1 files changed, 115 insertions, 0 deletions
diff --git a/library/HTMLPurifier/Length.php b/library/HTMLPurifier/Length.php
new file mode 100644
index 000000000..8d2a46b7d
--- /dev/null
+++ b/library/HTMLPurifier/Length.php
@@ -0,0 +1,115 @@
+<?php
+
+/**
+ * Represents a measurable length, with a string numeric magnitude
+ * and a unit. This object is immutable.
+ */
+class HTMLPurifier_Length
+{
+
+    /**
+     * String numeric magnitude.
+     */
+    protected $n;
+
+    /**
+     * String unit. False is permitted if $n = 0.
+     */
+    protected $unit;
+
+    /**
+     * Whether or not this length is valid. Null if not calculated yet.
+     */
+    protected $isValid;
+
+    /**
+     * Lookup array of units recognized by CSS 2.1
+     */
+    protected static $allowedUnits = array(
+        'em' => true, 'ex' => true, 'px' => true, 'in' => true,
+        'cm' => true, 'mm' => true, 'pt' => true, 'pc' => true
+    );
+
+    /**
+     * @param number $n Magnitude
+     * @param string $u Unit
+     */
+    public function __construct($n = '0', $u = false) {
+        $this->n = (string) $n;
+        $this->unit = $u !== false ? (string) $u : false;
+    }
+
+    /**
+     * @param string $s Unit string, like '2em' or '3.4in'
+     * @warning Does not perform validation.
+     */
+    static public function make($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, $unit);
+    }
+
+    /**
+     * Validates the number and unit.
+     */
+    protected function validate() {
+        // Special case:
+        if ($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 = $result;
+        return true;
+    }
+
+    /**
+     * Returns string representation of number.
+     */
+    public function toString() {
+        if (!$this->isValid()) return false;
+        return $this->n . $this->unit;
+    }
+
+    /**
+     * Retrieves string numeric magnitude.
+     */
+    public function getN() {return $this->n;}
+
+    /**
+     * Retrieves string unit.
+     */
+    public function getUnit() {return $this->unit;}
+
+    /**
+     * Returns true if this length unit is valid.
+     */
+    public function isValid() {
+        if ($this->isValid === null) $this->isValid = $this->validate();
+        return $this->isValid;
+    }
+
+    /**
+     * Compares two lengths, and returns 1 if greater, -1 if less and 0 if equal.
+     * @warning If both values are too large or small, this calculation will
+     *          not work properly
+     */
+    public function compareTo($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