Element::_decodeFromDER() - Code Metrics - Inspection of "Backport constructed strings from php72" - sop/asn1 - Measure and Improve Code Quality continuously with Scrutinizer

Test Failed

Branch — php70 (fbdf5b)

by Joni

created 2019-05-13 16:26 UTC

Element::_decodeFromDER() A

↳ Parent: Element

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	6
rs	10
c	0
b	0
f	0
cc	1
nc	1
nop	3

<?php
declare(strict_types = 1);

namespace ASN1;

use ASN1\Component\Identifier;
use ASN1\Component\Length;
use ASN1\Exception\DecodeException;
use ASN1\Feature\ElementBase;
use ASN1\Type\Constructed;
use ASN1\Type\Constructed\ConstructedString;
use ASN1\Type\Primitive;
use ASN1\Type\PrimitiveString;
use ASN1\Type\StringType;
use ASN1\Type\TaggedType;
use ASN1\Type\TimeType;
use ASN1\Type\UnspecifiedType;
use ASN1\Type\Tagged\ApplicationType;
use ASN1\Type\Tagged\ContextSpecificType;
use ASN1\Type\Tagged\PrivateType;

/**
 * Base class for all ASN.1 type elements.
 */
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 = [ /* @formatter:off */
        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
        /* @formatter:on */
    ];
    
    /**
     * 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;
    
    /**
     * Mapping from universal type tag to human readable name.
     *
     * @internal
     *
     * @var array
     */
    const MAP_TYPE_TO_NAME = [ /* @formatter:off */
        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"
        /* @formatter:on */
    ];
    
    /**
     * Element's type tag.
     *
     * @var int
     */
    protected $_typeTag;
    
    /**
     * Whether type shall be encoded with indefinite length.
     *
     * @var bool
     */
    protected $_indefiniteLength = false;
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::typeClass()
     * @return int
     */
    abstract public function typeClass(): int;
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::isConstructed()
     * @return bool
     */
    abstract public function isConstructed(): bool;
    
    /**
     * 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.");
    }
    
    /**
     * Decode element from DER data.
     *
     * @param string $data DER encoded data
     * @param int|null $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;
    }
    
    /**
     *
     * @see \ASN1\Feature\Encodable::toDER()
     * @return string
     */
    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();
        } else {
            $length = new Length(strlen($content));
            return $identifier->toDER() . $length->toDER() . $content;
        }
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::tag()
     * @return int
     */
    public function tag(): int
    {
        return $this->_typeTag;
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::isType()
     * @return bool
     */
    public function isType(int $tag): bool
    {
        // if element is context specific
        if ($this->typeClass() == Identifier::CLASS_CONTEXT_SPECIFIC) {
            return false;
        }
        // negative tags identify an abstract pseudotype
        if ($tag < 0) {
            return $this->_isPseudoType($tag);
        }
        return $this->_isConcreteType($tag);
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::expectType()
     * @return ElementBase
     */
    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;
    }
    
    /**
     * 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() != $tag) {
            return false;
        }
        // if type is universal check that instance is of a correct class
        if ($this->typeClass() == Identifier::CLASS_UNIVERSAL) {
            $cls = self::_determineUniversalImplClass($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;
        }
        return false;
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::isTagged()
     * @return bool
     */
    public function isTagged(): bool
    {
        return $this instanceof TaggedType;
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::expectTagged()
     * @return TaggedType
     */
    public function expectTagged($tag = null): TaggedType
    {
        if (!$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;
    }
    
    /**
     *
     * @see \ASN1\Feature\ElementBase::asElement()
     * @return Element
     */
    final public function asElement(): Element
    {
        return $this;
    }
    
    /**
     * Get element decorated with UnspecifiedType object.
     *
     * @return UnspecifiedType
     */
    public function asUnspecified(): UnspecifiedType
    {
        return new UnspecifiedType($this);
    }
    
    /**
     * 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, PrimitiveString::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 ($this->typeClass() == Identifier::CLASS_UNIVERSAL) {
            return self::tagToName($this->_typeTag);
        }
        return sprintf("%s TAG %d", Identifier::classToName($this->typeClass()),
            $this->_typeTag);
    }
    
