Issue #15424: Add a __sizeof__ implementation for array objects.

Patch by Ludwig Hähne.

Lib/test/test_array.py

@@ -985,6 +985,19 @@ class UnsignedNumberTest(NumberTest):
         upper = long(pow(2, a.itemsize * 8)) - 1L
         self.check_overflow(lower, upper)
 
+    @test_support.cpython_only
+    def test_sizeof_with_buffer(self):
+        a = array.array(self.typecode, self.example)
+        basesize = test_support.calcvobjsize('4P')
+        buffer_size = a.buffer_info()[1] * a.itemsize
+        test_support.check_sizeof(self, a, basesize + buffer_size)
+
+    @test_support.cpython_only
+    def test_sizeof_without_buffer(self):
+        a = array.array(self.typecode)
+        basesize = test_support.calcvobjsize('4P')
+        test_support.check_sizeof(self, a, basesize)
+
 
 class ByteTest(SignedNumberTest):
     typecode = 'b'

Misc/ACKS

@@ -393,6 +393,7 @@ Jim Hugunin
 Greg Humphreys
 Eric Huss
 Jeremy Hylton
+Ludwig Hähne
 Gerhard Häring
 Fredrik Håård
 Catalin Iacob

Misc/NEWS

@@ -94,6 +94,9 @@ Library
 
 - Issue #15567: Fix NameError when running threading._test
 
+- Issue #15424: Add a __sizeof__ implementation for array objects.
+  Patch by Ludwig Hähne.
+
 - Issue #13052: Fix IDLE crashing when replace string in Search/Replace dialog
   ended with '\'. Patch by Roger Serwy.
 

Modules/arraymodule.c

@@ -1532,6 +1532,19 @@ array_reduce(arrayobject *array)
 
 PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");
 
+static PyObject *
+array_sizeof(arrayobject *self, PyObject *unused)
+{
+    Py_ssize_t res;
+    res = sizeof(arrayobject) + self->allocated * self->ob_descr->itemsize;
+    return PyLong_FromSsize_t(res);
+}
+
+PyDoc_STRVAR(sizeof_doc,
+"__sizeof__() -> int\n\
+\n\
+Size of the array in memory, in bytes.");
+
 static PyObject *
 array_get_typecode(arrayobject *a, void *closure)
 {
@@ -1606,6 +1619,8 @@ static PyMethodDef array_methods[] = {
 #endif
     {"write",           (PyCFunction)array_tofile_as_write,     METH_O,
      tofile_doc},
+    {"__sizeof__",      (PyCFunction)array_sizeof,      METH_NOARGS,
+     sizeof_doc},
     {NULL,              NULL}           /* sentinel */
 };