Add functionality for converting mlarrow record batches to pyarrow record batches

Author: sgilmore10

matlab/src/matlab/+arrow/+c/mlarrow2pyarrow.m

@@ -1,13 +1,22 @@
 function pyarrowArray = mlarrow2pyarrow(mlarrowArray)
-    [cArrayWrapper, cSchemaWrapper] = pyrunfile(fullfile(pwd, "+internal/FFIWrapper.py"), ["cArrayWrapper" "cSchemaWrapper"]);
+    folder = fileparts(mfilename("fullpath"));
+    
+    [cArrayWrapper, cSchemaWrapper] = pyrunfile(fullfile(folder, "+internal/FFIWrapper.py"), ["cArrayWrapper" "cSchemaWrapper"]);
 
     cArrayAddress = uint64(cArrayWrapper.getAddress());
     cSchemaAdress = uint64(cSchemaWrapper.getAddress());
 
     mlarrowArray.exportToC(cArrayAddress, cSchemaAdress);
 
-    dummyArray = py.pyarrow.array([1 2]);
-    importFunc = py.getattr(dummyArray, "_import_from_c");
-    pyarrowArray = importFunc(cArrayAddress, cSchemaAdress);
+    if isa(mlarrowArray, "arrow.array.Array")
+        dummyArray = py.pyarrow.array([1 2]);
+        importFunc = py.getattr(dummyArray, "_import_from_c");
+        pyarrowArray = importFunc(cArrayAddress, cSchemaAdress);
+    else
+        dummyArray = py.pyarrow.array([1 2]);
+        dummyRB = py.pyarrow.record_batch(py.list({dummyArray}), names={'Var1'});
+        importFunc = py.getattr(dummyRB, "_import_from_c");
+        pyarrowArray = importFunc(cArrayAddress, cSchemaAdress);
+    end
 end
 

matlab/src/matlab/+arrow/+c/pyarrow2mlarrow.m

@@ -5,6 +5,10 @@
     exportFunc = py.getattr(pyarrowArray, "_export_to_c");
     exportFunc(cArray.Address, cSchema.Address);
 
-    mlarrowArray = arrow.array.Array.importFromC(cArray, cSchema);
-
+    if isa(pyarrowArray, "py.pyarrow.lib.Array")
+        mlarrowArray = arrow.array.Array.importFromC(cArray, cSchema);
+    else
+        importer = arrow.c.internal.RecordBatchImporter();
+        mlarrowArray = importer.import(cArray, cSchema);
+    end
 end

matlab/src/matlab/+arrow/+tabular/RecordBatch.m

@@ -144,8 +144,15 @@ function displayScalarObject(obj)
     end
 
     methods(Hidden)
-        function exportToC(cArrayAddress, cSchemaAddress)
-            obj.Proxy.exportToC(cArrayAddress, cSchemaAddress);
+        function exportToC(obj, cArrayAddress, cSchemaAddress)
+            arguments
+                obj(1, 1) arrow.tabular.RecordBatch
+                cArrayAddress(1, 1) uint64
+                cSchemaAddress(1, 1) uint64
+            end
+            args = struct(ArrowArrayAddress=cArrayAddress,...
+                ArrowSchemaAddress=cSchemaAddress);
+            obj.Proxy.exportToC(args);
         end
     end
 end