BUG: Fixing bitness issues on 32-bit systems

by being explicit with sizes

tests/utils/daily_bar_writer.py

@@ -1,6 +1,7 @@
 from numpy import (
     float64,
-    uint32
+    uint32,
+    int64,
 )
 from bcolz import ctable
 
@@ -37,8 +38,9 @@ class DailyBarWriterFromDataFrames(BcolzDailyBarWriter):
             return array.astype(uint32)
         elif colname == 'day':
             nanos_per_second = (1000 * 1000 * 1000)
-            self.check_uint_safe(arrmax.view(int) / nanos_per_second, colname)
-            return (array.view(int) / nanos_per_second).astype(uint32)
+            self.check_uint_safe(arrmax.view(int64) / nanos_per_second,
+                                 colname)
+            return (array.view(int64) / nanos_per_second).astype(uint32)
 
     @staticmethod
     def check_uint_safe(value, colname):