<?php

/**
 * Validates an integer representation of pixels according to the HTML spec.
 */
class HTMLPurifier_AttrDef_HTML_Pixels extends HTMLPurifier_AttrDef {
	
	/**
	 * @type int
	 */
	protected $max;
	
	/**
	 *
	 * @param int $max        	
	 */
	public function __construct($max = null) {
		$this->max = $max;
	}
	
	/**
	 *
	 * @param string $string        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return bool|string
	 */
	public function validate($string, $config, $context) {
		$string = trim ( $string );
		if ($string === '0') {
			return $string;
		}
		if ($string === '') {
			return false;
		}
		$length = strlen ( $string );
		if (substr ( $string, $length - 2 ) == 'px') {
			$string = substr ( $string, 0, $length - 2 );
		}
		if (! is_numeric ( $string )) {
			return false;
		}
		$int = ( int ) $string;
		
		if ($int < 0) {
			return '0';
		}
		
		// upper-bound value, extremely high values can
		// crash operating systems, see <http://ha.ckers.org/imagecrash.html>
		// WARNING, above link WILL crash you if you're using Windows
		
		if ($this->max !== null && $int > $this->max) {
			return ( string ) $this->max;
		}
		return ( string ) $int;
	}
	
	/**
	 *
	 * @param string $string        	
	 * @return HTMLPurifier_AttrDef
	 */
	public function make($string) {
		if ($string === '') {
			$max = null;
		} else {
			$max = ( int ) $string;
		}
		$class = get_class ( $this );
		return new $class ( $max );
	}
}

// vim: et sw=4 sts=4