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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #ifndef THIRD_PARTY_LIBADDRESSINPUT_CHROMIUM_TRIE_H_ | |
| 6 #define THIRD_PARTY_LIBADDRESSINPUT_CHROMIUM_TRIE_H_ | |
| 7 | |
| 8 #include <stdint.h> | |
| 9 #include <map> | |
| 10 #include <set> | |
| 11 #include <vector> | |
| 12 | |
| 13 namespace autofill { | |
| 14 | |
| 15 // A prefix search tree. Can return all objects whose keys start with a prefix | |
| 16 // byte sequence. | |
| 17 // | |
| 18 // Maps keys to multiple objects. This property is useful when mapping region | |
| 19 // names to region objects. For example, there's a "St. Petersburg" in Florida, | |
| 20 // and there's a "St. Petersburg" in Russia. A lookup for "St. Petersburg" key | |
| 21 // should return two distinct objects. | |
| 22 template <typename T> | |
| 23 class Trie { | |
| 24 public: | |
| 25 Trie(); | |
| 26 ~Trie(); | |
| 27 | |
| 28 // Returns true if no data was added in AddDataForKey(). | |
| 29 bool empty() const { return data_list_.empty() && sub_nodes_.empty(); } | |
| 30 | |
| 31 // Adds a mapping from the 0 terminated |key| to |data_item|. Can be called | |
| 32 // with the same |key| multiple times. | |
| 33 void AddDataForKey(const std::vector<uint8_t>& key, const T& data_item); | |
| 34 | |
| 35 // Adds all objects whose keys start with the 0 terminated |key_prefix| to the | |
| 36 // |results| parameter. The |results| parameter should not be NULL. | |
| 37 void FindDataForKeyPrefix(const std::vector<uint8_t>& key_prefix, | |
| 38 std::set<T>* results) const; | |
| 39 | |
| 40 private: | |
| 41 // All objects for this node in the Trie. This field is a collection to enable | |
| 42 // mapping the same key to multiple objects. | |
| 43 std::set<T> data_list_; | |
| 44 | |
| 45 // Trie sub nodes. The root Trie stores the objects for the empty key. The | |
| 46 // children of the root Trie store the objects for the one-byte keys. The | |
| 47 // grand-children of the root Trie store the objects for the two-byte keys, | |
| 48 // and so on. | |
| 49 std::map<uint8_t, Trie<T> > sub_nodes_; | |
| 50 }; | |
| 51 | |
| 52 } // namespace autofill | |
| 53 | |
| 54 #endif // THIRD_PARTY_LIBADDRESSINPUT_CHROMIUM_TRIE_H_ | |
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