Element::fromDER() - Code Metrics - sop/asn1 - Measure and Improve Code Quality continuously with Scrutinizer

Element::fromDER() A
last analyzed 2025-01-08 14:01 UTC

↳ Parent: Element

Complexity

Conditions	4
Paths	5

Size

Total Lines	23
Code Lines	12

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	13
CRAP Score	4

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	4
eloc	12
c	1
b	0
f	0
nc	5
nop	2
dl	0
loc	23
ccs	13
cts	13
cp	1
crap	4
rs	9.8666

<?php

declare(strict_types = 1);

namespace Sop\ASN1;

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

/**
 * 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 = [
        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
     */
    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);
        // decode remaining element
        $element = $cls::_decodeFromDER($identifier, $data, $idx);
        // 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.
     */
    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
     */
    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.
     */
    public function asUnspecified(): UnspecifiedType
    {
        return new UnspecifiedType($this);
    }

    /**
     * Get human readable name for an universal tag.
     */
    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.
     */
    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
     */
    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.
     *
     * @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.
     *
     * @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.
     */
    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.
     */
    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.
     */
    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;
    }
}


1		<?php
2
3		declare(strict_types = 1);
4
5		namespace Sop\ASN1;
6
7		use Sop\ASN1\Component\Identifier;
8		use Sop\ASN1\Component\Length;
9		use Sop\ASN1\Exception\DecodeException;
10		use Sop\ASN1\Feature\ElementBase;
11		use Sop\ASN1\Type\Constructed;
12		use Sop\ASN1\Type\Constructed\ConstructedString;
13		use Sop\ASN1\Type\Primitive;
14		use Sop\ASN1\Type\StringType;
15		use Sop\ASN1\Type\Tagged\ApplicationType;
16		use Sop\ASN1\Type\Tagged\ContextSpecificType;
17		use Sop\ASN1\Type\Tagged\PrivateType;
18		use Sop\ASN1\Type\TaggedType;
19		use Sop\ASN1\Type\TimeType;
20		use Sop\ASN1\Type\UnspecifiedType;
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 = [
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		];
94
95		/**
96		* Pseudotype for all string types.
97		*
98		* May be used as an expectation parameter.
99		*
100		* @var int
101		*/
102		const TYPE_STRING = -1;
103
104		/**
105		* Pseudotype for all time types.
106		*
107		* May be used as an expectation parameter.
108		*
109		* @var int
110		*/
111		const TYPE_TIME = -2;
112
113		/**
114		* Pseudotype for constructed strings.
115		*
116		* May be used as an expectation parameter.
117		*
118		* @var int
119		*/
120		const TYPE_CONSTRUCTED_STRING = -3;
121
122		/**
123		* Mapping from universal type tag to human readable name.
124		*
125		* @internal
126		*
127		* @var array
128		*/
129		const MAP_TYPE_TO_NAME = [
130		self::TYPE_EOC => 'EOC',
131		self::TYPE_BOOLEAN => 'BOOLEAN',
132		self::TYPE_INTEGER => 'INTEGER',
133		self::TYPE_BIT_STRING => 'BIT STRING',
134		self::TYPE_OCTET_STRING => 'OCTET STRING',
135		self::TYPE_NULL => 'NULL',
136		self::TYPE_OBJECT_IDENTIFIER => 'OBJECT IDENTIFIER',
137		self::TYPE_OBJECT_DESCRIPTOR => 'ObjectDescriptor',
138		self::TYPE_EXTERNAL => 'EXTERNAL',
139		self::TYPE_REAL => 'REAL',
140		self::TYPE_ENUMERATED => 'ENUMERATED',
141		self::TYPE_EMBEDDED_PDV => 'EMBEDDED PDV',
142		self::TYPE_UTF8_STRING => 'UTF8String',
143		self::TYPE_RELATIVE_OID => 'RELATIVE-OID',
144		self::TYPE_SEQUENCE => 'SEQUENCE',
145		self::TYPE_SET => 'SET',
146		self::TYPE_NUMERIC_STRING => 'NumericString',
147		self::TYPE_PRINTABLE_STRING => 'PrintableString',
148		self::TYPE_T61_STRING => 'T61String',
149		self::TYPE_VIDEOTEX_STRING => 'VideotexString',
150		self::TYPE_IA5_STRING => 'IA5String',
151		self::TYPE_UTC_TIME => 'UTCTime',
152		self::TYPE_GENERALIZED_TIME => 'GeneralizedTime',
153		self::TYPE_GRAPHIC_STRING => 'GraphicString',
154		self::TYPE_VISIBLE_STRING => 'VisibleString',
155		self::TYPE_GENERAL_STRING => 'GeneralString',
156		self::TYPE_UNIVERSAL_STRING => 'UniversalString',
157		self::TYPE_CHARACTER_STRING => 'CHARACTER STRING',
158		self::TYPE_BMP_STRING => 'BMPString',
