Objects/boolobject.c

   1 /* Boolean type, a subtype of int */
   2
   3 #include "Python.h"
   4
   5 /* We need to define bool_print to override int_print */
   6
   7 static int
   8 bool_print(PyBoolObject *self, FILE *fp, int flags)
   9 {
  10         Py_BEGIN_ALLOW_THREADS
  11         fputs(self->ob_ival == 0 ? "False" : "True", fp);
  12         Py_END_ALLOW_THREADS
  13         return 0;
  14 }
  15
  16 /* We define bool_repr to return "False" or "True" */
  17
  18 static PyObject *false_str = NULL;
  19 static PyObject *true_str = NULL;
  20
  21 static PyObject *
  22 bool_repr(PyBoolObject *self)
  23 {
  24         PyObject *s;
  25
  26         if (self->ob_ival)
  27                 s = true_str ? true_str :
  28                         (true_str = PyString_InternFromString("True"));
  29         else
  30                 s = false_str ? false_str :
  31                         (false_str = PyString_InternFromString("False"));
  32         Py_XINCREF(s);
  33         return s;
  34 }
  35
  36 /* Function to return a bool from a C long */
  37
  38 PyObject *PyBool_FromLong(long ok)
  39 {
  40         PyObject *result;
  41
  42         if (ok)
  43                 result = Py_True;
  44         else
  45                 result = Py_False;
  46         Py_INCREF(result);
  47         return result;
  48 }
  49
  50 /* We define bool_new to always return either Py_True or Py_False */
  51
  52 static PyObject *
  53 bool_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  54 {
  55         static char *kwlist[] = {"x", 0};
  56         PyObject *x = Py_False;
  57         long ok;
  58
  59         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|O:bool", kwlist, &x))
  60                 return NULL;
  61         ok = PyObject_IsTrue(x);
  62         if (ok < 0)
  63                 return NULL;
  64         return PyBool_FromLong(ok);
  65 }
  66
  67 /* Arithmetic operations redefined to return bool if both args are bool. */
  68
  69 static PyObject *
  70 bool_and(PyObject *a, PyObject *b)
  71 {
  72         if (!PyBool_Check(a) || !PyBool_Check(b))
  73                 return PyInt_Type.tp_as_number->nb_and(a, b);
  74         return PyBool_FromLong(
  75                 ((PyBoolObject *)a)->ob_ival & ((PyBoolObject *)b)->ob_ival);
  76 }
  77
  78 static PyObject *
  79 bool_or(PyObject *a, PyObject *b)
  80 {
  81         if (!PyBool_Check(a) || !PyBool_Check(b))
  82                 return PyInt_Type.tp_as_number->nb_or(a, b);
  83         return PyBool_FromLong(
  84                 ((PyBoolObject *)a)->ob_ival | ((PyBoolObject *)b)->ob_ival);
  85 }
  86
  87 static PyObject *
  88 bool_xor(PyObject *a, PyObject *b)
  89 {
  90         if (!PyBool_Check(a) || !PyBool_Check(b))
  91                 return PyInt_Type.tp_as_number->nb_xor(a, b);
  92         return PyBool_FromLong(
  93                 ((PyBoolObject *)a)->ob_ival ^ ((PyBoolObject *)b)->ob_ival);
  94 }
  95
  96 /* Doc string */
  97
  98 PyDoc_STRVAR(bool_doc,
  99 "bool(x) -> bool\n\
 100 \n\
 101 Returns True when the argument x is true, False otherwise.\n\
 102 The builtins True and False are the only two instances of the class bool.\n\
 103 The class bool is a subclass of the class int, and cannot be subclassed.");
 104
 105 /* Arithmetic methods -- only so we can override &, |, ^. */
 106
 107 static PyNumberMethods bool_as_number = {
 108         0,                      /* nb_add */
 109         0,                      /* nb_subtract */
 110         0,                      /* nb_multiply */
 111         0,                      /* nb_divide */
 112         0,                      /* nb_remainder */
 113         0,                      /* nb_divmod */
 114         0,                      /* nb_power */
 115         0,                      /* nb_negative */
 116         0,                      /* nb_positive */
 117         0,                      /* nb_absolute */
 118         0,                      /* nb_nonzero */
 119         0,                      /* nb_invert */
 120         0,                      /* nb_lshift */
 121         0,                      /* nb_rshift */
 122         bool_and,               /* nb_and */
 123         bool_xor,               /* nb_xor */
