Online PHP editor | perf for FQV94

@ 2015-12-23T13:30:39Z

<?

/**
 * Blame Scott Arciszewski of Paragon Initiative Enterprises for this atrocity.
 * 
 * https://paragonie.com
 */
class DeterministicRandom
{
    protected $counter;
    
    public function __construct(string $seed = '', int $counter = 0)
    {
        $this->seed('set', $seed);
        $this->counter = 0;
    }
    
    private function seed(string $action = 'get', string $data = '')
    {
        static $seed = null;
        if ($action === 'set') {
            $seed = $data;
        } elseif ($action === 'get') {
            return $data;
        } else {
            throw new \Error(
                'Unknown action'
            );
        }
    }
    
    public function getBytes(int $numBytes): string
    {
        return \openssl_encrypt(
            \str_repeat("\0", $numBytes),
            'aes-128-ctr',
            $this->seed('get'),
            OPENSSL_RAW_DATA,
            $this->getNonce($numBytes)
        );
    }
    
    public function getInt(int $min, int $max): int
    {
        /**
         * Now that we've verified our weak typing system has given us an integer,
         * let's validate the logic then we can move forward with generating random
         * integers along a given range.
         */
        if ($min > $max) {
            throw new Error(
                'Minimum value must be less than or equal to the maximum value'
            );
        }
        if ($max === $min) {
            return $min;
        }
    
        /**
         * Initialize variables to 0
         * 
         * We want to store:
         * $bytes => the number of random bytes we need
         * $mask => an integer bitmask (for use with the &) operator
         *          so we can minimize the number of discards
         */
        $attempts = $bits = $bytes = $mask = $valueShift = 0;
    
        /**
         * At this point, $range is a positive number greater than 0. It might
         * overflow, however, if $max - $min > PHP_INT_MAX. PHP will cast it to
         * a float and we will lose some precision.
         */
        $range = $max - $min;
    
        /**
         * Test for integer overflow:
         */
        if (!is_int($range)) {
            /**
             * Still safely calculate wider ranges.
             * Provided by @CodesInChaos, @oittaa
             * 
             * @ref https://gist.github.com/CodesInChaos/03f9ea0b58e8b2b8d435
             * 
             * We use ~0 as a mask in this case because it generates all 1s
             * 
             * @ref https://eval.in/400356 (32-bit)
             * @ref http://3v4l.org/XX9r5  (64-bit)
             */
            $bytes = PHP_INT_SIZE;
            $mask = ~0;
        } else {
            /**
             * $bits is effectively ceil(log($range, 2)) without dealing with 
             * type juggling
             */
            while ($range > 0) {
                if ($bits % 8 === 0) {
                   ++$bytes;
                }
                ++$bits;
                $range >>= 1;
                $mask = $mask << 1 | 1;
            }
            $valueShift = $min;
        }
    
        /**
         * Now that we have our parameters set up, let's begin generating
         * random integers until one falls between $min and $max
         */
        do {
            /**
             * The rejection probability is at most 0.5, so this corresponds
             * to a failure probability of 2^-128 for a working RNG
             */
            if ($attempts > 128) {
                throw new Exception(
                    'random_int: RNG is broken - too many rejections'
                );
            }
    
            /**
             * Let's grab the necessary number of random bytes
             */
            $randomByteString = $this->getBytes($bytes);
            if ($randomByteString === false) {
                throw new Exception(
                    'Random number generator failure'
                );
            }
    
            /**
             * Let's turn $randomByteString into an integer
             * 
             * This uses bitwise operators (<< and |) to build an integer
             * out of the values extracted from ord()
             * 
             * Example: [9F] | [6D] | [32] | [0C] =>
             *   159 + 27904 + 3276800 + 201326592 =>
             *   204631455
             */
            $val = 0;
            for ($i = 0; $i < $bytes; ++$i) {
                $val |= ord($randomByteString[$i]) << ($i * 8);
            }
    
            /**
             * Apply mask
             */
            $val &= $mask;
            $val += $valueShift;
    
            ++$attempts;
            /**
             * If $val overflows to a floating point number,
             * ... or is larger than $max,
             * ... or smaller than $min,
             * then try again.
             */
        } while (!is_int($val) || $val > $max || $val < $min);
        return (int) $val;
    }
    
    protected function getNonce(int $increment = 0): string
    {
        $nonce = '';
        $ctr = $this->counter;
        while ($ctr > 0) {
            $nonce = \chr($ctr & 0xFF) . $nonce;
            $ctr >>= 8;
        }
        $this->counter += $increment;
        return \str_pad($nonce, 16, "\0", STR_PAD_LEFT);
    }
}

$seed = str_repeat("\x80", 16);

$rnd1 = new DeterministicRandom($seed);
$rnd2 = new DeterministicRandom($seed);

$out1 = $rnd1->getBytes(16);
$out2 = $rnd1->getBytes(16);
$out3 = $rnd2->getBytes(32);

$int1 = $rnd1->getInt(0, 255);
$int2 = $rnd2->getInt(0, 255);

var_dump([
    bin2hex($out1),
    bin2hex($out2),
    bin2hex($out3),
    $int1,
    $int2
]);

Here you find the average performance (time & memory) of each version. A grayed out version indicates it didn't complete successfully (based on exit-code).

