Decoder::prematureEndOfDataError() - Code Metrics - Inspection of "WiP" - s9e/Bencode - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — Exceptions ( 4789cf...69c4e2 )

by Josh

created 2020-09-23 22:50 UTC

Decoder::prematureEndOfDataError() A

↳ Parent: Decoder

Complexity

Conditions	1
Paths	1

Size

Total Lines	3
Code Lines	1

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	2
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	1
nc	1
nop	0
dl	0
loc	3
ccs	2
cts	2
cp	1
crap	1
rs	10
c	0
b	0
f	0

<?php declare(strict_types=1);

/**
* @package   s9e\Bencode
* @copyright Copyright (c) 2014-2020 The s9e authors
* @license   http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\Bencode;

use ArrayObject;
use InvalidArgumentException;
use RuntimeException;
use s9e\Bencode\Exceptions\ComplianceError;
use s9e\Bencode\Exceptions\IllegalCharacter;
use s9e\Bencode\Exceptions\PrematureEndOfData;

class Decoder
{
	/**
	* @var string Bencoded string being decoded
	*/
	protected string $bencoded;

	/**
	* @var int Length of the bencoded string
	*/
	protected int $len;

	/**
	* @var int Safe rightmost boundary
	*/
	protected int $max;

	/**
	* @var int Position of the cursor while decoding
	*/
	protected int $offset;

	public static function decode(string $bencoded)
	{
		$decoder = new static($bencoded);
		$value   = $decoder->decodeAnything();

		$decoder->checkCursorPosition();

		return $value;
	}

	protected function __construct(string $bencoded)
	{
		$this->bencoded = $bencoded;
		$this->len      = strlen($bencoded);
		$this->offset   = 0;

		if ($bencoded === '')
		{
			$this->prematureEndOfDataError();
		}
		$this->computeSafeBoundary();
	}

	protected function checkBoundary(): void
	{
		if ($this->max < 1)
		{
			if (strpos('-e', $this->bencoded[0]) !== false)
			{
				throw new IllegalCharacter(0);
			}

			$this->prematureEndOfDataError();
		}
	}

	/**
	* Check the cursor's position after decoding is done
	*/
	protected function checkCursorPosition(): void
	{
		if ($this->offset !== $this->len)
		{
			if ($this->offset > $this->len)
			{
				$this->prematureEndOfDataError();
			}

			$this->complianceError($this->offset, 'Superfluous content');
		}
	}

	protected function complianceError(int $offset, string $message = 'Illegal character'): void
	{
		throw new ComplianceError($offset, $message);
	}

	/**
	* Adjust the rightmost boundary to the last safe character that can start a value
	*
	* Will rewind the boundary to skip the rightmost digits, optionally preceded by "i" or "i-"
	*/
	protected function computeSafeBoundary(): void
	{
		$boundary = $this->len - 1;
		$c = $this->bencoded[$boundary];
		while (is_numeric($c) && --$boundary >= 0)
		{
			$c = $this->bencoded[$boundary];
		}
		if ($c === '-')
		{
			$boundary -= 2;
		}
		elseif ($c === 'i')
		{
			--$boundary;
		}

		$this->max = $boundary;
		$this->checkBoundary();
	}

	protected function decodeAnything()
	{
		$c = $this->bencoded[$this->offset];
		if ($c === 'i')
		{
			return $this->decodeInteger();
		}
		if ($c === 'd')
		{
			return $this->decodeDictionary();
		}
		if ($c === 'l')
		{
			return $this->decodeList();
		}

		return $this->decodeString();
	}

	protected function decodeDictionary(): ArrayObject
	{
		$values  = [];
		$lastKey = null;

