1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #include <stddef.h> 19 #include <map> 20 #include <list> 21 22 #ifndef ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_ 23 #define ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_ 24 25 namespace utils { 26 template <typename K, typename V> 27 class ScopedHashtable { 28 public: 29 explicit ScopedHashtable():scopes() { 30 } 31 32 void OpenScope() { 33 scopes.push_front(std::map<K, V>()); 34 } 35 36 // Lookups entry K starting from the current (topmost) scope 37 // and returns its value if found or NULL. 38 V Lookup(K k) const { 39 for (typename std::list<std::map<K, V> >::const_iterator scopes_it = scopes.begin(); 40 scopes_it != scopes.end(); scopes_it++) { 41 typename std::map<K, V>::const_iterator result_it = (*scopes_it).find(k); 42 if (result_it != (*scopes_it).end()) { 43 return (*result_it).second; 44 } 45 } 46 return NULL; 47 } 48 49 // Adds a new entry in the current (topmost) scope. 50 void Add(K k, V v) { 51 scopes.front().erase(k); 52 scopes.front().insert(std::pair< K, V >(k, v)); 53 } 54 55 // Removes the topmost scope. 56 bool CloseScope() { 57 // Added check to uniformly handle undefined behavior 58 // when removing scope and the list of scopes is empty. 59 if (scopes.size() > 0) { 60 scopes.pop_front(); 61 return true; 62 } 63 return false; 64 } 65 66 private: 67 std::list<std::map<K, V> > scopes; 68 }; 69 } // namespace utils 70 71 #endif // ART_COMPILER_UTILS_SCOPED_HASHTABLE_H_ 72
