sop / asn1

lib/ASN1/Element.php

Indentation +478 added lines, -478 removed lines

@@ -24,482 +24,482 @@
  */
 abstract class Element implements ElementBase
 {
-    // Universal type tags
-    const TYPE_EOC = 0x00;
-    const TYPE_BOOLEAN = 0x01;
-    const TYPE_INTEGER = 0x02;
-    const TYPE_BIT_STRING = 0x03;
-    const TYPE_OCTET_STRING = 0x04;
-    const TYPE_NULL = 0x05;
-    const TYPE_OBJECT_IDENTIFIER = 0x06;
-    const TYPE_OBJECT_DESCRIPTOR = 0x07;
-    const TYPE_EXTERNAL = 0x08;
-    const TYPE_REAL = 0x09;
-    const TYPE_ENUMERATED = 0x0a;
-    const TYPE_EMBEDDED_PDV = 0x0b;
-    const TYPE_UTF8_STRING = 0x0c;
-    const TYPE_RELATIVE_OID = 0x0d;
-    const TYPE_SEQUENCE = 0x10;
-    const TYPE_SET = 0x11;
-    const TYPE_NUMERIC_STRING = 0x12;
-    const TYPE_PRINTABLE_STRING = 0x13;
-    const TYPE_T61_STRING = 0x14;
-    const TYPE_VIDEOTEX_STRING = 0x15;
-    const TYPE_IA5_STRING = 0x16;
-    const TYPE_UTC_TIME = 0x17;
-    const TYPE_GENERALIZED_TIME = 0x18;
-    const TYPE_GRAPHIC_STRING = 0x19;
-    const TYPE_VISIBLE_STRING = 0x1a;
-    const TYPE_GENERAL_STRING = 0x1b;
-    const TYPE_UNIVERSAL_STRING = 0x1c;
-    const TYPE_CHARACTER_STRING = 0x1d;
-    const TYPE_BMP_STRING = 0x1e;
-
-    /**
-     * Mapping from universal type tag to implementation class name.
-     *
-     * @internal
-     *
-     * @var array
-     */
-    const MAP_TAG_TO_CLASS = [
-        self::TYPE_EOC => Primitive\EOC::class,
-        self::TYPE_BOOLEAN => Primitive\Boolean::class,
-        self::TYPE_INTEGER => Primitive\Integer::class,
-        self::TYPE_BIT_STRING => Primitive\BitString::class,
-        self::TYPE_OCTET_STRING => Primitive\OctetString::class,
-        self::TYPE_NULL => Primitive\NullType::class,
-        self::TYPE_OBJECT_IDENTIFIER => Primitive\ObjectIdentifier::class,
-        self::TYPE_OBJECT_DESCRIPTOR => Primitive\ObjectDescriptor::class,
-        self::TYPE_REAL => Primitive\Real::class,
-        self::TYPE_ENUMERATED => Primitive\Enumerated::class,
-        self::TYPE_UTF8_STRING => Primitive\UTF8String::class,
-        self::TYPE_RELATIVE_OID => Primitive\RelativeOID::class,
-        self::TYPE_SEQUENCE => Constructed\Sequence::class,
-        self::TYPE_SET => Constructed\Set::class,
-        self::TYPE_NUMERIC_STRING => Primitive\NumericString::class,
-        self::TYPE_PRINTABLE_STRING => Primitive\PrintableString::class,
-        self::TYPE_T61_STRING => Primitive\T61String::class,
-        self::TYPE_VIDEOTEX_STRING => Primitive\VideotexString::class,
-        self::TYPE_IA5_STRING => Primitive\IA5String::class,
-        self::TYPE_UTC_TIME => Primitive\UTCTime::class,
-        self::TYPE_GENERALIZED_TIME => Primitive\GeneralizedTime::class,
-        self::TYPE_GRAPHIC_STRING => Primitive\GraphicString::class,
-        self::TYPE_VISIBLE_STRING => Primitive\VisibleString::class,
-        self::TYPE_GENERAL_STRING => Primitive\GeneralString::class,
-        self::TYPE_UNIVERSAL_STRING => Primitive\UniversalString::class,
-        self::TYPE_CHARACTER_STRING => Primitive\CharacterString::class,
-        self::TYPE_BMP_STRING => Primitive\BMPString::class,
-    ];
-
-    /**
-     * Pseudotype for all string types.
