xref: /frameworks/minikin/include/minikin/GraphemeBreak.h

/*
 * Copyright (C) 2014 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.
 */

#ifndef MINIKIN_GRAPHEME_BREAK_H
#define MINIKIN_GRAPHEME_BREAK_H

namespace android {

class GraphemeBreak {
public:
    // These values must be kept in sync with CURSOR_AFTER etc in Paint.java
    enum MoveOpt {
        AFTER = 0,
        AT_OR_AFTER = 1,
        BEFORE = 2,
        AT_OR_BEFORE = 3,
        AT = 4
    };

    // Determine whether the given offset is a grapheme break.
    // This implementation generally follows Unicode TR29 extended
    // grapheme break, but with some tweaks to more closely match
    // existing implementations.
    static bool isGraphemeBreak(const uint16_t* buf, size_t start, size_t count, size_t offset);

    // Matches Android's Java API. Note, return (size_t)-1 for AT to
    // signal non-break because unsigned return type.
    static size_t getTextRunCursor(const uint16_t* buf, size_t start, size_t count,
            size_t offset, MoveOpt opt);
};

}  // namespace android

#endif  // MINIKIN_GRAPHEME_BREAK_H