1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_
18 #define LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_
19 
20 #include <vector>
21 
22 #include "utils/strings/stringpiece.h"
23 
24 namespace libtextclassifier3 {
25 
26 class StringSet {
27  public:
28   struct Match {
MatchMatch29     Match() {}
MatchMatch30     Match(int id, int match_length) : id(id), match_length(match_length) {}
31     int id = -1;
32     int match_length = -1;
33   };
34 
~StringSet()35   virtual ~StringSet() {}
36 
37   // Find matches that are prefixes of a string.
38   virtual bool FindAllPrefixMatches(StringPiece input,
39                                     std::vector<Match>* matches) const = 0;
40 
41   // Find the longest prefix match of a string.
42   virtual bool LongestPrefixMatch(StringPiece input,
43                                   Match* longest_match) const = 0;
44 
45   // Finds an exact string match.
Find(StringPiece input,int * value)46   virtual bool Find(StringPiece input, int* value) const {
47     Match match;
48     if (LongestPrefixMatch(input, &match) &&
49         match.match_length == input.length()) {
50       *value = match.id;
51       return true;
52     }
53     return false;
54   }
55 };
56 
57 }  // namespace libtextclassifier3
58 
59 #endif  // LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_
60