Guy Rutenberg » Smarty http://www.guyrutenberg.com Keeping track of what I do Sat, 14 Jan 2012 11:30:25 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Multibyte String Truncate Modifier for Smarty – mb_truncate http://www.guyrutenberg.com/2007/12/04/multibyte-string-truncate-modifier-for-smarty-mb_truncate/ http://www.guyrutenberg.com/2007/12/04/multibyte-string-truncate-modifier-for-smarty-mb_truncate/#comments Tue, 04 Dec 2007 12:53:36 +0000 Guy http://www.guyrutenberg.com/2007/12/04/multibyte-string-truncate-modifier-for-smarty-mb_truncate/ When working with Smarty, a PHP templating engine, I discovered that while the regular truncate modifier works great on ASCII strings, it doesn’t work with multibyte strings, i.e. UTF-8 encoded strings. This leads to problems in internationalization (i18n), as UTF-8 is the popular encoding for non-Latin alphabets nowdays. The problem can be solved by modifying the built-in truncate modifier and create a new one that takes an additional argument, the charset of the string, and acts accordingly. The new modified modifier, mb_truncate is implemented below.

<?php
/**
 * Smarty plugin
 * @package Smarty
 * @subpackage plugins
 */
 
 
/**
 * Smarty truncate modifier plugin
 *
 * Type:     modifier<br>
 * Name:     mb_truncate<br>
 * Purpose:  Truncate a string to a certain length if necessary,
 *           optionally splitting in the middle of a word, and
 *           appending the $etc string or inserting $etc into the middle.
 *           This version also supports multibyte strings.
 * @link http://smarty.php.net/manual/en/language.modifier.truncate.php
 *          truncate (Smarty online manual)
 * @author   Guy Rutenberg <guyrutenberg@gmail.com> based on the original 
 *           truncate by Monte Ohrt <monte at ohrt dot com>
 * @param string
 * @param integer
 * @param string
 * @param string
 * @param boolean
 * @param boolean
 * @return string
 */
function smarty_modifier_mb_truncate($string, $length = 80, $etc = '...', $charset='UTF-8',
                                  $break_words = false, $middle = false)
{
    if ($length == 0)
        return '';
 
    if (strlen($string) > $length) {
        $length -= min($length, strlen($etc));
        if (!$break_words && !$middle) {
            $string = preg_replace('/\s+?(\S+)?$/', '', mb_substr($string, 0, $length+1, $charset));
        }
        if(!$middle) {
            return mb_substr($string, 0, $length, $charset) . $etc;
        } else {
            return mb_substr($string, 0, $length/2, $charset) . $etc . mb_substr($string, -$length/2, $charset);
        }
    } else {
        return $string;
    }
}
 
/* vim: set expandtab: */
?>

The license for the code is LGPL (same as Smarty’s). To install to modifier just put it under /smarty/plugins/modifier.mb_truncate.php.

Using the mb_truncate modifier is similar to truncate.

//$some_string is a string of utf-8 variables assign via php
{$some_string|mb_truncate:13:"...":'UTF-8'}

The modifier also supports the break words, and truncate in the middle flags of the original truncate.

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