youknowone
diff --git a/‎Lib/ctypes/__init__.py‎
Lines changed: 90 additions & 10 deletions b/‎Lib/ctypes/__init__.py‎
Lines changed: 90 additions & 10 deletions
@@ -14,14 +14,15 @@
 from _ctypes import RTLD_LOCAL, RTLD_GLOBAL
 from _ctypes import ArgumentError
 from _ctypes import SIZEOF_TIME_T
+from _ctypes import CField
 
 from struct import calcsize as _calcsize
 
 if __version__ != _ctypes_version:
     raise Exception("Version number mismatch", __version__, _ctypes_version)
 
 if _os.name == "nt":
-    from _ctypes import FormatError
+    from _ctypes import COMError, CopyComPointer, FormatError
 
 DEFAULT_MODE = RTLD_LOCAL
 if _os.name == "posix" and _sys.platform == "darwin":
@@ -208,6 +209,18 @@ class c_longdouble(_SimpleCData):
 if sizeof(c_longdouble) == sizeof(c_double):
     c_longdouble = c_double
 
+try:
+    class c_double_complex(_SimpleCData):
+        _type_ = "D"
+    _check_size(c_double_complex)
+    class c_float_complex(_SimpleCData):
+        _type_ = "F"
+    _check_size(c_float_complex)
+    class c_longdouble_complex(_SimpleCData):
+        _type_ = "G"
+except AttributeError:
+    pass
+
 if _calcsize("l") == _calcsize("q"):
     # if long and long long have the same size, make c_longlong an alias for c_long
     c_longlong = c_long
@@ -255,7 +268,72 @@ class c_void_p(_SimpleCData):
 class c_bool(_SimpleCData):
     _type_ = "?"
 
-from _ctypes import POINTER, pointer, _pointer_type_cache
+def POINTER(cls):
+    """Create and return a new ctypes pointer type.
+
+    Pointer types are cached and reused internally,
+    so calling this function repeatedly is cheap.
+    """
+    if cls is None:
+        return c_void_p
+    try:
+        return cls.__pointer_type__
+    except AttributeError:
+        pass
+    if isinstance(cls, str):
+        # handle old-style incomplete types (see test_ctypes.test_incomplete)
+        import warnings
+        warnings._deprecated("ctypes.POINTER with string", remove=(3, 19))
+        try:
+            return _pointer_type_cache_fallback[cls]
+        except KeyError:
+            result = type(f'LP_{cls}', (_Pointer,), {})
+            _pointer_type_cache_fallback[cls] = result
+            return result
+
+    # create pointer type and set __pointer_type__ for cls
+    return type(f'LP_{cls.__name__}', (_Pointer,), {'_type_': cls})
+
+def pointer(obj):
+    """Create a new pointer instance, pointing to 'obj'.
+
+    The returned object is of the type POINTER(type(obj)). Note that if you
+    just want to pass a pointer to an object to a foreign function call, you
+    should use byref(obj) which is much faster.
+    """
+    typ = POINTER(type(obj))
+    return typ(obj)
+
+class _PointerTypeCache:
+    def __setitem__(self, cls, pointer_type):
+        import warnings
+        warnings._deprecated("ctypes._pointer_type_cache", remove=(3, 19))
+        try:
+            cls.__pointer_type__ = pointer_type
+        except AttributeError:
+            _pointer_type_cache_fallback[cls] = pointer_type
+
+    def __getitem__(self, cls):
+        import warnings
+        warnings._deprecated("ctypes._pointer_type_cache", remove=(3, 19))
+        try:
+            return cls.__pointer_type__
+        except AttributeError:
+            return _pointer_type_cache_fallback[cls]
+
+    def get(self, cls, default=None):
+        import warnings
+        warnings._deprecated("ctypes._pointer_type_cache", remove=(3, 19))
+        try:
+            return cls.__pointer_type__
+        except AttributeError:
+            return _pointer_type_cache_fallback.get(cls, default)
+
+    def __contains__(self, cls):
+        return hasattr(cls, '__pointer_type__')
+
+_pointer_type_cache_fallback = {}
+_pointer_type_cache = _PointerTypeCache()
 
 class c_wchar_p(_SimpleCData):
     _type_ = "Z"
@@ -266,15 +344,14 @@ class c_wchar(_SimpleCData):
     _type_ = "u"
 
 def _reset_cache():
-    _pointer_type_cache.clear()
+    _pointer_type_cache_fallback.clear()
     _c_functype_cache.clear()
     if _os.name == "nt":
         _win_functype_cache.clear()
     # _SimpleCData.c_wchar_p_from_param
     POINTER(c_wchar).from_param = c_wchar_p.from_param
     # _SimpleCData.c_char_p_from_param
     POINTER(c_char).from_param = c_char_p.from_param
-    _pointer_type_cache[None] = c_void_p
 
 def create_unicode_buffer(init, size=None):
     """create_unicode_buffer(aString) -> character array
@@ -308,13 +385,7 @@ def create_unicode_buffer(init, size=None):
 def SetPointerType(pointer, cls):
     import warnings
     warnings._deprecated("ctypes.SetPointerType", remove=(3, 15))
-    if _pointer_type_cache.get(cls, None) is not None:
-        raise RuntimeError("This type already exists in the cache")
-    if id(pointer) not in _pointer_type_cache:
-        raise RuntimeError("What's this???")
     pointer.set_type(cls)
-    _pointer_type_cache[cls] = pointer
-    del _pointer_type_cache[id(pointer)]
 
 def ARRAY(typ, len):
     return typ * len
@@ -521,6 +592,7 @@ def WinError(code=None, descr=None):
 # functions
 
 from _ctypes import _memmove_addr, _memset_addr, _string_at_addr, _cast_addr
+from _ctypes import _memoryview_at_addr
 
 ## void *memmove(void *, const void *, size_t);
 memmove = CFUNCTYPE(c_void_p, c_void_p, c_void_p, c_size_t)(_memmove_addr)
@@ -546,6 +618,14 @@ def string_at(ptr, size=-1):
     Return the byte string at void *ptr."""
     return _string_at(ptr, size)
 
+_memoryview_at = PYFUNCTYPE(
+    py_object, c_void_p, c_ssize_t, c_int)(_memoryview_at_addr)
+def memoryview_at(ptr, size, readonly=False):
+    """memoryview_at(ptr, size[, readonly]) -> memoryview
+
+    Return a memoryview representing the memory at void *ptr."""
+    return _memoryview_at(ptr, size, bool(readonly))
+
 try:
     from _ctypes import _wstring_at_addr
 except ImportError: