SecureRandom::getByteNumber() - Code Metrics - Inspection of "Refactor code into methods" - Riimu/Kit-SecureRandom - Measure and Improve Code Quality continuously with Scrutinizer

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by Riikka

created 2016-05-11 10:27 UTC

SecureRandom::getByteNumber() A

↳ Parent: SecureRandom

Complexity

Conditions	3
Paths	2

Size

Total Lines	14
Code Lines	8

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	8
CRAP Score	3

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
c	1
b	0
f	0
dl	0
loc	14
ccs	8
cts	8
cp	1
rs	9.4285
cc	3
eloc	8
nc	2
nop	1
crap	3

<?php

namespace Riimu\Kit\SecureRandom;

use Riimu\Kit\SecureRandom\Generator\Generator;
use Riimu\Kit\SecureRandom\Generator\NumberGenerator;

/**
 * Library for normalizing bytes returned by secure random byte generators.
 *
 * SecureRandom takes bytes generated by secure random byte generators and
 * normalizes (i.e. provides even distribution) for other common usages, such
 * as generation of integers, floats and randomizing arrays.
 *
 * @author Riikka Kalliomäki <[email protected]>
 * @copyright Copyright (c) 2014, Riikka Kalliomäki
 * @license http://opensource.org/licenses/mit-license.php MIT License
 */
class SecureRandom
{
    /** @var Generator The secure random byte generator used to generate bytes */
    private $generator;

    /** @var string[] List of default generators */
    private static $defaultGenerators = [
        '\Riimu\Kit\SecureRandom\Generator\Internal',
        '\Riimu\Kit\SecureRandom\Generator\RandomReader',
        '\Riimu\Kit\SecureRandom\Generator\Mcrypt',
        '\Riimu\Kit\SecureRandom\Generator\OpenSSL',
    ];

    /**
     * Creates a new instance of SecureRandom.
     *
     * You can either provide a generator to use for generating random bytes or
     * give null as the argument to use default generators. If null is provided,
     * the constructor will attempt to create the random byte generators in the
     * following order until it finds one that is supported:
     *
     * - Internal
     * - RandomReader
     * - Mcrypt
     * - OpenSSL
     *
     * Note that since most cases require non-blocking random generation, the
     * default generators use /dev/urandom as the random source. If you do not
     * think this provides enough security, create the desired random generator
     * using /dev/random as the source.
     *
     * @param Generator|null $generator Random byte generator or null for default
     * @throws GeneratorException If the provided or default generators are not supported
     */
    public function __construct(Generator $generator = null)
    {
        if ($generator === null) {
            $generator = $this->getDefaultGenerator();
        } elseif (!$generator->isSupported()) {
            throw new GeneratorException('The provided secure random byte generator is not supported by the system');
        }

        $this->generator = $generator;
    }

    /**
     * Returns the first supported default secure random byte generator.
     * @return Generator Supported secure random byte generator
     * @throws GeneratorException If none of the default generators are supported
     */
    private function getDefaultGenerator()
    {
        foreach (self::$defaultGenerators as $generator) {
            $generator = new $generator();

            if ($generator->isSupported()) {
                return $generator;
            }
        }

        throw new GeneratorException('Default secure random byte generators are not supported by the system');
    }

    /**
     * Returns a number of random bytes.
     * @param int $count Number of random bytes to return
     * @return string Randomly generated bytes
     * @throws \InvalidArgumentException If the count is invalid
     */
    public function getBytes($count)
    {
        $count = (int) $count;

        if ($count < 0) {
            throw new \InvalidArgumentException('Number of bytes must be 0 or more');
        } elseif ($count === 0) {
            return '';
        }

        return $this->generator->getBytes($count);
    }

    /**
     * Returns a random number between 0 and the limit.
     * @param int $limit Maximum random number
     * @return int Random number between 0 and the limit
     */
    private function getNumber($limit)
    {
        if ($limit === 0) {
            return 0;
        } elseif ($this->generator instanceof NumberGenerator) {
            return $this->generator->getNumber(0, $limit);
        }

        return $this->getByteNumber($limit);
    }

    /**
     * Returns a random number generated using the random byte generator.
     * @param int $limit Maximum value for the random number
     * @return int The generated random number between 0 and the limit
     */
    private function getByteNumber($limit)
    {
        for ($bits = 1, $mask = 1; $limit >> $bits > 0; $bits++) {
            $mask |= 1 << $bits;
        }