    /**
     * 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];
    }
}


1			<?php
2			declare(strict_types = 1);
3
4			namespace ASN1;
5
6			use ASN1\Component\Identifier;
7			use ASN1\Component\Length;
8			use ASN1\Exception\DecodeException;
9			use ASN1\Feature\ElementBase;
10			use ASN1\Type\Constructed;
11			use ASN1\Type\Constructed\ConstructedString;
12			use ASN1\Type\Primitive;
13			use ASN1\Type\PrimitiveString;
14			use ASN1\Type\StringType;
15			use ASN1\Type\TaggedType;
16			use ASN1\Type\TimeType;
17			use ASN1\Type\UnspecifiedType;
18			use ASN1\Type\Tagged\ApplicationType;
19			use ASN1\Type\Tagged\ContextSpecificType;
20			use ASN1\Type\Tagged\PrivateType;
21
22			/**
23			* Base class for all ASN.1 type elements.
24			*/
25			abstract class Element implements ElementBase
26			{
27			// Universal type tags
28			const TYPE_EOC = 0x00;
29			const TYPE_BOOLEAN = 0x01;
30			const TYPE_INTEGER = 0x02;
31			const TYPE_BIT_STRING = 0x03;
32			const TYPE_OCTET_STRING = 0x04;
33			const TYPE_NULL = 0x05;
34			const TYPE_OBJECT_IDENTIFIER = 0x06;
35			const TYPE_OBJECT_DESCRIPTOR = 0x07;
36			const TYPE_EXTERNAL = 0x08;
37			const TYPE_REAL = 0x09;
38			const TYPE_ENUMERATED = 0x0a;
39			const TYPE_EMBEDDED_PDV = 0x0b;
40			const TYPE_UTF8_STRING = 0x0c;
41			const TYPE_RELATIVE_OID = 0x0d;
42			const TYPE_SEQUENCE = 0x10;
43			const TYPE_SET = 0x11;
44			const TYPE_NUMERIC_STRING = 0x12;
45			const TYPE_PRINTABLE_STRING = 0x13;
46			const TYPE_T61_STRING = 0x14;
47			const TYPE_VIDEOTEX_STRING = 0x15;
48			const TYPE_IA5_STRING = 0x16;
49			const TYPE_UTC_TIME = 0x17;
50			const TYPE_GENERALIZED_TIME = 0x18;
51			const TYPE_GRAPHIC_STRING = 0x19;
52			const TYPE_VISIBLE_STRING = 0x1a;
53			const TYPE_GENERAL_STRING = 0x1b;
54			const TYPE_UNIVERSAL_STRING = 0x1c;
55			const TYPE_CHARACTER_STRING = 0x1d;
56			const TYPE_BMP_STRING = 0x1e;
57
58			/**
59			* Mapping from universal type tag to implementation class name.
60			*
61			* @internal
62			*
63			* @var array
64			*/
65			const MAP_TAG_TO_CLASS = [ /* @formatter:off */
66			self::TYPE_EOC => Primitive\EOC::class,
67			self::TYPE_BOOLEAN => Primitive\Boolean::class,
68			self::TYPE_INTEGER => Primitive\Integer::class,
69			self::TYPE_BIT_STRING => Primitive\BitString::class,
70			self::TYPE_OCTET_STRING => Primitive\OctetString::class,
71			self::TYPE_NULL => Primitive\NullType::class,
72			self::TYPE_OBJECT_IDENTIFIER => Primitive\ObjectIdentifier::class,
73			self::TYPE_OBJECT_DESCRIPTOR => Primitive\ObjectDescriptor::class,
74			self::TYPE_REAL => Primitive\Real::class,
75			self::TYPE_ENUMERATED => Primitive\Enumerated::class,
76			self::TYPE_UTF8_STRING => Primitive\UTF8String::class,
77			self::TYPE_RELATIVE_OID => Primitive\RelativeOID::class,
78			self::TYPE_SEQUENCE => Constructed\Sequence::class,
79			self::TYPE_SET => Constructed\Set::class,
80			self::TYPE_NUMERIC_STRING => Primitive\NumericString::class,
81			self::TYPE_PRINTABLE_STRING => Primitive\PrintableString::class,
82			self::TYPE_T61_STRING => Primitive\T61String::class,
83			self::TYPE_VIDEOTEX_STRING => Primitive\VideotexString::class,
84			self::TYPE_IA5_STRING => Primitive\IA5String::class,
85			self::TYPE_UTC_TIME => Primitive\UTCTime::class,
86			self::TYPE_GENERALIZED_TIME => Primitive\GeneralizedTime::class,
87			self::TYPE_GRAPHIC_STRING => Primitive\GraphicString::class,
88			self::TYPE_VISIBLE_STRING => Primitive\VisibleString::class,
89			self::TYPE_GENERAL_STRING => Primitive\GeneralString::class,
90			self::TYPE_UNIVERSAL_STRING => Primitive\UniversalString::class,
91			self::TYPE_CHARACTER_STRING => Primitive\CharacterString::class,
92			self::TYPE_BMP_STRING => Primitive\BMPString::class
93			/* @formatter:on */
94			];
95
96			/**
97			* Pseudotype for all string types.
98			*
99			* May be used as an expectation parameter.
100			*
101			* @var int
102			*/
103			const TYPE_STRING = -1;
104
105			/**
106			* Pseudotype for all time types.
107			*
108			* May be used as an expectation parameter.
109			*
110			* @var int