Version	System time (s)	User time (s)	Memory (MiB)
8.3.6	0.004	0.011	16.50
8.3.5	0.014	0.007	16.35
8.3.4	0.012	0.008	18.75
8.3.3	0.012	0.003	18.59
8.3.2	0.000	0.008	20.34
8.3.1	0.008	0.000	21.85
8.3.0	0.008	0.000	23.32
8.2.18	0.010	0.010	18.16
8.2.17	0.007	0.010	22.96
8.2.16	0.003	0.010	20.35
8.2.15	0.004	0.004	24.18
8.2.14	0.004	0.004	24.66
8.2.13	0.008	0.000	19.66
8.2.12	0.004	0.004	26.35
8.2.11	0.003	0.006	21.18
8.2.10	0.004	0.007	18.03
8.2.9	0.004	0.004	19.27
8.2.8	0.000	0.009	17.97
8.2.7	0.003	0.006	17.50
8.2.6	0.000	0.008	17.91
8.2.5	0.000	0.008	18.07
8.2.4	0.004	0.004	22.27
8.2.3	0.004	0.004	19.23
8.2.2	0.004	0.004	17.49
8.2.1	0.005	0.003	17.89
8.2.0	0.007	0.000	17.92
8.1.28	0.014	0.000	25.92
8.1.27	0.003	0.006	23.91
8.1.26	0.008	0.000	28.09
8.1.25	0.004	0.004	28.09
8.1.24	0.006	0.003	23.98
8.1.23	0.008	0.004	19.16
8.1.22	0.004	0.004	17.74
8.1.21	0.000	0.008	18.77
8.1.20	0.004	0.004	17.23
8.1.19	0.004	0.004	17.11
8.1.18	0.003	0.006	18.10
8.1.17	0.004	0.004	18.46
8.1.16	0.005	0.002	20.64
8.1.15	0.004	0.004	18.77
8.1.14	0.000	0.008	19.41
8.1.13	0.003	0.003	17.45
8.1.12	0.007	0.000	17.23
8.1.11	0.004	0.004	17.32
8.1.10	0.003	0.005	17.27
8.1.9	0.004	0.004	17.21
8.1.8	0.000	0.007	17.30
8.1.7	0.004	0.004	17.33
8.1.6	0.005	0.003	17.36
8.1.5	0.006	0.003	17.42
8.1.4	0.002	0.005	17.31
8.1.3	0.000	0.008	17.49
8.1.2	0.003	0.006	17.51
8.1.1	0.004	0.004	17.45
8.1.0	0.000	0.009	17.45
8.0.30	0.005	0.003	18.77
8.0.29	0.005	0.002	16.75
8.0.28	0.000	0.007	18.38
8.0.27	0.003	0.003	17.27
8.0.26	0.000	0.006	17.20
8.0.25	0.003	0.003	16.83
8.0.24	0.004	0.004	16.77
8.0.23	0.003	0.003	16.74
8.0.22	0.004	0.004	16.76
8.0.21	0.004	0.004	16.72
8.0.20	0.000	0.007	16.72
8.0.19	0.005	0.003	16.71
8.0.18	0.007	0.000	16.70
8.0.17	0.005	0.003	16.70
8.0.16	0.000	0.007	16.76
8.0.15	0.004	0.004	16.79
8.0.14	0.003	0.006	16.61
8.0.13	0.000	0.006	13.41
8.0.12	0.000	0.008	16.69
8.0.11	0.000	0.008	16.66
8.0.10	0.007	0.000	16.64
8.0.9	0.005	0.003	16.55
8.0.8	0.009	0.006	16.69
8.0.7	0.004	0.004	16.66
8.0.6	0.007	0.000	16.79
8.0.5	0.005	0.003	16.79
8.0.3	0.008	0.011	17.04
8.0.2	0.010	0.008	17.40
8.0.1	0.004	0.004	16.77
8.0.0	0.010	0.012	16.87
7.4.33	0.000	0.005	16.79
7.4.32	0.003	0.003	16.29
7.4.30	0.000	0.010	16.52
7.4.29	0.003	0.003	16.40
7.4.28	0.000	0.009	16.41
7.4.27	0.000	0.008	16.39
7.4.26	0.000	0.007	16.40
7.4.25	0.004	0.004	16.38
7.4.24	0.003	0.003	16.50
7.4.23	0.005	0.002	16.58
7.4.22	0.015	0.009	16.40
7.4.21	0.012	0.007	16.51
7.4.20	0.000	0.007	16.51
7.4.16	0.009	0.006	16.32
7.4.15	0.016	0.008	17.40
7.4.14	0.011	0.009	17.86
7.4.13	0.011	0.007	16.32
7.4.12	0.007	0.010	16.51
7.4.11	0.008	0.008	16.32
