1 /*
2  * Copyright (C) 2015 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 /**
18  * An implementation of Liang's hyphenation algorithm.
19  */
20 
21 #include <memory>
22 #include <unordered_map>
23 
24 #ifndef MINIKIN_HYPHENATOR_H
25 #define MINIKIN_HYPHENATOR_H
26 
27 namespace android {
28 
29 class Trie {
30 public:
31     std::vector<uint8_t> result;
32     std::unordered_map<uint16_t, Trie> succ;
33 };
34 
35 class Hyphenator {
36 public:
37     // Note: this will also require a locale, for proper case folding behavior
38     static Hyphenator* load(const uint16_t* patternData, size_t size);
39 
40     // Compute the hyphenation of a word, storing the hyphenation in result vector. Each
41     // entry in the vector is a "hyphen edit" to be applied at the corresponding code unit
42     // offset in the word. Currently 0 means no hyphen and 1 means insert hyphen and break,
43     // but this will be expanded to other edits for nonstandard hyphenation.
44     // Example: word is "hyphen", result is [0 0 1 0 0 0], corresponding to "hy-phen".
45     void hyphenate(std::vector<uint8_t>* result, const uint16_t* word, size_t len);
46 
47 private:
48     void addPattern(const uint16_t* pattern, size_t size);
49 
50     void hyphenateSoft(std::vector<uint8_t>* result, const uint16_t* word, size_t len);
51 
52     // TODO: these should become parameters, as they might vary by locale, screen size, and
53     // possibly explicit user control.
54     static const int MIN_PREFIX = 2;
55     static const int MIN_SUFFIX = 3;
56 
57     Trie root;
58 };
59 
60 }  // namespace android
61 
62 #endif   // MINIKIN_HYPHENATOR_H