-     *
-     * May be used as an expectation parameter.
-     *
-     * @var int
-     */
-    const TYPE_STRING = -1;
-
-    /**
-     * Pseudotype for all time types.
-     *
-     * May be used as an expectation parameter.
-     *
-     * @var int
-     */
-    const TYPE_TIME = -2;
-
-    /**
-     * Pseudotype for constructed strings.
-     *
-     * May be used as an expectation parameter.
-     *
-     * @var int
-     */
-    const TYPE_CONSTRUCTED_STRING = -3;
-
-    /**
-     * Mapping from universal type tag to human readable name.
-     *
-     * @internal
-     *
-     * @var array
-     */
-    const MAP_TYPE_TO_NAME = [
-        self::TYPE_EOC => 'EOC',
-        self::TYPE_BOOLEAN => 'BOOLEAN',
-        self::TYPE_INTEGER => 'INTEGER',
-        self::TYPE_BIT_STRING => 'BIT STRING',
-        self::TYPE_OCTET_STRING => 'OCTET STRING',
-        self::TYPE_NULL => 'NULL',
-        self::TYPE_OBJECT_IDENTIFIER => 'OBJECT IDENTIFIER',
-        self::TYPE_OBJECT_DESCRIPTOR => 'ObjectDescriptor',
-        self::TYPE_EXTERNAL => 'EXTERNAL',
-        self::TYPE_REAL => 'REAL',
-        self::TYPE_ENUMERATED => 'ENUMERATED',
-        self::TYPE_EMBEDDED_PDV => 'EMBEDDED PDV',
-        self::TYPE_UTF8_STRING => 'UTF8String',
-        self::TYPE_RELATIVE_OID => 'RELATIVE-OID',
-        self::TYPE_SEQUENCE => 'SEQUENCE',
-        self::TYPE_SET => 'SET',
-        self::TYPE_NUMERIC_STRING => 'NumericString',
-        self::TYPE_PRINTABLE_STRING => 'PrintableString',
-        self::TYPE_T61_STRING => 'T61String',
-        self::TYPE_VIDEOTEX_STRING => 'VideotexString',
-        self::TYPE_IA5_STRING => 'IA5String',
-        self::TYPE_UTC_TIME => 'UTCTime',
-        self::TYPE_GENERALIZED_TIME => 'GeneralizedTime',
-        self::TYPE_GRAPHIC_STRING => 'GraphicString',
-        self::TYPE_VISIBLE_STRING => 'VisibleString',
-        self::TYPE_GENERAL_STRING => 'GeneralString',
-        self::TYPE_UNIVERSAL_STRING => 'UniversalString',
-        self::TYPE_CHARACTER_STRING => 'CHARACTER STRING',
-        self::TYPE_BMP_STRING => 'BMPString',
-        self::TYPE_STRING => 'Any String',
-        self::TYPE_TIME => 'Any Time',
-        self::TYPE_CONSTRUCTED_STRING => 'Constructed String',
-    ];
-
-    /**
-     * Element's type tag.
-     *
-     * @var int
-     */
-    protected $_typeTag;
-
-    /**
-     * Whether type shall be encoded with indefinite length.
-     *
-     * @var bool
-     */
-    protected $_indefiniteLength = false;
-
-    /**
-     * {@inheritdoc}
-     */
-    abstract public function typeClass(): int;
-
-    /**
-     * {@inheritdoc}
-     */
-    abstract public function isConstructed(): bool;
-
-    /**
-     * Decode element from DER data.
-     *
-     * @param string   $data   DER encoded data
-     * @param null|int $offset Reference to the variable that contains offset
-     *                         into the data where to start parsing.
-     *                         Variable is updated to the offset next to the
-     *                         parsed element. If null, start from offset 0.
