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

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Push — 2.0/master ( 9cf05b...3441b5 )

by Josh

created 2020-08-29 14:56 UTC

Decoder::complianceError() A

↳ Parent: Decoder

Complexity

Conditions	1
Paths	1

Size

Total Lines	3
Code Lines	1

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

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

<?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;

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 $pos;

	protected function __construct(string $bencoded)
	{
		if ($bencoded === '')
		{
			throw new InvalidArgumentException;
		}

		$this->bencoded = $bencoded;
		$this->len      = strlen($bencoded);
		$this->pos      = 0;

		$this->computeSafeBoundary();
	}

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

		$decoder->checkCursorPosition();

		return $value;
	}

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

			throw new RuntimeException('Premature end of data');
		}
	}

	protected function checkCursorPosition(): void
	{
		if ($this->pos !== $this->len)
		{
			if ($this->pos > $this->len)
			{
				throw new RuntimeException('Premature end of data');
			}

			$this->complianceError('Superfluous content found at offset ' . $this->pos);
		}
	}

	protected function complianceError(string $message): void
	{
		throw new RuntimeException($message);
	}

	/**
	* Adjust the rightmost boundary to the last safe character
	*
	* 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->pos];
		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
	{
		$dictionary = new ArrayObject;
		$dictionary->setFlags(ArrayObject::ARRAY_AS_PROPS);

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

				return $dictionary;
			}

			$pos = $this->pos;
			$key = $this->decodeString();
			if (isset($dictionary->$key))
			{
				$this->complianceError("Duplicate dictionary entry '" . $key . "' at pos " . $pos);
			}
			if ($this->pos > $this->max)
			{
				break;
			}
			$dictionary->$key = $this->decodeAnything();
		}

		throw new RuntimeException('Premature end of data');
	}

	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', $this->pos);
		if (!$spn)
		{
			throw new RuntimeException('Illegal character found at offset ' . $this->pos);
		}
		if ($this->bencoded[$this->pos] === '0' && $spn > 1)
		{
			$this->complianceError('Illegal character found at offset ' . (1 + $this->pos));
		}

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

		$this->pos += $spn;
		if ($this->bencoded[$this->pos] !== $terminator)
		{
			throw new RuntimeException('Illegal character found at offset ' . $this->pos);
		}
		++$this->pos;

