implement suggestion for dealing with _Unsigned attribute in issue #656

Unidata · May 8, 2017 · 98e19ab · 98e19ab
1 parent 37f582b
commit 98e19ab
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diff --git a/Changelog b/Changelog
@@ -1,5 +1,7 @@
- version 1.2.8a0 (tag XXXX)
+ version 1.2.8a0 (not yet released)
 ===========================
+ * recognize _Unsigned attribute used by netcdf-java to designate unsigned
+   integer data stored with a signed integer type in netcdf-3.
  * add Dataset init memory parameter to allow loading a file from memory
 
  version 1.2.7 (tag v1.2.7rel)

diff --git a/netCDF4/_netCDF4.c b/netCDF4/_netCDF4.c
diff --git a/netCDF4/_netCDF4.pyx b/netCDF4/_netCDF4.pyx
@@ -3822,6 +3822,13 @@ rename a `netCDF4.Variable` attribute named `oldname` to `newname`."""
             # else if variable has only add_offset attributes, rescale.
             elif hasattr(self, 'add_offset') and self.add_offset != 0.0:
                 data = data + self.add_offset
+
+        # if attribute _Unsigned is True, and variable has signed integer
+        # dtype, return view with corresponding unsigned dtype (issue #656)
+        is_unsigned = getattr(self, '_Unsigned', False)
+        if is_unsigned and data.dtype.str[1] == 'i':
+            data = data.view('u'+data.dtype.str[2])
+
         return data
 
     def _toma(self,data):