中文字符串截取无乱码方法定义

<?php


class StringComponent{

public static function cutString($sourceStr, $cutLength = 10, $extStr = '...'){
$returnStr = ''; $i = 0; $n = 0;
$strLength = strlen($sourceStr);
if ($strLength > $cutLength){
while (($n < $cutLength) and ($i <= $strLength)){
$tempStr = substr($sourceStr, $i, 1);
$ascnum = Ord($tempStr);
if ($ascnum >= 224){
$returnStr = $returnStr . substr($sourceStr, $i, 3);
$i = $i+3;
$n++;
}elseif ($ascnum >= 192){ 
$returnStr=$returnStr.substr($sourceStr,$i,2);
$i=$i+2;
$n++;
}elseif ($ascnum >= 65 && $ascnum <= 90){
$returnStr = $returnStr.substr($sourceStr, $i, 1);
$i = $i+1;
$n++;
}else{ 
$returnStr = $returnStr.substr($sourceStr, $i, 1);
$i = $i+1;
$n = $n+0.5;
}
}
if ($strLength > $i){
$returnStr = $returnStr.$extStr;
}
return $returnStr;
}
else
return $sourceStr;
}
}


?>