Utilities::convertRemainingLengthStringToInt() - Code Metrics - unreal4u/mqtt - Measure and Improve Code Quality continuously with Scrutinizer

Utilities::convertRemainingLengthStringToInt() A
last analyzed 2020-09-22 18:34 UTC

↳ Parent: Utilities

Complexity

Conditions	3
Paths	2

Size

Total Lines	22
Code Lines	12

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	11
CRAP Score	3.0052

Importance

Changes

Metric	Value
eloc	12
c	0
b	0
f	0
dl	0
loc	22
ccs	11
cts	12
cp	0.9167
rs	9.8666
cc	3
nc	2
nop	1
crap	3.0052

<?php

declare(strict_types=1);

namespace unreal4u\MQTT;

use LogicException;
use OutOfRangeException;
use unreal4u\MQTT\Exceptions\MessageTooBig;

use function chr;
use function dechex;
use function hexdec;
use function ord;
use function str_pad;

/**
 * Functionality that is shared across the entire package
 * @package unreal4u\MQTT
 */
final class Utilities
{
    /**
     * Swaps the given number from endian format (INT16, not to be confused with UINT16)
     *
     * @param int $number
     * @return int
     * @throws OutOfRangeException
     */
    public static function convertEndianness(int $number): int
    {
        if ($number > 65535) {
            throw new OutOfRangeException('This is an INT16 conversion, so the maximum is 65535');
        }

        $finalNumber = hexdec(
            // Invert first byte and make it a complete hexadecimal number
            str_pad(dechex($number & 255), 2, '0', STR_PAD_LEFT) .
            // Invert second byte and make a complete hexadecimal number
            str_pad(dechex($number >> 8), 2, '0', STR_PAD_LEFT)
        );

        return (int)$finalNumber;
    }

    /**
     * Converts a number to a binary string that the MQTT protocol understands
     *
     * @param int $number
     * @return string
     * @throws OutOfRangeException
     */
    public static function convertNumberToBinaryString(int $number): string
    {
        if ($number > 65535) {
            throw new OutOfRangeException('This is an INT16 conversion, so the maximum is 65535');
        }

        return chr($number >> 8) . chr($number & 255);
    }

    /**
     * Converts a binary representation of a number to an actual int
     *
     * @param string $binaryString
     * @return int
     * @throws OutOfRangeException
     */
    public static function convertBinaryStringToNumber(string $binaryString): int
    {
        return self::convertEndianness((ord($binaryString[1]) << 8) + (ord($binaryString[0]) & 255));
    }

    /**
     * Returns the correct format for the length in bytes of the remaining bytes
     *
     * Original pseudo-code algorithm as per the documentation:
     * <pre>
     * do
     *     encodedByte = X MOD 128
     *     X = X DIV 128
     *     // if there are more data to encode, set the top bit of this byte
     *     if ( X > 0 )
     *         encodedByte = encodedByte OR 128
     *     endif
     *     'output' encodedByte
     * while ( X > 0 )
     * </pre>
     * @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc385349213
     *
     * @param int $lengthInBytes
     * @return string
     * @throws MessageTooBig
     */
    public static function formatRemainingLengthOutput(int $lengthInBytes): string
    {
        if ($lengthInBytes > 268435455) {
            throw new MessageTooBig('The message cannot exceed 268435455 bytes in length');
        }

        $x = $lengthInBytes;
        $outputString = '';
        do {
            $encodedByte = $x % 128;
            $x >>= 7; // Shift 7 bytes
            // if there are more data to encode, set the top bit of this byte
            if ($x > 0) {
                $encodedByte |= 128;
            }
            $outputString .= chr($encodedByte);
        } while ($x > 0);

        return $outputString;
    }

    /**
     * The remaining length of a message is encoded in this specific way, the opposite of formatRemainingLengthOutput
     *
     * Many thanks to Peter's blog for your excellent examples and knowledge.
     * @see http://indigoo.com/petersblog/?p=263
     *
     * Original pseudo-algorithm as per the documentation:
     * <pre>
     * multiplier = 1
     * value = 0
     * do
     *     encodedByte = 'next byte from stream'
     *     value += (encodedByte & 127) * multiplier
     *     if (multiplier > 128*128*128)
     *         throw Error(Malformed Remaining Length)
     *     multiplier *= 128
     * while ((encodedByte & 128) != 0)
     * </pre>
     *
     * @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc385349213
     * @see Utilities::formatRemainingLengthOutput()
     *
     * @param string $remainingLengthField
     * @return int
     */
    public static function convertRemainingLengthStringToInt(string $remainingLengthField): int
    {
        $multiplier = 128;
        $value = 0;
        $iteration = 0;

        do {
            // Extract the next byte in the sequence
            $encodedByte = ord($remainingLengthField[$iteration]);

            // Add the current multiplier^iteration * first half of byte
            $value += ($encodedByte & 127) * (128 ** $iteration);
            if ($multiplier > (128 ** 3)) {
                throw new LogicException('Malformed remaining length field');
            }

