public function validate($number, $config, $context)
{
$number = $this->parseCDATA($number);
if ($number === '') {
return false;
}
if ($number === '0') {
return '0';
}
$sign = '';
switch ($number[0]) {
case '-':
if ($this->non_negative) {
return false;
}
$sign = '-';
case '+':
$number = substr($number, 1);
}
if (ctype_digit($number)) {
$number = ltrim($number, '0');
return $number ? $sign . $number : '0';
}
// Period is the only non-numeric character allowed
if (strpos($number, '.') === false) {
return false;
}
list($left, $right) = explode('.', $number, 2);
if ($left === '' && $right === '') {
return false;
}
if ($left !== '' && !ctype_digit($left)) {
return false;
}
$left = ltrim($left, '0');
$right = rtrim($right, '0');
if ($right === '') {
return $left ? $sign . $left : '0';
} elseif (!ctype_digit($right)) {
return false;
}
return $sign . $left . '.' . $right;
}