Source/platform/text/BidiCharacterRun.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2003, 2004, 2006, 2007, 2008 Apple Inc.  All right reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef BidiCharacterRun_h
#define BidiCharacterRun_h

#include "platform/text/BidiContext.h"
#include "platform/text/TextDirection.h"

namespace WebCore {

struct BidiCharacterRun {
    BidiCharacterRun(int start, int stop, BidiContext* context, WTF::Unicode::Direction dir)
        : m_override(context->override())
        , m_next(0)
        , m_start(start)
        , m_stop(stop)
    {
        ASSERT(m_start <= m_stop);
        if (dir == WTF::Unicode::OtherNeutral)
            dir = context->dir();

        m_level = context->level();

        // add level of run (cases I1 & I2)
        if (m_level % 2) {
            if (dir == WTF::Unicode::LeftToRight || dir == WTF::Unicode::ArabicNumber || dir == WTF::Unicode::EuropeanNumber)
                m_level++;
        } else {
            if (dir == WTF::Unicode::RightToLeft)
                m_level++;
            else if (dir == WTF::Unicode::ArabicNumber || dir == WTF::Unicode::EuropeanNumber)
                m_level += 2;
        }
    }

    // BidiCharacterRun are allocated out of the rendering partition.
    PLATFORM_EXPORT void* operator new(size_t);
    PLATFORM_EXPORT void operator delete(void*);

    int start() const { return m_start; }
    int stop() const { return m_stop; }
    unsigned char level() const { return m_level; }
    bool reversed(bool visuallyOrdered) const { return m_level % 2 && !visuallyOrdered; }
    bool dirOverride(bool visuallyOrdered) { return m_override || visuallyOrdered; }
    TextDirection direction() const { return reversed(false) ? RTL : LTR; }

    BidiCharacterRun* next() const { return m_next; }
    void setNext(BidiCharacterRun* next) { m_next = next; }

    // Do not add anything apart from bitfields until after m_next. See https://bugs.webkit.org/show_bug.cgi?id=100173
    bool m_override : 1;
    bool m_hasHyphen : 1; // Used by BidiRun subclass which is a layering violation but enables us to save 8 bytes per object on 64-bit.
    unsigned char m_level;
    BidiCharacterRun* m_next;
    int m_start;
    int m_stop;
};

} // namespace WebCore

#endif // BidiCharacterRun_h