        $bytes = (int) ceil($bits / 8);

        do {
            $result = hexdec(bin2hex($this->generator->getBytes($bytes))) & $mask;
        } while ($result > $limit);

        return $result;
    }

    /**
     * Returns a random integer between two positive integers (inclusive).
     * @param int $min Minimum limit
     * @param int $max Maximum limit
     * @return int Random integer between minimum and maximum limit
     * @throws \InvalidArgumentException If the limits are invalid
     */
    public function getInteger($min, $max)
    {
        $min = (int) $min;
        $max = (int) $max;

        if ($min < 0 || $max < $min) {
            throw new \InvalidArgumentException('Invalid minimum or maximum value');
        }

        return $min + $this->getNumber($max - $min);
    }

    /**
     * Returns a random float between 0 and 1 (inclusive).
     * @return float Random float between 0 and 1
     */
    public function getFloat()
    {
        return (float) ($this->getNumber(PHP_INT_MAX) / PHP_INT_MAX);
    }

    /**
     * Returns a number of randomly selected elements from the array.
     *
     * This method returns randomly selected elements from the array. The number
     * of elements is determined by by the second argument. The elements are
     * returned in random order but the keys are preserved.
     *
     * @param array $array Array of elements
     * @param int $count Number of elements to return from the array
     * @return array Randomly selected elements in random order
     * @throws \InvalidArgumentException If the count is invalid
     */
    public function getArray(array $array, $count)
    {
        $count = (int) $count;
        $size = count($array);

        if ($count < 0 || $count > $size) {
            throw new \InvalidArgumentException('Invalid number of elements');
        }

        $result = [];

        for ($i = 0; $i < $count; $i++) {
            $element = array_slice($array, $this->getNumber($size - $i - 1), 1, true);
            $result += $element;
            unset($array[key($element)]);
        }

        return $result;
    }

    /**
     * Returns one randomly selected value from the array.
     * @param array $array Array to choose from
     * @return mixed One randomly selected value from the array
     * @throws \InvalidArgumentException If the array is empty
     */
    public function choose(array $array)
    {
        if (count($array) < 1) {
            throw new \InvalidArgumentException('Array must have at least one value');
        }

        return current(array_slice($array, $this->getNumber(count($array) - 1), 1));
    }

    /**
     * Returns the array with the elements reordered in random order.
     * @param array $array Array to shuffle
     * @return array The provided array with elements in random order
     */
    public function shuffle(array $array)
    {
        return $this->getArray($array, count($array));
    }

    /**
     * Returns a random sequence of values.
     *
     * If a string is provided as the first argument, the method returns a
     * string with characters selected from the provided string. The length of
     * the returned string is determined by the second argument.
     *
     * If an array is provided as the first argument, the method returns an
     * array with elements selected from the provided array. The size of the
     * returned array is determined by the second argument.
     *
     * The functionality is similar to getArray(), except for the fact that the
     * returned value can contain the same character or element multiple times.
     * If the same character or element appears multiple times in the provided
     * argument, it will increase the relative chance of it appearing in the
     * returned value.
     *
     * @param string|array $choices Values to choose from
     * @param int $length Length of the sequence
     * @return array|string The generated random sequence
     * @throws \InvalidArgumentException If the choices or length is invalid
     */
    public function getSequence($choices, $length)
    {
        $length = (int) $length;
        $string = is_string($choices);

        if ($length < 0) {
            throw new \InvalidArgumentException('Invalid sequence length');
        }

        $result = $this->getSequenceValues(
            $string ? str_split($choices) : array_values($choices),
            $length
        );

        return $string ? implode('', $result) : $result;
    }

    /**
     * Returns the selected list of values for the sequence.
     * @param array $values List of possible values
     * @param int $length Number of values to return
     * @return array Selected list of values for the sequence
     */
    private function getSequenceValues(array $values, $length)
    {
        if ($length < 1) {
            return [];
        } elseif (count($values) < 1) {
            throw new \InvalidArgumentException('Cannot generate sequence from empty value set');
        }

