Merge pull request #12 from msabramo/buffer_memoryview_py3

Deal with lack of `buffer` in py3

Author: msabramo

smmap/mman.py

@@ -6,6 +6,7 @@
                     is_64_bit,
                     align_to_mmap,
                     string_types,
+                    buffer,
                 )
 
 from weakref import ref

smmap/test/test_tutorial.py

@@ -44,6 +44,7 @@ def test_example(self):
         # its recommended not to create big slices when feeding the buffer
         # into consumers (e.g. struct or zlib). 
         # Instead, either give the buffer directly, or use pythons buffer command.
+        from smmap.util import buffer
         buffer(c.buffer(), 1, 9)    # first 9 bytes without copying them
 
         # you can query absolute offsets, and check whether an offset is included

smmap/util.py

@@ -12,11 +12,20 @@
     from mmap import PAGESIZE as ALLOCATIONGRANULARITY
 #END handle pythons missing quality assurance
 
-__all__ = [ "align_to_mmap", "is_64_bit",
+__all__ = [ "align_to_mmap", "is_64_bit", "buffer",
             "MapWindow", "MapRegion", "MapRegionList", "ALLOCATIONGRANULARITY"]
 
 #{ Utilities
 
+try:
+    # Python 2
+    buffer = buffer
+except NameError:
+    # Python 3 has no `buffer`; only `memoryview`
+    def buffer(obj, offset, size):
+        return memoryview(obj[offset:offset+size])
+
+
 def string_types():
     if sys.version_info[0] >= 3:
         return str