AbstractCRC::generateTable() - Code Metrics - Inspection of "# added phpstan static analyzer and fixed all prob..." - pburggraf/CRC - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( a018f1...1aa741 )

by Philip

created 2018-09-27 18:20 UTC

AbstractCRC::generateTable() A

↳ Parent: AbstractCRC

Complexity

Conditions	6
Paths	13

Size

Total Lines	33
Code Lines	19

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	19
dl	0
loc	33
rs	9.0111
c	0
b	0
f	0
cc	6
nc	13
nop	1

<?php

declare(strict_types=1);

namespace PBurggraf\CRC;

/**
 * @author Philip Burggraf <[email protected]>
 */
abstract class AbstractCRC
{
    /**
     * @var int
     */
    protected $poly;

    /**
     * @var int
     */
    protected $init;

    /**
     * @var bool
     */
    protected $reverseIn;

    /**
     * @var bool
     */
    protected $reverseOut;

    /**
     * @var int
     */
    protected $xorOut;

    /**
     * @var array
     */
    protected $lookupTable;

    /**
     * @var int
     */
    protected $bitLength;

    /**
     * @param string $buffer
     *
     * @return int
     */
    public function calculate(string $buffer): int
    {
        $bufferLength = \strlen($buffer);

        $mask = (((1 << ($this->bitLength - 1)) - 1) << 1) | 1;
        $highBit = 1 << ($this->bitLength - 1);

        $crc = $this->init;

        for ($iterator = 0; $iterator < $bufferLength; ++$iterator) {
            $character = \ord($buffer[$iterator]);
            if ($this->reverseIn) {
                $character = $this->binaryReverse($character, 8);
            }

            for ($j = 0x80; $j; $j >>= 1) {
                $bit = $crc & $highBit;
                $crc <<= 1;

                if ($character & $j) {
                    $bit ^= $highBit;
                }

                if ($bit) {
                    $crc ^= $this->poly;
                }
            }
        }

        if ($this->reverseOut) {
            $crc = $this->binaryReverse($crc, $this->bitLength);
        }

        $crc ^= $this->xorOut;

        return $crc & $mask;
    }

    /**
     * @param int $polynomial
     *
     * @return array
     */
    protected function generateTable(int $polynomial): array
    {
        $tableSize = 256;

        $mask = (((1 << ($this->bitLength - 1)) - 1) << 1) | 1;
        $highBit = 1 << ($this->bitLength - 1);

        $crctab = [];

        for ($i = 0; $i < $tableSize; ++$i) {
            $crc = $i;
            if ($this->reverseIn) {
                $crc = $this->binaryReverse($crc, 8);
            }

            $crc <<= $this->bitLength - 8;

            for ($j = 0; $j < 8; ++$j) {
                $bit = $crc & $highBit;
                $crc <<= 1;
                if ($bit) {
                    $crc ^= $polynomial;
                }
            }

            if ($this->reverseOut) {
                $crc = $this->binaryReverse($crc, $this->bitLength);
            }
            $crc &= $mask;
            $crctab[] = $crc;
        }

        return $crctab;
    }

    /**
     * @param int $binaryInput
     * @param int $bitlen
     *
     * @return int
     */
    protected function binaryReverse(int $binaryInput, int $bitlen): int
    {
        $cloneBits = $binaryInput;
        $binaryInput = 0;
        $count = 0;

        while ($count < $bitlen) {
            ++$count;
            $binaryInput <<= 1;
            $binaryInput |= ($cloneBits & 0x1);
            $cloneBits >>= 1;
        }

        return $binaryInput;
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace PBurggraf\CRC;
6
7			/**
8			* @author Philip Burggraf <[email protected]>
9			*/
10			abstract class AbstractCRC
11			{
12			/**
13			* @var int
14			*/
15			protected $poly;
16
17			/**
18			* @var int
19			*/
20			protected $init;
21
22			/**
23			* @var bool
24			*/
25			protected $reverseIn;
26
27			/**
28			* @var bool
29			*/
30			protected $reverseOut;
31
32			/**
33			* @var int
34			*/
35			protected $xorOut;
36
37			/**
38			* @var array
39			*/
40			protected $lookupTable;
41
42			/**
43			* @var int
44			*/
45			protected $bitLength;
46
47			/**
48			* @param string $buffer
49			*
50			* @return int
51			*/
52			public function calculate(string $buffer): int
53			{
54			$bufferLength = \strlen($buffer);
55
56			$mask = (((1 << ($this->bitLength - 1)) - 1) << 1) \| 1;
57			$highBit = 1 << ($this->bitLength - 1);
58
59			$crc = $this->init;
60
61			for ($iterator = 0; $iterator < $bufferLength; ++$iterator) {
62			$character = \ord($buffer[$iterator]);
63			if ($this->reverseIn) {
64			$character = $this->binaryReverse($character, 8);
65			}
66
67			for ($j = 0x80; $j; $j >>= 1) {
68			$bit = $crc & $highBit;
69			$crc <<= 1;
70
71			if ($character & $j) {
72			$bit ^= $highBit;
73			}
74
75			if ($bit) {
76			$crc ^= $this->poly;
77			}
78			}
79			}
80
81			if ($this->reverseOut) {
82			$crc = $this->binaryReverse($crc, $this->bitLength);
83			}
84
85			$crc ^= $this->xorOut;
86
87			return $crc & $mask;
88			}
89
90			/**
91			* @param int $polynomial
92			*
93			* @return array
94			*/
95			protected function generateTable(int $polynomial): array
96			{
97			$tableSize = 256;
98
99			$mask = (((1 << ($this->bitLength - 1)) - 1) << 1) \| 1;
100			$highBit = 1 << ($this->bitLength - 1);
101
102			$crctab = [];
103
104			for ($i = 0; $i < $tableSize; ++$i) {
105			$crc = $i;
106			if ($this->reverseIn) {
107			$crc = $this->binaryReverse($crc, 8);
108			}
109
110			$crc <<= $this->bitLength - 8;
111
112			for ($j = 0; $j < 8; ++$j) {
113			$bit = $crc & $highBit;
114			$crc <<= 1;
115			if ($bit) {
116			$crc ^= $polynomial;
117			}
118			}
119
120			if ($this->reverseOut) {
121			$crc = $this->binaryReverse($crc, $this->bitLength);
122			}
123			$crc &= $mask;
124			$crctab[] = $crc;
125			}
126
127			return $crctab;
128			}
129
130			/**
131			* @param int $binaryInput
132			* @param int $bitlen
133			*
134			* @return int
135			*/
136			protected function binaryReverse(int $binaryInput, int $bitlen): int
137			{
138			$cloneBits = $binaryInput;
139			$binaryInput = 0;
140			$count = 0;
141
142			while ($count < $bitlen) {
143			++$count;
144			$binaryInput <<= 1;
145			$binaryInput \|= ($cloneBits & 0x1);
146			$cloneBits >>= 1;
147			}
148
149			return $binaryInput;
150			}
151			}
152

pburggraf / CRC

Push — master ( a018f1...1aa741 )

AbstractCRC::generateTable() A

Complexity

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