qtextboundaryfinder.cpp

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#include <QtCore/qtextboundaryfinder.h>
#include <QtCore/qvarlengtharray.h>
#include <private/qunicodetables_p.h>
#include <qdebug.h>
#include "private/qharfbuzz_p.h"

QT_BEGIN_NAMESPACE

class QTextBoundaryFinderPrivate
{
public:
    HB_CharAttributes attributes[1];
};

static void init(QTextBoundaryFinder::BoundaryType type, const QChar *chars, int length, HB_CharAttributes *attributes)
{
    QVarLengthArray<HB_ScriptItem> scriptItems;

    const ushort *string = reinterpret_cast<const ushort *>(chars);
    const ushort *unicode = string;
    // correctly assign script, isTab and isObject to the script analysis
    const ushort *uc = unicode;
    const ushort *e = uc + length;
    int script = QUnicodeTables::Common;
    int lastScript = QUnicodeTables::Common;
    const ushort *start = uc;
    while (uc < e) {
        int s = QUnicodeTables::script(*uc);
        if (s != QUnicodeTables::Inherited)
            script = s;
        if (*uc == QChar::ObjectReplacementCharacter || *uc == QChar::LineSeparator || *uc == 9) 
            script = QUnicodeTables::Common;
        if (script != lastScript) {
            if (uc != start) {
                HB_ScriptItem item;
                item.pos = start - string;
                item.length = uc - start;
                item.script = (HB_Script)lastScript;
                item.bidiLevel = 0; // ### what's the proper value?
                scriptItems.append(item);
                start = uc;
            }
            lastScript = script;
        }
        ++uc;
    }
    if (uc != start) {
        HB_ScriptItem item;
        item.pos = start - string;
        item.length = uc - start;
        item.script = (HB_Script)lastScript;
        item.bidiLevel = 0; // ### what's the proper value?
        scriptItems.append(item);
    }

    qGetCharAttributes(string, length, scriptItems.data(), scriptItems.count(), attributes);
    if (type == QTextBoundaryFinder::Word)
        HB_GetWordBoundaries(string, length, scriptItems.data(), scriptItems.count(), attributes);
    else if (type == QTextBoundaryFinder::Sentence)
        HB_GetSentenceBoundaries(string, length, scriptItems.data(), scriptItems.count(), attributes);
}

QTextBoundaryFinder::QTextBoundaryFinder()
    : t(Grapheme)
    , chars(0)
    , length(0)
    , freePrivate(true)
    , d(0)
{
}

QTextBoundaryFinder::QTextBoundaryFinder(const QTextBoundaryFinder &other)
    : t(other.t)
    , s(other.s)
    , chars(other.chars)
    , length(other.length)
    , pos(other.pos)
    , freePrivate(true)
{
    d = (QTextBoundaryFinderPrivate *) malloc(length*sizeof(HB_CharAttributes));
    Q_CHECK_PTR(d);
    memcpy(d, other.d, length*sizeof(HB_CharAttributes));
}

QTextBoundaryFinder &QTextBoundaryFinder::operator=(const QTextBoundaryFinder &other)
{
    if (&other == this)
        return *this;

    t = other.t;
    s = other.s;
    chars = other.chars;
    length = other.length;
    pos = other.pos;

    QTextBoundaryFinderPrivate *newD = (QTextBoundaryFinderPrivate *)
        realloc(freePrivate ? d : 0, length*sizeof(HB_CharAttributes));
    Q_CHECK_PTR(newD);
    freePrivate = true;
    d = newD;
    memcpy(d, other.d, length*sizeof(HB_CharAttributes));

    return *this;
}

QTextBoundaryFinder::~QTextBoundaryFinder()
{
    if (freePrivate)
        free(d);
}

QTextBoundaryFinder::QTextBoundaryFinder(BoundaryType type, const QString &string)
    : t(type)
    , s(string)
    , chars(string.unicode())
    , length(string.length())
    , pos(0)
    , freePrivate(true)
{
    d = (QTextBoundaryFinderPrivate *) malloc(length*sizeof(HB_CharAttributes));
    Q_CHECK_PTR(d);
    init(t, chars, length, d->attributes);
}