-     *
-     * @throws DecodeException           If decoding fails
-     * @throws \UnexpectedValueException If called in the context of an expected
-     *                                   type, but decoding yields another type
-     *
-     * @return ElementBase
-     */
-    public static function fromDER(string $data, int &$offset = null): ElementBase
-    {
-        $idx = $offset ?? 0;
-        // decode identifier
-        $identifier = Identifier::fromDER($data, $idx);
-        // determine class that implements type specific decoding
-        $cls = self::_determineImplClass($identifier);
-        try {
-            // decode remaining element
-            $element = $cls::_decodeFromDER($identifier, $data, $idx);
-        } catch (\LogicException $e) {
-            // rethrow as a RuntimeException for unified exception handling
-            throw new DecodeException(
-                sprintf('Error while decoding %s.',
-                    self::tagToName($identifier->intTag())), 0, $e);
-        }
-        // if called in the context of a concrete class, check
-        // that decoded type matches the type of a calling class
-        $called_class = get_called_class();
-        if (self::class !== $called_class) {
-            if (!$element instanceof $called_class) {
-                throw new \UnexpectedValueException(
-                    sprintf('%s expected, got %s.', $called_class,
-                        get_class($element)));
-            }
-        }
-        // update offset for the caller
-        if (isset($offset)) {
-            $offset = $idx;
-        }
-        return $element;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function toDER(): string
-    {
-        $identifier = new Identifier($this->typeClass(),
-            $this->isConstructed() ? Identifier::CONSTRUCTED : Identifier::PRIMITIVE,
-            $this->_typeTag);
-        $content = $this->_encodedContentDER();
-        if ($this->_indefiniteLength) {
-            $length = new Length(0, true);
-            $eoc = new Primitive\EOC();
-            return $identifier->toDER() . $length->toDER() . $content . $eoc->toDER();
-        }
-        $length = new Length(strlen($content));
-        return $identifier->toDER() . $length->toDER() . $content;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function tag(): int
-    {
-        return $this->_typeTag;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function isType(int $tag): bool
-    {
-        // if element is context specific
-        if (Identifier::CLASS_CONTEXT_SPECIFIC === $this->typeClass()) {
-            return false;
-        }
-        // negative tags identify an abstract pseudotype
-        if ($tag < 0) {
-            return $this->_isPseudoType($tag);
-        }
-        return $this->_isConcreteType($tag);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function expectType(int $tag): ElementBase
-    {
-        if (!$this->isType($tag)) {
-            throw new \UnexpectedValueException(
-                sprintf('%s expected, got %s.', self::tagToName($tag),
-                    $this->_typeDescriptorString()));
-        }
-        return $this;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function isTagged(): bool
-    {
-        return $this instanceof TaggedType;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function expectTagged(?int $tag = null): TaggedType
-    {
-        if (!$this->isTagged()) {
-            throw new \UnexpectedValueException(
-                sprintf('Context specific element expected, got %s.',
-                    Identifier::classToName($this->typeClass())));
-        }
-        if (isset($tag) && $this->tag() !== $tag) {
-            throw new \UnexpectedValueException(
-                sprintf('Tag %d expected, got %d.', $tag, $this->tag()));
-        }
-        return $this;
-    }
-
-    /**
-     * Whether element has indefinite length.
-     *
-     * @return bool
-     */
-    public function hasIndefiniteLength(): bool
-    {
-        return $this->_indefiniteLength;
-    }
-
-    /**
-     * Get self with indefinite length encoding set.
-     *
-     * @param bool $indefinite True for indefinite length, false for definite length
-     *
-     * @return self
-     */
-    public function withIndefiniteLength(bool $indefinite = true): self
-    {
-        $obj = clone $this;
-        $obj->_indefiniteLength = $indefinite;
-        return $obj;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    final public function asElement(): Element
-    {
-        return $this;
-    }
-
-    /**
-     * Get element decorated with UnspecifiedType object.
-     *
-     * @return UnspecifiedType
-     */
-    public function asUnspecified(): UnspecifiedType
-    {
-        return new UnspecifiedType($this);
-    }
-
-    /**
-     * Get human readable name for an universal tag.
-     *
-     * @param int $tag
-     *
-     * @return string
-     */
-    public static function tagToName(int $tag): string
-    {
-        if (!array_key_exists($tag, self::MAP_TYPE_TO_NAME)) {
-            return "TAG {$tag}";
-        }
-        return self::MAP_TYPE_TO_NAME[$tag];
-    }
-
-    /**
-     * Get the content encoded in DER.
-     *
-     * Returns the DER encoded content without identifier and length header octets.
-     *
-     * @return string
-     */
-    abstract protected function _encodedContentDER(): string;
-
-    /**
-     * Decode type-specific element from DER.
