qv4stringiterator.cpp

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// Copyright (C) 2017 Crimson AS <info@crimson.no>
// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <private/qv4iterator_p.h>
#include <private/qv4stringiterator_p.h>
#include <private/qv4symbol_p.h>
 
using namespace QV4;
 
DEFINE_OBJECT_VTABLE(StringIteratorObject);
 
void StringIteratorPrototype::init(ExecutionEngine *e)
{
    defineDefaultProperty(QStringLiteral("next"), method_next, 0);
 
    Scope scope(e);
    ScopedString val(scope, e->newString(QLatin1String("String Iterator")));
    defineReadonlyConfigurableProperty(e->symbol_toStringTag(), val);
}
 
ReturnedValue StringIteratorPrototype::method_next(const FunctionObject *b, const Value *that, const Value *, int)
{
    Scope scope(b);
    const StringIteratorObject *thisObject = that->as<StringIteratorObject>();
    if (!thisObject)
        return scope.engine->throwTypeError(QLatin1String("Not an String Iterator instance"));
 
    ScopedString s(scope, thisObject->d()->iteratedString);
    if (!s) {
        QV4::Value undefined = Value::undefinedValue();
        return IteratorPrototype::createIterResultObject(scope.engine, undefined, true);
    }
 
    quint32 index = thisObject->d()->nextIndex;
 
    QString str = s->toQString();
    quint32 len = str.size();
 
    if (index >= len) {
        thisObject->d()->iteratedString.set(scope.engine, nullptr);
        QV4::Value undefined = Value::undefinedValue();
        return IteratorPrototype::createIterResultObject(scope.engine, undefined, true);
    }
 
    QChar ch = str.at(index);
    int num = 1;
    if (ch.unicode() >= 0xd800 && ch.unicode() <= 0xdbff && index + 1 != len) {
        ch = str.at(index + 1);
        if (ch.unicode() >= 0xdc00 && ch.unicode() <= 0xdfff)
            num = 2;
    }
 
    thisObject->d()->nextIndex += num;
 
    ScopedString resultString(scope, scope.engine->newString(s->toQString().mid(index, num)));
    return IteratorPrototype::createIterResultObject(scope.engine, resultString, false);
}