add FallbackCounter class used with Python 2.6 since collections.Counter was added in Python 2.7

saucebrush/stats.py

@@ -1,4 +1,5 @@
 from saucebrush.filters import Filter
+from saucebrush.utils import FallbackCounter
 import collections
 import itertools
 import math
@@ -193,7 +194,10 @@ class Histogram(StatsFilter):
 
     def __init__(self, field, **kwargs):
         super(Histogram, self).__init__(field, **kwargs)
-        self._counter = collections.Counter()
+        if hasattr(collections, 'Counter'):
+            self._counter = collections.Counter()
+        else:
+            self._counter = FallbackCounter()
 
     def process_field(self, item):
         self._counter[self.prep_field(item)] += 1

saucebrush/utils.py

@@ -1,3 +1,4 @@
+import collections
 import os
 
 try:
@@ -62,6 +63,24 @@ def str_or_list(obj):
 # utility classes
 #
 
+class FallbackCounter(collections.defaultdict):
+    """ Python 2.6 does not have collections.Counter.
+        This is class that does the basics of what we need from Counter.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super(FallbackCounter, self).__init__(int)
+
+    def most_common(n=None):
+
+        l = sorted(self.items(),
+                cmp=lambda x,y: cmp(x[1], y[1]))
+
+        if n is not None:
+            l = l[:n]
+
+        return l
+
 class Files(object):
     """ Iterate over multiple files as a single file. Pass the paths of the
         files as arguments to the class constructor: