php

<?php


function size($size, $precision = 2){
    $base = log($size, 1024);
    //$suffixes = array('', 'K', 'M', 'G', 'T');
    $suffixes = array('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB');

    return round(pow(1024, $base - floor($base)), $precision) .' '. $suffixes[floor($base)];
}

function bytes($bytes, $force_unit = NULL, $format = NULL, $si = TRUE)
{
    // Format string
    $format = ($format === NULL) ? '%01.2f %s' : (string) $format;

    // IEC prefixes (binary)
    if ($si == FALSE OR strpos($force_unit, 'i') !== FALSE)
    {
        $units = array('B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB');
        $mod   = 1024;
    }
    // SI prefixes (decimal)
    else
    {
        $units = array('B', 'kB', 'MB', 'GB', 'TB', 'PB');
        $mod   = 1000;
    }

    // Determine unit to use
    if (($power = array_search((string) $force_unit, $units)) === FALSE)
    {
        $power = ($bytes > 0) ? floor(log($bytes, $mod)) : 0;
    }

    return sprintf($format, $bytes / pow($mod, $power), $units[$power]);
}