		++$this->offset;
		while ($this->offset <= $this->max)
		{
			if ($this->bencoded[$this->offset] === 'e')
			{
				++$this->offset;

				return new ArrayObject($values, ArrayObject::ARRAY_AS_PROPS);
			}

			$offset = $this->offset;
			$key    = $this->decodeString();
			if ($key <= $lastKey)
			{
				$this->dictionaryComplianceError($offset, $key, $lastKey);
			}
			if ($this->offset > $this->max)
			{
				break;
			}
			$values[$key] = $this->decodeAnything();
			$lastKey      = $key;
		}

		$this->prematureEndOfDataError();
interface ReturnsInt {
    public function returnsIntHinted(): int;
}

class MyClass implements ReturnsInt {
    public function returnsIntHinted(): int
    {
        if (foo()) {
            return 123;
        }
        // here: null is implicitly returned
    }
}
	}

	protected function decodeDigits(string $terminator): int
	{
		// Digits sorted by decreasing frequency as observed on a random sample of torrent files
		$spn = strspn($this->bencoded, '4615302879', $this->offset);
		if (!$spn)
		{
			throw new IllegalCharacter($this->offset);
		}
		if ($this->bencoded[$this->offset] === '0' && $spn > 1)
		{
			$this->complianceError(1 + $this->offset);
		}

		// Capture the value and cast it as an integer
		$value = (int) substr($this->bencoded, $this->offset, $spn);

		$this->offset += $spn;
		if ($this->bencoded[$this->offset] !== $terminator)
		{
			throw new IllegalCharacter($this->offset);
		}
		++$this->offset;

		return $value;
	}

	protected function decodeInteger(): int
	{
		$negative = ($this->bencoded[++$this->offset] === '-');
		if ($negative && $this->bencoded[++$this->offset] === '0')
		{
			$this->complianceError($this->offset);
		}

		$value = $this->decodeDigits('e');

		return ($negative) ? -$value : $value;
	}

	protected function decodeList(): array
	{
		++$this->offset;

		$list = [];
		while ($this->offset <= $this->max)
		{
			if ($this->bencoded[$this->offset] === 'e')
			{
				++$this->offset;

				return $list;
			}

			$list[] = $this->decodeAnything();
		}

		$this->prematureEndOfDataError();
interface ReturnsInt {
    public function returnsIntHinted(): int;
}

class MyClass implements ReturnsInt {
    public function returnsIntHinted(): int
    {
        if (foo()) {
            return 123;
        }
        // here: null is implicitly returned
    }
}
	}

	protected function decodeString(): string
	{
		$len           = $this->decodeDigits(':');
		$string        = substr($this->bencoded, $this->offset, $len);
		$this->offset += $len;

		return $string;
	}

	protected function dictionaryComplianceError(int $offset, string $key, ?string $lastKey): void
	{
		if ($key === $lastKey)
		{
			$this->complianceError($offset, "Duplicate dictionary entry '" . $key . "'");
		}
		elseif ($key < $lastKey)
		{
			$this->complianceError($offset, "Out of order dictionary entry '" . $key . "'");
		}
	}

	protected function prematureEndOfDataError(): void
	{
		throw new PrematureEndOfData(max(0, $this->len - 1));
	}
}

