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<?php
/**
* GMP BigInteger Engine
*
* PHP version 5 and 7
*
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2017 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://pear.php.net/package/Math_BigInteger
*/
namespace phpseclib3\Math\BigInteger\Engines;
use phpseclib3\Exception\BadConfigurationException;
/**
* GMP Engine.
*
* @author Jim Wigginton <terrafrost@php.net>
*/
class GMP extends Engine
{
/**
* Can Bitwise operations be done fast?
*
* @see parent::bitwise_leftRotate()
* @see parent::bitwise_rightRotate()
*/
const FAST_BITWISE = true;
/**
* Engine Directory
*
* @see parent::setModExpEngine
*/
const ENGINE_DIR = 'GMP';
/**
* Test for engine validity
*
* @return bool
* @see parent::__construct()
*/
public static function isValidEngine()
{
return extension_loaded('gmp');
}
/**
* Default constructor
*
* @param mixed $x integer Base-10 number or base-$base number if $base set.
* @param int $base
* @see parent::__construct()
*/
public function __construct($x = 0, $base = 10)
{
if (!isset(static::$isValidEngine[static::class])) {
static::$isValidEngine[static::class] = self::isValidEngine();
}
if (!static::$isValidEngine[static::class]) {
throw new BadConfigurationException('GMP is not setup correctly on this system');
}
if ($x instanceof \GMP) {
$this->value = $x;
return;
}
$this->value = gmp_init(0);
parent::__construct($x, $base);
}
/**
* Initialize a GMP BigInteger Engine instance
*
* @param int $base
* @see parent::__construct()
*/
protected function initialize($base)
{
switch (abs($base)) {
case 256:
$this->value = gmp_import($this->value);
if ($this->is_negative) {
$this->value = -$this->value;
}
break;
case 16:
$temp = $this->is_negative ? '-0x' . $this->value : '0x' . $this->value;
$this->value = gmp_init($temp);
break;
case 10:
$this->value = gmp_init(isset($this->value) ? $this->value : '0');
}
}
/**
* Converts a BigInteger to a base-10 number.
*
* @return string
*/
public function toString()
{
return (string)$this->value;
}
/**
* Converts a BigInteger to a bit string (eg. base-2).
*
* Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're
* saved as two's compliment.
*
* @param bool $twos_compliment
* @return string
*/
public function toBits($twos_compliment = false)
{
$hex = $this->toHex($twos_compliment);
$bits = gmp_strval(gmp_init($hex, 16), 2);
if ($this->precision > 0) {
$bits = substr($bits, -$this->precision);
}
if ($twos_compliment && $this->compare(new static()) > 0 && $this->precision <= 0) {
return '0' . $bits;
}
return $bits;
}
/**
* Converts a BigInteger to a byte string (eg. base-256).
*
* @param bool $twos_compliment
* @return string
*/
public function toBytes($twos_compliment = false)
{
if ($twos_compliment) {
return $this->toBytesHelper();
}
if (gmp_cmp($this->value, gmp_init(0)) == 0) {
return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';
}
$temp = gmp_export($this->value);
return $this->precision > 0 ?
substr(str_pad($temp, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :
ltrim($temp, chr(0));
}
/**
* Adds two BigIntegers.
*
* @param GMP $y
* @return GMP
*/
public function add(GMP $y)
{
$temp = new self();
$temp->value = $this->value + $y->value;
return $this->normalize($temp);
}
/**
* Subtracts two BigIntegers.
*
* @param GMP $y
* @return GMP
*/
public function subtract(GMP $y)
{
$temp = new self();
$temp->value = $this->value - $y->value;
return $this->normalize($temp);
}
/**
* Multiplies two BigIntegers.
*
* @param GMP $x
* @return GMP
*/
public function multiply(GMP $x)
{
$temp = new self();
$temp->value = $this->value * $x->value;
return $this->normalize($temp);
}
/**
* Divides two BigIntegers.
*
* Returns an array whose first element contains the quotient and whose second element contains the
* "common residue". If the remainder would be positive, the "common residue" and the remainder are the
* same. If the remainder would be negative, the "common residue" is equal to the sum of the remainder
* and the divisor (basically, the "common residue" is the first positive modulo).
*
* @param GMP $y
* @return array{GMP, GMP}
*/
public function divide(GMP $y)
{
$quotient = new self();
$remainder = new self();
list($quotient->value, $remainder->value) = gmp_div_qr($this->value, $y->value);
if (gmp_sign($remainder->value) < 0) {
$remainder->value = $remainder->value + gmp_abs($y->value);
}
return [$this->normalize($quotient), $this->normalize($remainder)];
}
/**
* Compares two numbers.
