bidiresolver.h

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

    appendRun();
    emptyRun = true;
    // sor for the new run is determined by the higher level (rule X10)
    setLastDir(from);
    setLastStrongDir(from);
    eor = Iterator();
}

template <class Iterator, class Run>
void BidiResolver<Iterator, Run>::raiseExplicitEmbeddingLevel(WTF::Unicode::Direction from, WTF::Unicode::Direction to)
{
    using namespace WTF::Unicode;

    if (!emptyRun && eor != last) {
        ASSERT(m_status.eor != OtherNeutral || eor.atEnd());
        // bidi.sor ... bidi.eor ... bidi.last eor; need to append the bidi.sor-bidi.eor run or extend it through bidi.last
        ASSERT(m_status.last == EuropeanNumberSeparator
            || m_status.last == EuropeanNumberTerminator
            || m_status.last == CommonNumberSeparator
            || m_status.last == BoundaryNeutral
            || m_status.last == BlockSeparator
            || m_status.last == SegmentSeparator
            || m_status.last == WhiteSpaceNeutral
            || m_status.last == OtherNeutral);
        if (m_direction == OtherNeutral)
            m_direction = m_status.lastStrong == LeftToRight ? LeftToRight : RightToLeft;
        if (to == LeftToRight) {
            // bidi.sor ... bidi.eor ... bidi.last L
            if (m_status.eor == EuropeanNumber) {
                if (m_status.lastStrong != LeftToRight) {
                    m_direction = EuropeanNumber;
                    appendRun();
                }
            } else if (m_status.eor == ArabicNumber) {
                m_direction = ArabicNumber;
                appendRun();
            } else if (m_status.lastStrong != LeftToRight && from == LeftToRight) {
                appendRun();
                m_direction = LeftToRight;
            }
        } else if (m_status.eor == ArabicNumber
            || m_status.eor == EuropeanNumber && (m_status.lastStrong != LeftToRight || from == RightToLeft)
            || m_status.eor != EuropeanNumber && m_status.lastStrong == LeftToRight && from == RightToLeft) {
            appendRun();
            m_direction = RightToLeft;
        }
        eor = last;
    }
    appendRun();
    emptyRun = true;
    setLastDir(to);
    setLastStrongDir(to);
    eor = Iterator();
}

template <class Iterator, class Run>
void BidiResolver<Iterator, Run>::commitExplicitEmbedding()
{
    using namespace WTF::Unicode;

    unsigned char fromLevel = context()->level();
    RefPtr<BidiContext> toContext = context();

    for (size_t i = 0; i < m_currentExplicitEmbeddingSequence.size(); ++i) {
        Direction embedding = m_currentExplicitEmbeddingSequence[i];
        if (embedding == PopDirectionalFormat) {
            if (BidiContext* parentContext = toContext->parent())
                toContext = parentContext;
        } else {
            Direction direction = (embedding == RightToLeftEmbedding || embedding == RightToLeftOverride) ? RightToLeft : LeftToRight;
            bool override = embedding == LeftToRightOverride || embedding == RightToLeftOverride;
            unsigned char level = toContext->level();
            if (direction == RightToLeft) {
                // Go to the least greater odd integer
                level += 1;
                level |= 1;
            } else {
                // Go to the least greater even integer
                level += 2;
                level &= ~1;
            }
            if (level < 61)
                toContext = new BidiContext(level, direction, override, toContext.get());
        }
    }

    unsigned char toLevel = toContext->level();

    if (toLevel > fromLevel)
        raiseExplicitEmbeddingLevel(fromLevel % 2 ? RightToLeft : LeftToRight, toLevel % 2 ? RightToLeft : LeftToRight);
    else if (toLevel < fromLevel)
        lowerExplicitEmbeddingLevel(fromLevel % 2 ? RightToLeft : LeftToRight);

    setContext(toContext);

    m_currentExplicitEmbeddingSequence.clear();
}

template <class Iterator, class Run>
void BidiResolver<Iterator, Run>::deleteRuns()
{
    emptyRun = true;
    if (!m_firstRun)
        return;

    Run* curr = m_firstRun;
    while (curr) {
        Run* s = curr->next();
        curr->destroy();
        curr = s;
    }

    m_firstRun = 0;
    m_lastRun = 0;
    m_runCount = 0;
}

template <class Iterator, class Run>
void BidiResolver<Iterator, Run>::reverseRuns(unsigned start, unsigned end)
{
    if (start >= end)
        return;

    ASSERT(end < m_runCount);
    
    // Get the item before the start of the runs to reverse and put it in
    // |beforeStart|.  |curr| should point to the first run to reverse.
    Run* curr = m_firstRun;
    Run* beforeStart = 0;
    unsigned i = 0;
    while (i < start) {
        i++;
        beforeStart = curr;
        curr = curr->next();
    }

    Run* startRun = curr;
    while (i < end) {
        i++;
        curr = curr->next();
    }
    Run* endRun = curr;
    Run* afterEnd = curr->next();

    i = start;
    curr = startRun;
    Run* newNext = afterEnd;
    while (i <= end) {
        // Do the reversal.
        Run* next = curr->next();
        curr->m_next = newNext;
        newNext = curr;
        curr = next;
        i++;
    }

