feat: modify VectorInit to handle numpy multi dimensional arrays

src/Pythonize.cxx

@@ -52,6 +52,24 @@ bool HasAttrDirect(PyObject* pyclass, PyObject* pyname, bool mustBeCPyCppyy = fa
     return false;
 }
 
+template <typename T>
+T Get_IndexValue(Py_buffer *view, int i)
+{
+    if (!view || !view->buf)
+    {
+        // Handle the error, e.g., throw an exception or return a default value
+        PyErr_SetString(PyExc_RuntimeError, "Buffer is not valid");
+    }
+
+    if (i < 0 || i >= view->len / view->itemsize)
+    {
+        // Handle the error, e.g., throw an exception or return a default value
+        PyErr_SetString(PyExc_IndexError, "Index out of range");
+    }
+    // get the value at index i in the view
+    return *(T *)((char *)view->buf + i * view->strides[0]);
+}
+
 PyObject* GetAttrDirect(PyObject* pyclass, PyObject* pyname) {
 // get an attribute without causing getattr lookups
     PyObject* dct = PyObject_GetAttr(pyclass, PyStrings::gDict);
@@ -459,7 +477,96 @@ PyObject* VectorIAdd(PyObject* self, PyObject* args, PyObject* /* kwds */)
         PyErr_SetString(PyExc_TypeError, "argument is not iterable");
     return nullptr;               // error already set
 }
+PyObject *recursive_vector_init(PyObject *self, Py_buffer *view, PyObject *result, int ndim)
+{
+    // PyObject *tmp_result = PyList_New(0);
+    if (ndim == 1)
+    {
+        if (!result)
+            return nullptr;
+
+        Py_ssize_t fillsz = view->len / view->itemsize;
+        PyObject *pb_call = PyObject_GetAttrString(self, "push_back");
 
+        for (Py_ssize_t i = 0; i < fillsz; i++)
+        {
+            int val = Get_IndexValue<int>(view, i);
+            PyObject *item = PyLong_FromLong(val);
+
+            if (!item)
+            {
+                Py_DECREF(result);
+                Py_XDECREF(pb_call);
+                return nullptr;
+            }
+
+            PyObject *pbres = PyObject_CallFunctionObjArgs(pb_call, item, nullptr);
+            Py_DECREF(item);
+
+            if (!pbres)
+            {
+                Py_DECREF(result);
+                Py_XDECREF(pb_call);
+                return nullptr;
+            }
+
+            Py_DECREF(pbres);
+        }
+
+        Py_XDECREF(pb_call);
+        return result;
+    }
+
+    if (!result)
+        return nullptr;
+
+    Py_ssize_t *shape = (Py_ssize_t *)view->shape;
+    Py_ssize_t *strides = (Py_ssize_t *)view->strides;
+    Py_ssize_t *subshape = shape + 1;
+    Py_ssize_t *substrides = strides + 1;
+
+    for (Py_ssize_t i = 0; i < view->ndim; i++)
+    {
+        Py_buffer subview;
+        subview.buf = (void *)((char *)view->buf + i * strides[0]);
+        subview.obj = NULL;
+        subview.len = subshape[0] * substrides[0];
+        subview.readonly = view->readonly;
+        subview.itemsize = view->itemsize;
+        subview.format = view->format;
+        subview.ndim = ndim - 1;
+        subview.shape = subshape;
+        subview.strides = substrides;
+        subview.suboffsets = view->suboffsets;
+        subview.internal = view->internal;
+
+        PyObject *subresult = recursive_vector_init(self, &subview, result, ndim - 1);
+        if (!subresult)
+        {
+            Py_DECREF(result);
+            return nullptr;
+        }
+        PyObject *pb_call = PyObject_GetAttrString(self, "push_back");
+
+
+        PyObject *pbres = PyObject_CallFunctionObjArgs(pb_call, subresult, nullptr);
+
+        if (!pbres)
+        {
+            Py_DECREF(result);
+            Py_XDECREF(pb_call);
+            return nullptr;
+        }
+
+
+        Py_DECREF(pbres);
+        Py_DECREF(pb_call);
+
+        Py_DECREF(subresult);
+    }
+
+    return result;
+}
 
 PyObject* VectorInit(PyObject* self, PyObject* args, PyObject* /* kwds */)
 {
@@ -490,10 +597,41 @@ PyObject* VectorInit(PyObject* self, PyObject* args, PyObject* /* kwds */)
         return result;
     }
 
-// The given argument wasn't iterable: simply forward to regular constructor
-    PyObject* realInit = PyObject_GetAttr(self, PyStrings::gRealInit);
-    if (realInit) {
-        PyObject* result = PyObject_Call(realInit, args, nullptr);
+    // get the first argument
+    PyObject* fi = PyTuple_GET_ITEM(args, 0);
+    if (fi == Py_None) 
+    {
+        // empty vector
+        return PyObject_CallMethodNoArgs(self, PyStrings::gRealInit);
+    }
+
+    // check if numpy is passed
+    if (PyObject_CheckBuffer(fi)){
+        // create a memoryview
+        PyObject* memoryview = PyMemoryView_FromObject(fi);
+        Py_buffer* view = PyMemoryView_GET_BUFFER(memoryview);
+
+        // check if memoryview is valid
+        if (view->buf == NULL) return nullptr;
+
+        PyObject *result = PyObject_CallMethodNoArgs(self, PyStrings::gRealInit);
+
+        result = recursive_vector_init(self, view, result, view->ndim);
+
+        // dereference the memoryview buffer
+        PyBuffer_Release(view);
+        Py_DECREF(memoryview);
+        Py_DECREF(fi);
+
+        return result;
+
+    }
+
+    // The given argument wasn't iterable or a numpy array: simply forward to regular constructor
+    PyObject *realInit = PyObject_GetAttr(self, PyStrings::gRealInit);
+    if (realInit)
+    {
+        PyObject *result = PyObject_Call(realInit, args, nullptr);
         Py_DECREF(realInit);
         return result;
     }