Got it. I think I am just going to use arraydata::make for this for now. Thanks a bundle!
Felipe On Fri, Mar 22, 2019 at 8:43 AM Francois Saint-Jacques < fsaintjacq...@gmail.com> wrote: > It is not frowned upon to use the ArrayData::Make classes, you just have to > ensure the order of buffers matches what the specialized Array class > expects (also matching the type you're passing to ArrayData). I'd say it is > the "preferred" way if your data is already in the required layout, and the > best way if you want effective zero-copy. > > I created https://issues.apache.org/jira/browse/ARROW-4999 to track > improving the documentation. > > François > > On Fri, Mar 22, 2019 at 11:26 AM Felipe Aramburu <fel...@blazingdb.com> > wrote: > > > Is there a way to use a builder to be able to provide a bit per value LSB > > as is described in the documentation? I have this already and it seems > > silly to convert it to something else so that arrow can then make it the > > same format as what I had to begin with. I know there is the ArrayData > > class that has a make function that seems to allow me to do this but I am > > trying to do things as the documentation suggest which I assumed was the > > preferred method of doing this. > > > > > > > > On Fri, Mar 22, 2019 at 8:13 AM Francois Saint-Jacques < > > fsaintjacq...@gmail.com> wrote: > > > > > Actually, this specific method seems to use a byte per value as you > > > questioned. I think it's worth adding documentation and an explicit > > warning > > > if it confused me. I'll let bkietz chime in to comment on the usage. > > > > > > François > > > > > > On Fri, Mar 22, 2019 at 10:57 AM Francois Saint-Jacques < > > > fsaintjacq...@gmail.com> wrote: > > > > > > > Hello Felipe, > > > > > > > > it's a bit per value as per memory layout documentation. > > > > > > > > François > > > > > > > > > > > > > > > > On Fri, Mar 22, 2019 at 10:48 AM Felipe Aramburu < > fel...@blazingdb.com > > > > > > > wrote: > > > > > > > >> In the builder base class I see this api > > > >> > > > >> > > > >> > > > > > > https://github.com/apache/arrow/blob/ad1697e5d25eeaff5630421f55b0120f45cf0ce1/cpp/src/arrow/array/builder_base.h#L149 > > > >> > > > >> // Vector append. Treat each zero byte as a nullzero. If > > valid_bytes > > > >> is > > > >> null > > > >> // assume all of length bits are valid. > > > >> void UnsafeAppendToBitmap(const uint8_t* valid_bytes, int64_t > > > length) > > > >> > > > >> Is valid_bytes an allocation of size (int8_t) * length, using an > > entire > > > >> byte to indicate validity for each element in the array or is this a > > > null > > > >> bitmask where in each byte in valid_bytes encodes 8 values, one per > > bit? > > > >> > > > >> If this is using a byte per value is there an approved way of using > a > > > >> builder to initialize an array using the memory layout described > here > > > >> https://arrow.apache.org/docs/memory_layout.html#null-bitmaps? > > > >> > > > > > > > > > >
