Generator::status() - Code Metrics - Inspection of "Corrected scrutinizer issues." - Gendoria/cruftflake - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( cd0397...35e616 )

by Tomasz

created 2016-02-04 14:16 UTC

Generator::status() A

↳ Parent: Generator

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	0
CRAP Score	2

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
c	1
b	0
f	0
dl	0
loc	4
rs	10
ccs	0
cts	2
cp	0
cc	1
eloc	2
nc	1
nop	0
crap	2

<?php
/**
 * Like the Twitter one.
 * 
 * 64 bits:
 * 
 * time - 41 bits (millisecond precision w/ a custom epoch gives us 69 years)
 * configured machine id - 10 bits - gives us up to 1024 machines
 * sequence number - 12 bits - rolls over every 4096 per machine (with protection to avoid rollover in the same ms)
 * 
 * 32 bits + 9 = 41 bits of time
 * 2199023255552 < milliseconds = 2199023255 seconds
 *                                2147483647 < max 31 bit int (signed)
 *
 * @author @davegardnerisme
 */

namespace Gendoria\CruftFlake\Generator;

use Gendoria\CruftFlake\Config\ConfigInterface;
use Gendoria\CruftFlake\Timer\TimerInterface;
use InvalidArgumentException;
use OverflowException;
use UnexpectedValueException;

class Generator
{
    /**
     * Max timestamp.
     */
    const MAX_ADJUSTED_TIMESTAMP = 2199023255551;

    /**
     * Hexdec lookup.
     * 
     * @staticvar array
     */
    private static $hexdec = array(
        '0' => 0,
        '1' => 1,
        '2' => 2,
        '3' => 3,
        '4' => 4,
        '5' => 5,
        '6' => 6,
        '7' => 7,
        '8' => 8,
        '9' => 9,
        'a' => 10,
        'b' => 11,
        'c' => 12,
        'd' => 13,
        'e' => 14,
        'f' => 15,
        );

    /**
     * Timer.
     * 
     * @var TimerInterface
     */
    private $timer;

    /**
     * Configured machine ID - 10 bits (dec 0 -> 1023).
     *
     * @var int
     */
    private $machine;

    /**
     * Epoch - in UTC millisecond timestamp.
     *
     * @var int
     */
    private $epoch = 1325376000000;

    /**
     * Sequence number - 12 bits, we auto-increment for same-millisecond collisions.
     *
     * @var int
     */
    private $sequence = 1;

    /**
     * The most recent millisecond time window encountered.
     *
     * @var integer
     */
    private $lastTime = null;

    /**
     * Constructor.
     * 
     * @param @inject ConfigInterface $config
     * @param @inject TimerInterface  $timer
     */
    public function __construct(ConfigInterface $config, TimerInterface $timer)
    {
        $this->machine = $config->getMachine();
        if (!is_int($this->machine) || $this->machine < 0 || $this->machine > 1023) {
            throw new InvalidArgumentException(
                    'Machine identifier invalid -- must be 10 bit integer (0 to 1023)'
                    );
        }
        $this->timer = $timer;
    }

    /**
     * Generate ID.
     *
     * @return string A 64 bit integer as a string of numbers (so we can deal
     *                with this on 32 bit platforms) 
     */
    public function generate()
    {
        $t = (int)floor($this->timer->getUnixTimestamp() - $this->epoch);
        if ($t !== $this->lastTime) {
            if ($t < $this->lastTime) {
                throw new UnexpectedValueException(
                        'Time moved backwards. We cannot generate IDs for '
                        .($this->lastTime - $t).' milliseconds'
                        );
            } elseif ($t < 0) {
                throw new UnexpectedValueException(
                        'Time is currently set before our epoch - unable '
                        .'to generate IDs for '.(-$t).' milliseconds'
                        );
            } elseif ($t > self::MAX_ADJUSTED_TIMESTAMP) {
                throw new OverflowException(
                        'Timestamp overflow (past end of lifespan) - unable to generate any more IDs'
                        );
            }
            $this->sequence = 0;
            $this->lastTime = $t;
        } else {
            ++$this->sequence;
            if ($this->sequence > 4095) {
                throw new OverflowException(
                        'Sequence overflow (too many IDs generated) - unable to generate IDs for 1 milliseconds'
                        );
            }
        }

        if (PHP_INT_SIZE === 4) {
            return $this->mintId32($t, $this->machine, $this->sequence);
        } else {
            return $this->mintId64($t, $this->machine, $this->sequence);
        }
    }

