C++ (Cpp) Datum::SetSize示例

void Scope::Adopt(Scope& child, const std::string& key, std::uint32_t index)
{
    if (key == std::string())
        throw std::exception("Key cannot be an empty string.");

    child.Orphan();
    child.mParent = this;

    // try to find entry first in this scope
    Datum* d = Find(key);
    if (d != nullptr)
    {
        if (d->GetType() != Datum::Table)
            throw std::exception("Found entry is not a table!");
        if (d->IsExternal())
            throw std::exception("Table is external. Cannot modify data owned by something else.");

        std::uint32_t originalDatumSize = d->Size();

        // if a scope is empty or not pointing to anything at the given index, we can just have it point to something else
        if (originalDatumSize <= index || d->GetTable(index) == nullptr || d->GetTable(index)->mOrder.Size() == 0)
            d->Set(&child, index);

        // otherwise, we add in the child scope and rearrange the datum array if necessary
        else
        {
            if (index < originalDatumSize)
            {
                d->SetSize(originalDatumSize + 1);
                for (std::uint32_t i = originalDatumSize; i > index; --i)
                {
                    d->Set(d->GetTable(i - 1), i);
                }
            }
            else if (index > originalDatumSize)
            {
                index = originalDatumSize;
            }
            d->Set(&child, index);
        }
    }
    else
    {
        Datum scopeDatum;
        scopeDatum = &child;

        std::pair<std::string, Datum> pair(key, scopeDatum);
        HashMap<std::string, Datum>::Iterator iterator = mTable.Insert(pair);
        mOrder.PushBack(&(*iterator));
    }
}