-     *
-     * @param Identifier $identifier Pre-parsed identifier
-     * @param string     $data       DER data
-     * @param int        $offset     Offset in data to the next byte after identifier
-     *
-     * @throws DecodeException If decoding fails
-     *
-     * @return ElementBase
-     */
-    protected static function _decodeFromDER(Identifier $identifier,
-        string $data, int &$offset): ElementBase
-    {
-        throw new \BadMethodCallException(
-            __METHOD__ . ' must be implemented in derived class.');
-    }
-
-    /**
-     * Determine the class that implements the type.
-     *
-     * @param Identifier $identifier
-     *
-     * @return string Class name
-     */
-    protected static function _determineImplClass(Identifier $identifier): string
-    {
-        switch ($identifier->typeClass()) {
-            case Identifier::CLASS_UNIVERSAL:
-                $cls = self::_determineUniversalImplClass($identifier->intTag());
-                // constructed strings may be present in BER
-                if ($identifier->isConstructed() &&
-                    is_subclass_of($cls, StringType::class)) {
-                    $cls = ConstructedString::class;
-                }
-                return $cls;
-            case Identifier::CLASS_CONTEXT_SPECIFIC:
-                return ContextSpecificType::class;
-            case Identifier::CLASS_APPLICATION:
-                return ApplicationType::class;
-            case Identifier::CLASS_PRIVATE:
-                return PrivateType::class;
-        }
-        throw new \UnexpectedValueException(
-            sprintf('%s %d not implemented.',
-                Identifier::classToName($identifier->typeClass()),
-                $identifier->tag()));
-    }
-
-    /**
-     * Determine the class that implements an universal type of the given tag.
-     *
-     * @param int $tag
-     *
-     * @throws \UnexpectedValueException
-     *
-     * @return string Class name
-     */
-    protected static function _determineUniversalImplClass(int $tag): string
-    {
-        if (!array_key_exists($tag, self::MAP_TAG_TO_CLASS)) {
-            throw new \UnexpectedValueException(
-                "Universal tag {$tag} not implemented.");
-        }
-        return self::MAP_TAG_TO_CLASS[$tag];
-    }
-
-    /**
-     * Get textual description of the type for debugging purposes.
-     *
-     * @return string
-     */
-    protected function _typeDescriptorString(): string
-    {
-        if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
-            return self::tagToName($this->_typeTag);
-        }
-        return sprintf('%s TAG %d', Identifier::classToName($this->typeClass()),
-            $this->_typeTag);
-    }
-
-    /**
-     * Check whether the element is a concrete type of a given tag.
-     *
-     * @param int $tag
-     *
-     * @return bool
-     */
-    private function _isConcreteType(int $tag): bool
-    {
-        // if tag doesn't match
-        if ($this->tag() !== $tag) {
-            return false;
-        }
-        // if type is universal check that instance is of a correct class
-        if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
-            $cls = self::_determineUniversalImplClass($tag);
-            if (!$this instanceof $cls) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    /**
-     * Check whether the element is a pseudotype.
-     *
-     * @param int $tag
-     *
-     * @return bool
-     */
-    private function _isPseudoType(int $tag): bool
-    {
-        switch ($tag) {
-            case self::TYPE_STRING:
-                return $this instanceof StringType;
-            case self::TYPE_TIME:
-                return $this instanceof TimeType;
-            case self::TYPE_CONSTRUCTED_STRING:
-                return $this instanceof ConstructedString;
-        }
-        return false;
-    }
+	// Universal type tags
+	const TYPE_EOC = 0x00;
+	const TYPE_BOOLEAN = 0x01;
+	const TYPE_INTEGER = 0x02;
+	const TYPE_BIT_STRING = 0x03;
+	const TYPE_OCTET_STRING = 0x04;
+	const TYPE_NULL = 0x05;
+	const TYPE_OBJECT_IDENTIFIER = 0x06;
+	const TYPE_OBJECT_DESCRIPTOR = 0x07;
+	const TYPE_EXTERNAL = 0x08;
+	const TYPE_REAL = 0x09;
+	const TYPE_ENUMERATED = 0x0a;
+	const TYPE_EMBEDDED_PDV = 0x0b;
+	const TYPE_UTF8_STRING = 0x0c;
+	const TYPE_RELATIVE_OID = 0x0d;
+	const TYPE_SEQUENCE = 0x10;
+	const TYPE_SET = 0x11;
+	const TYPE_NUMERIC_STRING = 0x12;
+	const TYPE_PRINTABLE_STRING = 0x13;
+	const TYPE_T61_STRING = 0x14;
+	const TYPE_VIDEOTEX_STRING = 0x15;
+	const TYPE_IA5_STRING = 0x16;
+	const TYPE_UTC_TIME = 0x17;
+	const TYPE_GENERALIZED_TIME = 0x18;
+	const TYPE_GRAPHIC_STRING = 0x19;
+	const TYPE_VISIBLE_STRING = 0x1a;
+	const TYPE_GENERAL_STRING = 0x1b;
+	const TYPE_UNIVERSAL_STRING = 0x1c;
+	const TYPE_CHARACTER_STRING = 0x1d;
+	const TYPE_BMP_STRING = 0x1e;
+
+	/**
+	 * Mapping from universal type tag to implementation class name.
