[libcamera-devel] [RFC PATCH 02/10] libcamera: ipa_data_serializer: Modify (de)serialization for offset

[Laurent Pinchart]

Hi,

On Wed, Aug 18, 2021 at 11:58:29AM +0200, Jacopo Mondi wrote:
> On Mon, Aug 16, 2021 at 01:31:30PM +0900, Hirokazu Honda wrote:
> > The offset variable is added to FrameBuffer::Plane. This modifies
> > the serialization and deserialization code for the offset variable.
> >
> > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > ---
> >  src/libcamera/ipa_data_serializer.cpp | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/libcamera/ipa_data_serializer.cpp b/src/libcamera/ipa_data_serializer.cpp
> > index fb941e6b..144c3248 100644
> > --- a/src/libcamera/ipa_data_serializer.cpp
> > +++ b/src/libcamera/ipa_data_serializer.cpp
> > @@ -562,6 +562,7 @@ FileDescriptor IPADataSerializer<FileDescriptor>::deserialize(const std::vector<
> >   * FrameBuffer::Plane is serialized as:
> >   *
> >   * 1 byte  - FileDescriptor
> > + * 4 bytes - uint32_t Offset
> >   * 4 bytes - uint32_t Length
> >   */
> >  template<>
> > @@ -580,6 +581,7 @@ IPADataSerializer<FrameBuffer::Plane>::serialize(const FrameBuffer::Plane &data,
> >  	fdsVec.insert(fdsVec.end(), fdFds.begin(), fdFds.end());
> >
> >  	appendPOD<uint32_t>(dataVec, data.length);
> > +	appendPOD<uint32_t>(dataVec, data.offset);
> >
> >  	return { dataVec, fdsVec };
> >  }
> > @@ -596,7 +598,8 @@ IPADataSerializer<FrameBuffer::Plane>::deserialize(std::vector<uint8_t>::const_i
> >
> >  	ret.fd = IPADataSerializer<FileDescriptor>::deserialize(dataBegin, dataBegin + 1,
> >  								fdsBegin, fdsBegin + 1);
> > -	ret.length = readPOD<uint32_t>(dataBegin, 1, dataEnd);
> > +	ret.offset = readPOD<uint32_t>(dataBegin, 1, dataBegin + 2);
> > +	ret.length = readPOD<uint32_t>(dataBegin + 1, 1, dataEnd);
> 
> Am I wrong ot offset is appeneded at the end of dataVec (after lenght) and
> then read from the beginning (before lenght) ?

How did I miss that ? :-S Let's serialize the fields in the order
they're defined in the structure. Also, the dataBegin + 2 isn't correct,
deserializing an uint32_t requires 4 bytes, and dataBegin + 1 is thus
incorrect too.

Paul, is there an easy way to get the serdes code for
FrameBuffer::Plane generated ?

> >
> >  	return ret;
> >  }

-- 
Regards,

Laurent Pinchart