Truncate a string keeping word boundary

Takes a string and truncates it to the last word at string length $MAX, adding periods at the end of the text.

<?php

      

      function truncate_string($details,$max)

      {

          if(strlen($details)>$max)

          {

              $details = substr($details,0,$max);

              $i = strrpos($details," ");

              $details = substr($details,0,$i);

              $details = $details." ..... ";

          }

          return $details;

      }

      

      ?>

Example:

<?php

      

      $text = truncate_string("hello there. This is a long string",19);

      

      ?>
      returns
      hello there. This .....