<?php

    namespace ncc\ZiProto\Abstracts;

    /**
     * Class Regex
     * @package ncc\ZiProto\Abstracts
     */
    abstract class Regex
    {
        const UTF8_REGEX = '/\A(?:
          [\x00-\x7F]++                      # ASCII
        | [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
        |  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
        | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
        |  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
        |  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
        | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
        |  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
        )*+\z/x';
    }