protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$length = Length::expectFromDER($data, $idx);
$str = substr($data, $idx, $length->length());
$idx += $length->length();
if (!preg_match(self::REGEX, $str, $match)) {
throw new DecodeException("Invalid GeneralizedTime format.");
}
list(, $year, $month, $day, $hour, $minute, $second) = $match;
if (isset($match[7])) {
$frac = $match[7];
// DER restricts trailing zeroes in fractional seconds component
if ($frac[strlen($frac) - 1] === '0') {
throw new DecodeException("Fractional seconds must omit trailing zeroes.");
}
$frac = (int) $frac;
} else {
$frac = 0;
}
$time = $year . $month . $day . $hour . $minute . $second . "." . $frac . self::TZ_UTC;
$dt = \DateTimeImmutable::createFromFormat("!YmdHis.uT", $time, self::_createTimeZone(self::TZ_UTC));
if (!$dt) {
throw new DecodeException("Failed to decode GeneralizedTime: " . self::_getLastDateTimeImmutableErrorsStr());
}
$offset = $idx;
return new self($dt);
}
/**
* Constructor
*
* @param string $data DER encoded data
* @throws DecodeException If data does not adhere to DER
*/
public function __construct($data)
{
$this->_identifier = Identifier::fromDER($data, $this->_contentOffset);
Length::expectFromDER($data, $this->_contentOffset);
$this->_der = $data;
$this->_typeTag = intval($this->_identifier->tag());
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$type = new DERTaggedType($identifier, $data, $idx);
$length = Length::expectFromDER($data, $idx);
$offset = $idx + $length->length();
return $type;
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$len = Length::expectFromDER($data, $idx)->length();
$subids = self::_decodeSubIDs(substr($data, $idx, $len));
$offset = $idx + $len;
return new self(self::_implodeSubIDs(...$subids));
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
if (!$identifier->isPrimitive()) {
throw new DecodeException("Null value must be primitive.");
}
// null type has always zero length
Length::expectFromDER($data, $idx, 0);
$offset = $idx;
return new self();
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
Length::expectFromDER($data, $idx, 1);
$byte = ord($data[$idx++]);
if ($byte != 0) {
if ($byte != 0xff) {
throw new DecodeException("DER encoded boolean true must have all bits set to 1.");
}
}
$offset = $idx;
return new self($byte != 0);
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$len = Length::expectFromDER($data, $idx)->length();
$subids = self::_decodeSubIDs(substr($data, $idx, $len));
$idx += $len;
// decode first subidentifier according to spec section 8.19.4
if (isset($subids[0])) {
list($x, $y) = gmp_div_qr($subids[0], "40");
array_splice($subids, 0, 1, array($x, $y));
}
$offset = $idx;
return new self(self::_implodeSubIDs(...$subids));
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$length = Length::expectFromDER($data, $idx);
$str = substr($data, $idx, $length->length());
$idx += $length->length();
if (!preg_match(self::REGEX, $str, $match)) {
throw new DecodeException("Invalid UTCTime format.");
}
list(, $year, $month, $day, $hour, $minute, $second) = $match;
$time = $year . $month . $day . $hour . $minute . $second . self::TZ_UTC;
$dt = \DateTimeImmutable::createFromFormat("!ymdHisT", $time, self::_createTimeZone(self::TZ_UTC));
if (!$dt) {
throw new DecodeException("Failed to decode UTCTime: " . self::_getLastDateTimeImmutableErrorsStr());
}
$offset = $idx;
return new self($dt);
}
/**
*
* @see \ASN1\Element::_decodeFromDER()
* @return self
*/
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
if (!$identifier->isPrimitive()) {
throw new DecodeException("DER encoded string must be primitive.");
}
$length = Length::expectFromDER($data, $idx);
$str = $length->length() ? substr($data, $idx, $length->length()) : "";
// substr should never return false, since length is
// checked by Length::expectFromDER.
