Serializing in C then deserializing in python

[Mani Abedini]

Hi

I have a bit of issue for serializing in C and deserializing it in python,

I defined a message to carry data, serialize it into array in C, then send it over to python (via ctype).

I noticed that since the serialized array may contains 0 (zero) values, It is better of to send as array of int to python,

otherwise truncated message would be transferred ( python expects strings are NULL terminated ). In this case

when I receive an array of int values in python, I don't know how to reconstruct a string from those values and feed it to ParseFromString()

because ParseFromString() does not accept array_of_int, because it does not have len(). I can not build a string in python especially some of the values are negative and python does not let me convert negative value to char.

Any comment ?

Codes:

message siftOut{

message keypoint {

required float x = 1;

repeated float descr= 2 [packed=true];

}

repeated keypoint keypoints= 1;

} ; 

 

When I filled a message such as:

siftOut vFrmDescr;

siftOut_keypoint *frmDescr = vFrmDescr.add_keypoints();

int l ;

frmDescr->set_x ( (float) k -> x );

for (l = 0 ; l < 128 ; ++l) {

frmDescr->add_descr (   (512.0 * descr [l]) ) ;

}

Then   

  

char * charOut = new char[vFrmDescr.ByteSize()];

vFrmDescr.SerializeToArray( charOut , vFrmDescr.ByteSize()); 

and send it to python

in python

           LIB = cdll[_loc]

            LIB.protoBufFunc.argtypes =[c_char_p , c_int32 ]

            LIB.protoBufFunc.restype  = POINTER(c_int32)

            stDescriptors = LIB.protoBufFunc( " A sample dataa in string format " , 50 );

 Now how can I use parsefromString() in python to read  stDescriptors  ?

Appreciate your help in advance.

Regards

Mani