<?php
/**
 * patTemplate modfifier Substr
 *
 * $Id$
 *
 * @package patTemplate
 * @package Modifiers
 * @author gERD Schaufelberger <gerd@php-tools.net>
 */

/**
 * patTemplate modifier Substr
 *
 * Parameter:
 *
 * @package patTemplate
 * @package Modifiers
 * @author gERD Schaufelberger <gerd@php-tools.net>
 */
class patTemplate_Modifier_Substr extends patTemplate_Modifier
{
    /**
     * Modify the value
     *
     *
     * @see substr()
     * @param string value
     * @param array list of parameter
     * @return string modified value
     */
    public function modify($value, $params = array())
    {
        $params =   array_merge(array(
                    'start'     =>  0,
                    'length'    =>  '__NULL',
                    ), $params);

        $value  =   strval($value);
        if (empty($value)) {
            return '';
        }

        $params['start']    =   intval($params['start']);
        if ('__NULL' == $params['length']) {
            return substr($value, $params['start']);
        }
        
        $params['length']   =   intval($params['length']);
        return substr($value, $params['start'], $params['length']);
    }
}