    // Now hook up beforeStart and afterEnd to the startRun and endRun.
    if (beforeStart)
        beforeStart->m_next = endRun;
    else
        m_firstRun = endRun;

    startRun->m_next = afterEnd;
    if (!afterEnd)
        m_lastRun = startRun;
}

template <class Iterator, class Run>
void BidiResolver<Iterator, Run>::createBidiRunsForLine(const Iterator& end, bool visualOrder, bool hardLineBreak)
{
    using namespace WTF::Unicode;

    ASSERT(m_direction == OtherNeutral);

    emptyRun = true;

    eor = Iterator();

    last = current;
    bool pastEnd = false;
    BidiResolver<Iterator, Run> stateAtEnd;

    while (true) {
        Direction dirCurrent;
        if (pastEnd && (hardLineBreak || current.atEnd())) {
            BidiContext* c = context();
            while (c->parent())
                c = c->parent();
            dirCurrent = c->dir();
            if (hardLineBreak) {
                // A deviation from the Unicode Bidi Algorithm in order to match
                // Mac OS X text and WinIE: a hard line break resets bidi state.
                stateAtEnd.setContext(c);
                stateAtEnd.setEorDir(dirCurrent);
                stateAtEnd.setLastDir(dirCurrent);
                stateAtEnd.setLastStrongDir(dirCurrent);
            }
        } else {
            dirCurrent = current.direction();
            if (context()->override()
                    && dirCurrent != RightToLeftEmbedding
                    && dirCurrent != LeftToRightEmbedding
                    && dirCurrent != RightToLeftOverride
                    && dirCurrent != LeftToRightOverride
                    && dirCurrent != PopDirectionalFormat)
                dirCurrent = context()->dir();
            else if (dirCurrent == NonSpacingMark)
                dirCurrent = m_status.last;
        }

        ASSERT(m_status.eor != OtherNeutral || eor.atEnd());
        switch (dirCurrent) {

        // embedding and overrides (X1-X9 in the Bidi specs)
        case RightToLeftEmbedding:
        case LeftToRightEmbedding:
        case RightToLeftOverride:
        case LeftToRightOverride:
        case PopDirectionalFormat:
            embed(dirCurrent);
            commitExplicitEmbedding();
            break;

            // strong types
        case LeftToRight:
            switch(m_status.last) {
                case RightToLeft:
                case RightToLeftArabic:
                case EuropeanNumber:
                case ArabicNumber:
                    if (m_status.last != EuropeanNumber || m_status.lastStrong != LeftToRight)
                        appendRun();
                    break;
                case LeftToRight:
                    break;
                case EuropeanNumberSeparator:
                case EuropeanNumberTerminator:
                case CommonNumberSeparator:
                case BoundaryNeutral:
                case BlockSeparator:
                case SegmentSeparator:
                case WhiteSpaceNeutral:
                case OtherNeutral:
                    if (m_status.eor == EuropeanNumber) {
                        if (m_status.lastStrong != LeftToRight) {
                            // the numbers need to be on a higher embedding level, so let's close that run
                            m_direction = EuropeanNumber;
                            appendRun();
                            if (context()->dir() != LeftToRight) {
                                // the neutrals take the embedding direction, which is R
                                eor = last;
                                m_direction = RightToLeft;
                                appendRun();
                            }
                        }
                    } else if (m_status.eor == ArabicNumber) {
                        // Arabic numbers are always on a higher embedding level, so let's close that run
                        m_direction = ArabicNumber;
                        appendRun();
                        if (context()->dir() != LeftToRight) {
                            // the neutrals take the embedding direction, which is R
                            eor = last;
                            m_direction = RightToLeft;
                            appendRun();
                        }
                    } else if (m_status.lastStrong != LeftToRight) {
                        //last stuff takes embedding dir
                        if (context()->dir() == RightToLeft) {
                            eor = last; 
                            m_direction = RightToLeft;
                        }
                        appendRun();
                    }
                default:
                    break;
            }
            eor = current;
            m_status.eor = LeftToRight;
            m_status.lastStrong = LeftToRight;
            m_direction = LeftToRight;
            break;
        case RightToLeftArabic:
        case RightToLeft:
            switch (m_status.last) {
                case LeftToRight:
                case EuropeanNumber:
                case ArabicNumber:
                    appendRun();
                case RightToLeft:
                case RightToLeftArabic:
                    break;
                case EuropeanNumberSeparator:
                case EuropeanNumberTerminator:
                case CommonNumberSeparator:
                case BoundaryNeutral:
                case BlockSeparator:
                case SegmentSeparator:
                case WhiteSpaceNeutral:
                case OtherNeutral:
                    if (m_status.eor == EuropeanNumber) {
                        if (m_status.lastStrong == LeftToRight && context()->dir() == LeftToRight)
                            eor = last;
                        appendRun();
                    } else if (m_status.eor == ArabicNumber)
                        appendRun();
                    else if (m_status.lastStrong == LeftToRight) {
                        if (context()->dir() == LeftToRight)
                            eor = last;
                        appendRun();
                    }
                default:
                    break;
            }