1 files changed, 7 insertions, 5 deletions
diff --git a/happybase/util.py b/happybase/util.py
index c697f90..f975464 100644
--- a/happybase/util.py
+++ b/happybase/util.py
@@ -69,7 +69,7 @@ def ensure_bytes(str_or_bytes, binary_type=six.binary_type,
         .format(type(str_or_bytes).__name__))
 
 
-def str_increment(s):
+def bytes_increment(b):
     """Increment and truncate a byte string (for sorting purposes)
 
     This functions returns the shortest string that sorts after the given
@@ -79,8 +79,10 @@ def str_increment(s):
     drops everything after it. If the string only contains ``0xFF`` bytes,
     `None` is returned.
     """
-    for i in range(len(s) - 1, -1, -1):
-        if s[i] != '\xff':
-            return s[:i] + chr(ord(s[i]) + 1)
-
+    assert isinstance(b, six.binary_type)
+    b = bytearray(b)  # Used subset of its API is the same on Python 2 and 3.
+    for i in range(len(b) - 1, -1, -1):
+        if b[i] != 0xff:
+            b[i] += 1
+            return bytes(b[:i+1])
     return None