Function executeString

src/Functions/FunctionsHashing.h:1157–1234

    template <bool first>
    void executeString(const KeyColumnsType & key_cols, const IColumn * column, typename ColumnVector<ToType>::Container & vec_to) const
    {
        KeyType key{};
        if constexpr (Keyed)
            key = Impl::getKey(key_cols, 0);
        if (const ColumnString * col_from = checkAndGetColumn<ColumnString>(column))
        {
            const typename ColumnString::Chars & data = col_from->getChars();
            const typename ColumnString::Offsets & offsets = col_from->getOffsets();
            size_t size = offsets.size();

            ColumnString::Offset current_offset = 0;
            for (size_t i = 0; i < size; ++i)
            {
                if constexpr (Keyed)
                    if (!key_cols.is_const && i != 0)
                        key = Impl::getKey(key_cols, i);
                const ToType hash = apply(key,
                    reinterpret_cast<const char *>(&data[current_offset]),
                    offsets[i] - current_offset);

                if constexpr (first)
                    vec_to[i] = hash;
                else
                    vec_to[i] = combineHashes(key, vec_to[i], hash);

                current_offset = offsets[i];
            }
        }
        else if (const ColumnFixedString * col_from_fixed = checkAndGetColumn<ColumnFixedString>(column))
        {
            const typename ColumnString::Chars & data = col_from_fixed->getChars();
            size_t n = col_from_fixed->getN();
            size_t size = data.size() / n;

            for (size_t i = 0; i < size; ++i)
            {
                if constexpr (Keyed)
                    if (!key_cols.is_const && i != 0)
                        key = Impl::getKey(key_cols, i);
                const ToType hash = apply(key, reinterpret_cast<const char *>(&data[i * n]), n);
                if constexpr (first)
                    vec_to[i] = hash;
                else
                    vec_to[i] = combineHashes(key, vec_to[i], hash);
            }
        }
        else if (const ColumnConst * col_from_const = checkAndGetColumnConstStringOrFixedString(column))
        {
            if constexpr (Keyed)
            {
                if (!key_cols.is_const)
                {
                    ColumnPtr full_column = col_from_const->convertToFullColumn();
                    return executeString<first>(key_cols, full_column.get(), vec_to);
                }
            }
            String value = col_from_const->getValue<String>();