amazonwebservices/aws-sdk-for-php — pull request #12 by chandeeland (2011-12-14 16:01:12+00:00)
Title: json_last_error doesn't exist before php v 5.3.0,

and using a previous version causes exceptions even when there is no error with json_decode.

I tried to cover the case of an encoded NULL value.
it's a little ugly, but unavoidable if you aren't using PHP with json_last_error() implemented