Function split

Source/external/json.hpp:14347–14405

! @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<string_t> split(const string_t& reference_string)
	{
		std::vector<string_t> 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, detail::concat("JSON pointer must be empty or begin with '/' - was: '", reference_string, "'"), nullptr));
		}

		// 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 == string_t::npos)
			start != 0;
			// set the beginning of the next reference token
			// (will eventually be 0 if slash == string_t::npos)
			start = (slash == string_t::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 != string_t::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'", nullptr));
				}
			}

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

		return result;