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<?php |
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|
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namespace WP_DEFENDER_VENDOR\FG\ASN1; |
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|
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use WP_DEFENDER_VENDOR\FG\Utility\BigInteger; |
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use InvalidArgumentException; |
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|
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/** |
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* A base-128 decoder. |
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*/ |
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class Base128 |
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{ |
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/** |
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* @param int $value |
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* |
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* @return string |
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*/ |
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public static function encode($value) |
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{ |
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$value = BigInteger::create($value); |
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$octets = chr($value->modulus(0x80)->toInteger()); |
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|
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$value = $value->shiftRight(7); |
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while ($value->compare(0) > 0) { |
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$octets .= chr(0x80 | $value->modulus(0x80)->toInteger()); |
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$value = $value->shiftRight(7); |
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} |
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|
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return strrev($octets); |
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} |
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|
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/** |
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* @param string $octets |
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* |
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* @throws InvalidArgumentException if the given octets represent a malformed base-128 value or the decoded value would exceed the the maximum integer length |
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* |
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* @return int |
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*/ |
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public static function decode($octets) |
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{ |
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$bitsPerOctet = 7; |
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$value = BigInteger::create(0); |
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$i = 0; |
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|
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while (true) { |
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if (!isset($octets[$i])) { |
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throw new InvalidArgumentException(sprintf('Malformed base-128 encoded value (0x%s).', strtoupper(bin2hex($octets)) ?: '0')); |
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} |
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|
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$octet = ord($octets[$i++]); |
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|
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$l1 = $value->shiftLeft($bitsPerOctet); |
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$r1 = $octet & 0x7f; |
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$value = $l1->add($r1); |
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|
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if (0 === ($octet & 0x80)) { |
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break; |
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} |
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} |
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|
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return (string)$value; |
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} |
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} |
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|
