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/*
* 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_