First version

src/Twig/AppExtension.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Twig;
+
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Twig\Extension\AbstractExtension;
+use Twig\TwigFilter;
+
+class AppExtension extends AbstractExtension
+{
+    public function getFilters()
+    {
+        return array(
+            new TwigFilter('formatBytes', array($this, 'formatBytes')),
+        );
+    }
+
+    /**
+     * @param $bytes
+     * @param int $precision
+     * @return string
+     */
+    public function formatBytes($bytes, $precision = 2)
+    {
+        $size = ['B','kB','MB','GB','TB','PB','EB','ZB','YB'];
+        $factor = floor((strlen($bytes) - 1) / 3);
+        return sprintf("%.{$precision}f", $bytes / pow(1024, $factor)) . @$size[$factor];
+    }
+
+}