Description:
------------
finfo_file fails with "allowed memory size of nnn bytes exhausted" on some file types. In my case it's csv, which you can download here
https://www.dropbox.com/s/oivtic8g4r9tb20/products_general_11052014.csv?dl=0

The problem reproduces approximately since 5.5.14 to the latest 5.6.6.

Test script:
---------------
<?php

$f = finfo_open(FILEINFO_MIME);
finfo_file($f, './products_general_11052014.csv');

echo('ok');

Expected result:
----------------
"ok" should be output

Actual result:
--------------
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 4294947908 bytes) in test.php on line 4