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