Doc/includes/noddy4.c

   1 #include <Python.h>
   2 #include "structmember.h"
   3
   4 typedef struct {
   5     PyObject_HEAD
   6     PyObject *first;
   7     PyObject *last;
   8     int number;
   9 } Noddy;
  10
  11 static int
  12 Noddy_traverse(Noddy *self, visitproc visit, void *arg)
  13 {
  14     int vret;
  15
  16     if (self->first) {
  17         vret = visit(self->first, arg);
  18         if (vret != 0)
  19             return vret;
  20     }
  21     if (self->last) {
  22         vret = visit(self->last, arg);
  23         if (vret != 0)
  24             return vret;
  25     }
  26
  27     return 0;
  28 }
  29
  30 static int
  31 Noddy_clear(Noddy *self)
  32 {
  33     PyObject *tmp;
  34
  35     tmp = self->first;
  36     self->first = NULL;
  37     Py_XDECREF(tmp);
  38
  39     tmp = self->last;
  40     self->last = NULL;
  41     Py_XDECREF(tmp);
  42
  43     return 0;
  44 }
  45
  46 static void
  47 Noddy_dealloc(Noddy* self)
  48 {
  49     Noddy_clear(self);
  50     self->ob_type->tp_free((PyObject*)self);
  51 }
  52
  53 static PyObject *
  54 Noddy_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  55 {
  56     Noddy *self;
  57
  58     self = (Noddy *)type->tp_alloc(type, 0);
  59     if (self != NULL) {
  60         self->first = PyString_FromString("");
  61         if (self->first == NULL)
  62           {
  63             Py_DECREF(self);
  64             return NULL;
  65           }
  66
  67         self->last = PyString_FromString("");
  68         if (self->last == NULL)
  69           {
  70             Py_DECREF(self);
  71             return NULL;
  72           }
  73
  74         self->number = 0;
  75     }
  76
  77     return (PyObject *)self;
  78 }
  79
  80 static int
  81 Noddy_init(Noddy *self, PyObject *args, PyObject *kwds)
  82 {
  83     PyObject *first=NULL, *last=NULL, *tmp;
  84
  85     static char *kwlist[] = {"first", "last", "number", NULL};
  86
  87     if (! PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
  88                                       &first, &last,
  89                                       &self->number))
  90         return -1;
  91
  92     if (first) {
  93         tmp = self->first;
  94         Py_INCREF(first);
  95         self->first = first;
  96         Py_XDECREF(tmp);
  97     }
  98
  99     if (last) {
 100         tmp = self->last;
 101         Py_INCREF(last);
 102         self->last = last;
 103         Py_XDECREF(tmp);
 104     }
 105
 106     return 0;
 107 }
 108
 109
 110 static PyMemberDef Noddy_members[] = {
 111     {"first", T_OBJECT_EX, offsetof(Noddy, first), 0,
 112      "first name"},
 113     {"last", T_OBJECT_EX, offsetof(Noddy, last), 0,
 114      "last name"},
 115     {"number", T_INT, offsetof(Noddy, number), 0,
 116      "noddy number"},
 117     {NULL}  /* Sentinel */
 118 };
 119
 120 static PyObject *
 121 Noddy_name(Noddy* self)
 122 {
 123     static PyObject *format = NULL;
 124     PyObject *args, *result;
 125
 126     if (format == NULL) {
 127         format = PyString_FromString("%s %s");
 128         if (format == NULL)
 129             return NULL;
 130     }
 131
 132     if (self->first == NULL) {
 133         PyErr_SetString(PyExc_AttributeError, "first");
 134         return NULL;
 135     }
 136
 137     if (self->last == NULL) {
 138         PyErr_SetString(PyExc_AttributeError, "last");
 139         return NULL;
 140     }
 141
 142     args = Py_BuildValue("OO", self->first, self->last);
 143     if (args == NULL)
 144         return NULL;
 145
 146     result = PyString_Format(format, args);
 147     Py_DECREF(args);
 148
 149     return result;
 150 }
 151
 152 static PyMethodDef Noddy_methods[] = {
 153     {"name", (PyCFunction)Noddy_name, METH_NOARGS,
 154      "Return the name, combining the first and last name"
 155     },
 156     {NULL}  /* Sentinel */
 157 };
 158
 159 static PyTypeObject NoddyType = {
 160     PyObject_HEAD_INIT(NULL)
 161     0,                         /*ob_size*/
 162     "noddy.Noddy",             /*tp_name*/
 163     sizeof(Noddy),             /*tp_basicsize*/
 164     0,                         /*tp_itemsize*/
 165     (destructor)Noddy_dealloc, /*tp_dealloc*/
 166     0,                         /*tp_print*/
 167     0,                         /*tp_getattr*/
 168     0,                         /*tp_setattr*/
 169     0,                         /*tp_compare*/
 170     0,                         /*tp_repr*/
 171     0,                         /*tp_as_number*/
 172     0,                         /*tp_as_sequence*/
 173     0,                         /*tp_as_mapping*/
 174     0,                         /*tp_hash */
 175     0,                         /*tp_call*/
 176     0,                         /*tp_str*/
 177     0,                         /*tp_getattro*/
 178     0,                         /*tp_setattro*/
 179     0,                         /*tp_as_buffer*/
 180     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, /*tp_flags*/
 181     "Noddy objects",           /* tp_doc */
 182     (traverseproc)Noddy_traverse,   /* tp_traverse */
 183     (inquiry)Noddy_clear,           /* tp_clear */
 184     0,                         /* tp_richcompare */
 185     0,                         /* tp_weaklistoffset */
 186     0,                         /* tp_iter */
 187     0,                         /* tp_iternext */
 188     Noddy_methods,             /* tp_methods */
 189     Noddy_members,             /* tp_members */
 190     0,                         /* tp_getset */
 191     0,                         /* tp_base */
 192     0,                         /* tp_dict */
 193     0,                         /* tp_descr_get */
 194     0,                         /* tp_descr_set */
 195     0,                         /* tp_dictoffset */
 196     (initproc)Noddy_init,      /* tp_init */
 197     0,                         /* tp_alloc */
 198     Noddy_new,                 /* tp_new */
 199 };
 200
 201 static PyMethodDef module_methods[] = {
 202     {NULL}  /* Sentinel */
 203 };
 204
 205 #ifndef PyMODINIT_FUNC  /* declarations for DLL import/export */
 206 #define PyMODINIT_FUNC void
 207 #endif
 208 PyMODINIT_FUNC
 209 initnoddy4(void)
 210 {
 211     PyObject* m;
 212
 213     if (PyType_Ready(&NoddyType) < 0)
 214         return;
 215
 216     m = Py_InitModule3("noddy4", module_methods,
 217                        "Example module that creates an extension type.");
 218
 219     if (m == NULL)
 220       return;
 221
 222     Py_INCREF(&NoddyType);
 223     PyModule_AddObject(m, "Noddy", (PyObject *)&NoddyType);
 224 }