159		self::TYPE_STRING => 'Any String',
160		self::TYPE_TIME => 'Any Time',
161		self::TYPE_CONSTRUCTED_STRING => 'Constructed String',
162		];
163
164		/**
165		* Element's type tag.
166		*
167		* @var int
168		*/
169		protected $_typeTag;
170
171		/**
172		* Whether type shall be encoded with indefinite length.
173		*
174		* @var bool
175		*/
176		protected $_indefiniteLength = false;
177
178		/**
179		* {@inheritdoc}
180		*/
181		abstract public function typeClass(): int;
182
183		/**
184		* {@inheritdoc}
185		*/
186		abstract public function isConstructed(): bool;
187
188		/**
189		* Decode element from DER data.
190		*
191		* @param string $data DER encoded data
192		* @param null\|int $offset Reference to the variable that contains offset
193		* into the data where to start parsing.
194		* Variable is updated to the offset next to the
195		* parsed element. If null, start from offset 0.
196		*
197		* @throws DecodeException If decoding fails
198		* @throws \UnexpectedValueException If called in the context of an expected
199		* type, but decoding yields another type
200		*/
201	273	public static function fromDER(string $data, ?int &$offset = null): ElementBase
202		{
203	273	$idx = $offset ?? 0;
204		// decode identifier
205	273	$identifier = Identifier::fromDER($data, $idx);
206		// determine class that implements type specific decoding
207	273	$cls = self::_determineImplClass($identifier);
208		// decode remaining element
209	272	$element = $cls::_decodeFromDER($identifier, $data, $idx);
210		// if called in the context of a concrete class, check
211		// that decoded type matches the type of a calling class
212	234	$called_class = get_called_class();
213	234	if (self::class !== $called_class) {
214	205	if (!$element instanceof $called_class) {
215	2	throw new \UnexpectedValueException(
216	2	sprintf('%s expected, got %s.', $called_class, get_class($element)));
217		}
218		}
219		// update offset for the caller
220	232	if (isset($offset)) {
221	41	$offset = $idx;
222		}
223	232	return $element;
224		}
225
226		/**
227		* {@inheritdoc}
228		*/
229	183	public function toDER(): string
230		{
231	183	$identifier = new Identifier($this->typeClass(),
232	183	$this->isConstructed() ? Identifier::CONSTRUCTED : Identifier::PRIMITIVE,
233	183	$this->_typeTag);
234	183	$content = $this->_encodedContentDER();
235	181	if ($this->_indefiniteLength) {
236	21	$length = new Length(0, true);
237	21	$eoc = new Primitive\EOC();
238	21	return $identifier->toDER() . $length->toDER() . $content . $eoc->toDER();
239		}
240	181	$length = new Length(strlen($content));
241	181	return $identifier->toDER() . $length->toDER() . $content;
242		}
243
244		/**
245		* {@inheritdoc}
246		*/
247	128	public function tag(): int
248		{
249	128	return $this->_typeTag;
250		}
251
252		/**
253		* {@inheritdoc}
254		*/
255	42	public function isType(int $tag): bool
256		{
257		// if element is context specific
258	42	if (Identifier::CLASS_CONTEXT_SPECIFIC === $this->typeClass()) {
259	2	return false;
260		}
261		// negative tags identify an abstract pseudotype
262	40	if ($tag < 0) {
263	5	return $this->_isPseudoType($tag);
264		}
265	35	return $this->_isConcreteType($tag);
266		}
267
268		/**
269		* {@inheritdoc}
270		*/
271	10	public function expectType(int $tag): ElementBase
272		{
273	10	if (!$this->isType($tag)) {
274	3	throw new \UnexpectedValueException(
275	3	sprintf('%s expected, got %s.', self::tagToName($tag),
276	3	$this->_typeDescriptorString()));
277		}
278	7	return $this;
279		}
280
281		/**
282		* {@inheritdoc}
283		*/
284	20	public function isTagged(): bool
285		{
286	20	return $this instanceof TaggedType;
287		}
288
289		/**
290		* {@inheritdoc}
291		*/
292	13	public function expectTagged(?int $tag = null): TaggedType
293		{
294	13	if (!$this->isTagged()) {
295	1	throw new \UnexpectedValueException(
296	1	sprintf('Context specific element expected, got %s.',
297	1	Identifier::classToName($this->typeClass())));
298		}
299	12	if (isset($tag) && $this->tag() !== $tag) {
300	5	throw new \UnexpectedValueException(
301	5	sprintf('Tag %d expected, got %d.', $tag, $this->tag()));
302		}
303	7	return $this;
304		}
305
306		/**
307		* Whether element has indefinite length.
308		*/
309	3	public function hasIndefiniteLength(): bool
310		{
311	3	return $this->_indefiniteLength;
312		}
313
314		/**
315		* Get self with indefinite length encoding set.
316		*
317		* @param bool $indefinite True for indefinite length, false for definite length
318		*/
319	21	public function withIndefiniteLength(bool $indefinite = true): self