            // Prepare for the next iteration
            $iteration++;
            $multiplier *= $iteration;
        } while (($encodedByte & 128) !== 0);

        return (int)$value;
    }
}


1		<?php
2
3		declare(strict_types=1);
4
5		namespace unreal4u\MQTT;
6
7		use LogicException;
8		use OutOfRangeException;
9		use unreal4u\MQTT\Exceptions\MessageTooBig;
10
11		use function chr;
12		use function dechex;
13		use function hexdec;
14		use function ord;
15		use function str_pad;
16
17		/**
18		* Functionality that is shared across the entire package
19		* @package unreal4u\MQTT
20		*/
21		final class Utilities
22		{
23		/**
24		* Swaps the given number from endian format (INT16, not to be confused with UINT16)
25		*
26		* @param int $number
27		* @return int
28		* @throws OutOfRangeException
29		*/
30	35	public static function convertEndianness(int $number): int
31		{
32	35	if ($number > 65535) {
33	1	throw new OutOfRangeException('This is an INT16 conversion, so the maximum is 65535');
34		}
35
36	34	$finalNumber = hexdec(
37		// Invert first byte and make it a complete hexadecimal number
38	34	str_pad(dechex($number & 255), 2, '0', STR_PAD_LEFT) .
39		// Invert second byte and make a complete hexadecimal number
40	34	str_pad(dechex($number >> 8), 2, '0', STR_PAD_LEFT)
41		);
42
43	34	return (int)$finalNumber;
44		}
45
46		/**
47		* Converts a number to a binary string that the MQTT protocol understands
48		*
49		* @param int $number
50		* @return string
51		* @throws OutOfRangeException
52		*/
53	34	public static function convertNumberToBinaryString(int $number): string
54		{
55	34	if ($number > 65535) {
56	1	throw new OutOfRangeException('This is an INT16 conversion, so the maximum is 65535');
57		}
58
59	33	return chr($number >> 8) . chr($number & 255);
60		}
61
62		/**
63		* Converts a binary representation of a number to an actual int
64		*
65		* @param string $binaryString
66		* @return int
67		* @throws OutOfRangeException
68		*/
69	26	public static function convertBinaryStringToNumber(string $binaryString): int
70		{
71	26	return self::convertEndianness((ord($binaryString[1]) << 8) + (ord($binaryString[0]) & 255));
72		}
73
74		/**
75		* Returns the correct format for the length in bytes of the remaining bytes
76		*
77		* Original pseudo-code algorithm as per the documentation:
78		* <pre>
79		* do
80		* encodedByte = X MOD 128
81		* X = X DIV 128
82		* // if there are more data to encode, set the top bit of this byte
83		* if ( X > 0 )
84		* encodedByte = encodedByte OR 128
85		* endif
86		* 'output' encodedByte
87		* while ( X > 0 )
88		* </pre>
89		* @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc385349213
90		*
91		* @param int $lengthInBytes
92		* @return string
93		* @throws MessageTooBig
94		*/
95	18	public static function formatRemainingLengthOutput(int $lengthInBytes): string
96		{
97	18	if ($lengthInBytes > 268435455) {
98	1	throw new MessageTooBig('The message cannot exceed 268435455 bytes in length');
99		}
100
101	17	$x = $lengthInBytes;
102	17	$outputString = '';
103		do {
104	17	$encodedByte = $x % 128;
105	17	$x >>= 7; // Shift 7 bytes
106		// if there are more data to encode, set the top bit of this byte
107	17	if ($x > 0) {
108	9	$encodedByte \|= 128;
109		}
110	17	$outputString .= chr($encodedByte);
111	17	} while ($x > 0);
112
113	17	return $outputString;
114		}
115
116		/**
117		* The remaining length of a message is encoded in this specific way, the opposite of formatRemainingLengthOutput
118		*
119		* Many thanks to Peter's blog for your excellent examples and knowledge.
120		* @see http://indigoo.com/petersblog/?p=263
121		*
122		* Original pseudo-algorithm as per the documentation:
123		* <pre>
124		* multiplier = 1
125		* value = 0
126		* do
127		* encodedByte = 'next byte from stream'
128		* value += (encodedByte & 127) * multiplier
129		* if (multiplier > 128128128)
130		* throw Error(Malformed Remaining Length)
131		* multiplier *= 128
132		* while ((encodedByte & 128) != 0)
133		* </pre>
134		*
135		* @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc385349213
136		* @see Utilities::formatRemainingLengthOutput()
137		*
138		* @param string $remainingLengthField
139		* @return int
140		*/
141	18	public static function convertRemainingLengthStringToInt(string $remainingLengthField): int
142		{
143	18	$multiplier = 128;
144	18	$value = 0;
145	18	$iteration = 0;
146
147		do {
148		// Extract the next byte in the sequence
149	18	$encodedByte = ord($remainingLengthField[$iteration]);
150
151		// Add the current multiplier^iteration * first half of byte
152	18	$value += ($encodedByte & 127) * (128 ** $iteration);
153	18	if ($multiplier > (128 ** 3)) {
154		throw new LogicException('Malformed remaining length field');
155		}
156
157		// Prepare for the next iteration
158	18	$iteration++;
159	18	$multiplier *= $iteration;
160	18	} while (($encodedByte & 128) !== 0);
161
162	18	return (int)$value;
163		}
164		}
165

unreal4u / mqtt

Utilities::convertRemainingLengthStringToInt() A last analyzed 2020-09-22 18:34 UTC

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Utilities::convertRemainingLengthStringToInt() A
last analyzed 2020-09-22 18:34 UTC