int LibRaw_abstract_datastream::tempbuffer_open(void  *buf, size_t size)
{
    if(substream) return EBUSY;
    substream = new LibRaw_buffer_datastream(buf,size);
    return substream?0:EINVAL;
}
int LibRaw_abstract_datastream::tempbuffer_open(void  *buf, size_t size)
{
    if(substream) return EBUSY;
    substream = new LibRaw_buffer_datastream(buf,size);
    return substream?0:EINVAL;
}