Class FreeSpace for calculating hard disk space

DiskSpace.php

<?php

namespace backend\components;

/**
 * Class FreeSpace for calculating free hard disk space
 * only php 7.0 or later
 * @package backend\components
 */
class DiskSpace
{
    /**
     * @param string $dir default(__DIR__)
     * @param string $unit
     * @values $unit (kb, mb, 'gb' or empty)
     * @return float
     */
    public static function showFree(string $dir = __DIR__, string $unit = null) : float
    {
        $freeSpaceByte = self::getFreeSpace($dir);

        return self::calcSize($freeSpaceByte, $unit);

    }

    /**
     * @param string $dir default(__DIR__)
     * @param string $unit
     * @values $unit (kb, mb, 'gb' or empty)
     * @return float
     */
    public static function showTotal(string $dir = __DIR__, string $unit = null) : float
    {
        $totalSpaceByte = self::getTotalSpace($dir);

        return self::calcSize($totalSpaceByte, $unit);

    }

    /**
     * Returns the difference between the total size of the disk space and the free space, in other words, returns the occupied space
     * @param string $dir
     * @param string $unit
     * @values $unit (kb, mb, 'gb' or empty)
     * @return float
     */
    public static function getOccupied(string $dir = __DIR__, string $unit = null) : float
    {

        $freeSpaceByte = self::getFreeSpace($dir);
        $totalSpaceByte = self::getTotalSpace($dir);

        $different =  $totalSpaceByte - $freeSpaceByte;

        return self::calcSize($different, $unit);

    }

    /**
     * Method returns an array of values of different units of measure
     * @param string $dir default(__DIR__)
     * @return array
     */
    public static function getArrayFreeSpace(string $dir = __DIR__) : array
    {
        $freeSpaceByte = self::getFreeSpace($dir);

        return [
            'byte' => $freeSpaceByte,
            'kb' => self::calcSize($freeSpaceByte, 'kb'),
            'mb' => self::calcSize($freeSpaceByte, 'mb'),
            'gb' => self::calcSize($freeSpaceByte, 'gb'),
        ];

    }

    /**
     * Method returns an array of values of different units of measure
     * @param string $dir default(__DIR__)
     * @return array
     */
    public static function getArrayTotalSpace(string $dir = __DIR__) : array
    {
        $totalSpaceByte = self::getTotalSpace($dir);

        return [
            'byte' => $totalSpaceByte,
            'kb' => self::calcSize($totalSpaceByte, 'kb'),
            'mb' => self::calcSize($totalSpaceByte, 'mb'),
            'gb' => self::calcSize($totalSpaceByte, 'gb'),
        ];

    }

    /**
     * If you need to change the system of obtaining free space,
     * you need to override this method, now it uses `disk_free_space`
     * @param string $dir default(__DIR__)
     * @return bool|float
     */
    protected static function getFreeSpace(string $dir = __DIR__) : float
    {
        return disk_free_space ($dir);
    }

    /**
     * If you need to change the system of obtaining total space,
     * you need to override this method, now it uses `disk_free_space`
     * @param string $dir default(__DIR__)
     * @return bool|float
     */
    protected static function getTotalSpace(string $dir = __DIR__) : float
    {
        return disk_total_space($dir);
    }

    /**
     * @param $byte_size
     * @param $unit
     * @values $unit (kb, mb, 'gb')
     * @return float
     */
    protected static function calcSize(float $byte_size, string $unit) : float
    {
        switch ($unit) {
            case 'kb':
                return round($byte_size/1024, 2);
            case 'mb':
                return round($byte_size/1024/1024, 2);
            case 'gb':
                return round($byte_size/1024/1024/1024);
            default:
                return $byte_size;
        }
    }


}