assert('is_string($str)', "substr");
$offset = $idx + $length->length();
try {
return new static($str);
} catch (\InvalidArgumentException $e) {
throw new DecodeException($e->getMessage(), null, $e);
}
}
/**
*
* @see \ASN1\Feature\Encodable::toDER()
* @return string
*/
public function toDER()
{
$identifier = new Identifier($this->typeClass(), $this->isConstructed() ? Identifier::CONSTRUCTED : Identifier::PRIMITIVE, $this->_typeTag);
$content = $this->_encodedContentDER();
$length = new Length(strlen($content));
return $identifier->toDER() . $length->toDER() . $content;
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$length = Length::expectFromDER($data, $idx);
// if length is zero, value is zero (spec 8.5.2)
if (!$length->length()) {
$obj = new self(self::NR3_ZERO);
} else {
$bytes = substr($data, $idx, $length->length());
$byte = ord($bytes[0]);
if (0x80 & $byte) {
// bit 8 = 1
$obj = self::_decodeBinaryEncoding($bytes);
} else {
if ($byte >> 6 == 0x0) {
// bit 8 = 0, bit 7 = 0
$obj = self::_decodeDecimalEncoding($bytes);
} else {
// bit 8 = 0, bit 7 = 1
$obj = self::_decodeSpecialRealValue($bytes);
}
}
}
$offset = $idx + $length->length();
return $obj;
}
/**
* Explode DER structure to DER encoded components that it contains.
*
* @param string $data
* @throws DecodeException
* @return string[]
*/
public static function explodeDER($data)
{
$offset = 0;
$identifier = Identifier::fromDER($data, $offset);
if (!$identifier->isConstructed()) {
throw new DecodeException("Element is not constructed.");
}
$length = Length::expectFromDER($data, $offset);
$end = $offset + $length->length();
$parts = array();
while ($offset < $end) {
// start of the element
$idx = $offset;
// skip identifier
Identifier::fromDER($data, $offset);
// decode element length
$length = Length::expectFromDER($data, $offset);
// extract der encoding of the element
$parts[] = substr($data, $idx, $offset - $idx + $length->length());
// update offset over content
$offset += $length->length();
}
return $parts;
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$length = Length::expectFromDER($data, $idx);
$bytes = substr($data, $idx, $length->length());
$idx += $length->length();
$neg = ord($bytes[0]) & 0x80;
// negative, apply inversion of two's complement
if ($neg) {
$len = strlen($bytes);
for ($i = 0; $i < $len; $i++) {
$bytes[$i] = ~$bytes[$i];
}
}
$num = gmp_init(bin2hex($bytes), 16);
// negative, apply addition of two's complement
// and produce negative result
if ($neg) {
$num = gmp_neg($num + 1);
}
$offset = $idx;
// late static binding since enumerated extends integer type
return new static(gmp_strval($num, 10));
}
/**
*
* @see \ASN1\Type\Tagged\ExplicitTagging::explicit()
* @return UnspecifiedType
*/
public function explicit($expectedTag = null)
{
$idx = $this->_offset;
Length::expectFromDER($this->_data, $idx);
$element = Element::fromDER($this->_data, $idx);
if (isset($expectedTag)) {
$element->expectType($expectedTag);
}
return new UnspecifiedType($element);
}
protected static function _decodeFromDER(Identifier $identifier, $data, &$offset)
{
$idx = $offset;
$length = Length::expectFromDER($data, $idx);
if ($length->length() < 1) {
throw new DecodeException("Bit string length must be at least 1.");
}
$unused_bits = ord($data[$idx++]);
if ($unused_bits > 7) {
throw new DecodeException("Unused bits in a bit string must be less than 8.");
}
$str_len = $length->length() - 1;
if ($str_len) {
$str = substr($data, $idx, $str_len);
if ($unused_bits) {
$mask = (1 << $unused_bits) - 1;
if (ord($str[strlen($str) - 1]) & $mask) {
throw new DecodeException("DER encoded bit string must have zero padding.");
}
}
} else {
$str = "";
}
$offset = $idx + $str_len;
return new self($str, $unused_bits);
}
