<?php
/**
* Represents a measurable length, with a string numeric magnitude
* and a unit. This object is immutable.
*/
class HTMLPurifier_Length
{
/**
* String numeric magnitude.
* @type string
*/
protected $n;
/**
* String unit. False is permitted if $n = 0.
* @type string|bool
*/
protected $unit;
/**
* Whether or not this length is valid. Null if not calculated yet.
* @type bool
*/
protected $isValid;
/**
* Array Lookup array of units recognized by CSS 3
* @type array
*/
protected static $allowedUnits = array(
'em' => true, 'ex' => true, 'px' => true, 'in' => true,
'cm' => true, 'mm' => true, 'pt' => true, 'pc' => true,
'ch' => true, 'rem' => true, 'vw' => true, 'vh' => true,
'vmin' => true, 'vmax' => true
);
/**
* @param string $n Magnitude
* @param bool|string $u Unit
*/
public function __construct($n = '0', $u = false)
{
$this->n = (string) $n;
$this->unit = $u !== false ? (string) $u : false;
}
/**
* @param string $s Unit string, like '2em' or '3.4in'
* @return HTMLPurifier_Length
* @warning Does not perform validation.
*/
public static function make($s)
{
if ($s instanceof HTMLPurifier_Length) {
return $s;
}
$n_length = strspn($s, '1234567890.+-');
$n = substr($s, 0, $n_length);
$unit = substr($s, $n_length);
if ($unit === '') {
$unit = false;
}
return new HTMLPurifier_Length($n, $unit);
}
/**
* Validates the number and unit.
* @return bool
*/
protected function validate()
{
// Special case:
if ($this->n === '+0' || $this->n === '-0') {
$this->n = '0';
}
if ($this->n === '0' && $this->unit === false) {
return true;
}
if (!ctype_lower($this->unit)) {
$this->unit = strtolower($this->unit);
}
if (!isset(HTMLPurifier_Length::$allowedUnits[$this->unit])) {
return false;
}
// Hack:
$def = new HTMLPurifier_AttrDef_CSS_Number();
$result = $def->validate($this->n, false, false);
if ($result === false) {
return false;
}
$this->n = $result;
return true;
}
/**
* Returns string representation of number.
* @return string
*/
public function toString()
{
if (!$this->isValid()) {
return false;
}
return $this->n . $this->unit;
}
/**
* Retrieves string numeric magnitude.
* @return string
*/
public function getN()
{
return $this->n;
}
/**
* Retrieves string unit.
* @return string
*/
public function getUnit()
{
return $this->unit;
}
/**
* Returns true if this length unit is valid.
* @return bool
*/
public function isValid()
{
if ($this->isValid === null) {
$this->isValid = $this->validate();
}
return $this->isValid;
}
/**
* Compares two lengths, and returns 1 if greater, -1 if less and 0 if equal.
* @param HTMLPurifier_Length $l
* @return int
* @warning If both values are too large or small, this calculation will
* not work properly
*/
public function compareTo($l)
{
if ($l === false) {
return false;
}
if ($l->unit !== $this->unit) {
$converter = new HTMLPurifier_UnitConverter();
$l = $converter->convert($l, $this->unit);
if ($l === false) {
return false;
}
}
return $this->n - $l->n;
}
}
// vim: et sw=4 sts=4