+	 *
+	 * @internal
+	 *
+	 * @var array
+	 */
+	const MAP_TAG_TO_CLASS = [
+		self::TYPE_EOC => Primitive\EOC::class,
+		self::TYPE_BOOLEAN => Primitive\Boolean::class,
+		self::TYPE_INTEGER => Primitive\Integer::class,
+		self::TYPE_BIT_STRING => Primitive\BitString::class,
+		self::TYPE_OCTET_STRING => Primitive\OctetString::class,
+		self::TYPE_NULL => Primitive\NullType::class,
+		self::TYPE_OBJECT_IDENTIFIER => Primitive\ObjectIdentifier::class,
+		self::TYPE_OBJECT_DESCRIPTOR => Primitive\ObjectDescriptor::class,
+		self::TYPE_REAL => Primitive\Real::class,
+		self::TYPE_ENUMERATED => Primitive\Enumerated::class,
+		self::TYPE_UTF8_STRING => Primitive\UTF8String::class,
+		self::TYPE_RELATIVE_OID => Primitive\RelativeOID::class,
+		self::TYPE_SEQUENCE => Constructed\Sequence::class,
+		self::TYPE_SET => Constructed\Set::class,
+		self::TYPE_NUMERIC_STRING => Primitive\NumericString::class,
+		self::TYPE_PRINTABLE_STRING => Primitive\PrintableString::class,
+		self::TYPE_T61_STRING => Primitive\T61String::class,
+		self::TYPE_VIDEOTEX_STRING => Primitive\VideotexString::class,
+		self::TYPE_IA5_STRING => Primitive\IA5String::class,
+		self::TYPE_UTC_TIME => Primitive\UTCTime::class,
+		self::TYPE_GENERALIZED_TIME => Primitive\GeneralizedTime::class,
+		self::TYPE_GRAPHIC_STRING => Primitive\GraphicString::class,
+		self::TYPE_VISIBLE_STRING => Primitive\VisibleString::class,
+		self::TYPE_GENERAL_STRING => Primitive\GeneralString::class,
+		self::TYPE_UNIVERSAL_STRING => Primitive\UniversalString::class,
+		self::TYPE_CHARACTER_STRING => Primitive\CharacterString::class,
+		self::TYPE_BMP_STRING => Primitive\BMPString::class,
+	];
+
+	/**
+	 * Pseudotype for all string types.
+	 *
+	 * May be used as an expectation parameter.
+	 *
+	 * @var int
+	 */
+	const TYPE_STRING = -1;
+
+	/**
+	 * Pseudotype for all time types.
+	 *
+	 * May be used as an expectation parameter.
+	 *
+	 * @var int
+	 */
+	const TYPE_TIME = -2;
+
+	/**
+	 * Pseudotype for constructed strings.
+	 *
+	 * May be used as an expectation parameter.
+	 *
+	 * @var int
+	 */
+	const TYPE_CONSTRUCTED_STRING = -3;
+
+	/**
+	 * Mapping from universal type tag to human readable name.
