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<?php
declare(strict_types=1);
namespace ZipStream;
use OverflowException;
class Bigint
{
/**
* @var int[]
*/
private $bytes = [0, 0, 0, 0, 0, 0, 0, 0];
/**
* Initialize the bytes array
*
* @param int $value
*/
public function __construct(int $value = 0)
{
$this->fillBytes($value, 0, 8);
}
/**
* Get an instance
*
* @param int $value
* @return Bigint
*/
public static function init(int $value = 0): self
{
return new self($value);
}
/**
* Fill bytes from low to high
*
* @param int $low
* @param int $high
* @return Bigint
*/
public static function fromLowHigh(int $low, int $high): self
{
$bigint = new self();
$bigint->fillBytes($low, 0, 4);
$bigint->fillBytes($high, 4, 4);
return $bigint;
}
/**
* Get high 32
*
* @return int
*/
public function getHigh32(): int
{
return $this->getValue(4, 4);
}
/**
* Get value from bytes array
*
* @param int $end
* @param int $length
* @return int
*/
public function getValue(int $end = 0, int $length = 8): int
{
$result = 0;
for ($i = $end + $length - 1; $i >= $end; $i--) {
$result <<= 8;
$result |= $this->bytes[$i];
}
return $result;
}
/**
* Get low FF
*
* @param bool $force
* @return float
*/
public function getLowFF(bool $force = false): float
{
if ($force || $this->isOver32()) {
return (float)0xFFFFFFFF;
}
return (float)$this->getLow32();
}
/**
* Check if is over 32
*
* @psalm-suppress ArgumentTypeCoercion
* @param bool $force
* @return bool
*/
public function isOver32(bool $force = false): bool
{
// value 0xFFFFFFFF already needs a Zip64 header
return $force ||
max(array_slice($this->bytes, 4, 4)) > 0 ||
min(array_slice($this->bytes, 0, 4)) === 0xFF;
}
/**
* Get low 32
*
* @return int
*/
public function getLow32(): int
{
return $this->getValue(0, 4);
}
/**
* Get hexadecimal
*
* @return string
*/
public function getHex64(): string
{
$result = '0x';
for ($i = 7; $i >= 0; $i--) {
$result .= sprintf('%02X', $this->bytes[$i]);
}
return $result;
}
/**
* Add
*
* @param Bigint $other
* @return Bigint
*/
public function add(self $other): self
{
$result = clone $this;
$overflow = false;
for ($i = 0; $i < 8; $i++) {
$result->bytes[$i] += $other->bytes[$i];
if ($overflow) {
$result->bytes[$i]++;
$overflow = false;
}
if ($result->bytes[$i] & 0x100) {
$overflow = true;
$result->bytes[$i] &= 0xFF;
}
}
if ($overflow) {
throw new OverflowException();
}
return $result;
}
/**
* Fill the bytes field with int
*
* @param int $value
* @param int $start
* @param int $count
* @return void
*/
protected function fillBytes(int $value, int $start, int $count): void
{
for ($i = 0; $i < $count; $i++) {
$this->bytes[$start + $i] = $i >= PHP_INT_SIZE ? 0 : $value & 0xFF;
$value >>= 8;
}
}
}
|
