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
23namespace latinime {
24
25class DamerauLevenshteinEditDistancePolicy : public EditDistancePolicy {
26 public:
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) {}
31    ~DamerauLevenshteinEditDistancePolicy() {}
32
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
39    AK_FORCE_INLINE float getDeletionCost(const int index0, const int index1) const {
40        return 1.0f;
41    }
42
43    AK_FORCE_INLINE float getInsertionCost(const int index0, const int index1) const {
44        return 1.0f;
45    }
46
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
57    AK_FORCE_INLINE float getTranspositionCost(const int index0, const int index1) const {
58        return getSubstitutionCost(index0, index1);
59    }
60
61    AK_FORCE_INLINE int getString0Length() const {
62        return mString0Length;
63    }
64
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