Random::extractEntropy() - Code Metrics - Inspection of "improve noinspection tags" - tfboe/fm-lib - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Branch — merging-leagues-tournaments (a75688)

by Benedikt

created 2019-12-03 12:45 UTC

Random::extractEntropy() C

↳ Parent: Random

Complexity

Conditions	12
Paths	5

Size

Total Lines	29
Code Lines	21

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	21
c	0
b	0
f	0
dl	0
loc	29
rs	6.9666
cc	12
nc	5
nop	2

How to fix Complexity

<?php
declare(strict_types=1);


namespace Tfboe\FmLib\Helpers;


use Tfboe\FmLib\Exceptions\Internal;

/**
 * Class Random
 * @package Tfboe\FmLib\Helpers
 */
class Random
{
//<editor-fold desc="Fields">
  private const ENTROPY = [
    1 => 2,
    2 => 4,
    3 => 8
  ];

  /**
   * @var string
   */
  private $hexString;

  /**
   * @var int
   */
  private $remainingBitsFirstChar;
//</editor-fold desc="Fields">

//<editor-fold desc="Constructor">
  /**
   * Random constructor.
   * @param string $hexString
   */
  public function __construct(string $hexString)
  {
    $this->hexString = $hexString;
    $this->remainingBitsFirstChar = 4;
  }
//</editor-fold desc="Constructor">

//<editor-fold desc="Public Methods">
  /**
   * @param int $max
   * @param int $min
   * @return int
   */
  public function extractEntropy(int $max, int $min = 0): int
  {
    Internal::assert($max <= PHP_INT_MAX && $min >= PHP_INT_MIN && $min <= $max);
    $maxInt = (PHP_INT_MAX >> 1);
    if (($max > $maxInt && ($min <= 0 || $max - $min > $maxInt)) ||
      ($min < -$maxInt && ($max >= 0 || $max - $min > $maxInt)) || ($max - $min) > $maxInt) {
      //calculate floor(($max - $min) / 16) considering overflows
      $max16 = $max % 16;
      $min16 = $min % 16;
      $max1 = (($max - $max16) >> 4) - (($min - $min16) >> 4);
      $rest = $max16 - $min16;
      if ($rest >= 16) {
        $max1++;
        $rest -= 16;
      }

      $z1 = $this->extractEntropy($max1);
      $max2 = 15;
      if ($z1 == $max1) {
        $max2 = $rest;
      }
      $z2 = $this->extractEntropy($max2);
      return (($min + 8 * $z1) + 8 * $z1) + $z2;
    }
    $range = $max - $min;
    Internal::assert($range <= PHP_INT_MAX);
    $bits = static::countBits($range);

    return $min + ($this->extractEntropyByBits($bits) % ($range + 1));
  }

  /**
   * @param int $bits
   * @return int
   */
  public function extractEntropyByBits(int $bits): int
  {
    Internal::assert($bits >= 0);
    if ($bits === 0 || empty($this->hexString)) {
      return 0; //no entropy
    }
    $value = 0;
    if ($bits >= $this->remainingBitsFirstChar) {
      //extract full positions
      $fullExtractLength = 1 + (($bits - $this->remainingBitsFirstChar) >> 2);
      $value = hexdec(substr($this->hexString, 0, $fullExtractLength));
      $bits -= $this->remainingBitsFirstChar + ($fullExtractLength - 1) * 4;
      $this->remainingBitsFirstChar = 4;
      $this->hexString = substr($this->hexString, $fullExtractLength);
      if (empty($this->hexString)) {
        return $value;

      }
    }
    if ($bits > 0) {
      $digit = hexdec(substr($this->hexString, 0, 1));
      $r = self::ENTROPY[$bits];
      $value *= $r;
      $this->remainingBitsFirstChar -= $bits;
      $value += $digit >> $this->remainingBitsFirstChar;
      $this->hexString = dechex($digit & (self::ENTROPY[$this->remainingBitsFirstChar] - 1))
        . substr($this->hexString, 1);
    }
    return $value;

  }

  /**
   * @param $str
   * @return Random
   */
  public static function stringToRandom($str): Random
  {
    return new Random(hash("sha256", $str));
  }
//</editor-fold desc="Public Methods">

//<editor-fold desc="Private Methods">
  /**
   * @param $n
   * @return int
   */
  private static function countBits(int $n): int
  {
    $count = 0;
    while ($n > 0) {
      $count++;
      $n >>= 1;
    }
    return $count;
  }
//</editor-fold desc="Private Methods">
}

