library/HTMLPurifier/Length.php

   1 <?php
   2
   3 /**
   4  * Represents a measurable length, with a string numeric magnitude
   5  * and a unit. This object is immutable.
   6  */
   7 class HTMLPurifier_Length
   8 {
   9
  10     /**
  11      * String numeric magnitude.
  12      * @type string
  13      */
  14     protected $n;
  15
  16     /**
  17      * String unit. False is permitted if $n = 0.
  18      * @type string|bool
  19      */
  20     protected $unit;
  21
  22     /**
  23      * Whether or not this length is valid. Null if not calculated yet.
  24      * @type bool
  25      */
  26     protected $isValid;
  27
  28     /**
  29      * Array Lookup array of units recognized by CSS 2.1
  30      * @type array
  31      */
  32     protected static $allowedUnits = array(
  33         'em' => true, 'ex' => true, 'px' => true, 'in' => true,
  34         'cm' => true, 'mm' => true, 'pt' => true, 'pc' => true
  35     );
  36
  37     /**
  38      * @param string $n Magnitude
  39      * @param bool|string $u Unit
  40      */
  41     public function __construct($n = '0', $u = false)
  42     {
  43         $this->n = (string) $n;
  44         $this->unit = $u !== false ? (string) $u : false;
  45     }
  46
  47     /**
  48      * @param string $s Unit string, like '2em' or '3.4in'
  49      * @return HTMLPurifier_Length
  50      * @warning Does not perform validation.
  51      */
  52     public static function make($s)
  53     {
  54         if ($s instanceof HTMLPurifier_Length) {
  55             return $s;
  56         }
  57         $n_length = strspn($s, '1234567890.+-');
  58         $n = substr($s, 0, $n_length);
  59         $unit = substr($s, $n_length);
  60         if ($unit === '') {
  61             $unit = false;
  62         }
  63         return new HTMLPurifier_Length($n, $unit);
  64     }
  65
  66     /**
  67      * Validates the number and unit.
  68      * @return bool
  69      */
  70     protected function validate()
  71     {
  72         // Special case:
  73         if ($this->n === '+0' || $this->n === '-0') {
  74             $this->n = '0';
  75         }
  76         if ($this->n === '0' && $this->unit === false) {
  77             return true;
  78         }
  79         if (!ctype_lower($this->unit)) {
  80             $this->unit = strtolower($this->unit);
  81         }
  82         if (!isset(HTMLPurifier_Length::$allowedUnits[$this->unit])) {
  83             return false;
  84         }
  85         // Hack:
  86         $def = new HTMLPurifier_AttrDef_CSS_Number();
  87         $result = $def->validate($this->n, false, false);
  88         if ($result === false) {
  89             return false;
  90         }
  91         $this->n = $result;
  92         return true;
  93     }
  94
  95     /**
  96      * Returns string representation of number.
  97      * @return string
  98      */
  99     public function toString()
 100     {
 101         if (!$this->isValid()) {
 102             return false;
 103         }
 104         return $this->n . $this->unit;
 105     }
 106
 107     /**
 108      * Retrieves string numeric magnitude.
 109      * @return string
 110      */
 111     public function getN()
 112     {
 113         return $this->n;
 114     }
 115
 116     /**
 117      * Retrieves string unit.
 118      * @return string
 119      */
 120     public function getUnit()
 121     {
 122         return $this->unit;
 123     }
 124
 125     /**
 126      * Returns true if this length unit is valid.
 127      * @return bool
 128      */
 129     public function isValid()
 130     {
 131         if ($this->isValid === null) {
 132             $this->isValid = $this->validate();
 133         }
 134         return $this->isValid;
 135     }
 136
 137     /**
 138      * Compares two lengths, and returns 1 if greater, -1 if less and 0 if equal.
 139      * @param HTMLPurifier_Length $l
 140      * @return int
 141      * @warning If both values are too large or small, this calculation will
 142      *          not work properly
 143      */
 144     public function compareTo($l)
 145     {
 146         if ($l === false) {
 147             return false;
 148         }
 149         if ($l->unit !== $this->unit) {
 150             $converter = new HTMLPurifier_UnitConverter();
 151             $l = $converter->convert($l, $this->unit);
 152             if ($l === false) {
 153                 return false;
 154             }
 155         }
 156         return $this->n - $l->n;
 157     }
 158 }
 159
 160 // vim: et sw=4 sts=4