Patch #1649190: Adding support for _Bool to ctypes as c_bool, by David Remahl.

Author: Thomas Heller

Doc/lib/libctypes.tex

@@ -2294,6 +2294,12 @@ \subsubsection{Fundamental data types\label{ctypes-fundamental-data-types}}
 an integer address, or a string.
 \end{classdesc*}
 
+\begin{classdesc*}{c_bool}
+Represent the C \code{bool} datatype (more accurately, _Bool from C99).
+Its value can be True or False, and the constructor accepts any object that
+has a truth value.
+\end{classdesc*}
+
 \begin{classdesc*}{HRESULT}
 Windows only: Represents a \class{HRESULT} value, which contains success
 or error information for a function or method call.

Lib/ctypes/__init__.py

@@ -233,6 +233,9 @@ class c_void_p(_SimpleCData):
 c_voidp = c_void_p # backwards compatibility (to a bug)
 _check_size(c_void_p)
 
+class c_bool(_SimpleCData):
+	_type_ = "t"
+
 # This cache maps types to pointers to them.
 _pointer_type_cache = {}
 

Lib/ctypes/test/test_numbers.py

@@ -24,6 +24,8 @@ def valid_ranges(*types):
 unsigned_types = [c_ubyte, c_ushort, c_uint, c_ulong]
 signed_types = [c_byte, c_short, c_int, c_long, c_longlong]
 
+bool_types = []
+
 float_types = [c_double, c_float]
 
 try:
@@ -35,8 +37,16 @@ def valid_ranges(*types):
     unsigned_types.append(c_ulonglong)
     signed_types.append(c_longlong)
 
+try:
+    c_bool
+except NameError:
+    pass
+else:
+    bool_types.append(c_bool)
+
 unsigned_ranges = valid_ranges(*unsigned_types)
 signed_ranges = valid_ranges(*signed_types)
+bool_values = [True, False, 0, 1, -1, 5000, 'test', [], [1]]
 
 ################################################################
 
@@ -59,6 +69,11 @@ def test_signed_values(self):
         for t, (l, h) in zip(signed_types, signed_ranges):
             self.failUnlessEqual(t(l).value, l)
             self.failUnlessEqual(t(h).value, h)
+    
+    def test_bool_values(self):
+        from operator import truth
+        for t, v in zip(bool_types, bool_values):
+            self.failUnlessEqual(t(v).value, truth(v))
 
     def test_typeerror(self):
         # Only numbers are allowed in the contructor,
@@ -82,7 +97,7 @@ def test_from_param(self):
 
     def test_byref(self):
         # calling byref returns also a PyCArgObject instance
-        for t in signed_types + unsigned_types + float_types:
+        for t in signed_types + unsigned_types + float_types + bool_types:
             parm = byref(t())
             self.failUnlessEqual(ArgType, type(parm))
 
@@ -101,7 +116,7 @@ def test_integers(self):
             self.assertRaises(TypeError, t, 3.14)
 
     def test_sizes(self):
-        for t in signed_types + unsigned_types + float_types:
+        for t in signed_types + unsigned_types + float_types + bool_types:
             size = struct.calcsize(t._type_)
             # sizeof of the type...
             self.failUnlessEqual(sizeof(t), size)
@@ -163,6 +178,18 @@ def test_char_from_address(self):
 
         a[0] = '?'
         self.failUnlessEqual(v.value, a[0])
+    
+    # array does not support c_bool / 't'
+    # def test_bool_from_address(self):
+    #     from ctypes import c_bool
+    #     from array import array
+    #     a = array(c_bool._type_, [True])
+    #     v = t.from_address(a.buffer_info()[0])
+    #     self.failUnlessEqual(v.value, a[0])
+    #     self.failUnlessEqual(type(v) is t)
+    #     a[0] = False
+    #     self.failUnlessEqual(v.value, a[0])
+    #     self.failUnlessEqual(type(v) is t)
 
     def test_init(self):
         # c_int() can be initialized from Python's int, and c_int.

Lib/ctypes/test/test_repr.py

@@ -4,7 +4,7 @@
 subclasses = []
 for base in [c_byte, c_short, c_int, c_long, c_longlong,
         c_ubyte, c_ushort, c_uint, c_ulong, c_ulonglong,
-        c_float, c_double]:
+        c_float, c_double, c_bool]:
     class X(base):
         pass
     subclasses.append(X)

Misc/NEWS

@@ -168,6 +168,8 @@ Core and builtins
 Library
 -------
 
+- Patch #1649190: Adding support for _Bool to ctypes as c_bool.
+
 - Patch #1530482: add pydoc.render_doc() which returns the documentation
   for a thing instead of paging it to stdout, which pydoc.doc() does.
 

Modules/_ctypes/_ctypes.c

@@ -1101,7 +1101,7 @@ _type_ attribute.
 
 */
 
-static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOv";
+static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOvt";
 
 static PyObject *
 c_wchar_p_from_param(PyObject *type, PyObject *value)

Modules/_ctypes/cfield.c

@@ -725,6 +725,35 @@ vBOOL_get(void *ptr, unsigned size)
 }
 #endif
 
+#ifdef HAVE_C99_BOOL
+#define BOOL_TYPE _Bool
+#else
+#define BOOL_TYPE char
+#undef SIZEOF__BOOL
+#define SIZEOF__BOOL 1
+#endif
+
+static PyObject *
+t_set(void *ptr, PyObject *value, unsigned size)
+{
+	switch (PyObject_IsTrue(value)) {
+	case -1:
+		return NULL;
+	case 0:
+		*(BOOL_TYPE *)ptr = 0;
+		_RET(value);
+	default:
+		*(BOOL_TYPE *)ptr = 1;
+		_RET(value);
+	}
+}
+
+static PyObject *
+t_get(void *ptr, unsigned size)
+{
+	return PyBool_FromLong((long)*(BOOL_TYPE *)ptr);
+}
+
 static PyObject *
 I_set(void *ptr, PyObject *value, unsigned size)
 {
@@ -1585,6 +1614,17 @@ static struct fielddesc formattable[] = {
 	{ 'X', BSTR_set, BSTR_get, &ffi_type_pointer},
 	{ 'v', vBOOL_set, vBOOL_get, &ffi_type_sshort},
 #endif
+#if SIZEOF__BOOL == 1
+	{ 't', t_set, t_get, &ffi_type_uchar}, /* Also fallback for no native _Bool support */
+#elif SIZEOF__BOOL == SIZEOF_SHORT
+	{ 't', t_set, t_get, &ffi_type_ushort},
+#elif SIZEOF__BOOL == SIZEOF_INT
+	{ 't', t_set, t_get, &ffi_type_uint, I_set_sw, I_get_sw},
+#elif SIZEOF__BOOL == SIZEOF_LONG
+	{ 't', t_set, t_get, &ffi_type_ulong, L_set_sw, L_get_sw},
+#elif SIZEOF__BOOL == SIZEOF_LONG_LONG
+	{ 't', t_set, t_get, &ffi_type_ulong, Q_set_sw, Q_get_sw},
+#endif /* SIZEOF__BOOL */
 	{ 'O', O_set, O_get, &ffi_type_pointer},
 	{ 0, NULL, NULL, NULL},
 };