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f0be43de02
In the current state, hyphenation in all languages than Sanskrit seems to work (case-folding edge cases). Thus, we just disable Sanskrit. Packed tries are implemented, but not the finite state machine (space/speed tradeoff). This commit contains a throw-away test app, which runs on the host. I think I want to replace it with unit tests, but I'm including it in the CL because it's useful during development. Bug: 21562869 Bug: 21826930 Bug: 23317038 Bug: 23317904 Change-Id: I7479a565a4a062fa319651c2c14c0fa18c5ceaea
84 lines
3.2 KiB
C++
84 lines
3.2 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* An implementation of Liang's hyphenation algorithm.
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*/
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#include <memory>
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#include <unordered_map>
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#ifndef MINIKIN_HYPHENATOR_H
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#define MINIKIN_HYPHENATOR_H
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namespace android {
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// hyb file header; implementation details are in the .cpp file
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struct Header;
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class Hyphenator {
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public:
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// Note: this will also require a locale, for proper case folding behavior
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static Hyphenator* load(const uint16_t* patternData, size_t size);
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// Compute the hyphenation of a word, storing the hyphenation in result vector. Each
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// entry in the vector is a "hyphen edit" to be applied at the corresponding code unit
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// offset in the word. Currently 0 means no hyphen and 1 means insert hyphen and break,
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// but this will be expanded to other edits for nonstandard hyphenation.
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// Example: word is "hyphen", result is [0 0 1 0 0 0], corresponding to "hy-phen".
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void hyphenate(std::vector<uint8_t>* result, const uint16_t* word, size_t len);
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// pattern data is in binary format, as described in doc/hyb_file_format.md. Note:
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// the caller is responsible for ensuring that the lifetime of the pattern data is
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// at least as long as the Hyphenator object.
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// Note: nullptr is valid input, in which case the hyphenator only processes soft hyphens
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static Hyphenator* loadBinary(const uint8_t* patternData);
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private:
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// apply soft hyphens only, ignoring patterns
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void hyphenateSoft(uint8_t* result, const uint16_t* word, size_t len);
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// try looking up word in alphabet table, return false if any code units fail to map
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// Note that this methor writes len+2 entries into alpha_codes (including start and stop)
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bool alphabetLookup(uint16_t* alpha_codes, const uint16_t* word, size_t len);
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// calculate hyphenation from patterns, assuming alphabet lookup has already been done
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void hyphenateFromCodes(uint8_t* result, const uint16_t* codes, size_t len);
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// TODO: these should become parameters, as they might vary by locale, screen size, and
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// possibly explicit user control.
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static const int MIN_PREFIX = 2;
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static const int MIN_SUFFIX = 3;
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// See also LONGEST_HYPHENATED_WORD in LineBreaker.cpp. Here the constant is used so
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// that temporary buffers can be stack-allocated without waste, which is a slightly
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// different use case. It measures UTF-16 code units.
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static const size_t MAX_HYPHENATED_SIZE = 64;
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const uint8_t* patternData;
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// accessors for binary data
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const Header* getHeader() const {
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return reinterpret_cast<const Header*>(patternData);
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}
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};
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} // namespace android
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#endif // MINIKIN_HYPHENATOR_H
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