merged branch jfsimon/issue-7413 (PR #7456)

This PR was merged into the master branch.

Discussion
----------

Improve bytes conversion method

This PR improves bytes conversion `regex` method introduced in #7413 (thanks to @vicb's comments).

* Adds support of `+` prefix.
* Adds support of blank chars between `+`, number and unit.
* Adds support of octal/hexa bases.

Notice that this can not be unit tested for `ServerParams` and `UploadedFile` classes because `ini_set()` function does not work with `post_max_size` and `upload_max_filesize` settings.

For information, this convertion is located in 3 classes:
* `Symfony\Component\Form\Extension\Validator\Util\ServerParams`
* `Symfony\Component\HttpFoundation\File\UploadedFile`
* `Symfony\Component\HttpKernel\DataCollector\MemoryDataCollector`

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7413

Commits
-------

21291ca improved bytes conversion method

Author: fabpot

Extension/Validator/Util/ServerParams.php

@@ -29,12 +29,14 @@ public function getPostMaxSize()
             return null;
         }
 
-        if (preg_match('#^(\d+)([bkmgt])#i', $iniMax, $match)) {
-            $shift = array('b' => 0, 'k' => 10, 'm' => 20, 'g' => 30, 't' => 40);
-            $iniMax = ($match[1] * (1 << $shift[strtolower($match[2])]));
+        if (preg_match('#^\+?(0x?)?([^kmg]*)([KMG]?)#', $iniMax, $match)) {
+            $shifts = array('' => 0, 'K' => 10, 'M' => 20, 'G' => 30);
+            $bases = array('' => 10, '0' => 8, '0x' => 16);
+
+            return (intval($match[2], $bases[$match[1]]) * (1 << $shifts[$match[3]]));
         }
 
-        return (int) $iniMax;
+        return 0;
     }
 
     /**