<?php
declare(strict_types=1);
/*
* The MIT License (MIT)
*
* Copyright (c) 2018-2020 Spomky-Labs
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
namespace CBOR\OtherObject;
use Assert\Assertion;
use Brick\Math\BigInteger;
use CBOR\OtherObject as Base;
use CBOR\Utils;
use InvalidArgumentException;
final class HalfPrecisionFloatObject extends Base
{
public static function supportedAdditionalInformation(): array
{
return [25];
}
public static function createFromLoadedData(int $additionalInformation, ?string $data): Base
{
return new self($additionalInformation, $data);
}
/**
* @return HalfPrecisionFloatObject
*/
public static function create(string $value): self
{
if (4 !== mb_strlen($value, '8bit')) {
throw new InvalidArgumentException('The value is not a valid half precision floating point');
}
return new self(25, $value);
}
public function getNormalizedData(bool $ignoreTags = false)
{
$exp = $this->getExponent();
$mant = $this->getMantissa();
$sign = $this->getSign();
if (0 === $exp) {
$val = $mant * 2 ** (-24);
} elseif (0b11111 !== $exp) {
$val = ($mant + (1 << 10)) * 2 ** ($exp - 25);
} else {
$val = 0 === $mant ? INF : NAN;
}
return $sign * $val;
}
public function getExponent(): int
{
$data = $this->data;
Assertion::string($data, 'Invalid data');
return Utils::binToBigInteger($data)->shiftedRight(10)->and(Utils::hexToBigInteger('1f'))->toInt();
}
public function getMantissa(): int
{
$data = $this->data;
Assertion::string($data, 'Invalid data');
return Utils::binToBigInteger($data)->and(Utils::hexToBigInteger('3ff'))->toInt();
}
public function getSign(): int
{
$data = $this->data;
Assertion::string($data, 'Invalid data');
$sign = Utils::binToBigInteger($data)->shiftedRight(15);
return $sign->isEqualTo(BigInteger::one()) ? -1 : 1;
}
}