7.4.10	0.009	0.009	16.29
7.4.9	0.012	0.009	16.55
7.4.8	0.012	0.006	19.39
7.4.7	0.003	0.013	16.55
7.4.6	0.008	0.008	16.52
7.4.5	0.011	0.008	16.39
7.4.4	0.003	0.013	16.50
7.4.3	0.009	0.013	16.56
7.4.0	0.007	0.010	14.82
7.3.33	0.005	0.000	13.50
7.3.32	0.000	0.005	13.46
7.3.31	0.003	0.003	15.93
7.3.30	0.007	0.000	16.13
7.3.29	0.003	0.003	16.19
7.3.28	0.012	0.007	16.13
7.3.27	0.013	0.004	17.40
7.3.26	0.017	0.000	16.24
7.3.25	0.012	0.007	16.42
7.3.24	0.007	0.010	16.48
7.3.23	0.011	0.006	16.39
7.3.21	0.013	0.009	16.35
7.3.20	0.014	0.014	19.39
7.3.19	0.013	0.006	16.13
7.3.18	0.010	0.006	16.19
7.3.17	0.009	0.012	16.27
7.3.16	0.013	0.010	16.22
7.3.12	0.003	0.014	14.55
7.3.11	0.009	0.006	14.84
7.3.10	0.008	0.008	14.75
7.3.9	0.000	0.019	14.86
7.3.8	0.006	0.006	14.39
7.3.7	0.005	0.006	14.65
7.3.6	0.006	0.003	14.63
7.3.5	0.007	0.003	14.64
7.3.4	0.003	0.009	14.83
7.3.3	0.000	0.012	14.66
7.3.2	0.011	0.004	16.65
7.3.1	0.012	0.003	16.45
7.3.0	0.006	0.006	16.58
7.2.33	0.003	0.014	16.50
7.2.32	0.013	0.009	16.63
7.2.31	0.000	0.017	16.39
7.2.30	0.010	0.007	16.25
7.2.29	0.006	0.016	16.68
7.2.25	0.003	0.016	14.84
7.2.24	0.007	0.014	14.94
7.2.23	0.012	0.003	15.00
7.2.22	0.006	0.009	14.72
7.2.21	0.006	0.006	15.00
7.2.20	0.009	0.006	14.98
7.2.19	0.013	0.000	14.86
7.2.18	0.011	0.003	14.77
7.2.17	0.000	0.009	14.46
7.2.6	0.010	0.007	16.81
7.2.0	0.009	0.003	19.67
7.1.33	0.009	0.009	15.44
7.1.32	0.004	0.012	15.43
7.1.31	0.007	0.010	15.66
7.1.30	0.003	0.006	15.69
7.1.29	0.003	0.008	15.27
7.1.28	0.004	0.011	15.66
7.1.27	0.000	0.011	15.62
7.1.26	0.008	0.000	15.38
7.1.20	0.004	0.007	15.59
7.1.10	0.007	0.007	18.06
7.1.7	0.005	0.002	17.08
7.1.6	0.004	0.014	19.30
7.1.5	0.012	0.009	17.09
7.1.0	0.003	0.077	22.66
7.0.20	0.000	0.008	16.46
7.0.6	0.020	0.080	21.75
7.0.5	0.000	0.070	18.02
7.0.4	0.003	0.057	20.12
7.0.3	0.023	0.070	20.51
7.0.2	0.033	0.070	20.21
7.0.1	0.007	0.083	20.18
7.0.0	0.003	0.097	20.18
5.6.28	0.003	0.057	20.79
5.6.21	0.010	0.043	20.48
5.6.20	0.007	0.043	18.24
5.6.19	0.013	0.077	20.41
5.6.18	0.027	0.043	20.55
5.6.17	0.017	0.050	20.55
5.6.16	0.007	0.040	20.45
5.6.15	0.010	0.077	18.17
5.6.14	0.010	0.077	18.21
5.6.13	0.000	0.043	18.14
5.6.12	0.003	0.090	21.13
5.6.11	0.007	0.080	21.02
5.6.10	0.003	0.083	20.93
5.6.9	0.017	0.037	20.95
5.6.8	0.013	0.070	20.51
5.5.35	0.033	0.077	20.41
5.5.34	0.000	0.083	17.99
5.5.33	0.010	0.070	20.32
5.5.32	0.067	0.067	20.36
5.5.31	0.017	0.043	20.26
5.5.30	0.010	0.067	18.03
5.5.29	0.017	0.077	18.05
5.5.28	0.007	0.050	20.77
5.5.27	0.010	0.067	20.73
5.5.26	0.010	0.040	20.76
5.5.25	0.003	0.050	20.79
5.5.24	0.017	0.077	20.27

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