rendertext.cpp

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    return prev;
}

void RenderText::setTextInternal(PassRefPtr<StringImpl> text)
{
    m_text = text;
    ASSERT(m_text);

    m_text = document()->displayStringModifiedByEncoding(PassRefPtr<StringImpl>(m_text));
#if ENABLE(SVG)
    if (isSVGText()) {
        if (style() && style()->whiteSpace() == PRE) {
            // Spec: When xml:space="preserve", the SVG user agent will do the following using a
            // copy of the original character data content. It will convert all newline and tab
            // characters into space characters. Then, it will draw all space characters, including
            // leading, trailing and multiple contiguous space characters.

            m_text = m_text->replace('\n', ' ');

            // If xml:space="preserve" is set, white-space is set to "pre", which
            // preserves leading, trailing & contiguous space character for us.
       } else {
            // Spec: When xml:space="default", the SVG user agent will do the following using a
            // copy of the original character data content. First, it will remove all newline
            // characters. Then it will convert all tab characters into space characters.
            // Then, it will strip off all leading and trailing space characters.
            // Then, all contiguous space characters will be consolidated.    

           m_text = m_text->replace('\n', StringImpl::empty());

           // If xml:space="default" is set, white-space is set to "nowrap", which handles
           // leading, trailing & contiguous space character removal for us.
        }

        m_text = m_text->replace('\t', ' ');
    }
#endif

    if (style()) {
        switch (style()->textTransform()) {
            case TTNONE:
                break;
            case CAPITALIZE: {
                m_text = m_text->capitalize(previousCharacter());
                break;
            }
            case UPPERCASE:
                m_text = m_text->upper();
                break;
            case LOWERCASE:
                m_text = m_text->lower();
                break;
        }

        // We use the same characters here as for list markers.
        // See the listMarkerText function in RenderListMarker.cpp.
        switch (style()->textSecurity()) {
            case TSNONE:
                break;
            case TSCIRCLE:
                m_text = m_text->secure(whiteBullet);
                break;
            case TSDISC:
                m_text = m_text->secure(bullet);
                break;
            case TSSQUARE:
                m_text = m_text->secure(blackSquare);
        }
    }

    ASSERT(m_text);
    ASSERT(!isBR() || (textLength() == 1 && (*m_text)[0] == '\n'));

    m_isAllASCII = charactersAreAllASCII(m_text.get());
}

void RenderText::setText(PassRefPtr<StringImpl> text, bool force)
{
    ASSERT(text);

    if (!force && equal(m_text.get(), text.get()))
        return;

    setTextInternal(text);
    setNeedsLayoutAndPrefWidthsRecalc();
}

int RenderText::lineHeight(bool firstLine, bool) const
{
    // Always use the interior line height of the parent (e.g., if our parent is an inline block).
    return parent()->lineHeight(firstLine, true);
}

void RenderText::dirtyLineBoxes(bool fullLayout)
{
    if (fullLayout)
        deleteTextBoxes();
    else if (!m_linesDirty) {
        for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
            box->dirtyLineBoxes();
    }
    m_linesDirty = false;
}

InlineTextBox* RenderText::createTextBox()
{
    return new (renderArena()) InlineTextBox(this);
}

InlineTextBox* RenderText::createInlineTextBox()
{
    InlineTextBox* textBox = createTextBox();
    if (!m_firstTextBox)
        m_firstTextBox = m_lastTextBox = textBox;
    else {
        m_lastTextBox->setNextLineBox(textBox);
        textBox->setPreviousLineBox(m_lastTextBox);
        m_lastTextBox = textBox;
    }
    return textBox;
}

void RenderText::positionLineBox(InlineBox* box)
{
    InlineTextBox* s = static_cast<InlineTextBox*>(box);

    // FIXME: should not be needed!!!
    if (!s->len()) {
        // We want the box to be destroyed.
        s->remove();
        s->destroy(renderArena());
        m_firstTextBox = m_lastTextBox = 0;
        return;
    }

    m_containsReversedText |= s->direction() == RTL;
}

unsigned RenderText::width(unsigned from, unsigned len, int xPos, bool firstLine) const
{
    if (from >= textLength())
        return 0;

    if (from + len > textLength())
        len = textLength() - from;

    return width(from, len, style(firstLine)->font(), xPos);
}

unsigned RenderText::width(unsigned from, unsigned len, const Font& f, int xPos) const
{
    ASSERT(from + len <= textLength());
    if (!characters())
        return 0;

    int w;
    if (&f == &style()->font()) {
        if (!style()->preserveNewline() && !from && len == textLength())
            w = maxPrefWidth();
        else
            w = widthFromCache(f, from, len, xPos);
    } else
        w = f.width(TextRun(text()->characters() + from, len, allowTabs(), xPos));

    return w;
}

IntRect RenderText::linesBoundingBox() const
{
    IntRect result;
    