+	 *
+	 * @internal
+	 *
+	 * @var array
+	 */
+	const MAP_TYPE_TO_NAME = [
+		self::TYPE_EOC => 'EOC',
+		self::TYPE_BOOLEAN => 'BOOLEAN',
+		self::TYPE_INTEGER => 'INTEGER',
+		self::TYPE_BIT_STRING => 'BIT STRING',
+		self::TYPE_OCTET_STRING => 'OCTET STRING',
+		self::TYPE_NULL => 'NULL',
+		self::TYPE_OBJECT_IDENTIFIER => 'OBJECT IDENTIFIER',
+		self::TYPE_OBJECT_DESCRIPTOR => 'ObjectDescriptor',
+		self::TYPE_EXTERNAL => 'EXTERNAL',
+		self::TYPE_REAL => 'REAL',
+		self::TYPE_ENUMERATED => 'ENUMERATED',
+		self::TYPE_EMBEDDED_PDV => 'EMBEDDED PDV',
+		self::TYPE_UTF8_STRING => 'UTF8String',
+		self::TYPE_RELATIVE_OID => 'RELATIVE-OID',
+		self::TYPE_SEQUENCE => 'SEQUENCE',
+		self::TYPE_SET => 'SET',
+		self::TYPE_NUMERIC_STRING => 'NumericString',
+		self::TYPE_PRINTABLE_STRING => 'PrintableString',
+		self::TYPE_T61_STRING => 'T61String',
+		self::TYPE_VIDEOTEX_STRING => 'VideotexString',
+		self::TYPE_IA5_STRING => 'IA5String',
+		self::TYPE_UTC_TIME => 'UTCTime',
+		self::TYPE_GENERALIZED_TIME => 'GeneralizedTime',
+		self::TYPE_GRAPHIC_STRING => 'GraphicString',
+		self::TYPE_VISIBLE_STRING => 'VisibleString',
+		self::TYPE_GENERAL_STRING => 'GeneralString',
+		self::TYPE_UNIVERSAL_STRING => 'UniversalString',
+		self::TYPE_CHARACTER_STRING => 'CHARACTER STRING',
+		self::TYPE_BMP_STRING => 'BMPString',
+		self::TYPE_STRING => 'Any String',
+		self::TYPE_TIME => 'Any Time',
+		self::TYPE_CONSTRUCTED_STRING => 'Constructed String',
+	];
+
+	/**
+	 * Element's type tag.
+	 *
+	 * @var int
+	 */
+	protected $_typeTag;
+
+	/**
+	 * Whether type shall be encoded with indefinite length.
+	 *
+	 * @var bool
+	 */
+	protected $_indefiniteLength = false;
+
+	/**
+	 * {@inheritdoc}
+	 */
+	abstract public function typeClass(): int;
+
+	/**
+	 * {@inheritdoc}
+	 */
+	abstract public function isConstructed(): bool;
+
+	/**
+	 * Decode element from DER data.
+	 *
+	 * @param string   $data   DER encoded data
+	 * @param null|int $offset Reference to the variable that contains offset
+	 *                         into the data where to start parsing.
+	 *                         Variable is updated to the offset next to the
+	 *                         parsed element. If null, start from offset 0.
+	 *
+	 * @throws DecodeException           If decoding fails
+	 * @throws \UnexpectedValueException If called in the context of an expected
+	 *                                   type, but decoding yields another type
+	 *
+	 * @return ElementBase
+	 */
+	public static function fromDER(string $data, int &$offset = null): ElementBase
+	{
+		$idx = $offset ?? 0;
+		// decode identifier
+		$identifier = Identifier::fromDER($data, $idx);
+		// determine class that implements type specific decoding
+		$cls = self::_determineImplClass($identifier);
+		try {
+			// decode remaining element
+			$element = $cls::_decodeFromDER($identifier, $data, $idx);
+		} catch (\LogicException $e) {
+			// rethrow as a RuntimeException for unified exception handling
+			throw new DecodeException(
+				sprintf('Error while decoding %s.',
+					self::tagToName($identifier->intTag())), 0, $e);
+		}
+		// if called in the context of a concrete class, check
+		// that decoded type matches the type of a calling class
+		$called_class = get_called_class();
+		if (self::class !== $called_class) {
+			if (!$element instanceof $called_class) {
+				throw new \UnexpectedValueException(
+					sprintf('%s expected, got %s.', $called_class,
+						get_class($element)));
+			}
+		}
+		// update offset for the caller
+		if (isset($offset)) {
+			$offset = $idx;
+		}
+		return $element;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function toDER(): string
+	{
+		$identifier = new Identifier($this->typeClass(),
+			$this->isConstructed() ? Identifier::CONSTRUCTED : Identifier::PRIMITIVE,
+			$this->_typeTag);
+		$content = $this->_encodedContentDER();
+		if ($this->_indefiniteLength) {
+			$length = new Length(0, true);
+			$eoc = new Primitive\EOC();
+			return $identifier->toDER() . $length->toDER() . $content . $eoc->toDER();
+		}
+		$length = new Length(strlen($content));
+		return $identifier->toDER() . $length->toDER() . $content;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function tag(): int
