result operator()() {
auto dict = std::dynamic_pointer_cast<OrderPreservingDictionary<R>>(_main->dictionaryAt(_column));
std::set<R> data;
// Build unified dictionary
size_t deltaSize = _delta->size();
for(size_t i=0; i < deltaSize; ++i) {
data.insert(_delta->getValue<R>(_column, i));
}
size_t dictSize = dict->size();
for(size_t i=0; i < dictSize; ++i)
data.insert(dict->getValueForValueId(i));
// Build mapping table for old dictionary
auto start = data.cbegin();
auto end = data.cend();
size_t mapped = 0;
std::vector<value_id_t> mapping;
for(size_t i=0; i < dictSize; ++i) {
auto val = dict->getValueForValueId(i);
// Skip until we are equal
while(start != end && *start != val) {
++mapped; ++start;
}
if (start != end)
++start;
mapping.push_back(mapped++);
}
auto resultDict = std::make_shared<OrderPreservingDictionary<R>>(data.size());
for(auto e : data)
resultDict->addValue(e);
result r = {std::move(mapping), std::move(resultDict)};
return r;
}