    ASSERT(!firstTextBox() == !lastTextBox());  // Either both are null or both exist.
    if (firstTextBox() && lastTextBox()) {
        // Return the width of the minimal left side and the maximal right side.
        int leftSide = 0;
        int rightSide = 0;
        for (InlineTextBox* curr = firstTextBox(); curr; curr = curr->nextTextBox()) {
            if (curr == firstTextBox() || curr->x() < leftSide)
                leftSide = curr->x();
            if (curr == firstTextBox() || curr->x() + curr->width() > rightSide)
                rightSide = curr->x() + curr->width();
        }
        result.setWidth(rightSide - leftSide);
        result.setX(leftSide);
        result.setHeight(lastTextBox()->y() + lastTextBox()->height() - firstTextBox()->y());
        result.setY(firstTextBox()->y());
    }

    return result;
}

IntRect RenderText::clippedOverflowRectForRepaint(RenderBoxModelObject* repaintContainer)
{
    RenderObject* cb = containingBlock();
    return cb->clippedOverflowRectForRepaint(repaintContainer);
}

IntRect RenderText::selectionRectForRepaint(RenderBoxModelObject* repaintContainer, bool clipToVisibleContent)
{
    ASSERT(!needsLayout());

    if (selectionState() == SelectionNone)
        return IntRect();
    RenderBlock* cb =  containingBlock();
    if (!cb)
        return IntRect();

    // Now calculate startPos and endPos for painting selection.
    // We include a selection while endPos > 0
    int startPos, endPos;
    if (selectionState() == SelectionInside) {
        // We are fully selected.
        startPos = 0;
        endPos = textLength();
    } else {
        selectionStartEnd(startPos, endPos);
        if (selectionState() == SelectionStart)
            endPos = textLength();
        else if (selectionState() == SelectionEnd)
            startPos = 0;
    }

    if (startPos == endPos)
        return IntRect();

    IntRect rect;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        rect.unite(box->selectionRect(0, 0, startPos, endPos));

    if (clipToVisibleContent)
        computeRectForRepaint(repaintContainer, rect);
    else {
        if (cb->hasColumns())
            cb->adjustRectForColumns(rect);

        rect = localToContainerQuad(FloatRect(rect), repaintContainer).enclosingBoundingBox();
    }

    return rect;
}

int RenderText::caretMinOffset() const
{
    InlineTextBox* box = firstTextBox();
    if (!box)
        return 0;
    int minOffset = box->start();
    for (box = box->nextTextBox(); box; box = box->nextTextBox())
        minOffset = min<int>(minOffset, box->start());
    return minOffset;
}

int RenderText::caretMaxOffset() const
{
    InlineTextBox* box = lastTextBox();
    if (!box)
        return textLength();
    int maxOffset = box->start() + box->len();
    for (box = box->prevTextBox(); box; box = box->prevTextBox())
        maxOffset = max<int>(maxOffset, box->start() + box->len());
    return maxOffset;
}

unsigned RenderText::caretMaxRenderedOffset() const
{
    int l = 0;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        l += box->len();
    return l;
}

int RenderText::previousOffset(int current) const
{
    StringImpl* si = m_text.get();
    TextBreakIterator* iterator = cursorMovementIterator(si->characters(), si->length());
    if (!iterator)
        return current - 1;

    long result = textBreakPreceding(iterator, current);
    if (result == TextBreakDone)
        result = current - 1;