111			*/
112			const TYPE_TIME = -2;
113
114			/**
115			* Mapping from universal type tag to human readable name.
116			*
117			* @internal
118			*
119			* @var array
120			*/
121			const MAP_TYPE_TO_NAME = [ /* @formatter:off */
122			self::TYPE_EOC => "EOC",
123			self::TYPE_BOOLEAN => "BOOLEAN",
124			self::TYPE_INTEGER => "INTEGER",
125			self::TYPE_BIT_STRING => "BIT STRING",
126			self::TYPE_OCTET_STRING => "OCTET STRING",
127			self::TYPE_NULL => "NULL",
128			self::TYPE_OBJECT_IDENTIFIER => "OBJECT IDENTIFIER",
129			self::TYPE_OBJECT_DESCRIPTOR => "ObjectDescriptor",
130			self::TYPE_EXTERNAL => "EXTERNAL",
131			self::TYPE_REAL => "REAL",
132			self::TYPE_ENUMERATED => "ENUMERATED",
133			self::TYPE_EMBEDDED_PDV => "EMBEDDED PDV",
134			self::TYPE_UTF8_STRING => "UTF8String",
135			self::TYPE_RELATIVE_OID => "RELATIVE-OID",
136			self::TYPE_SEQUENCE => "SEQUENCE",
137			self::TYPE_SET => "SET",
138			self::TYPE_NUMERIC_STRING => "NumericString",
139			self::TYPE_PRINTABLE_STRING => "PrintableString",
140			self::TYPE_T61_STRING => "T61String",
141			self::TYPE_VIDEOTEX_STRING => "VideotexString",
142			self::TYPE_IA5_STRING => "IA5String",
143			self::TYPE_UTC_TIME => "UTCTime",
144			self::TYPE_GENERALIZED_TIME => "GeneralizedTime",
145			self::TYPE_GRAPHIC_STRING => "GraphicString",
146			self::TYPE_VISIBLE_STRING => "VisibleString",
147			self::TYPE_GENERAL_STRING => "GeneralString",
148			self::TYPE_UNIVERSAL_STRING => "UniversalString",
149			self::TYPE_CHARACTER_STRING => "CHARACTER STRING",
150			self::TYPE_BMP_STRING => "BMPString",
151			self::TYPE_STRING => "Any String",
152			self::TYPE_TIME => "Any Time"
153			/* @formatter:on */
154			];
155
156			/**
157			* Element's type tag.
158			*
159			* @var int
160			*/
161			protected $_typeTag;
162
163			/**
164			* Whether type shall be encoded with indefinite length.
165			*
166			* @var bool
167			*/
168			protected $_indefiniteLength = false;
169
170			/**
171			*
172			* @see \ASN1\Feature\ElementBase::typeClass()
173			* @return int
174			*/
175			abstract public function typeClass(): int;
176
177			/**
178			*
179			* @see \ASN1\Feature\ElementBase::isConstructed()
180			* @return bool
181			*/
182			abstract public function isConstructed(): bool;
183
184			/**
185			* Get the content encoded in DER.
186			*
187			* Returns the DER encoded content without identifier and length header
188			* octets.
189			*
190			* @return string
191			*/
192			abstract protected function _encodedContentDER(): string;
193
194			/**
195			* Decode type-specific element from DER.
196			*
197			* @param Identifier $identifier Pre-parsed identifier
198			* @param string $data DER data
199			* @param int $offset Offset in data to the next byte after identifier
200			* @throws DecodeException If decoding fails
201			* @return ElementBase
202			*/
203			protected static function _decodeFromDER(Identifier $identifier,
204			string $data, int &$offset): ElementBase
205			{
206			throw new \BadMethodCallException(
207			__METHOD__ . " must be implemented in derived class.");
208			}
209
210			/**
211			* Decode element from DER data.
212			*
213			* @param string $data DER encoded data
214			* @param int\|null $offset Reference to the variable that contains offset
215			* into the data where to start parsing. Variable is updated to
216			* the offset next to the parsed element. If null, start from offset
217			* 0.
218			* @throws DecodeException If decoding fails
219			* @throws \UnexpectedValueException If called in the context of an expected
220			* type, but decoding yields another type
221			* @return ElementBase
222			*/
223			public static function fromDER(string $data, int &$offset = null): ElementBase
224			{
225			$idx = $offset ?? 0;
226			// decode identifier
227			$identifier = Identifier::fromDER($data, $idx);
228			// determine class that implements type specific decoding
229			$cls = self::_determineImplClass($identifier);
230			try {
231			// decode remaining element
232			$element = $cls::_decodeFromDER($identifier, $data, $idx);
