[master] 17c92e4 hack up vsctool to work with python 2 and 3

[Nils Goroll]

commit 17c92e43fda114bf5341e51d752e882238b8fe8c
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Oct 5 13:39:23 2017 +0200

    hack up vsctool to work with python 2 and 3
    
    StringIO does not exist any more in python3, yet requiring 2.7 would
    not pave the path forward, so try to be compatible with both.
    
    Works for me on Python 2.7.9 and Python 3.4
    
    I would appreciate if someone more fluent in serpentinous programming
    language reviewed and/or rewrote this.

diff --git a/lib/libvcc/vsctool.py b/lib/libvcc/vsctool.py
index 854968e..829c6e5 100644
--- a/lib/libvcc/vsctool.py
+++ b/lib/libvcc/vsctool.py
@@ -37,7 +37,10 @@ import getopt
 import json
 import sys
 import gzip
-import StringIO
+try:
+    import StringIO
+except ImportError:
+    import io
 import collections
 import struct
 
@@ -54,9 +57,22 @@ PARAMS = {
 	"format":	[ "integer", FORMATS],
 }
 
+# http://python3porting.com/problems.html#bytes-strings-and-unicode
+if sys.version_info < (3,):
+    def b(x):
+        return x
+else:
+    import codecs
+    def b(x):
+        return codecs.latin_1_encode(x)[0]
+
 def gzip_str(s):
-	out = StringIO.StringIO()
-	gzip.GzipFile(fileobj=out, mode="w").write(s)
+	try:
+		out = StringIO.StringIO()
+	except NameError:
+		out = io.BytesIO()
+
+	gzip.GzipFile(fileobj=out, mode="w").write(b(s))
 	out.seek(4)
 	out.write(struct.pack("<L", 0x12bfd58))
 	return out.getvalue()
@@ -285,7 +301,7 @@ class rst_vsc(directive):
 	def __init__(self, s):
 		super(rst_vsc, self).__init__(s)
 
-		for i,v in PARAMS.iteritems():
+		for i,v in PARAMS.items():
 			if v is not True:
 				self.do_default(i, v[0], v[1])