QTextBoundaryFinder::QTextBoundaryFinder(BoundaryType type, const QChar *chars, int length, unsigned char *buffer, int bufferSize)
    : t(type)
    , chars(chars)
    , length(length)
    , pos(0)
{
    if (buffer && (uint)bufferSize >= length*sizeof(HB_CharAttributes)) {
        d = (QTextBoundaryFinderPrivate *)buffer;
        freePrivate = false;
    } else {
        d = (QTextBoundaryFinderPrivate *) malloc(length*sizeof(HB_CharAttributes));
        Q_CHECK_PTR(d);
        freePrivate = true;
    }
    init(t, chars, length, d->attributes);
}

void QTextBoundaryFinder::toStart()
{
    pos = 0;
}

void QTextBoundaryFinder::toEnd()
{
    pos = length;
}

int QTextBoundaryFinder::position() const
{
    return pos;
}

void QTextBoundaryFinder::setPosition(int position)
{
    pos = qBound(0, position, length);
}

QString QTextBoundaryFinder::string() const
{
    if (chars == s.unicode() && length == s.length())
        return s;
    return QString(chars, length);
}


int QTextBoundaryFinder::toNextBoundary()
{
    if (!d) {
        pos = -1;
        return pos;
    }

    if (pos < 0 || pos >= length) {
        pos = -1;
        return pos;
    }
    ++pos;
    if (pos == length)
        return pos;
    
    switch(t) {
    case Grapheme:
        while (pos < length && !d->attributes[pos].charStop)
            ++pos;
        break;
    case Word:
        while (pos < length && !d->attributes[pos].wordBoundary)
            ++pos;
        break;
    case Sentence:
        while (pos < length && !d->attributes[pos].sentenceBoundary)
            ++pos;
        break;
    case Line:
        Q_ASSERT(pos);
        while (pos < length && d->attributes[pos-1].lineBreakType < HB_Break)
            ++pos;
        break;
    }

    return pos;
}

int QTextBoundaryFinder::toPreviousBoundary()
{
    if (!d) {
        pos = -1;
        return pos;
    }

    if (pos <= 0 || pos > length) {
        pos = -1;
        return pos;
    }
    --pos;
    if (pos == 0)
        return pos;

    switch(t) {
    case Grapheme:
        while (pos > 0 && !d->attributes[pos].charStop)
            --pos;
        break;
    case Word:
        while (pos > 0 && !d->attributes[pos].wordBoundary)
            --pos;
        break;
    case Sentence:
        while (pos > 0 && !d->attributes[pos].sentenceBoundary)
            --pos;
        break;
    case Line:
        while (pos > 0 && d->attributes[pos-1].lineBreakType < HB_Break)
            --pos;
        break;
    }

    return pos;
}

bool QTextBoundaryFinder::isAtBoundary() const
{
    if (!d || pos < 0)
        return false;

    if (pos == length)
        return true;

    switch(t) {
    case Grapheme:
        return d->attributes[pos].charStop;
    case Word:
        return d->attributes[pos].wordBoundary;
    case Line:
        return (pos > 0) ? d->attributes[pos-1].lineBreakType >= HB_Break : true;
    case Sentence:
        return d->attributes[pos].sentenceBoundary;
    }
    return false;
}

QTextBoundaryFinder::BoundaryReasons QTextBoundaryFinder::boundaryReasons() const
{
    if (!d)
        return NotAtBoundary;
    if (! isAtBoundary())
        return NotAtBoundary;
    if (pos == 0) {
        if (d->attributes[pos].whiteSpace)
            return NotAtBoundary;
        return StartWord;
    }
    if (pos == length) {
        if (d->attributes[length-1].whiteSpace)
            return NotAtBoundary;
        return EndWord;
    }

    const bool nextIsSpace = d->attributes[pos].whiteSpace;
    const bool prevIsSpace = d->attributes[pos - 1].whiteSpace;

    if (prevIsSpace && !nextIsSpace)
        return StartWord;
    else if (!prevIsSpace && nextIsSpace)
        return EndWord;
    else if (!prevIsSpace && !nextIsSpace)
        return BoundaryReasons(StartWord | EndWord);
    else
        return NotAtBoundary;
}

QT_END_NAMESPACE