233			} catch (\LogicException $e) {
234			// rethrow as a RuntimeException for unified exception handling
235			throw new DecodeException(
236			sprintf("Error while decoding %s.",
237			self::tagToName($identifier->intTag())), 0, $e);
238			}
239			// if called in the context of a concrete class, check
240			// that decoded type matches the type of a calling class
241			$called_class = get_called_class();
242			if (self::class != $called_class) {
243			if (!$element instanceof $called_class) {
244			throw new \UnexpectedValueException(
245			sprintf("%s expected, got %s.", $called_class,
246			get_class($element)));
247			}
248			}
249			// update offset for the caller
250			if (isset($offset)) {
251			$offset = $idx;
252			}
253			return $element;
254			}
255
256			/**
257			*
258			* @see \ASN1\Feature\Encodable::toDER()
259			* @return string
260			*/
261			public function toDER(): string
262			{
263			$identifier = new Identifier($this->typeClass(),
264			$this->isConstructed() ? Identifier::CONSTRUCTED : Identifier::PRIMITIVE,
265			$this->_typeTag);
266			$content = $this->_encodedContentDER();
267			if ($this->_indefiniteLength) {
268			$length = new Length(0, true);
269			$eoc = new Primitive\EOC();
270			return $identifier->toDER() . $length->toDER() . $content .
271			$eoc->toDER();
272			} else {
273			$length = new Length(strlen($content));
274			return $identifier->toDER() . $length->toDER() . $content;
275			}
276			}
277
278			/**
279			*
280			* @see \ASN1\Feature\ElementBase::tag()
281			* @return int
282			*/
283			public function tag(): int
284			{
285			return $this->_typeTag;
286			}
287
288			/**
289			*
290			* @see \ASN1\Feature\ElementBase::isType()
291			* @return bool
292			*/
293			public function isType(int $tag): bool
294			{
295			// if element is context specific
296			if ($this->typeClass() == Identifier::CLASS_CONTEXT_SPECIFIC) {
297			return false;
298			}
299			// negative tags identify an abstract pseudotype
300			if ($tag < 0) {
301			return $this->_isPseudoType($tag);
302			}
303			return $this->_isConcreteType($tag);
304			}
305
306			/**
307			*
308			* @see \ASN1\Feature\ElementBase::expectType()
309			* @return ElementBase
310			*/
311			public function expectType(int $tag): ElementBase
312			{
313			if (!$this->isType($tag)) {
314			throw new \UnexpectedValueException(
315			sprintf("%s expected, got %s.", self::tagToName($tag),
316			$this->_typeDescriptorString()));
317			}
318			return $this;
319			}
320
321			/**
322			* Check whether the element is a concrete type of a given tag.
323			*
324			* @param int $tag
325			* @return bool
326			*/
327			private function _isConcreteType(int $tag): bool
328			{
329			// if tag doesn't match
330			if ($this->tag() != $tag) {
331			return false;
332			}
333			// if type is universal check that instance is of a correct class
334			if ($this->typeClass() == Identifier::CLASS_UNIVERSAL) {
335			$cls = self::_determineUniversalImplClass($tag);
336			if (!$this instanceof $cls) {
337			return false;
338			}
339			}
340			return true;
341			}
342
343			/**
344			* Check whether the element is a pseudotype.
345			*
346			* @param int $tag
347			* @return bool
348			*/
349			private function _isPseudoType(int $tag): bool
350			{
351			switch ($tag) {
352			case self::TYPE_STRING:
353			return $this instanceof StringType;
354			case self::TYPE_TIME:
355			return $this instanceof TimeType;
356			}
357			return false;
358			}
359
360			/**
361			*
362			* @see \ASN1\Feature\ElementBase::isTagged()
363			* @return bool
364			*/
365			public function isTagged(): bool
366			{
367			return $this instanceof TaggedType;
368			}
369
370			/**
371			*
372			* @see \ASN1\Feature\ElementBase::expectTagged()
373			* @return TaggedType
374			*/
375			public function expectTagged($tag = null): TaggedType
376			{
377			if (!$this->isTagged()) {
378			throw new \UnexpectedValueException(
379			sprintf("Context specific element expected, got %s.",
380			Identifier::classToName($this->typeClass())));
