/**
* Parses a string containing an integer in an arbitrary base.
*
* The string can optionally be prefixed with the `+` or `-` sign.
*
* @param string $number The number to parse.
* @param int $base The base of the number, between 2 and 36.
*
* @return BigInteger
*
* @throws \InvalidArgumentException If the number is invalid or the base is out of range.
*/
public static function parse($number, $base = 10)
{
$number = (string) $number;
$base = (int) $base;
$dictionary = '0123456789abcdefghijklmnopqrstuvwxyz';
if ($number === '') {
throw new \InvalidArgumentException('The value cannot be empty.');
}
if ($base < 2 || $base > 36) {
throw new \InvalidArgumentException(sprintf('Base %d is not in range 2 to 36.', $base));
}
if ($number[0] === '-') {
$sign = '-';
$number = substr($number, 1);
} elseif ($number[0] === '+') {
$sign = '';
$number = substr($number, 1);
} else {
$sign = '';
}
if ($number === false || $number === '') {
throw new \InvalidArgumentException('The value cannot be empty.');
}
$number = ltrim($number, '0');
if ($number === '') {
// The result will be the same in any base, avoid further calculation.
return BigInteger::zero();
}
if ($number === '1') {
// The result will be the same in any base, avoid further calculation.
return new BigInteger($sign . '1');
}
if ($base === 10 && ctype_digit($number)) {
// The number is usable as is, avoid further calculation.
return new BigInteger($sign . $number);
}
$calc = Calculator::get();
$number = strtolower($number);
$result = '0';
$power = '1';
for ($i = strlen($number) - 1; $i >= 0; $i--) {
$char = $number[$i];
$index = strpos($dictionary, $char);
if ($index === false || $index >= $base) {
throw new \InvalidArgumentException(sprintf('"%s" is not a valid character in base %d.', $char, $base));
}
if ($index !== 0) {
$add = $index === 1 ? $power : $calc->mul($power, (string) $index);
$result = $calc->add($result, $add);
}
$power = $calc->mul($power, (string) $base);
}
return new BigInteger($sign . $result);
}
/**
* Returns file size by reading whole files and counting read bites
* @link http://stackoverflow.com/questions/5501451/php-x86-how-to-get-filesize-of-2gb-file-without-external-program/5504829#5504829
* @inheritdoc
*/
public function getFileSize($path)
{
$fp = fopen($path, "rb");
if (!$fp) {
throw new Exception("Cannot read from file.");
}
flock($fp, LOCK_SH);
rewind($fp);
$fileSize = BigInteger::zero();
$chunkSize = 1024 * 1024;
while (!feof($fp)) {
$readBytes = strlen(fread($fp, $chunkSize));
$fileSize = $fileSize->plus($readBytes);
}
flock($fp, LOCK_UN);
fclose($fp);
return $fileSize;
}
/**
* Returns a BigRational representing zero.
*
* @return BigRational
*/
public static function zero()
{
static $zero;
if ($zero === null) {
$zero = new BigRational(BigInteger::zero(), BigInteger::one(), false);
}
return $zero;
}
/**
* @expectedException \LogicException
*/
public function testDirectCallToUnserialize()
{
BigInteger::zero()->unserialize('123');
}
