php截取中文字符串实现程序-PHP源码

//$str是要截取的字符串
//$start是要截取的字符的开始位置
//$len是指要截取的字符长度
function sub_str($str, $start, $len) {
$tmpstr = "";
$strlen = $start + $len;
for($i = 0; $i <$strlen; $i++) {
if(ord(substr($str, $i, 1)) > 0xa0) {
$tmpstr .= substr($str, $i, 2);
$i++;
} else
$tmpstr .= substr($str, $i, 1);
}
return $tmpstr."...";
}

//截取utf8字符串
function utf8substr($str, $from, $len)
{
return preg_replace('#^(?:[x00-x7f]|[xc0-xff][x80-xbf]+){0,'.$from.'}'.
'((?:[x00-x7f]|[xc0-xff][x80-xbf]+){0,'.$len.'}).*#s',
'$1',$str);
}
?>

/**
* @package BugFree
* @version $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $
*
*
* Return part of a string(Enhance the function substr())
*
* @author Chunsheng Wang
* @param string $String the string to cut.
* @param int $Length the length of returned string.
* @param booble $Append whether append "...": false|true
* @return string the cutted string.
*/
function sysSubStr($String,$Length,$Append = false)
{
if (strlen($String) <= $Length )
{
return $String;
}
else
{
$I = 0;
while ($I <$Length)
{
$StringTMP = substr($String,$I,1);
if ( ord($StringTMP) >=224 )
{
$StringTMP = substr($String,$I,3);
$I = $I + 3;
}
elseif( ord($StringTMP) >=192 )
{
$StringTMP = substr($String,$I,2);
$I = $I + 2;
}
else
{
$I = $I + 1;
}
$StringLast[] = $StringTMP;
}
$StringLast = implode("",$StringLast);
if($Append)
{
$StringLast .= "...";
}
return $StringLast;
}
}

$String = "www.111cn.net 走在中国自动化测试的前沿";
$Length = "18";
$Append = false;
echo sysSubStr($String,$Length,$Append);
?>