*
* Although one might think !$x->compare($y) means $x != $y, it, in fact, means the opposite. The reason for this
* is demonstrated thusly:
*
* $x > $y: $x->compare($y) > 0
* $x < $y: $x->compare($y) < 0
* $x == $y: $x->compare($y) == 0
*
* Note how the same comparison operator is used. If you want to test for equality, use $x->equals($y).
*
* {@internal Could return $this->subtract($x), but that's not as fast as what we do do.}
*
* @param GMP $y
* @return int in case < 0 if $this is less than $y; > 0 if $this is greater than $y, and 0 if they are equal.
* @see self::equals()
*/
public function compare(GMP $y)
{
$r = gmp_cmp($this->value, $y->value);
if ($r < -1) {
$r = -1;
}
if ($r > 1) {
$r = 1;
}
return $r;
}
/**
* Tests the equality of two numbers.
*
* If you need to see if one number is greater than or less than another number, use BigInteger::compare()
*
* @param GMP $x
* @return bool
*/
public function equals(GMP $x)
{
return $this->value == $x->value;
}
/**
* Calculates modular inverses.
*
* Say you have (30 mod 17 * x mod 17) mod 17 == 1. x can be found using modular inverses.
*
* @param GMP $n
* @return false|GMP
*/
public function modInverse(GMP $n)
{
$temp = new self();
$temp->value = gmp_invert($this->value, $n->value);
return $temp->value === false ? false : $this->normalize($temp);
}
/**
* Calculates the greatest common divisor and Bezout's identity.
*
* Say you have 693 and 609. The GCD is 21. Bezout's identity states that there exist integers x and y such that
* 693*x + 609*y == 21. In point of fact, there are actually an infinite number of x and y combinations and which
* combination is returned is dependent upon which mode is in use. See
* {@link http://en.wikipedia.org/wiki/B%C3%A9zout%27s_identity Bezout's identity - Wikipedia} for more information.
*
* @param GMP $n
* @return GMP[]
*/
public function extendedGCD(GMP $n)
{
extract(gmp_gcdext($this->value, $n->value));
return [
'gcd' => $this->normalize(new self($g)),
'x' => $this->normalize(new self($s)),
'y' => $this->normalize(new self($t))
];
}
/**
* Calculates the greatest common divisor
*
* Say you have 693 and 609. The GCD is 21.
*
* @param GMP $n
* @return GMP
*/
public function gcd(GMP $n)
{
$r = gmp_gcd($this->value, $n->value);
return $this->normalize(new self($r));
}
/**
* Absolute value.
*
* @return GMP
*/
public function abs()
{
$temp = new self();
$temp->value = gmp_abs($this->value);
return $temp;
}
/**
* Logical And
*
* @param GMP $x
* @return GMP
*/
public function bitwise_and(GMP $x)
{
$temp = new self();
$temp->value = $this->value & $x->value;
return $this->normalize($temp);
}
/**
* Logical Or
*
* @param GMP $x
* @return GMP
*/
public function bitwise_or(GMP $x)
{
$temp = new self();
$temp->value = $this->value | $x->value;
return $this->normalize($temp);
}
/**
* Logical Exclusive Or
*
* @param GMP $x
* @return GMP
*/
public function bitwise_xor(GMP $x)
{
$temp = new self();
$temp->value = $this->value ^ $x->value;
return $this->normalize($temp);
}
/**
* Logical Right Shift
*
* Shifts BigInteger's by $shift bits, effectively dividing by 2**$shift.
*
* @param int $shift
* @return GMP
*/
public function bitwise_rightShift($shift)
{
// 0xFFFFFFFF >> 2 == -1 (on 32-bit systems)
// gmp_init('0xFFFFFFFF') >> 2 == gmp_init('0x3FFFFFFF')
$temp = new self();
$temp->value = $this->value >> $shift;
return $this->normalize($temp);
}
/**
* Logical Left Shift
*
* Shifts BigInteger's by $shift bits, effectively multiplying by 2**$shift.
*
* @param int $shift
* @return GMP
*/
public function bitwise_leftShift($shift)
{
$temp = new self();
$temp->value = $this->value << $shift;
return $this->normalize($temp);
}
/**
* Performs modular exponentiation.
*
* @param GMP $e
* @param GMP $n
* @return GMP
*/
public function modPow(GMP $e, GMP $n)
{
return $this->powModOuter($e, $n);
}
/**
* Performs modular exponentiation.
*
* Alias for modPow().
*
* @param GMP $e
* @param GMP $n
* @return GMP
*/
public function powMod(GMP $e, GMP $n)
{
return $this->powModOuter($e, $n);
}
/**
* Performs modular exponentiation.