 124         bool_or,                /* nb_or */
 125         0,                      /* nb_coerce */
 126         0,                      /* nb_int */
 127         0,                      /* nb_long */
 128         0,                      /* nb_float */
 129         0,                      /* nb_oct */
 130         0,                      /* nb_hex */
 131         0,                      /* nb_inplace_add */
 132         0,                      /* nb_inplace_subtract */
 133         0,                      /* nb_inplace_multiply */
 134         0,                      /* nb_inplace_divide */
 135         0,                      /* nb_inplace_remainder */
 136         0,                      /* nb_inplace_power */
 137         0,                      /* nb_inplace_lshift */
 138         0,                      /* nb_inplace_rshift */
 139         0,                      /* nb_inplace_and */
 140         0,                      /* nb_inplace_xor */
 141         0,                      /* nb_inplace_or */
 142         0,                      /* nb_floor_divide */
 143         0,                      /* nb_true_divide */
 144         0,                      /* nb_inplace_floor_divide */
 145         0,                      /* nb_inplace_true_divide */
 146 };
 147
 148 /* The type object for bool.  Note that this cannot be subclassed! */
 149
 150 PyTypeObject PyBool_Type = {
 151         PyVarObject_HEAD_INIT(&PyType_Type, 0)
 152         "bool",
 153         sizeof(PyIntObject),
 154         0,
 155         0,                                      /* tp_dealloc */
 156         (printfunc)bool_print,                  /* tp_print */
 157         0,                                      /* tp_getattr */
 158         0,                                      /* tp_setattr */
 159         0,                                      /* tp_compare */
 160         (reprfunc)bool_repr,                    /* tp_repr */
 161         &bool_as_number,                        /* tp_as_number */
 162         0,                                      /* tp_as_sequence */
 163         0,                                      /* tp_as_mapping */
 164         0,                                      /* tp_hash */
 165         0,                                      /* tp_call */
 166         (reprfunc)bool_repr,                    /* tp_str */
 167         0,                                      /* tp_getattro */
 168         0,                                      /* tp_setattro */
 169         0,                                      /* tp_as_buffer */
 170         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES, /* tp_flags */
 171         bool_doc,                               /* tp_doc */
 172         0,                                      /* tp_traverse */
 173         0,                                      /* tp_clear */
 174         0,                                      /* tp_richcompare */
 175         0,                                      /* tp_weaklistoffset */
 176         0,                                      /* tp_iter */
 177         0,                                      /* tp_iternext */
 178         0,                                      /* tp_methods */
 179         0,                                      /* tp_members */
 180         0,                                      /* tp_getset */
 181         &PyInt_Type,                            /* tp_base */
 182         0,                                      /* tp_dict */
 183         0,                                      /* tp_descr_get */
 184         0,                                      /* tp_descr_set */
 185         0,                                      /* tp_dictoffset */
 186         0,                                      /* tp_init */
 187         0,                                      /* tp_alloc */
 188         bool_new,                               /* tp_new */
 189 };
 190
 191 /* The objects representing bool values False and True */
 192
 193 /* Named Zero for link-level compatibility */
 194 PyIntObject _Py_ZeroStruct = {
 195         PyObject_HEAD_INIT(&PyBool_Type)
 196         0
 197 };
 198
 199 PyIntObject _Py_TrueStruct = {
 200         PyObject_HEAD_INIT(&PyBool_Type)
 201         1
 202 };