381			}
382			if (isset($tag) && $this->tag() != $tag) {
383			throw new \UnexpectedValueException(
384			sprintf("Tag %d expected, got %d.", $tag, $this->tag()));
385			}
386			return $this;
387			}
388
389			/**
390			* Whether element has indefinite length.
391			*
392			* @return bool
393			*/
394			public function hasIndefiniteLength(): bool
395			{
396			return $this->_indefiniteLength;
397			}
398
399			/**
400			* Get self with indefinite length encoding set.
401			*
402			* @param bool $indefinite True for indefinite length, false for definite
403			* length
404			* @return self
405			*/
406			public function withIndefiniteLength(bool $indefinite = true): self
407			{
408			$obj = clone $this;
409			$obj->_indefiniteLength = $indefinite;
410			return $obj;
411			}
412
413			/**
414			*
415			* @see \ASN1\Feature\ElementBase::asElement()
416			* @return Element
417			*/
418			final public function asElement(): Element
419			{
420			return $this;
421			}
422
423			/**
424			* Get element decorated with UnspecifiedType object.
425			*
426			* @return UnspecifiedType
427			*/
428			public function asUnspecified(): UnspecifiedType
429			{
430			return new UnspecifiedType($this);
431			}
432
433			/**
434			* Determine the class that implements the type.
435			*
436			* @param Identifier $identifier
437			* @return string Class name
438			*/
439			protected static function _determineImplClass(Identifier $identifier): string
440			{
441			switch ($identifier->typeClass()) {
442			case Identifier::CLASS_UNIVERSAL:
443			$cls = self::_determineUniversalImplClass($identifier->intTag());
444			// constructed strings may be present in BER
445			if ($identifier->isConstructed() &&
446			is_subclass_of($cls, PrimitiveString::class)) {
			0 ignored issues – show Bug introduced 2019-05-13 16:28 UTC by Report Bug Copy Issue Report Due to PHP Bug #53727, `is_subclass_of` might return inconsistent results on some PHP versions if `\ASN1\Type\PrimitiveString::class` can be an interface. If so, you could instead use `ReflectionClass::implementsInterface`. Loading history...
447			$cls = ConstructedString::class;
448			}
449			return $cls;
450			case Identifier::CLASS_CONTEXT_SPECIFIC:
451			return ContextSpecificType::class;
452			case Identifier::CLASS_APPLICATION:
453			return ApplicationType::class;
454			case Identifier::CLASS_PRIVATE:
455			return PrivateType::class;
456			}
457			throw new \UnexpectedValueException(
458			sprintf("%s %d not implemented.",
459			Identifier::classToName($identifier->typeClass()),
460			$identifier->tag()));
461			}
462
463			/**
464			* Determine the class that implements an universal type of the given tag.
465			*
466			* @param int $tag
467			* @throws \UnexpectedValueException
468			* @return string Class name
469			*/
470			protected static function _determineUniversalImplClass(int $tag): string
471			{
472			if (!array_key_exists($tag, self::MAP_TAG_TO_CLASS)) {
473			throw new \UnexpectedValueException(
474			"Universal tag $tag not implemented.");
475			}
476			return self::MAP_TAG_TO_CLASS[$tag];
477			}
478
479			/**
480			* Get textual description of the type for debugging purposes.
481			*
482			* @return string
483			*/
484			protected function _typeDescriptorString(): string
485			{
486			if ($this->typeClass() == Identifier::CLASS_UNIVERSAL) {
487			return self::tagToName($this->_typeTag);
488			}
489			return sprintf("%s TAG %d", Identifier::classToName($this->typeClass()),
490			$this->_typeTag);
491			}
492
493			/**
494			* Get human readable name for an universal tag.
495			*
496			* @param int $tag
497			* @return string
498			*/
499			public static function tagToName(int $tag): string
500			{
501			if (!array_key_exists($tag, self::MAP_TYPE_TO_NAME)) {
502			return "TAG $tag";
503			}
504			return self::MAP_TYPE_TO_NAME[$tag];
505			}
506			}
507

sop / asn1

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Branch — php70 (fbdf5b)

Element::_decodeFromDER() A

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