    /**
     * Get stats.
     *
     * @return GeneratorStatus
     */
    public function status()
    {
        return new GeneratorStatus($this->machine, $this->lastTime, $this->sequence, (PHP_INT_SIZE === 4));
    }

    private function mintId32($timestamp, $machine, $sequence)
    {
        $hi = (int) ($timestamp / pow(2, 10));
        $lo = (int) ($timestamp * pow(2, 22));

        // stick in the machine + sequence to the low bit
        $lo = $lo | ($machine << 12) | $sequence;

        // reconstruct into a string of numbers
        $hex = pack('N2', $hi, $lo);
        $unpacked = unpack('H*', $hex);
        $value = $this->hexdec($unpacked[1]);

        return (string) $value;
    }

    private function mintId64($timestamp, $machine, $sequence)
    {
        $timestamp = (int) $timestamp;
        $value = ($timestamp << 22) | ($machine << 12) | $sequence;

        return (string) $value;
    }

    private function hexdec($hex)
    {
        $dec = 0;
        for ($i = strlen($hex) - 1, $e = 1; $i >= 0; $i--, $e = bcmul($e, 16)) {
            $factor = self::$hexdec[$hex[$i]];
            $dec = bcadd($dec, bcmul($factor, $e));
        }

        return $dec;
    }
}


1		<?php
2		/**
3		* Like the Twitter one.
4		*
5		* 64 bits:
6		*
7		* time - 41 bits (millisecond precision w/ a custom epoch gives us 69 years)
8		* configured machine id - 10 bits - gives us up to 1024 machines
9		* sequence number - 12 bits - rolls over every 4096 per machine (with protection to avoid rollover in the same ms)
10		*
11		* 32 bits + 9 = 41 bits of time
12		* 2199023255552 < milliseconds = 2199023255 seconds
13		* 2147483647 < max 31 bit int (signed)
14		*
15		* @author @davegardnerisme
16		*/
17
18		namespace Gendoria\CruftFlake\Generator;
19
20		use Gendoria\CruftFlake\Config\ConfigInterface;
21		use Gendoria\CruftFlake\Timer\TimerInterface;
22		use InvalidArgumentException;
23		use OverflowException;
24		use UnexpectedValueException;
25
26		class Generator
27		{
28		/**
29		* Max timestamp.
30		*/
31		const MAX_ADJUSTED_TIMESTAMP = 2199023255551;
32
33		/**
34		* Hexdec lookup.
35		*
36		* @staticvar array
37		*/
38		private static $hexdec = array(
39		'0' => 0,
40		'1' => 1,
41		'2' => 2,
42		'3' => 3,
43		'4' => 4,
44		'5' => 5,
45		'6' => 6,
46		'7' => 7,
47		'8' => 8,
48		'9' => 9,
49		'a' => 10,
50		'b' => 11,
51		'c' => 12,
52		'd' => 13,
53		'e' => 14,
54		'f' => 15,
55		);
56
57		/**
58		* Timer.
59		*
60		* @var TimerInterface
61		*/
62		private $timer;
63
64		/**
65		* Configured machine ID - 10 bits (dec 0 -> 1023).
66		*
67		* @var int
68		*/
69		private $machine;
70
71		/**
72		* Epoch - in UTC millisecond timestamp.
73		*
74		* @var int
75		*/
76		private $epoch = 1325376000000;
77
78		/**
79		* Sequence number - 12 bits, we auto-increment for same-millisecond collisions.
80		*
81		* @var int
82		*/
83		private $sequence = 1;
84
85		/**
86		* The most recent millisecond time window encountered.
87		*
88		* @var integer
89		*/
90		private $lastTime = null;
91
92		/**
93		* Constructor.
94		*
95		* @param @inject ConfigInterface $config
96		* @param @inject TimerInterface $timer
