중국어, 영어 멀티코드 문자의 왜곡된 문자를 가로채는 문제를 스마트하게 해결

<?php 
function smartDetectUTF8($string) 
{ 
    static $result = array();
    if(! array_key_exists($key = md5($string), $result)) 
    { 
        $utf8 = " 
            /^(?: 
                [\x09\x0A\x0D\x20-\x7E]                            # ASCII 
                | [\xC2-\xDF][\x80-\xBF]                             # non-overlong 2-byte 
                | \xE0[\xA0-\xBF][\x80-\xBF]                       # excluding overlongs 
                | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}           # straight 3-byte 
                | \xED[\x80-\x9F][\x80-\xBF]                      # excluding surrogates 
                | \xF0[\x90-\xBF][\x80-\xBF]{2}                 # planes 1-3 
                | [\xF1-\xF3][\x80-\xBF]{3}                          # planes 4-15 
                | \xF4[\x80-\x8F][\x80-\xBF]{2}                  # plane 16 
            )+$/xs 
        ";
        $result[$key] = preg_match(trim($utf8), $string); 
    }
    return $result[$key]; 
}
function smartStrlen($string) 
{ 
    $result = 0;
    $number = smartDetectUTF8($string) ? 3 : 2;
    for($i = 0; $i < strlen($string); $i += $bytes) 
    { 
        $bytes = ord(substr($string, $i, 1)) > 127 ? $number : 1;
        $result += $bytes > 1 ? 1.0 : 0.5; 
    }
    return $result; 
}
function smartSubstr($string, $start, $length = null) 
{ 
    $result = &#39;&#39;&#39;&#39;;
    $number = smartDetectUTF8($string) ? 3 : 2;
    if($start < 0) 
    { 
        $start = max(smartStrlen($string) + $start, 0); 
    }
    for($i = 0; $i < strlen($string); $i += $bytes) 
    { 
        if($start <= 0) 
        { 
            break; 
        }
        $bytes = ord(substr($string, $i, 1)) > 127 ? $number : 1;
        $start -= $bytes > 1 ? 1.0 : 0.5; 
    }
    if(is_null($length)) 
    { 
        $result = substr($string, $i); 
    } 
    else 
    { 
        for($j = $i; $j < strlen($string); $j += $bytes) 
        { 
            if($length <= 0) 
            { 
                break; 
            }
            if(($bytes = ord(substr($string, $j, 1)) > 127 ? $number : 1) > 1) 
            { 
                if($length < 1.0) 
                { 
                    break; 
                }
                $result .= substr($string, $j, $bytes); 
                $length -= 1.0; 
            } 
            else 
            { 
                $result .= substr($string, $j, 1); 
                $length -= 0.5; 
            } 
        } 
    }
    return $result; 
}
function smarty_modifier_smartTruncate($string, $length = 80, $etc = &#39;&#39;...&#39;&#39;, 
                                       $break_words = false, $middle = false) 
{ 
    if ($length == 0) 
        return &#39;&#39;&#39;&#39;;
    if (smartStrlen($string) > $length) { 
        $length -= smartStrlen($etc); 
        if (!$break_words && !$middle) { 
            $string = preg_replace(&#39;&#39;/\s+?(\S+)?$/&#39;&#39;, &#39;&#39;&#39;&#39;, smartSubstr($string, 0, $length+1)); 
        } 
        if(!$middle) { 
            return smartSubstr($string, 0, $length).$etc; 
        } else { 
            return smartSubstr($string, 0, $length/2) . $etc . smartSubstr($string, -$length/2); 
        } 
    } else { 
        return $string; 
    } 
} 
?>

{$content|smartTruncate:5:".."}（$content等于"A中B华C人D民E共F和G国H"）