Memory Usage / Time Testing PHP Hash Storing

memTest.php

<?php
/**
 * This is tested in PHP 7.1
 * As part of a system I'm looking to store a series of hashes, and look these up.
 * There could be many hashes, and I don't need to use these, I just need to know if they exist.
 *
 * The following tests pit arrays against strings to see which is the fastest.
 * I'll be searching for MTIzNDY5MTI1Njc4 which is the number 12345678 * 1000 base 64 encoded
**/


/**
  * Profiler
  *
  * @author     Matt Barber <[email protected]>
 **/
class Profiler
{
    // The current state of the data
    private $data = null;
    // The initial time (used to calculate overall)
    private $time = 0;
    // The initial memory (used to calculate overall)
    private $memory = 0;

    /**
     * Upon instantiation, setup the initial memory and time, and register the
     * tick method as the method to call on each line execution
     *
     * @return void
    **/
    public function __construct()
    {
        // store the start time
        $this->data = new StdClass();
        $this->time = microtime(true);
        $this->memory = memory_get_usage() / 1024 / 1024;
        // register the tick method on this class as the tick function (call it on each line execution)
        register_tick_function([$this, 'tick']);
        declare(ticks = 1);
    }

    /**
     * On unsetting (garbage collection) unregister the method as the tick function
     *
     * @return void
    **/
    public function __destruct()
    {
        unregister_tick_function([$this, 'tick']);
    }

    /**
     * On each 'tick' call this method and update the current memory and time state of
     * the profiler
     *
     * @return void
    **/
    public function tick() : void
    {
        $this->data->memory = memory_get_usage() / 1024 / 1024 - $this->memory;
        $this->data->time = microtime(true) - $this->time;
    }

    /**
     * Return the state of the profiler at any given time
     *
     * @return object
    **/
    public function getData() : \stdClass
    {
        return $this->data;
    }
}

/**
 * Array Testing
 ******************************************************************************
**/
echo "Testing Array Hashing....\n==================================\n";
$profiler = new Profiler();
$array = [];
// Foreach number in 1 to 1000000, store the hash as a key, and the value as true
foreach (range(1, 1000000) as $number) {
    $array[base64_encode(12345678 * $number)] = true;
}
// array_key_exists has a complexity of O(n) but really close to O(1) -
// this is because of linear polling in collisions, but because the chance of collisions is very small,
// the coefficient is also very small
echo 'Found MTIzNDY5MTI1Njc4 : ' . array_key_exists('MTIzNDY5MTI1Njc4', $array) . "\n";

$data = $profiler->getData();
echo "Memory Usage : {$data->memory} mb\n";
echo "Time taken: {$data->time} seconds\n\n\n";

// Reset values
unset($profiler);

/**
 * String Testing
 ******************************************************************************
**/
echo "Testing String Hashing....\n==================================\n";
$profiler = new Profiler();
$str = '';
// Foreach number in 1 to 1000000 store the hash as a string concatenated with a string option
// we use a delimiter that will be highly unlikely to exist in our encoding
foreach (range(1, 1000000) as $number) {
    $str .= '::::' . base64_encode((12345678 * $number));
}
// We use strstr to see if our string exists in our string, this will probably have a complexity of
// O(n)
echo 'Found MTIzNDY5MTI1Njc4 in ' . strpos($str, 'MTIzNDY5MTI1Njc4') . "\n";

$data = $profiler->getData();
echo "Memory Usage : {$data->memory} mb\n";
echo "Time taken: {$data->time} seconds\n\n\n";

// Reset values
unset($profiler);
/* 
 | => php memoryTests.php 
 Testing Array Hashing....
 ==================================
 Found MTIzNDY5MTI1Njc4 : 1
 Memory Usage : 88.788681030273 mb
 Time taken: 0.84828591346741 seconds
 
 Testing String Hashing....
 ==================================
 Found MTIzNDY5MTI1Njc4 in 199680
 Memory Usage : 22.582824707031 mb
 Time taken: 2.640704870224 seconds
*/