| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /** |
| * An implementation of Liang's hyphenation algorithm. |
| */ |
| |
| #include <memory> |
| #include <unordered_map> |
| |
| #ifndef MINIKIN_HYPHENATOR_H |
| #define MINIKIN_HYPHENATOR_H |
| |
| namespace android { |
| |
| // hyb file header; implementation details are in the .cpp file |
| struct Header; |
| |
| class Hyphenator { |
| public: |
| // Note: this will also require a locale, for proper case folding behavior |
| static Hyphenator* load(const uint16_t* patternData, size_t size); |
| |
| // Compute the hyphenation of a word, storing the hyphenation in result vector. Each |
| // entry in the vector is a "hyphen edit" to be applied at the corresponding code unit |
| // offset in the word. Currently 0 means no hyphen and 1 means insert hyphen and break, |
| // but this will be expanded to other edits for nonstandard hyphenation. |
| // Example: word is "hyphen", result is [0 0 1 0 0 0], corresponding to "hy-phen". |
| void hyphenate(std::vector<uint8_t>* result, const uint16_t* word, size_t len); |
| |
| // pattern data is in binary format, as described in doc/hyb_file_format.md. Note: |
| // the caller is responsible for ensuring that the lifetime of the pattern data is |
| // at least as long as the Hyphenator object. |
| |
| // Note: nullptr is valid input, in which case the hyphenator only processes soft hyphens |
| static Hyphenator* loadBinary(const uint8_t* patternData); |
| |
| private: |
| // apply soft hyphens only, ignoring patterns |
| void hyphenateSoft(uint8_t* result, const uint16_t* word, size_t len); |
| |
| // try looking up word in alphabet table, return false if any code units fail to map |
| // Note that this methor writes len+2 entries into alpha_codes (including start and stop) |
| bool alphabetLookup(uint16_t* alpha_codes, const uint16_t* word, size_t len); |
| |
| // calculate hyphenation from patterns, assuming alphabet lookup has already been done |
| void hyphenateFromCodes(uint8_t* result, const uint16_t* codes, size_t len); |
| |
| // TODO: these should become parameters, as they might vary by locale, screen size, and |
| // possibly explicit user control. |
| static const int MIN_PREFIX = 2; |
| static const int MIN_SUFFIX = 3; |
| |
| // See also LONGEST_HYPHENATED_WORD in LineBreaker.cpp. Here the constant is used so |
| // that temporary buffers can be stack-allocated without waste, which is a slightly |
| // different use case. It measures UTF-16 code units. |
| static const size_t MAX_HYPHENATED_SIZE = 64; |
| |
| const uint8_t* patternData; |
| |
| // accessors for binary data |
| const Header* getHeader() const { |
| return reinterpret_cast<const Header*>(patternData); |
| } |
| |
| }; |
| |
| } // namespace android |
| |
| #endif // MINIKIN_HYPHENATOR_H |