/**
* Decode a string using Crockford base-32
*
* {@see http://www.crockford.com/wrmg/base32.html}
*
* @param mixed $number The crockford number to convert
* @param mixed $base Desired output base for number
* @param boolean $checksum Crockford number includes checksum
*
* @return string The number decoded to desired base
*/
public static function decode($number, $base = 10, $checksum = false)
{
// Clean and check number
$crockford = strtoupper(trim(str_replace('-', '', $number)));
if ($invalid = self::check($crockford)) {
throw new \RuntimeException(sprintf('Found invalid characters "%s" for crockford number "%s"', implode('', $invalid), $number));
}
// Recode symbols (base-32) and convert to base-10
$base32 = strtr($checksum ? substr($crockford, 0, -1) : $crockford, self::CROCKFORD_SYMBOLS, self::CROCKFORD_FLIPPED);
$base10 = Base::convert($base32, 32, 10);
// Verify checksum
if ($checksum && substr($crockford, -1) != self::checksum($base10)) {
throw new RuntimeException(sprintf('Invalid crockford checksum for {%s}: found "%s" must be "%s"', $number, substr($crockford, -1), self::checksum($base10)));
}
// Convert to desired base
return Base::convert($base10, 10, $base);
}
/**
* Empty numbers must return 0 value
*/
public function testEmptyNumberMustReturnZero()
{
$this->assertEquals('0', Base::convert('', 32, 10), 'Empty string');
$this->assertEquals('0', Base::convert(null, 32, 16), 'Null value');
}