320		{
321	21	$obj = clone $this;
322	21	$obj->_indefiniteLength = $indefinite;
323	21	return $obj;
324		}
325
326		/**
327		* {@inheritdoc}
328		*/
329	72	final public function asElement(): Element
330		{
331	72	return $this;
332		}
333
334		/**
335		* Get element decorated with `UnspecifiedType` object.
336		*/
337	51	public function asUnspecified(): UnspecifiedType
338		{
339	51	return new UnspecifiedType($this);
340		}
341
342		/**
343		* Get human readable name for an universal tag.
344		*/
345	46	public static function tagToName(int $tag): string
346		{
347	46	if (!array_key_exists($tag, self::MAP_TYPE_TO_NAME)) {
348	1	return "TAG {$tag}";
349		}
350	45	return self::MAP_TYPE_TO_NAME[$tag];
351		}
352
353		/**
354		* Get the content encoded in DER.
355		*
356		* Returns the DER encoded content without identifier and length header octets.
357		*/
358		abstract protected function _encodedContentDER(): string;
359
360		/**
361		* Decode type-specific element from DER.
362		*
363		* @param Identifier $identifier Pre-parsed identifier
364		* @param string $data DER data
365		* @param int $offset Offset in data to the next byte after identifier
366		*
367		* @throws DecodeException If decoding fails
368		*/
369	1	protected static function _decodeFromDER(Identifier $identifier,
370		string $data, int &$offset): ElementBase
371		{
372	1	throw new \BadMethodCallException(
373	1	__METHOD__ . ' must be implemented in derived class.');
374		}
375
376		/**
377		* Determine the class that implements the type.
378		*
379		* @return string Class name
380		*/
381	276	protected static function _determineImplClass(Identifier $identifier): string
382		{
383	276	switch ($identifier->typeClass()) {
384		case Identifier::CLASS_UNIVERSAL:
385	258	$cls = self::_determineUniversalImplClass($identifier->intTag());
386		// constructed strings may be present in BER
387	257	if ($identifier->isConstructed()
388	257	&& is_subclass_of($cls, StringType::class)) {
389	22	$cls = ConstructedString::class;
390		}
391	257	return $cls;
392		case Identifier::CLASS_CONTEXT_SPECIFIC:
393	25	return ContextSpecificType::class;
394		case Identifier::CLASS_APPLICATION:
395	3	return ApplicationType::class;
396		case Identifier::CLASS_PRIVATE:
397	3	return PrivateType::class;
398		}
399	1	throw new \UnexpectedValueException(sprintf('%s %d not implemented.',
400	1	Identifier::classToName($identifier->typeClass()), $identifier->tag()));
401		}
402
403		/**
404		* Determine the class that implements an universal type of the given tag.
405		*
406		* @throws \UnexpectedValueException
407		*
408		* @return string Class name
409		*/
410	267	protected static function _determineUniversalImplClass(int $tag): string
411		{
412	267	if (!array_key_exists($tag, self::MAP_TAG_TO_CLASS)) {
413	1	throw new \UnexpectedValueException(
414	1	"Universal tag {$tag} not implemented.");
415		}
416	266	return self::MAP_TAG_TO_CLASS[$tag];
417		}
418
419		/**
420		* Get textual description of the type for debugging purposes.
421		*/
422	3	protected function _typeDescriptorString(): string
423		{
424	3	if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
425	1	return self::tagToName($this->_typeTag);
426		}
427	2	return sprintf('%s TAG %d', Identifier::classToName($this->typeClass()),
428	2	$this->_typeTag);
429		}
430
431		/**
432		* Check whether the element is a concrete type of a given tag.
433		*/
434	35	private function _isConcreteType(int $tag): bool
435		{
436		// if tag doesn't match
437	35	if ($this->tag() !== $tag) {
438	25	return false;
439		}
440		// if type is universal check that instance is of a correct class
441	33	if (Identifier::CLASS_UNIVERSAL === $this->typeClass()) {
442	33	$cls = self::_determineUniversalImplClass($tag);
443	33	if (!$this instanceof $cls) {
444	1	return false;
445		}
446		}
447	32	return true;
448		}
449
450		/**
451		* Check whether the element is a pseudotype.
452		*/
453	5	private function _isPseudoType(int $tag): bool
454		{
455		switch ($tag) {
456	5	case self::TYPE_STRING:
457	1	return $this instanceof StringType;
458	4	case self::TYPE_TIME:
459	2	return $this instanceof TimeType;
460	2	case self::TYPE_CONSTRUCTED_STRING:
461	1	return $this instanceof ConstructedString;
462		}
463	1	return false;
464		}
465		}
466

sop / asn1

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Element::fromDER() A last analyzed 2025-01-08 14:01 UTC

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Element::fromDER() A
last analyzed 2025-01-08 14:01 UTC