use CPython heap memory allocation for memory views where possible (outside of...

use CPython heap memory allocation for memory views where possible (outside of nogil sections) as it tends to be faster than plain malloc()

Cython/Utility/MemoryView.pyx

@@ -29,6 +29,9 @@ cdef extern from *:
     void Py_INCREF(PyObject *)
     void Py_DECREF(PyObject *)
 
+    void* PyMem_Malloc(size_t n)
+    void PyMem_Free(void *p)
+
     cdef struct __pyx_memoryview "__pyx_memoryview_obj":
         Py_buffer view
         PyObject *obj
@@ -132,7 +135,7 @@ cdef class array:
         self.format = self._format
 
         # use single malloc() for both shape and strides
-        self._shape = <Py_ssize_t *> malloc(sizeof(Py_ssize_t)*self.ndim*2)
+        self._shape = <Py_ssize_t *> PyMem_Malloc(sizeof(Py_ssize_t)*self.ndim*2)
         self._strides = self._shape + self.ndim
 
         if not self._shape:
@@ -164,7 +167,7 @@ cdef class array:
         self.free_data = allocate_buffer
         self.dtype_is_object = format == b'O'
         if allocate_buffer:
-            self.data = <char *>malloc(self.len)
+            self.data = <char *>PyMem_Malloc(self.len)
             if not self.data:
                 raise MemoryError("unable to allocate array data.")
 
@@ -208,8 +211,8 @@ cdef class array:
             if self.dtype_is_object:
                 refcount_objects_in_slice(self.data, self._shape,
                                           self._strides, self.ndim, False)
-            free(self.data)
-        free(self._shape)
+            PyMem_Free(self.data)
+        PyMem_Free(self._shape)
 
     property memview:
         @cname('get_memview')
@@ -405,7 +408,7 @@ cdef class memoryview(object):
         dst_slice = get_slice_from_memview(dst, &tmp_slice)
 
         if <size_t>self.view.itemsize > sizeof(array):
-            tmp = malloc(self.view.itemsize)
+            tmp = PyMem_Malloc(self.view.itemsize)
             if tmp == NULL:
                 raise MemoryError
             item = tmp
@@ -425,7 +428,7 @@ cdef class memoryview(object):
             slice_assign_scalar(dst_slice, dst.view.ndim, self.view.itemsize,
                                 item, self.dtype_is_object)
         finally:
-            free(tmp)
+            PyMem_Free(tmp)
 
     cdef setitem_indexed(self, index, value):
         cdef char *itemp = self.get_item_pointer(index)