- use a different bitwise approach here that doesn't require iterating

through all possible set values

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py
index 7f57e501a..b708665f9 100644
--- a/lib/sqlalchemy/util/langhelpers.py
+++ b/lib/sqlalchemy/util/langhelpers.py
@@ -92,6 +92,15 @@ def _unique_symbols(used, *bases):
             raise NameError("exhausted namespace for symbol base %s" % base)
 
 
+def map_bits(fn, n):
+    """Call the given function given each nonzero bit from n."""
+
+    while n:
+        b = n & (~n + 1)
+        yield fn(b)
+        n ^= b
+
+
 def decorator(target):
     """A signature-matching decorator factory."""