1 files changed, 36 insertions, 0 deletions
diff --git a/snips_inference_agl/common/dict_utils.py b/snips_inference_agl/common/dict_utils.py
new file mode 100644
index 0000000..a70b217
--- /dev/null
+++ b/snips_inference_agl/common/dict_utils.py
@@ -0,0 +1,36 @@
+from collections import OrderedDict
+
+
+class LimitedSizeDict(OrderedDict):
+    def __init__(self, *args, **kwds):
+        if "size_limit" not in kwds:
+            raise ValueError("'size_limit' must be passed as a keyword "
+                             "argument")
+        self.size_limit = kwds.pop("size_limit")
+        if len(args) > 1:
+            raise TypeError('expected at most 1 arguments, got %d' % len(args))
+        if len(args) == 1 and len(args[0]) + len(kwds) > self.size_limit:
+            raise ValueError("Tried to initialize LimitedSizedDict with more "
+                             "value than permitted with 'limit_size'")
+        super(LimitedSizeDict, self).__init__(*args, **kwds)
+
+    def __setitem__(self, key, value, dict_setitem=OrderedDict.__setitem__):
+        dict_setitem(self, key, value)
+        self._check_size_limit()
+
+    def _check_size_limit(self):
+        if self.size_limit is not None:
+            while len(self) > self.size_limit:
+                self.popitem(last=False)
+
+    def __eq__(self, other):
+        if self.size_limit != other.size_limit:
+            return False
+        return super(LimitedSizeDict, self).__eq__(other)
+
+
+class UnupdatableDict(dict):
+    def __setitem__(self, key, value):
+        if key in self:
+            raise KeyError("Can't update key '%s'" % key)
+        super(UnupdatableDict, self).__setitem__(key, value)