1 /*
2  * Copyright (C) 2013 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 LATINIME_DAEMARU_LEVENSHTEIN_EDIT_DISTANCE_POLICY_H
18 #define LATINIME_DAEMARU_LEVENSHTEIN_EDIT_DISTANCE_POLICY_H
19 
20 #include "suggest/policyimpl/utils/edit_distance_policy.h"
21 #include "utils/char_utils.h"
22 
23 namespace latinime {
24 
25 class DamerauLevenshteinEditDistancePolicy : public EditDistancePolicy {
26  public:
DamerauLevenshteinEditDistancePolicy(const int * const string0,const int length0,const int * const string1,const int length1)27     DamerauLevenshteinEditDistancePolicy(const int *const string0, const int length0,
28             const int *const string1, const int length1)
29             : mString0(string0), mString0Length(length0), mString1(string1),
30               mString1Length(length1) {}
~DamerauLevenshteinEditDistancePolicy()31     ~DamerauLevenshteinEditDistancePolicy() {}
32 
getSubstitutionCost(const int index0,const int index1)33     AK_FORCE_INLINE float getSubstitutionCost(const int index0, const int index1) const {
34         const int c0 = CharUtils::toBaseLowerCase(mString0[index0]);
35         const int c1 = CharUtils::toBaseLowerCase(mString1[index1]);
36         return (c0 == c1) ? 0.0f : 1.0f;
37     }
38 
getDeletionCost(const int index0,const int index1)39     AK_FORCE_INLINE float getDeletionCost(const int index0, const int index1) const {
40         return 1.0f;
41     }
42 
getInsertionCost(const int index0,const int index1)43     AK_FORCE_INLINE float getInsertionCost(const int index0, const int index1) const {
44         return 1.0f;
45     }
46 
allowTransposition(const int index0,const int index1)47     AK_FORCE_INLINE bool allowTransposition(const int index0, const int index1) const {
48         const int c0 = CharUtils::toBaseLowerCase(mString0[index0]);
49         const int c1 = CharUtils::toBaseLowerCase(mString1[index1]);
50         if (index0 > 0 && index1 > 0 && c0 == CharUtils::toBaseLowerCase(mString1[index1 - 1])
51                 && c1 == CharUtils::toBaseLowerCase(mString0[index0 - 1])) {
52             return true;
53         }
54         return false;
55     }
56 
getTranspositionCost(const int index0,const int index1)57     AK_FORCE_INLINE float getTranspositionCost(const int index0, const int index1) const {
58         return getSubstitutionCost(index0, index1);
59     }
60 
getString0Length()61     AK_FORCE_INLINE int getString0Length() const {
62         return mString0Length;
63     }
64 
getString1Length()65     AK_FORCE_INLINE int getString1Length() const {
66         return mString1Length;
67     }
68 
69  private:
70     DISALLOW_COPY_AND_ASSIGN (DamerauLevenshteinEditDistancePolicy);
71 
72     const int *const mString0;
73     const int mString0Length;
74     const int *const mString1;
75     const int mString1Length;
76 };
77 } // namespace latinime
78 
79 #endif  // LATINIME_DAEMARU_LEVENSHTEIN_EDIT_DISTANCE_POLICY_H
80