1			<?php
2			declare(strict_types=1);
3
4
5			namespace Tfboe\FmLib\Helpers;
6
7
8			use Tfboe\FmLib\Exceptions\Internal;
9
10			/**
11			* Class Random
12			* @package Tfboe\FmLib\Helpers
13			*/
14			class Random
15			{
16			//<editor-fold desc="Fields">
17			private const ENTROPY = [
18			1 => 2,
19			2 => 4,
20			3 => 8
21			];
22
23			/**
24			* @var string
25			*/
26			private $hexString;
27
28			/**
29			* @var int
30			*/
31			private $remainingBitsFirstChar;
32			//</editor-fold desc="Fields">
33
34			//<editor-fold desc="Constructor">
35			/**
36			* Random constructor.
37			* @param string $hexString
38			*/
39			public function __construct(string $hexString)
40			{
41			$this->hexString = $hexString;
42			$this->remainingBitsFirstChar = 4;
43			}
44			//</editor-fold desc="Constructor">
45
46			//<editor-fold desc="Public Methods">
47			/**
48			* @param int $max
49			* @param int $min
50			* @return int
51			*/
52			public function extractEntropy(int $max, int $min = 0): int
53			{
54			Internal::assert($max <= PHP_INT_MAX && $min >= PHP_INT_MIN && $min <= $max);
55			$maxInt = (PHP_INT_MAX >> 1);
56			if (($max > $maxInt && ($min <= 0 \|\| $max - $min > $maxInt)) \|\|
57			($min < -$maxInt && ($max >= 0 \|\| $max - $min > $maxInt)) \|\| ($max - $min) > $maxInt) {
58			//calculate floor(($max - $min) / 16) considering overflows
59			$max16 = $max % 16;
60			$min16 = $min % 16;
61			$max1 = (($max - $max16) >> 4) - (($min - $min16) >> 4);
62			$rest = $max16 - $min16;
63			if ($rest >= 16) {
64			$max1++;
65			$rest -= 16;
66			}
67
68			$z1 = $this->extractEntropy($max1);
69			$max2 = 15;
70			if ($z1 == $max1) {
71			$max2 = $rest;
72			}
73			$z2 = $this->extractEntropy($max2);
74			return (($min + 8 * $z1) + 8 * $z1) + $z2;
75			}
76			$range = $max - $min;
77			Internal::assert($range <= PHP_INT_MAX);
78			$bits = static::countBits($range);
79
80			return $min + ($this->extractEntropyByBits($bits) % ($range + 1));
81			}
82
83			/**
84			* @param int $bits
85			* @return int
86			*/
87			public function extractEntropyByBits(int $bits): int
88			{
89			Internal::assert($bits >= 0);
90			if ($bits === 0 \|\| empty($this->hexString)) {
91			return 0; //no entropy
92			}
93			$value = 0;
94			if ($bits >= $this->remainingBitsFirstChar) {
95			//extract full positions
96			$fullExtractLength = 1 + (($bits - $this->remainingBitsFirstChar) >> 2);
97			$value = hexdec(substr($this->hexString, 0, $fullExtractLength));
98			$bits -= $this->remainingBitsFirstChar + ($fullExtractLength - 1) * 4;
99			$this->remainingBitsFirstChar = 4;
100			$this->hexString = substr($this->hexString, $fullExtractLength);
101			if (empty($this->hexString)) {
102			return $value;
			0 ignored issues – show Bug Best Practice introduced 2019-12-03 12:52 UTC by Report Bug Copy Issue Report The expression `return $value` could return the type `double` which is incompatible with the type-hinted return `integer`. Consider adding an additional type-check to rule them out. Loading history...
103			}
104			}
105			if ($bits > 0) {
106			$digit = hexdec(substr($this->hexString, 0, 1));
107			$r = self::ENTROPY[$bits];
108			$value *= $r;
109			$this->remainingBitsFirstChar -= $bits;
110			$value += $digit >> $this->remainingBitsFirstChar;
111			$this->hexString = dechex($digit & (self::ENTROPY[$this->remainingBitsFirstChar] - 1))
112			. substr($this->hexString, 1);
113			}
114			return $value;
			0 ignored issues – show Bug Best Practice introduced 2019-12-03 12:52 UTC by Report Bug Copy Issue Report The expression `return $value` could return the type `double` which is incompatible with the type-hinted return `integer`. Consider adding an additional type-check to rule them out. Loading history...
115			}
116
117			/**
118			* @param $str
119			* @return Random
120			*/
121			public static function stringToRandom($str): Random
122			{
123			return new Random(hash("sha256", $str));
124			}
125			//</editor-fold desc="Public Methods">
126
127			//<editor-fold desc="Private Methods">
128			/**
129			* @param $n
130			* @return int
131			*/
132			private static function countBits(int $n): int
133			{
134			$count = 0;
135			while ($n > 0) {
136			$count++;
137			$n >>= 1;
138			}
139			return $count;
140			}
141			//</editor-fold desc="Private Methods">
142			}

tfboe / fm-lib

Branch — merging-leagues-tournaments (a75688)

Random::extractEntropy() C

Complexity

Size

Duplication

Importance

How to fix Complexity

Long Method

Duplication Side-by-Side

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