+	{
+		return $this->_typeTag;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function isType(int $tag): bool
+	{
+		// if element is context specific
+		if (Identifier::CLASS_CONTEXT_SPECIFIC === $this->typeClass()) {
+			return false;
+		}
+		// negative tags identify an abstract pseudotype
+		if ($tag < 0) {
+			return $this->_isPseudoType($tag);
+		}
+		return $this->_isConcreteType($tag);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function expectType(int $tag): ElementBase
+	{
+		if (!$this->isType($tag)) {
+			throw new \UnexpectedValueException(
+				sprintf('%s expected, got %s.', self::tagToName($tag),
+					$this->_typeDescriptorString()));
+		}
+		return $this;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function isTagged(): bool
+	{
+		return $this instanceof TaggedType;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function expectTagged(?int $tag = null): TaggedType
+	{
+		if (!$this->isTagged()) {
+			throw new \UnexpectedValueException(
+				sprintf('Context specific element expected, got %s.',
+					Identifier::classToName($this->typeClass())));
+		}
+		if (isset($tag) && $this->tag() !== $tag) {
+			throw new \UnexpectedValueException(
+				sprintf('Tag %d expected, got %d.', $tag, $this->tag()));
+		}
+		return $this;
+	}
+
+	/**
+	 * Whether element has indefinite length.
+	 *
+	 * @return bool
+	 */
+	public function hasIndefiniteLength(): bool
+	{
+		return $this->_indefiniteLength;
+	}
+
+	/**
+	 * Get self with indefinite length encoding set.
+	 *
+	 * @param bool $indefinite True for indefinite length, false for definite length
+	 *
+	 * @return self
+	 */
+	public function withIndefiniteLength(bool $indefinite = true): self
+	{
+		$obj = clone $this;
+		$obj->_indefiniteLength = $indefinite;
+		return $obj;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	final public function asElement(): Element
+	{
+		return $this;
+	}
+
+	/**
+	 * Get element decorated with UnspecifiedType object.
+	 *
+	 * @return UnspecifiedType
+	 */
+	public function asUnspecified(): UnspecifiedType
+	{
+		return new UnspecifiedType($this);
+	}
+
+	/**
+	 * Get human readable name for an universal tag.
+	 *
+	 * @param int $tag
+	 *
+	 * @return string
+	 */
+	public static function tagToName(int $tag): string
+	{
+		if (!array_key_exists($tag, self::MAP_TYPE_TO_NAME)) {
+			return "TAG {$tag}";
+		}
+		return self::MAP_TYPE_TO_NAME[$tag];
+	}
+
+	/**
+	 * Get the content encoded in DER.
+	 *
+	 * Returns the DER encoded content without identifier and length header octets.
+	 *
+	 * @return string
+	 */
+	abstract protected function _encodedContentDER(): string;
+
+	/**
+	 * Decode type-specific element from DER.
+	 *
+	 * @param Identifier $identifier Pre-parsed identifier
+	 * @param string     $data       DER data
+	 * @param int        $offset     Offset in data to the next byte after identifier
+	 *
+	 * @throws DecodeException If decoding fails
+	 *
+	 * @return ElementBase
+	 */
+	protected static function _decodeFromDER(Identifier $identifier,
+		string $data, int &$offset): ElementBase
+	{
+		throw new \BadMethodCallException(
+			__METHOD__ . ' must be implemented in derived class.');
+	}
+
+	/**
+	 * Determine the class that implements the type.
+	 *
+	 * @param Identifier $identifier
+	 *
+	 * @return string Class name
+	 */
+	protected static function _determineImplClass(Identifier $identifier): string
+	{
+		switch ($identifier->typeClass()) {
+			case Identifier::CLASS_UNIVERSAL:
+				$cls = self::_determineUniversalImplClass($identifier->intTag());
+				// constructed strings may be present in BER
+				if ($identifier->isConstructed() &&
+					is_subclass_of($cls, StringType::class)) {
+					$cls = ConstructedString::class;
+				}
+				return $cls;
+			case Identifier::CLASS_CONTEXT_SPECIFIC:
+				return ContextSpecificType::class;
+			case Identifier::CLASS_APPLICATION:
+				return ApplicationType::class;
+			case Identifier::CLASS_PRIVATE:
+				return PrivateType::class;
+		}
+		throw new \UnexpectedValueException(
+			sprintf('%s %d not implemented.',
+				Identifier::classToName($identifier->typeClass()),
+				$identifier->tag()));
+	}
+
+	/**
+	 * Determine the class that implements an universal type of the given tag.
