mb_str_split function. multibyte version of str_split.

mb_str_split.php

<?php

if (!function_exists('mb_str_split')) {
    /**
     * Convert a multibyte string to an array
     * 
     * @param  string  $string       The input string.
     * @param  integer $split_length Maximum length of the chunk.
     * @param  string  $encoding     The encoding parameter is the character encoding.
     * @return array
     */
    function mb_str_split($string, $split_length = 1, $encoding = null)
    {
        if (is_null($encoding)) {
            $encoding = mb_internal_encoding();
        }

        if ($split_length < 1) {
            return false;
        }

        $return_value = array();
        $string_length  = mb_strlen($string, $encoding);
        for ($i = 0; $i < $string_length; $i += $split_length)
        {
            $return_value[] = mb_substr($string, $i, $split_length, $encoding);
        }
        return $return_value;
    }
}