#ifdef BUILDING_ON_TIGER
    // ICU 3.2 allows character breaks before a half-width Katakana voiced mark.
    if (static_cast<unsigned>(result) < si->length()) {
        UChar character = (*si)[result];
        if (character == 0xFF9E || character == 0xFF9F)
            --result;
    }
#endif

    return result;
}

#define HANGUL_CHOSEONG_START (0x1100)
#define HANGUL_CHOSEONG_END (0x115F)
#define HANGUL_JUNGSEONG_START (0x1160)
#define HANGUL_JUNGSEONG_END (0x11A2)
#define HANGUL_JONGSEONG_START (0x11A8)
#define HANGUL_JONGSEONG_END (0x11F9)
#define HANGUL_SYLLABLE_START (0xAC00)
#define HANGUL_SYLLABLE_END (0xD7AF)
#define HANGUL_JONGSEONG_COUNT (28)

enum HangulState {
    HangulStateL,
    HangulStateV,
    HangulStateT,
    HangulStateLV,
    HangulStateLVT,
    HangulStateBreak
};

inline bool isHangulLVT(UChar32 character)
{
    return (character - HANGUL_SYLLABLE_START) % HANGUL_JONGSEONG_COUNT;
}

int RenderText::previousOffsetForBackwardDeletion(int current) const
{
#if PLATFORM(MAC)
    UChar32 character;
    while (current > 0) {
        if (U16_IS_TRAIL((*m_text)[--current]))
            --current;
        if (current < 0)
            break;

        UChar32 character = m_text->characterStartingAt(current);

        // We don't combine characters in Armenian ... Limbu range for backward deletion.
        if ((character >= 0x0530) && (character < 0x1950))
            break;

        if (u_isbase(character) && (character != 0xFF9E) && (character != 0xFF9F))
            break;
    }

    if (current <= 0)
        return current;

    // Hangul
    character = m_text->characterStartingAt(current);
    if (((character >= HANGUL_CHOSEONG_START) && (character <= HANGUL_JONGSEONG_END)) || ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END))) {
        HangulState state;
        HangulState initialState;

        if (character < HANGUL_JUNGSEONG_START)
            state = HangulStateL;
        else if (character < HANGUL_JONGSEONG_START)
            state = HangulStateV;
        else if (character < HANGUL_SYLLABLE_START)
            state = HangulStateT;
        else
            state = isHangulLVT(character) ? HangulStateLVT : HangulStateLV;

        initialState = state;

        while (current > 0 && ((character = m_text->characterStartingAt(current - 1)) >= HANGUL_CHOSEONG_START) && (character <= HANGUL_SYLLABLE_END) && ((character <= HANGUL_JONGSEONG_END) || (character >= HANGUL_SYLLABLE_START))) {
            switch (state) {
            case HangulStateV:
                if (character <= HANGUL_CHOSEONG_END)
                    state = HangulStateL;
                else if ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END) && !isHangulLVT(character))
                    state = HangulStateLV;
                else if (character > HANGUL_JUNGSEONG_END)
                    state = HangulStateBreak;
                break;
            case HangulStateT:
                if ((character >= HANGUL_JUNGSEONG_START) && (character <= HANGUL_JUNGSEONG_END))
                    state = HangulStateV;
                else if ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END))
                    state = (isHangulLVT(character) ? HangulStateLVT : HangulStateLV);
                else if (character < HANGUL_JUNGSEONG_START)
                    state = HangulStateBreak;
                break;
            default:
                state = (character < HANGUL_JUNGSEONG_START) ? HangulStateL : HangulStateBreak;
                break;
            }
            if (state == HangulStateBreak)
                break;

            --current;
        }
    }

    return current;
#else
    // Platforms other than Mac delete by one code point.
    return current - 1;
#endif
}

int RenderText::nextOffset(int current) const
{
    StringImpl* si = m_text.get();
    TextBreakIterator* iterator = cursorMovementIterator(si->characters(), si->length());
    if (!iterator)
        return current + 1;

    long result = textBreakFollowing(iterator, current);
    if (result == TextBreakDone)
        result = current + 1;

#ifdef BUILDING_ON_TIGER
    // ICU 3.2 allows character breaks before a half-width Katakana voiced mark.
    if (static_cast<unsigned>(result) < si->length()) {
        UChar character = (*si)[result];
        if (character == 0xFF9E || character == 0xFF9F)
            ++result;
    }
#endif

    return result;
}

#ifndef NDEBUG

void RenderText::checkConsistency() const
{
#ifdef CHECK_CONSISTENCY
    const InlineTextBox* prev = 0;
    for (const InlineTextBox* child = m_firstTextBox; child != 0; child = child->nextTextBox()) {
        ASSERT(child->object() == this);
        ASSERT(child->prevTextBox() == prev);
        prev = child;
    }
    ASSERT(prev == m_lastTextBox);
#endif
}

#endif

} // namespace WebCore