		return $value;
	}

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

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

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

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

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

				return $list;
			}

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

		throw new RuntimeException('Premature end of data');
	}

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

		return $string;
	}
}

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
14			class Decoder
15			{
16			/**
17			* @var string Bencoded string being decoded
18			*/
19			protected string $bencoded;
20
21			/**
22			* @var int Length of the bencoded string
23			*/
24			protected int $len;
25
26			/**
27			* @var int Safe rightmost boundary
28			*/
29			protected int $max;
30
31			/**
32			* @var int Position of the cursor while decoding
33			*/
34			protected int $pos;
35
36			protected function __construct(string $bencoded)
37			{
38			if ($bencoded === '')
39			{
40			throw new InvalidArgumentException;
41			}
42
43			$this->bencoded = $bencoded;
44			$this->len = strlen($bencoded);
45			$this->pos = 0;
46
47			$this->computeSafeBoundary();
48			}
49
50			public static function decode(string $bencoded)
51			{
52			$decoder = new static($bencoded);
53			$value = $decoder->decodeAnything();
54
55			$decoder->checkCursorPosition();
56
57			return $value;
58			}
59
60			protected function checkBoundary(): void
61			{
62			if ($this->max < 1)
63			{
64			if (strpos('-e', $this->bencoded[0]) !== false)
65			{
66			throw new RuntimeException('Illegal character found at offset 0');
67			}
68
69			throw new RuntimeException('Premature end of data');
70			}
71			}
72
73			protected function checkCursorPosition(): void
74			{
75			if ($this->pos !== $this->len)
76			{
77			if ($this->pos > $this->len)
78			{
79			throw new RuntimeException('Premature end of data');
80			}
81
82			$this->complianceError('Superfluous content found at offset ' . $this->pos);
83			}
84			}
85
86			protected function complianceError(string $message): void
87			{
88			throw new RuntimeException($message);
89			}
90
91			/**
92			* Adjust the rightmost boundary to the last safe character
93			*
94			* Will rewind the boundary to skip the rightmost digits, optionally preceded by "i" or "i-"
95			*/
96			protected function computeSafeBoundary(): void
97			{
98			$boundary = $this->len - 1;
99			$c = $this->bencoded[$boundary];
100			while (is_numeric($c) && --$boundary >= 0)
101			{
102			$c = $this->bencoded[$boundary];
103			}
104			if ($c === '-')
105			{
106			$boundary -= 2;
107			}
108			elseif ($c === 'i')
109			{
110			--$boundary;
111			}
112
113			$this->max = $boundary;
114			$this->checkBoundary();
115			}
116
117			protected function decodeAnything()
118			{
119			$c = $this->bencoded[$this->pos];
120			if ($c === 'i')
121			{
122			return $this->decodeInteger();
123			}
124			if ($c === 'd')
125			{
126			return $this->decodeDictionary();
127			}
128			if ($c === 'l')
129			{
130			return $this->decodeList();
131			}
132
133			return $this->decodeString();
134			}
135
136			protected function decodeDictionary(): ArrayObject
137			{
138			$dictionary = new ArrayObject;
139			$dictionary->setFlags(ArrayObject::ARRAY_AS_PROPS);
140
141			++$this->pos;
142			while ($this->pos <= $this->max)
143			{
144			if ($this->bencoded[$this->pos] === 'e')
145			{
146			++$this->pos;
147
148			return $dictionary;
149			}
150
151			$pos = $this->pos;
152			$key = $this->decodeString();
153			if (isset($dictionary->$key))
154			{
155			$this->complianceError("Duplicate dictionary entry '" . $key . "' at pos " . $pos);
156			}
157			if ($this->pos > $this->max)
158			{
159			break;
160			}
161			$dictionary->$key = $this->decodeAnything();
162			}
163
164			throw new RuntimeException('Premature end of data');
165			}
166
167			protected function decodeDigits(string $terminator): int
168			{
169			// Digits sorted by decreasing frequency as observed on a random sample of torrent files
170			$spn = strspn($this->bencoded, '4615302879', $this->pos);
171			if (!$spn)
172			{
173			throw new RuntimeException('Illegal character found at offset ' . $this->pos);
174			}
175			if ($this->bencoded[$this->pos] === '0' && $spn > 1)
176			{
177			$this->complianceError('Illegal character found at offset ' . (1 + $this->pos));
178			}
179
180			// Capture the value and cast it as an integer
181			$value = (int) substr($this->bencoded, $this->pos, $spn);
182
183			$this->pos += $spn;
184			if ($this->bencoded[$this->pos] !== $terminator)
185			{
186			throw new RuntimeException('Illegal character found at offset ' . $this->pos);
187			}
188			++$this->pos;
189
190			return $value;
191			}
192
193			protected function decodeInteger(): int
194			{
195			$negative = ($this->bencoded[++$this->pos] === '-');
196			if ($negative && $this->bencoded[++$this->pos] === '0')
197			{
198			$this->complianceError('Illegal character found at offset ' . $this->pos);
199			}
200
201			$value = $this->decodeDigits('e');
202
203			return ($negative) ? -$value : $value;
204			}
205
206			protected function decodeList(): array
207			{
208			++$this->pos;
209
210			$list = [];
211			while ($this->pos <= $this->max)
212			{
213			if ($this->bencoded[$this->pos] === 'e')
214			{
215			++$this->pos;
216
217			return $list;
218			}
219
220			$list[] = $this->decodeAnything();
221			}
222
223			throw new RuntimeException('Premature end of data');
224			}
225
226			protected function decodeString(): string
227			{
228			$len = $this->decodeDigits(':');
229			$string = substr($this->bencoded, $this->pos, $len);
230			$this->pos += $len;
231
232			return $string;
233			}
234			}

s9e / Bencode

Push — 2.0/master ( 9cf05b...3441b5 )

Decoder::complianceError() A

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