Trim a string to a specified length?

[+username:limit=5+] // limits the username to 5 characters to the nearest available space.

[*play:limit=`3`:is=`[*play:limit=`3`*]`:then=`[*play:limit=`3`*]...`:else=``*]

<?php
$output_truncated = substr($output, 0, $options);
$output_truncated .= "...";
return $output_truncated;
?>

[*play:len:gt=`3`:then=`[*play:character_limit=`3`*]`:else=`[*play*]`*]

// This goes in my content block
[*longtitle:len:gt=`5`:then=`[*longtitle:word_limit=`5`*]...`:else=`[*longtitle*]`*]

   <?php
   $retval = $output;
   $array = explode(" ", $output);
   if (count($array)<=$options)
   {
   $retval = $output;
   }
   else
   {
   array_splice($array,$options);
   $retval = implode(" ", $array).'...';
   }
   return $retval;
   ?>

[*longtitle:word_limit=`5`*]