Move ScopedHashtable files out of art/src

Change-Id: If854ee34dc81abb81bc7e021bc59c7b151cd6ab5

2 files changed, 139 insertions, 0 deletions

diff --git a/compiler/utils/scoped_hashtable.h b/compiler/utils/scoped_hashtable.h
new file mode 100644
index 0000000..5e6c64b
--- /dev/null
+++ 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 SCOPED_HASHTABLE_
+#define SCOPED_HASHTABLE_
+
+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;
+};
+} // end namespace utils
+
+#endif
diff --git a/compiler/utils/scoped_hashtable_test.cc b/compiler/utils/scoped_hashtable_test.cc
new file mode 100644
index 0000000..072da8c
--- /dev/null
+++ b/compiler/utils/scoped_hashtable_test.cc
@@ -0,0 +1,68 @@
+/*
+ * 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 "common_test.h"
+#include "scoped_hashtable.h"
+
+using utils::ScopedHashtable;
+
+namespace art {
+
+class Value {
+ public:
+  explicit Value(int v):value_(v) {}
+  int value_;
+};
+
+class ScopedHashtableTest : public CommonTest {
+};
+
+TEST_F(ScopedHashtableTest, Basics) {
+  ScopedHashtable<int, Value*> sht;
+  // Check table is empty when no scope is open.
+  EXPECT_TRUE(NULL == sht.Lookup(1));
+
+  // Check table is empty when scope open.
+  sht.OpenScope();
+  EXPECT_TRUE(NULL == sht.Lookup(1));
+  // Check table is empty after closing scope.
+  EXPECT_EQ(sht.CloseScope(), true);
+  // Check closing scope on empty table is no-op.
+  EXPECT_EQ(sht.CloseScope(), false);
+  // Check that find in current scope works.
+  sht.OpenScope();
+  sht.Add(1, new Value(1));
+  EXPECT_EQ(sht.Lookup(1)->value_, 1);
+  // Check that updating values in current scope works.
+  sht.Add(1, new Value(2));
+  EXPECT_EQ(sht.Lookup(1)->value_, 2);
+  // Check that find works in previous scope.
+  sht.OpenScope();
+  EXPECT_EQ(sht.Lookup(1)->value_, 2);
+  // Check that shadowing scopes works.
+  sht.Add(1, new Value(3));
+  EXPECT_EQ(sht.Lookup(1)->value_, 3);
+  // Check that having multiple keys work correctly.
+  sht.Add(2, new Value(4));
+  EXPECT_EQ(sht.Lookup(1)->value_, 3);
+  EXPECT_EQ(sht.Lookup(2)->value_, 4);
+  // Check that scope removal works corectly.
+  sht.CloseScope();
+  EXPECT_EQ(sht.Lookup(1)->value_, 2);
+  EXPECT_TRUE(NULL == sht.Lookup(2));
+}
+
+} // end namespace art