The substr function and strlen in php is not correct work with Russian characters. How to solve the problem?

and what is the impropriety then, you can learn ???

Here for example function:
\r
/**
* shortenText
* @param string
* @param int
* @param bool, default true
* @since 1.0.9
*/
function shortenText( $text, $count, $addbb=true )
{
if( $count > 0 )
{
$totalchars = strlen( $text );
$charcount = 0;
$fulltext = $text;
$buffer = ";
if( $totalchars >= $count )
{
$bbcode = false;
while( strlen( $fulltext ) > 0 )
{
$char = $fulltext{0};
if( $char == '[' ) $bbcode = true;
if( ( $bbcode && $addbb ) || $charcount < $count ) $buffer .= $char;
$fulltext = substr( $fulltext, 1 );
if( !$bbcode ) $charcount++;
if( $char == ']' ) $bbcode = false;
}
$text = $buffer.( $charcount >= $count? '...': ");
}
}
return $text;
}
\r
If $fultext — English letters. Reduces. If the Russian is an empty string

1. Use mb_substr, mb_strlen with parameter $encoding='utf-8'
2. Do not use $char=$fulltext{0}, replace mb_substr

iconv_substr($s, $from, $len, 'UTF-8')
iconv_strlen($s, 'UTF-8')
$s{$i} ==> iconv_substr($s, $i, 1, 'UTF-8')

You have $bbcode always $false, is this normal? Code is certainly fun...