Unable to read SITE_NUM from PIR

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Reading any STDF with test.py
2.
3.

What is the expected output? What do you see instead?
-Expect to see valid HEAD_NUM & SITE_NUM for PIR.
-SITE_NUM in PIR displays as None.

What version of the product are you using? On what operating system?
stdfparser-1.0.2, Windows 7

Please provide any additional information below.
Error is due to function "_get_Un" in stdfparser.py. When reading format "U1", 
function returns None if buffer length is < 2.

Workaround/Fix.
Edit line 315 to:
    if len(buf) < 1:

Original issue reported on code.google.com by chon...@gmail.com on 1 Nov 2013 at 9:26