Description:
------------
JSON Version 1.2.1

The following program causes PHP to exit with a segmentation fault:

<?php

json_decode("\"");

?>

Instead, it should fail gracefully ("\"" is not valid JSON) and return NULL.

The <a href="http://www.json.org/JSON_checker/">JSON checker</a> correctly reports that it is invalid input: 
"syntax error at character 0"


Reproduce code:
---------------
<?php

print_r(json_decode("\""));

?>

Expected result:
----------------
NULL

Actual result:
--------------
Segmentation fault (core dumped)