*
* @param GMP $e
* @param GMP $n
* @return GMP
*/
protected function powModInner(GMP $e, GMP $n)
{
$class = static::$modexpEngine[static::class];
return $class::powModHelper($this, $e, $n);
}
/**
* Normalize
*
* Removes leading zeros and truncates (if necessary) to maintain the appropriate precision
*
* @param GMP $result
* @return GMP
*/
protected function normalize(GMP $result)
{
$result->precision = $this->precision;
$result->bitmask = $this->bitmask;
if ($result->bitmask !== false) {
$flip = $result->value < 0;
if ($flip) {
$result->value = -$result->value;
}
$result->value = $result->value & $result->bitmask->value;
if ($flip) {
$result->value = -$result->value;
}
}
return $result;
}
/**
* Performs some post-processing for randomRangePrime
*
* @param Engine $x
* @param Engine $min
* @param Engine $max
* @return GMP
*/
protected static function randomRangePrimeInner(Engine $x, Engine $min, Engine $max)
{
$p = gmp_nextprime($x->value);
if ($p <= $max->value) {
return new self($p);
}
if ($min->value != $x->value) {
$x = new self($x->value - 1);
}
return self::randomRangePrime($min, $x);
}
/**
* Generate a random prime number between a range
*
* If there's not a prime within the given range, false will be returned.
*
* @param GMP $min
* @param GMP $max
* @return false|GMP
*/
public static function randomRangePrime(GMP $min, GMP $max)
{
return self::randomRangePrimeOuter($min, $max);
}
/**
* Generate a random number between a range
*
* Returns a random number between $min and $max where $min and $max
* can be defined using one of the two methods:
*
* BigInteger::randomRange($min, $max)
* BigInteger::randomRange($max, $min)
*
* @param GMP $min
* @param GMP $max
* @return GMP
*/
public static function randomRange(GMP $min, GMP $max)
{
return self::randomRangeHelper($min, $max);
}
/**
* Make the current number odd
*
* If the current number is odd it'll be unchanged. If it's even, one will be added to it.
*
* @see self::randomPrime()
*/
protected function make_odd()
{
gmp_setbit($this->value, 0);
}
/**
* Tests Primality
*
* @param int $t
* @return bool
*/
protected function testPrimality($t)
{
return gmp_prob_prime($this->value, $t) != 0;
}
/**
* Calculates the nth root of a biginteger.
*
* Returns the nth root of a positive biginteger, where n defaults to 2
*
* @param int $n
* @return GMP
*/
protected function rootInner($n)
{
$root = new self();
$root->value = gmp_root($this->value, $n);
return $this->normalize($root);
}
/**
* Performs exponentiation.
*
* @param GMP $n
* @return GMP
*/
public function pow(GMP $n)
{
$temp = new self();
$temp->value = $this->value ** $n->value;
return $this->normalize($temp);
}
/**
* Return the minimum BigInteger between an arbitrary number of BigIntegers.
*
* @param GMP ...$nums
* @return GMP
*/
public static function min(GMP ...$nums)
{
return self::minHelper($nums);
}
/**
* Return the maximum BigInteger between an arbitrary number of BigIntegers.
*
* @param GMP ...$nums
* @return GMP
*/
public static function max(GMP ...$nums)
{
return self::maxHelper($nums);
}
/**
* Tests BigInteger to see if it is between two integers, inclusive
*
* @param GMP $min
* @param GMP $max
* @return bool
*/
public function between(GMP $min, GMP $max)
{
return $this->compare($min) >= 0 && $this->compare($max) <= 0;
}
/**
* Create Recurring Modulo Function
*
* Sometimes it may be desirable to do repeated modulos with the same number outside of
* modular exponentiation
*
* @return callable
*/
public function createRecurringModuloFunction()
{
$temp = $this->value;
return function (GMP $x) use ($temp) {
return new GMP($x->value % $temp);
};
}
/**
* Scan for 1 and right shift by that amount
*
* ie. $s = gmp_scan1($n, 0) and $r = gmp_div_q($n, gmp_pow(gmp_init('2'), $s));
*
* @param GMP $r
* @return int
*/
public static function scan1divide(GMP $r)
{
$s = gmp_scan1($r->value, 0);
$r->value >>= $s;
return $s;
}
/**
* Is Odd?
*
* @return bool
*/
public function isOdd()
{
return gmp_testbit($this->value, 0);
}
/**
* Tests if a bit is set
*
* @return bool
*/
public function testBit($x)
{
return gmp_testbit($this->value, $x);
}
/**
* Is Negative?
*
* @return bool
*/
public function isNegative()
{
return gmp_sign($this->value) == -1;
}
/**
* Negate
*
* Given $k, returns -$k
*
* @return GMP
*/
public function negate()
{
$temp = clone $this;
$temp->value = -$this->value;
return $temp;
}
}