Add PyMemoryView_FromMemory

Author: msimacek

graalpython/com.oracle.graal.python.cext/src/memoryobject.c

@@ -107,6 +107,15 @@ PyObject* PyMemoryView_FromBuffer(Py_buffer *buffer) {
                 buffer->suboffsets ? polyglot_from_size_array(buffer->suboffsets, ndim) : NULL);
 }
 
+PyObject *PyMemoryView_FromMemory(char *mem, Py_ssize_t size, int flags)
+{
+    assert(mem != NULL);
+    assert(flags == PyBUF_READ || flags == PyBUF_WRITE);
+    int readonly = (flags == PyBUF_WRITE) ? 0 : 1;
+    return polyglot_invoke(PY_TRUFFLE_CEXT, "PyTruffle_MemoryViewFromBuffer",
+            NULL, NULL, NULL, size, readonly, 1, polyglot_from_string("B", "ascii"), 1, polyglot_from_i8_array((int8_t*)mem, size), NULL, NULL, NULL);
+}
+
 /* Macros taken from CPython */
 /* Memoryview buffer properties */
 #define MV_C_CONTIGUOUS(flags) (flags&(_Py_MEMORYVIEW_SCALAR|_Py_MEMORYVIEW_C))

graalpython/com.oracle.graal.python.test/src/tests/cpyext/test_memoryview.py

@@ -142,6 +142,31 @@ def compile_module(self, name):
         cmpfunc=unhandled_error_compare_with_message,
     )
 
+    test_memoryview_frommemory = CPyExtFunction(
+        lambda args: args[1],
+        lambda: (
+            (1, 50),
+            (2, 60),
+            (3, IndexError("index out of bounds on dimension 1"))
+        ),
+        code='''
+            char mem[] = {40, 50, 60};
+            static PyObject* test_frommemory(PyObject *key, PyObject* expected) {
+                PyObject *mv = PyMemoryView_FromMemory(mem, 3, PyBUF_READ);
+                if (!mv)
+                    return NULL;
+                PyObject *item = PyObject_GetItem(mv, key);
+                Py_DECREF(mv);
+                return item;
+            }
+        ''',
+        resultspec='O',
+        argspec='OO',
+        arguments=["PyObject* key", "PyObject* expected"],
+        callfunction="test_frommemory",
+        cmpfunc=unhandled_error_compare_with_message,
+    )
+
     test_memoryview_tolist = CPyExtFunction(
         lambda args: args[0],
         lambda: [