111 lines
3 KiB
PHP
111 lines
3 KiB
PHP
<?php
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/*
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* This file is part of the PHPASN1 library.
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*
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* Copyright © Friedrich Große <friedrich.grosse@gmail.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace FG\ASN1\Universal;
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use Exception;
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use FG\ASN1\Object;
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use FG\ASN1\Parsable;
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use FG\ASN1\Identifier;
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class Integer extends Object implements Parsable
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{
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/** @var int */
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private $value;
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/**
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* @param int $value
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*
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* @throws Exception if the value is not numeric
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*/
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public function __construct($value)
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{
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if (is_numeric($value) == false) {
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throw new Exception("Invalid VALUE [{$value}] for ASN1_INTEGER");
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}
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$this->value = $value;
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}
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public function getType()
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{
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return Identifier::INTEGER;
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}
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public function getContent()
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{
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return $this->value;
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}
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protected function calculateContentLength()
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{
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$nrOfOctets = 1; // we need at least one octet
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$tmpValue = gmp_abs(gmp_init($this->value, 10));
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while (gmp_cmp($tmpValue, 127) > 0) {
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$tmpValue = $this->rightShift($tmpValue, 8);
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$nrOfOctets++;
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}
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return $nrOfOctets;
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}
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/**
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* @param resource|\GMP $number
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* @param int $positions
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*
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* @return resource|\GMP
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*/
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private function rightShift($number, $positions)
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{
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// Shift 1 right = div / 2
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return gmp_div($number, gmp_pow(2, (int) $positions));
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}
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protected function getEncodedValue()
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{
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$numericValue = gmp_init($this->value, 10);
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$contentLength = $this->getContentLength();
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if (gmp_sign($numericValue) < 0) {
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$numericValue = gmp_add($numericValue, (gmp_sub(gmp_pow(2, 8 * $contentLength), 1)));
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$numericValue = gmp_add($numericValue, 1);
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}
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$result = '';
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for ($shiftLength = ($contentLength - 1) * 8; $shiftLength >= 0; $shiftLength -= 8) {
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$octet = gmp_strval(gmp_mod($this->rightShift($numericValue, $shiftLength), 256));
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$result .= chr($octet);
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}
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return $result;
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}
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public static function fromBinary(&$binaryData, &$offsetIndex = 0)
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{
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$parsedObject = new static(0);
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self::parseIdentifier($binaryData[$offsetIndex], $parsedObject->getType(), $offsetIndex++);
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$contentLength = self::parseContentLength($binaryData, $offsetIndex, 1);
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$isNegative = (ord($binaryData[$offsetIndex]) & 0x80) != 0x00;
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$number = gmp_init(ord($binaryData[$offsetIndex++]) & 0x7F, 10);
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for ($i = 0; $i < $contentLength - 1; $i++) {
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$number = gmp_or(gmp_mul($number, 0x100), ord($binaryData[$offsetIndex++]));
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}
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if ($isNegative) {
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$number = gmp_sub($number, gmp_pow(2, 8 * $contentLength - 1));
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}
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$parsedObject = new static(gmp_strval($number, 10));
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$parsedObject->setContentLength($contentLength);
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return $parsedObject;
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}
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}
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