1<?php
2
3/**
4 * Validates a color according to the HTML spec.
5 */
6class HTMLPurifier_AttrDef_HTML_Color extends HTMLPurifier_AttrDef
7{
8
9    /**
10     * @param string $string
11     * @param HTMLPurifier_Config $config
12     * @param HTMLPurifier_Context $context
13     * @return bool|string
14     */
15    public function validate($string, $config, $context)
16    {
17        static $colors = null;
18        if ($colors === null) {
19            $colors = $config->get('Core.ColorKeywords');
20        }
21
22        $string = trim($string);
23
24        if (empty($string)) {
25            return false;
26        }
27        $lower = strtolower($string);
28        if (isset($colors[$lower])) {
29            return $colors[$lower];
30        }
31        if ($string[0] === '#') {
32            $hex = substr($string, 1);
33        } else {
34            $hex = $string;
35        }
36
37        $length = strlen($hex);
38        if ($length !== 3 && $length !== 6) {
39            return false;
40        }
41        if (!ctype_xdigit($hex)) {
42            return false;
43        }
44        if ($length === 3) {
45            $hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
46        }
47        return "#$hex";
48    }
49}
50
51// vim: et sw=4 sts=4
52