presto-rcfile/src/main/java/io/prestosql/rcfile/text/StringEncoding.java/StringEncoding/decodeValueInto
class StringEncoding:    @Override
    public void decodeValueInto(int depth, BlockBuilder builder, Slice slice, int offset, int length)
    {
        length = calculateTruncationLength(type, slice, offset, length);
        type.writeSlice(builder, slice, offset, length);
    }