97		*/
98	18	public function __construct(ConfigInterface $config, TimerInterface $timer)
99		{
100	18	$this->machine = $config->getMachine();
101	18	if (!is_int($this->machine) \|\| $this->machine < 0 \|\| $this->machine > 1023) {
102	4	throw new InvalidArgumentException(
103		'Machine identifier invalid -- must be 10 bit integer (0 to 1023)'
104	4	);
105		}
106	14	$this->timer = $timer;
107	14	}
108
109		/**
110		* Generate ID.
111		*
112		* @return string A 64 bit integer as a string of numbers (so we can deal
113		* with this on 32 bit platforms)
114		*/
115	12	public function generate()
116		{
117	12	$t = (int)floor($this->timer->getUnixTimestamp() - $this->epoch);
118	12	if ($t !== $this->lastTime) {
119	12	if ($t < $this->lastTime) {
120	1	throw new UnexpectedValueException(
121		'Time moved backwards. We cannot generate IDs for '
122	1	.($this->lastTime - $t).' milliseconds'
123	1	);
124	12	} elseif ($t < 0) {
125	1	throw new UnexpectedValueException(
126		'Time is currently set before our epoch - unable '
127	1	.'to generate IDs for '.(-$t).' milliseconds'
128	1	);
129	11	} elseif ($t > self::MAX_ADJUSTED_TIMESTAMP) {
130	1	throw new OverflowException(
131		'Timestamp overflow (past end of lifespan) - unable to generate any more IDs'
132	1	);
133		}
134	10	$this->sequence = 0;
135	10	$this->lastTime = $t;
136	10	} else {
137	7	++$this->sequence;
138	7	if ($this->sequence > 4095) {
139	1	throw new OverflowException(
140		'Sequence overflow (too many IDs generated) - unable to generate IDs for 1 milliseconds'
141	1	);
142		}
143		}
144
145	10	if (PHP_INT_SIZE === 4) {
146		return $this->mintId32($t, $this->machine, $this->sequence);
147		} else {
148	10	return $this->mintId64($t, $this->machine, $this->sequence);
149		}
150		}
151
152		/**
153		* Get stats.
154		*
155		* @return GeneratorStatus
156		*/
157		public function status()
158		{
159		return new GeneratorStatus($this->machine, $this->lastTime, $this->sequence, (PHP_INT_SIZE === 4));
160		}
161
162		private function mintId32($timestamp, $machine, $sequence)
163		{
164		$hi = (int) ($timestamp / pow(2, 10));
165		$lo = (int) ($timestamp * pow(2, 22));
166
167		// stick in the machine + sequence to the low bit
168		$lo = $lo \| ($machine << 12) \| $sequence;
169
170		// reconstruct into a string of numbers
171		$hex = pack('N2', $hi, $lo);
172		$unpacked = unpack('H*', $hex);
173		$value = $this->hexdec($unpacked[1]);
174
175		return (string) $value;
176		}
177
178	10	private function mintId64($timestamp, $machine, $sequence)
179		{
180	10	$timestamp = (int) $timestamp;
181	10	$value = ($timestamp << 22) \| ($machine << 12) \| $sequence;
182
183	10	return (string) $value;
184		}
185
186		private function hexdec($hex)
187		{
188		$dec = 0;
189		for ($i = strlen($hex) - 1, $e = 1; $i >= 0; $i--, $e = bcmul($e, 16)) {
190		$factor = self::$hexdec[$hex[$i]];
191		$dec = bcadd($dec, bcmul($factor, $e));
192		}
193
194		return $dec;
195		}
196		}
197

Gendoria / cruftflake

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Generator::status() A

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