Added power2 function.

README.md

@@ -50,6 +50,14 @@ e = j1950_to_epoch(2191001400.0)
 j = epoch_to_to_j1950(1559849400.0)
 ```
 
+## power2
+
+Calculates the next power of two greater than or equal to x.
+
+```python
+power2(3)  # returns 4
+```
+
 ## bluefile
 
 xmextras locates the system installation of bluefile.py so it can be imported outside of an X-Midas environment.

tests/test_noxm.py

@@ -13,3 +13,11 @@ def test_j1950():
     assert datetime.fromtimestamp(t) == xmextras.noxm.j1950_to_datetime(
         xmextras.noxm.epoch_to_j1950(t)
     )
+
+def test_power2():
+    assert xmextras.noxm.power2(-3) == 1
+    assert xmextras.noxm.power2(0) == 1
+    assert xmextras.noxm.power2(1) == 1
+    assert xmextras.noxm.power2(2) == 2
+    assert xmextras.noxm.power2(3) == 4
+    assert xmextras.noxm.power2(65537) == 131072

xmextras/__init__.py

@@ -5,6 +5,7 @@
     epoch_to_j1950,
     j1950_to_datetime,
     j1950_to_epoch,
+    power2,
 )
 
 try:

xmextras/noxm.py

@@ -30,3 +30,13 @@ def datetime_to_j1950(dt):
     Returns the J1950 time from a datetime object.
     '''
     return epoch_to_j1950(dt.timestamp())
+
+def power2(x):
+    '''
+    Returns the next power of two greater than
+    or equal to x.
+    '''
+    if x < 1:
+        return 1
+
+    return 1 << (x-1).bit_length()