        $size = count($values);
        $result = [];

        for ($i = 0; $i < $length; $i++) {
            $result[] = $values[$this->getNumber($size - 1)];
        }

        return $result;
    }
}


1		<?php
2
3		namespace Riimu\Kit\SecureRandom;
4
5		use Riimu\Kit\SecureRandom\Generator\Generator;
6		use Riimu\Kit\SecureRandom\Generator\NumberGenerator;
7
8		/**
9		* Library for normalizing bytes returned by secure random byte generators.
10		*
11		* SecureRandom takes bytes generated by secure random byte generators and
12		* normalizes (i.e. provides even distribution) for other common usages, such
13		* as generation of integers, floats and randomizing arrays.
14		*
15		* @author Riikka Kalliomäki <[email protected]>
16		* @copyright Copyright (c) 2014, Riikka Kalliomäki
17		* @license http://opensource.org/licenses/mit-license.php MIT License
18		*/
19		class SecureRandom
20		{
21		/** @var Generator The secure random byte generator used to generate bytes */
22		private $generator;
23
24		/** @var string[] List of default generators */
25		private static $defaultGenerators = [
26		'\Riimu\Kit\SecureRandom\Generator\Internal',
27		'\Riimu\Kit\SecureRandom\Generator\RandomReader',
28		'\Riimu\Kit\SecureRandom\Generator\Mcrypt',
29		'\Riimu\Kit\SecureRandom\Generator\OpenSSL',
30		];
31
32		/**
33		* Creates a new instance of SecureRandom.
34		*
35		* You can either provide a generator to use for generating random bytes or
36		* give null as the argument to use default generators. If null is provided,
37		* the constructor will attempt to create the random byte generators in the
38		* following order until it finds one that is supported:
39		*
40		* - Internal
41		* - RandomReader
42		* - Mcrypt
43		* - OpenSSL
44		*
45		* Note that since most cases require non-blocking random generation, the
46		* default generators use /dev/urandom as the random source. If you do not
47		* think this provides enough security, create the desired random generator
48		* using /dev/random as the source.
49		*
50		* @param Generator\|null $generator Random byte generator or null for default
51		* @throws GeneratorException If the provided or default generators are not supported
52		*/
53	121	public function __construct(Generator $generator = null)
54		{
55	121	if ($generator === null) {
56	8	$generator = $this->getDefaultGenerator();
57	116	} elseif (!$generator->isSupported()) {
58	4	throw new GeneratorException('The provided secure random byte generator is not supported by the system');
59		}
60
61	113	$this->generator = $generator;
62	84	}
63
64		/**
65		* Returns the first supported default secure random byte generator.
66		* @return Generator Supported secure random byte generator
67		* @throws GeneratorException If none of the default generators are supported
68		*/
69	8	private function getDefaultGenerator()
70		{
71	8	foreach (self::$defaultGenerators as $generator) {
72	4	$generator = new $generator();
73
74	4	if ($generator->isSupported()) {
75	5	return $generator;
76		}
77	6	}
78
79	4	throw new GeneratorException('Default secure random byte generators are not supported by the system');
80		}
81
82		/**
83		* Returns a number of random bytes.
84		* @param int $count Number of random bytes to return
85		* @return string Randomly generated bytes
86		* @throws \InvalidArgumentException If the count is invalid
87		*/
88	12	public function getBytes($count)
89		{
90	12	$count = (int) $count;
91
92	12	if ($count < 0) {
93	4	throw new \InvalidArgumentException('Number of bytes must be 0 or more');
94	8	} elseif ($count === 0) {
95	4	return '';
96		}
97
98	4	return $this->generator->getBytes($count);
99		}
100
101		/**
102		* Returns a random number between 0 and the limit.
103		* @param int $limit Maximum random number
104		* @return int Random number between 0 and the limit
105		*/
106	49	private function getNumber($limit)
107		{
108	49	if ($limit === 0) {
109	16	return 0;
110	37	} elseif ($this->generator instanceof NumberGenerator) {
111	5	return $this->generator->getNumber(0, $limit);
112		}
113
114	32	return $this->getByteNumber($limit);
115		}
116
117		/**
118		* Returns a random number generated using the random byte generator.
119		* @param int $limit Maximum value for the random number
120		* @return int The generated random number between 0 and the limit
121		*/
122	32	private function getByteNumber($limit)
123		{
124	32	for ($bits = 1, $mask = 1; $limit >> $bits > 0; $bits++) {
125	32	$mask \|= 1 << $bits;
126	24	}
127
128	32	$bytes = (int) ceil($bits / 8);
129
130		do {
131	32	$result = hexdec(bin2hex($this->generator->getBytes($bytes))) & $mask;
132	32	} while ($result > $limit);
133
134	32	return $result;
135		}
136
137		/**
138		* Returns a random integer between two positive integers (inclusive).
139		* @param int $min Minimum limit
140		* @param int $max Maximum limit
141		* @return int Random integer between minimum and maximum limit