1		<?php declare(strict_types=1);
2
3		/**
4		* @package s9e\Bencode
5		* @copyright Copyright (c) 2014-2020 The s9e authors
6		* @license http://www.opensource.org/licenses/mit-license.php The MIT License
7		*/
8		namespace s9e\Bencode;
9
10		use ArrayObject;
11		use InvalidArgumentException;
12		use RuntimeException;
13		use s9e\Bencode\Exceptions\ComplianceError;
14		use s9e\Bencode\Exceptions\IllegalCharacter;
15		use s9e\Bencode\Exceptions\PrematureEndOfData;
16
17		class Decoder
18		{
19		/**
20		* @var string Bencoded string being decoded
21		*/
22		protected string $bencoded;
23
24		/**
25		* @var int Length of the bencoded string
26		*/
27		protected int $len;
28
29		/**
30		* @var int Safe rightmost boundary
31		*/
32		protected int $max;
33
34		/**
35		* @var int Position of the cursor while decoding
36		*/
37		protected int $offset;
38
39	61	public static function decode(string $bencoded)
40		{
41	61	$decoder = new static($bencoded);
42	50	$value = $decoder->decodeAnything();
43
44	26	$decoder->checkCursorPosition();
45
46	18	return $value;
47		}
48
49	61	protected function __construct(string $bencoded)
50		{
51	61	$this->bencoded = $bencoded;
52	61	$this->len = strlen($bencoded);
53	61	$this->offset = 0;
54
55	61	if ($bencoded === '')
56		{
57	1	$this->prematureEndOfDataError();
58		}
59	60	$this->computeSafeBoundary();
60		}
61
62	60	protected function checkBoundary(): void
63		{
64	60	if ($this->max < 1)
65		{
66	10	if (strpos('-e', $this->bencoded[0]) !== false)
67		{
68	2	throw new IllegalCharacter(0);
69		}
70
71	8	$this->prematureEndOfDataError();
72		}
73		}
74
75		/**
76		* Check the cursor's position after decoding is done
77		*/
78	26	protected function checkCursorPosition(): void
79		{
80	26	if ($this->offset !== $this->len)
81		{
82	8	if ($this->offset > $this->len)
83		{
84	3	$this->prematureEndOfDataError();
85		}
86
87	5	$this->complianceError($this->offset, 'Superfluous content');
88		}
89		}
90
91	12	protected function complianceError(int $offset, string $message = 'Illegal character'): void
92		{
93	12	throw new ComplianceError($offset, $message);
94		}
95
96		/**
97		* Adjust the rightmost boundary to the last safe character that can start a value
98		*
99		* Will rewind the boundary to skip the rightmost digits, optionally preceded by "i" or "i-"
100		*/
101	60	protected function computeSafeBoundary(): void
102		{
103	60	$boundary = $this->len - 1;
104	60	$c = $this->bencoded[$boundary];
105	60	while (is_numeric($c) && --$boundary >= 0)
106		{
107	7	$c = $this->bencoded[$boundary];
108		}
109	60	if ($c === '-')
110		{
111	6	$boundary -= 2;
112		}
113	54	elseif ($c === 'i')
114		{
115	6	--$boundary;
116		}
117
118	60	$this->max = $boundary;
119	60	$this->checkBoundary();
120		}
121
122	50	protected function decodeAnything()
123		{
124	50	$c = $this->bencoded[$this->offset];
125	50	if ($c === 'i')
126		{
127	17	return $this->decodeInteger();
128		}
129	41	if ($c === 'd')
130		{
131	15	return $this->decodeDictionary();
132		}
133	32	if ($c === 'l')
134		{
135	12	return $this->decodeList();
136		}
137
138	25	return $this->decodeString();
139		}
140
141	15	protected function decodeDictionary(): ArrayObject
142		{
143	15	$values = [];
144	15	$lastKey = null;
145
146	15	++$this->offset;
147	15	while ($this->offset <= $this->max)
148		{
149	15	if ($this->bencoded[$this->offset] === 'e')
150		{
151	7	++$this->offset;
152
153	7	return new ArrayObject($values, ArrayObject::ARRAY_AS_PROPS);
154		}
155
156	14	$offset = $this->offset;
157	14	$key = $this->decodeString();
158	13	if ($key <= $lastKey)
159		{
160	4	$this->dictionaryComplianceError($offset, $key, $lastKey);
161		}
162	13	if ($this->offset > $this->max)
163		{
164	1	break;
165		}
166	12	$values[$key] = $this->decodeAnything();
167	9	$lastKey = $key;
168		}
169
170	1	$this->prematureEndOfDataError();
