1<?php
2
3/**
4 * Validates a number as defined by the CSS spec.
5 */
6class HTMLPurifier_AttrDef_CSS_Number extends HTMLPurifier_AttrDef
7{
8
9    /**
10     * Indicates whether or not only positive values are allowed.
11     * @type bool
12     */
13    protected $non_negative = false;
14
15    /**
16     * @param bool $non_negative indicates whether negatives are forbidden
17     */
18    public function __construct($non_negative = false)
19    {
20        $this->non_negative = $non_negative;
21    }
22
23    /**
24     * @param string $number
25     * @param HTMLPurifier_Config $config
26     * @param HTMLPurifier_Context $context
27     * @return string|bool
28     * @warning Some contexts do not pass $config, $context. These
29     *          variables should not be used without checking HTMLPurifier_Length
30     */
31    public function validate($number, $config, $context)
32    {
33        $number = $this->parseCDATA($number);
34
35        if ($number === '') {
36            return false;
37        }
38        if ($number === '0') {
39            return '0';
40        }
41
42        $sign = '';
43        switch ($number[0]) {
44            case '-':
45                if ($this->non_negative) {
46                    return false;
47                }
48                $sign = '-';
49            case '+':
50                $number = substr($number, 1);
51        }
52
53        if (ctype_digit($number)) {
54            $number = ltrim($number, '0');
55            return $number ? $sign . $number : '0';
56        }
57
58        // Period is the only non-numeric character allowed
59        if (strpos($number, '.') === false) {
60            return false;
61        }
62
63        list($left, $right) = explode('.', $number, 2);
64
65        if ($left === '' && $right === '') {
66            return false;
67        }
68        if ($left !== '' && !ctype_digit($left)) {
69            return false;
70        }
71
72        // Remove leading zeros until positive number or a zero stays left
73        if (ltrim($left, '0') != '') {
74            $left = ltrim($left, '0');
75        } else {
76            $left = '0';
77        }
78
79        $right = rtrim($right, '0');
80
81        if ($right === '') {
82            return $left ? $sign . $left : '0';
83        } elseif (!ctype_digit($right)) {
84            return false;
85        }
86        return $sign . $left . '.' . $right;
87    }
88}
89
90// vim: et sw=4 sts=4
91