PHP在字符断点处截断文字

// Original PHP code by Chirp Internet: www.chirp.com.au
 // Please acknowledge use of this code by including this header.
 function myTruncate($string, $limit, $break=".", $pad="...") {
 // return with no change if string is shorter than $limit
 if(strlen($string) <= $limit)
 return $string;

 // is $break present between $limit and the end of the string?
 if(false !== ($breakpoint = strpos($string, $break, $limit))) {
 if($breakpoint < strlen($string) - 1) {
 $string = substr($string, 0, $breakpoint) . $pad;
 }
 }
 return $string;
 }
 /***** Example ****/
 $short_string=myTruncate($long_string, 100, ' ');