Refactor SliceTupleAndList utility code (GH-3087)

Cython/Utility/ObjectHandling.c

@@ -735,6 +735,55 @@ bad:
 }
 
 
+/////////////// TupleAndListFromArray.proto ///////////////
+
+#if CYTHON_COMPILING_IN_CPYTHON
+static CYTHON_INLINE PyObject* __Pyx_PyTuple_FromArray(PyObject *const *src, Py_ssize_t n);
+static CYTHON_INLINE PyObject* __Pyx_PyList_FromArray(PyObject *const *src, Py_ssize_t n);
+#endif
+
+/////////////// TupleAndListFromArray ///////////////
+//@substitute: naming
+
+#if CYTHON_COMPILING_IN_CPYTHON
+static CYTHON_INLINE void __Pyx_copy_object_array(PyObject *const *CYTHON_RESTRICT src, PyObject** CYTHON_RESTRICT dest, Py_ssize_t length) {
+    PyObject *v;
+    Py_ssize_t i;
+    for (i = 0; i < length; i++) {
+        v = dest[i] = src[i];
+        Py_INCREF(v);
+    }
+}
+
+static CYTHON_INLINE PyObject *
+__Pyx_PyTuple_FromArray(PyObject *const *src, Py_ssize_t n)
+{
+    PyObject *res;
+    if (n <= 0) {
+        Py_INCREF($empty_tuple);
+        return $empty_tuple;
+    }
+    res = PyTuple_New(n);
+    if (unlikely(res == NULL)) return NULL;
+    __Pyx_copy_object_array(src, ((PyTupleObject*)res)->ob_item, n);
+    return res;
+}
+
+static CYTHON_INLINE PyObject *
+__Pyx_PyList_FromArray(PyObject *const *src, Py_ssize_t n)
+{
+    PyObject *res;
+    if (n <= 0) {
+        return PyList_New(0);
+    }
+    res = PyList_New(n);
+    if (unlikely(res == NULL)) return NULL;
+    __Pyx_copy_object_array(src, ((PyListObject*)res)->ob_item, n);
+    return res;
+}
+#endif
+
+
 /////////////// SliceTupleAndList.proto ///////////////
 
 #if CYTHON_COMPILING_IN_CPYTHON
@@ -746,6 +795,7 @@ static CYTHON_INLINE PyObject* __Pyx_PyTuple_GetSlice(PyObject* src, Py_ssize_t
 #endif
 
 /////////////// SliceTupleAndList ///////////////
+//@requires: TupleAndListFromArray
 
 #if CYTHON_COMPILING_IN_CPYTHON
 static CYTHON_INLINE void __Pyx_crop_slice(Py_ssize_t* _start, Py_ssize_t* _stop, Py_ssize_t* _length) {
@@ -766,32 +816,12 @@ static CYTHON_INLINE void __Pyx_crop_slice(Py_ssize_t* _start, Py_ssize_t* _stop
     *_stop = stop;
 }
 
-static CYTHON_INLINE void __Pyx_copy_object_array(PyObject** CYTHON_RESTRICT src, PyObject** CYTHON_RESTRICT dest, Py_ssize_t length) {
-    PyObject *v;
-    Py_ssize_t i;
-    for (i = 0; i < length; i++) {
-        v = dest[i] = src[i];
-        Py_INCREF(v);
-    }
-}
-
 {{for type in ['List', 'Tuple']}}
 static CYTHON_INLINE PyObject* __Pyx_Py{{type}}_GetSlice(
             PyObject* src, Py_ssize_t start, Py_ssize_t stop) {
-    PyObject* dest;
     Py_ssize_t length = Py{{type}}_GET_SIZE(src);
     __Pyx_crop_slice(&start, &stop, &length);
-    if (unlikely(length <= 0))
-        return Py{{type}}_New(0);
-
-    dest = Py{{type}}_New(length);
-    if (unlikely(!dest))
-        return NULL;
-    __Pyx_copy_object_array(
-        ((Py{{type}}Object*)src)->ob_item + start,
-        ((Py{{type}}Object*)dest)->ob_item,
-        length);
-    return dest;
+    return __Pyx_Py{{type}}_FromArray(((Py{{type}}Object*)src)->ob_item + start, length);
 }
 {{endfor}}
 #endif