friendly-filesize.php

<?php

/**
 * filesize
 *
 * Formats a filesize into a human-readable format
 *
 * Usage:
 * <code>
 * filesize(50, false, '{size} <small>{unit}</small');
 * </code>
 *
 * @param int $size Filesize in bytes
 * @param int $precision Number of decimal places to round to
 * @param string $format Output format with placeholders "{size}" and "{unit}"
 *
 * @return string Formatted filesize
 */

public static function filesize($size, $precision = 0, $format = '{size} {unit}') {

    // If size is zero, skip the calculations
    if ($size !== 0) {

        // Calculate base
        $base = log($size) / log(1024);

        // Array of units
        $units = array('B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB');

        // Calculate size
        $size = round(pow(1024, $base - floor($base)), $precision);

        // Select unit
        $unit = $units[floor($base)];

    } else {

        // Size is zero so hardcode unit
        $unit = 'B';

    }


    // Construct output as per format
    $format = str_replace('{size}', $size, $format);
    $format = str_replace('{unit}', $unit, $format);

    return $format;

}