+	 *
+	 * @param int $tag
+	 *
+	 * @throws \UnexpectedValueException
+	 *
+	 * @return string Class name
+	 */
+	protected static function _determineUniversalImplClass(int $tag): string
+	{
+		if (!array_key_exists($tag, self::MAP_TAG_TO_CLASS)) {
+			throw new \UnexpectedValueException(
+				"Universal tag {$tag} not implemented.");
+		}
+		return self::MAP_TAG_TO_CLASS[$tag];
+	}
+
+	/**
+	 * Get textual description of the type for debugging purposes.
+	 *
+	 * @return string
+	 */
+	protected function _typeDescriptorString(): string
+	{
+		if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
+			return self::tagToName($this->_typeTag);
+		}
+		return sprintf('%s TAG %d', Identifier::classToName($this->typeClass()),
+			$this->_typeTag);
+	}
+
+	/**
+	 * Check whether the element is a concrete type of a given tag.
+	 *
+	 * @param int $tag
+	 *
+	 * @return bool
+	 */
+	private function _isConcreteType(int $tag): bool
+	{
+		// if tag doesn't match
+		if ($this->tag() !== $tag) {
+			return false;
+		}
+		// if type is universal check that instance is of a correct class
+		if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
+			$cls = self::_determineUniversalImplClass($tag);
+			if (!$this instanceof $cls) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Check whether the element is a pseudotype.
+	 *
+	 * @param int $tag
+	 *
+	 * @return bool
+	 */
+	private function _isPseudoType(int $tag): bool
+	{
+		switch ($tag) {
+			case self::TYPE_STRING:
+				return $this instanceof StringType;
+			case self::TYPE_TIME:
+				return $this instanceof TimeType;
+			case self::TYPE_CONSTRUCTED_STRING:
+				return $this instanceof ConstructedString;
+		}
+		return false;
+	}
 }

Switch Indentation +20 added lines, -20 removed lines

@@ -407,20 +407,20 @@ 
     protected static function _determineImplClass(Identifier $identifier): string
     {
         switch ($identifier->typeClass()) {
-            case Identifier::CLASS_UNIVERSAL:
-                $cls = self::_determineUniversalImplClass($identifier->intTag());
-                // constructed strings may be present in BER
-                if ($identifier->isConstructed() &&
-                    is_subclass_of($cls, StringType::class)) {
-                    $cls = ConstructedString::class;
-                }
-                return $cls;
-            case Identifier::CLASS_CONTEXT_SPECIFIC:
-                return ContextSpecificType::class;
-            case Identifier::CLASS_APPLICATION:
-                return ApplicationType::class;
-            case Identifier::CLASS_PRIVATE:
-                return PrivateType::class;
+        case Identifier::CLASS_UNIVERSAL:
+            $cls = self::_determineUniversalImplClass($identifier->intTag());
+            // constructed strings may be present in BER
+            if ($identifier->isConstructed() &&
+                is_subclass_of($cls, StringType::class)) {
+                $cls = ConstructedString::class;
+            }
+            return $cls;
+        case Identifier::CLASS_CONTEXT_SPECIFIC:
+            return ContextSpecificType::class;
+        case Identifier::CLASS_APPLICATION:
+            return ApplicationType::class;
+        case Identifier::CLASS_PRIVATE:
+            return PrivateType::class;
         }
         throw new \UnexpectedValueException(
             sprintf('%s %d not implemented.',
@@ -493,12 +493,12 @@ 
     private function _isPseudoType(int $tag): bool
     {
         switch ($tag) {
-            case self::TYPE_STRING:
-                return $this instanceof StringType;
-            case self::TYPE_TIME:
-                return $this instanceof TimeType;
-            case self::TYPE_CONSTRUCTED_STRING:
-                return $this instanceof ConstructedString;
+        case self::TYPE_STRING:
+            return $this instanceof StringType;
+        case self::TYPE_TIME:
+            return $this instanceof TimeType;
+        case self::TYPE_CONSTRUCTED_STRING:
+            return $this instanceof ConstructedString;
         }
         return false;
     }