<?php
/**
* Validates 'size' attribute of deprecated FONT tag
*
* @see https://developer.mozilla.org/en-US/docs/Web/HTML/Element/font#attr-size
*/
class HTMLPurifier_AttrDef_HTML_FontSize extends HTMLPurifier_AttrDef_CSS_Number
{
/**
* @param string $string
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return bool|string
*/
public function validate($string, $config, $context)
{
$string = trim($string);
switch (substr($string, 0, 1)) {
case '+':
$sign = 1;
break;
case '-':
$sign = -1;
break;
default:
$sign = 0;
break;
}
if ($sign) {
$string = substr($string, 1);
}
if (($string = parent::validate($string, $config, $context)) === false) {
return false;
}
// Browsers truncate float 'size' values to integers, so we do the same
$value = (int) $string;
// Size values range from 1 to 7 with 1 being the smallest and 3 the
// default. It can be defined using a relative value, like +2 or -3,
// which set it relative to the default value.
// This means that the relative values are between -2 and +4 (inclusive).
if ($sign) {
$value = max(-2, min(4, $sign * $value));
$value = $value >= 0 ? '+' . $value : $value;
} else {
$value = max(1, min(7, $value));
}
return (string) $value;
}
}