1 files changed, 71 insertions, 0 deletions
diff --git a/compiler/utils/scoped_hashtable.h b/compiler/utils/scoped_hashtable.h
new file mode 100644
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+++ b/compiler/utils/scoped_hashtable.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stddef.h>
+#include <map>
+#include <list>
+
+#ifndef ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_
+#define ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_
+
+namespace utils {
+template <typename K, typename V>
+class ScopedHashtable {
+ public:
+  explicit ScopedHashtable():scopes() {
+  }
+
+  void OpenScope() {
+    scopes.push_front(std::map<K, V>());
+  }
+
+  // Lookups entry K starting from the current (topmost) scope
+  // and returns its value if found or NULL.
+  V Lookup(K k) const {
+    for (typename std::list<std::map<K, V> >::const_iterator scopes_it = scopes.begin();
+        scopes_it != scopes.end(); scopes_it++) {
+      typename std::map<K, V>::const_iterator result_it = (*scopes_it).find(k);
+      if (result_it != (*scopes_it).end()) {
+        return (*result_it).second;
+      }
+    }
+    return NULL;
+  }
+
+  // Adds a new entry in the current (topmost) scope.
+  void Add(K k, V v) {
+    scopes.front().erase(k);
+    scopes.front().insert(std::pair< K, V >(k, v));
+  }
+
+  // Removes the topmost scope.
+  bool CloseScope() {
+    // Added check to uniformly handle undefined behavior
+    // when removing scope and the list of scopes is empty.
+    if (scopes.size() > 0) {
+      scopes.pop_front();
+      return true;
+    }
+    return false;
+  }
+
+ private:
+  std::list<std::map<K, V> > scopes;
+};
+}  // namespace utils
+
+#endif  // ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_