;
                    pos = reference_token.find_first_of('~', pos + 1))
            {
                JSON_ASSERT(reference_token[pos] == '~');

                // ~ must be followed by 0 or 1
                if (JSON_HEDLEY_UNLIKELY(pos == reference_token.size() - 1 ||
                                         (reference_token[pos + 1] != '0' &&
                                          reference_token[pos + 1] != '1')))
                {
                    JSON_THROW(detail::parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'"));
                }
            }

            // finally, store the reference token
            unescape(reference_token);
            result.push_back(reference_token);
        }