		0 ignored issues – show Bug Best Practice introduced 2020-09-23 12:48 UTC by Report Bug Copy Issue Report In this branch, the function will implicitly return `null` which is incompatible with the type-hinted return `ArrayObject`. Consider adding a return statement or allowing `null` as return value. For hinted functions/methods where all return statements with the correct type are only reachable via conditions, ?null? gets implicitly returned which may be incompatible with the hinted type. Let?s take a look at an example: interface ReturnsInt { public function returnsIntHinted(): int; } class MyClass implements ReturnsInt { public function returnsIntHinted(): int { if (foo()) { return 123; } // here: null is implicitly returned } } Loading history...
171		}
172
173	43	protected function decodeDigits(string $terminator): int
174		{
175		// Digits sorted by decreasing frequency as observed on a random sample of torrent files
176	43	$spn = strspn($this->bencoded, '4615302879', $this->offset);
177	43	if (!$spn)
178		{
179	7	throw new IllegalCharacter($this->offset);
180		}
181	38	if ($this->bencoded[$this->offset] === '0' && $spn > 1)
182		{
183	3	$this->complianceError(1 + $this->offset);
184		}
185
186		// Capture the value and cast it as an integer
187	35	$value = (int) substr($this->bencoded, $this->offset, $spn);
188
189	35	$this->offset += $spn;
190	35	if ($this->bencoded[$this->offset] !== $terminator)
191		{
192	5	throw new IllegalCharacter($this->offset);
193		}
194	30	++$this->offset;
195
196	30	return $value;
197		}
198
199	17	protected function decodeInteger(): int
200		{
201	17	$negative = ($this->bencoded[++$this->offset] === '-');
202	17	if ($negative && $this->bencoded[++$this->offset] === '0')
203		{
204	1	$this->complianceError($this->offset);
205		}
206
207	16	$value = $this->decodeDigits('e');
208
209	11	return ($negative) ? -$value : $value;
210		}
211
212	12	protected function decodeList(): array
213		{
214	12	++$this->offset;
215
216	12	$list = [];
217	12	while ($this->offset <= $this->max)
218		{
219	11	if ($this->bencoded[$this->offset] === 'e')
220		{
221	7	++$this->offset;
222
223	7	return $list;
224		}
225
226	8	$list[] = $this->decodeAnything();
227		}
228
229	4	$this->prematureEndOfDataError();
		0 ignored issues – show Bug Best Practice introduced 2020-09-23 12:48 UTC by Report Bug Copy Issue Report In this branch, the function will implicitly return `null` which is incompatible with the type-hinted return `array`. Consider adding a return statement or allowing `null` as return value. For hinted functions/methods where all return statements with the correct type are only reachable via conditions, ?null? gets implicitly returned which may be incompatible with the hinted type. Let?s take a look at an example: interface ReturnsInt { public function returnsIntHinted(): int; } class MyClass implements ReturnsInt { public function returnsIntHinted(): int { if (foo()) { return 123; } // here: null is implicitly returned } } Loading history...
230		}
231
232	34	protected function decodeString(): string
233		{
234	34	$len = $this->decodeDigits(':');
235	26	$string = substr($this->bencoded, $this->offset, $len);
236	26	$this->offset += $len;
237
238	26	return $string;
239		}
240
241	4	protected function dictionaryComplianceError(int $offset, string $key, ?string $lastKey): void
242		{
243	4	if ($key === $lastKey)
244		{
245	2	$this->complianceError($offset, "Duplicate dictionary entry '" . $key . "'");
246		}
247	2	elseif ($key < $lastKey)
248		{
249	1	$this->complianceError($offset, "Out of order dictionary entry '" . $key . "'");
250		}
251		}
252
253	17	protected function prematureEndOfDataError(): void
254		{
255	17	throw new PrematureEndOfData(max(0, $this->len - 1));
256		}
257		}

s9e / Bencode

Push — Exceptions ( 4789cf...69c4e2 )

Decoder::prematureEndOfDataError() A

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