142		* @throws \InvalidArgumentException If the limits are invalid
143		*/
144	29	public function getInteger($min, $max)
145		{
146	29	$min = (int) $min;
147	29	$max = (int) $max;
148
149	29	if ($min < 0 \|\| $max < $min) {
150	12	throw new \InvalidArgumentException('Invalid minimum or maximum value');
151		}
152
153	17	return $min + $this->getNumber($max - $min);
154		}
155
156		/**
157		* Returns a random float between 0 and 1 (inclusive).
158		* @return float Random float between 0 and 1
159		*/
160	4	public function getFloat()
161		{
162	4	return (float) ($this->getNumber(PHP_INT_MAX) / PHP_INT_MAX);
163		}
164
165		/**
166		* Returns a number of randomly selected elements from the array.
167		*
168		* This method returns randomly selected elements from the array. The number
169		* of elements is determined by by the second argument. The elements are
170		* returned in random order but the keys are preserved.
171		*
172		* @param array $array Array of elements
173		* @param int $count Number of elements to return from the array
174		* @return array Randomly selected elements in random order
175		* @throws \InvalidArgumentException If the count is invalid
176		*/
177	28	public function getArray(array $array, $count)
178		{
179	28	$count = (int) $count;
180	28	$size = count($array);
181
182	28	if ($count < 0 \|\| $count > $size) {
183	4	throw new \InvalidArgumentException('Invalid number of elements');
184		}
185
186	24	$result = [];
187
188	24	for ($i = 0; $i < $count; $i++) {
189	12	$element = array_slice($array, $this->getNumber($size - $i - 1), 1, true);
190	12	$result += $element;
191	12	unset($array[key($element)]);
192	9	}
193
194	24	return $result;
195		}
196
197		/**
198		* Returns one randomly selected value from the array.
199		* @param array $array Array to choose from
200		* @return mixed One randomly selected value from the array
201		* @throws \InvalidArgumentException If the array is empty
202		*/
203	12	public function choose(array $array)
204		{
205	12	if (count($array) < 1) {
206	4	throw new \InvalidArgumentException('Array must have at least one value');
207		}
208
209	8	return current(array_slice($array, $this->getNumber(count($array) - 1), 1));
210		}
211
212		/**
213		* Returns the array with the elements reordered in random order.
214		* @param array $array Array to shuffle
215		* @return array The provided array with elements in random order
216		*/
217	8	public function shuffle(array $array)
218		{
219	8	return $this->getArray($array, count($array));
220		}
221
222		/**
223		* Returns a random sequence of values.
224		*
225		* If a string is provided as the first argument, the method returns a
226		* string with characters selected from the provided string. The length of
227		* the returned string is determined by the second argument.
228		*
229		* If an array is provided as the first argument, the method returns an
230		* array with elements selected from the provided array. The size of the
231		* returned array is determined by the second argument.
232		*
233		* The functionality is similar to getArray(), except for the fact that the
234		* returned value can contain the same character or element multiple times.
235		* If the same character or element appears multiple times in the provided
236		* argument, it will increase the relative chance of it appearing in the
237		* returned value.
238		*
239		* @param string\|array $choices Values to choose from
240		* @param int $length Length of the sequence
241		* @return array\|string The generated random sequence
242		* @throws \InvalidArgumentException If the choices or length is invalid
243		*/
244	24	public function getSequence($choices, $length)
245		{
246	24	$length = (int) $length;
247	24	$string = is_string($choices);
248
249	24	if ($length < 0) {
250	4	throw new \InvalidArgumentException('Invalid sequence length');
251		}
252
253	20	$result = $this->getSequenceValues(
254	20	$string ? str_split($choices) : array_values($choices),
255		$length
256	15	);
257
258	16	return $string ? implode('', $result) : $result;
259		}
260
261		/**
262		* Returns the selected list of values for the sequence.
263		* @param array $values List of possible values
264		* @param int $length Number of values to return
265		* @return array Selected list of values for the sequence
266		*/
267	20	private function getSequenceValues(array $values, $length)
268		{
269	20	if ($length < 1) {
270	8	return [];
271	12	} elseif (count($values) < 1) {
272	4	throw new \InvalidArgumentException('Cannot generate sequence from empty value set');
273		}
274
275	8	$size = count($values);
276	8	$result = [];
277
278	8	for ($i = 0; $i < $length; $i++) {
279	8	$result[] = $values[$this->getNumber($size - 1)];
280	6	}
281
282	8	return $result;
283		}
284		}
285

Riimu / Kit-SecureRandom

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SecureRandom::getByteNumber() A

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