<?php

/**
 * Validates an IPv4 address
 * @author Feyd @ forums.devnetwork.net (public domain)
 */
class HTMLPurifier_AttrDef_URI_IPv4 extends HTMLPurifier_AttrDef {
	
	/**
	 * IPv4 regex, protected so that IPv6 can reuse it.
	 * @type string
	 */
	protected $ip4;
	
	/**
	 *
	 * @param string $aIP        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return bool|string
	 */
	public function validate($aIP, $config, $context) {
		if (! $this->ip4) {
			$this->_loadRegex ();
		}
		
		if (preg_match ( '#^' . $this->ip4 . '$#s', $aIP )) {
			return $aIP;
		}
		return false;
	}
	
	/**
	 * Lazy load function to prevent regex from being stuffed in
	 * cache.
	 */
	protected function _loadRegex() {
		$oct = '(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])'; // 0-255
		$this->ip4 = "(?:{$oct}\\.{$oct}\\.{$oct}\\.{$oct})";
	}
}

// vim: et sw=4 sts=4