Python/structmember.c

   1
   2 /* Map C struct members to Python object attributes */
   3
   4 #include "Python.h"
   5
   6 #include "structmember.h"
   7
   8 static PyObject *
   9 listmembers(struct memberlist *mlist)
  10 {
  11         int i, n;
  12         PyObject *v;
  13         for (n = 0; mlist[n].name != NULL; n++)
  14                 ;
  15         v = PyList_New(n);
  16         if (v != NULL) {
  17                 for (i = 0; i < n; i++)
  18                         PyList_SetItem(v, i,
  19                                        PyString_FromString(mlist[i].name));
  20                 if (PyErr_Occurred()) {
  21                         Py_DECREF(v);
  22                         v = NULL;
  23                 }
  24                 else {
  25                         PyList_Sort(v);
  26                 }
  27         }
  28         return v;
  29 }
  30
  31 PyObject *
  32 PyMember_Get(const char *addr, struct memberlist *mlist, const char *name)
  33 {
  34         struct memberlist *l;
  35
  36         if (strcmp(name, "__members__") == 0)
  37                 return listmembers(mlist);
  38         for (l = mlist; l->name != NULL; l++) {
  39                 if (strcmp(l->name, name) == 0) {
  40                         PyMemberDef copy;
  41                         copy.name = l->name;
  42                         copy.type = l->type;
  43                         copy.offset = l->offset;
  44                         copy.flags = l->flags;
  45                         copy.doc = NULL;
  46                         return PyMember_GetOne(addr, &copy);
  47                 }
  48         }
  49         PyErr_SetString(PyExc_AttributeError, name);
  50         return NULL;
  51 }
  52
  53 PyObject *
  54 PyMember_GetOne(const char *addr, PyMemberDef *l)
  55 {
  56         PyObject *v;
  57         if ((l->flags & READ_RESTRICTED) &&
  58             PyEval_GetRestricted()) {
  59                 PyErr_SetString(PyExc_RuntimeError, "restricted attribute");
  60                 return NULL;
  61         }
  62         addr += l->offset;
  63         switch (l->type) {
  64         case T_BOOL:
  65                 v = PyBool_FromLong(*(char*)addr);
  66                 break;
  67         case T_BYTE:
  68                 v = PyInt_FromLong(*(char*)addr);
  69                 break;
  70         case T_UBYTE:
  71                 v = PyLong_FromUnsignedLong(*(unsigned char*)addr);
  72                 break;
  73         case T_SHORT:
  74                 v = PyInt_FromLong(*(short*)addr);
  75                 break;
  76         case T_USHORT:
  77                 v = PyLong_FromUnsignedLong(*(unsigned short*)addr);
  78                 break;
  79         case T_INT:
  80                 v = PyInt_FromLong(*(int*)addr);
  81                 break;
  82         case T_UINT:
  83                 v = PyLong_FromUnsignedLong(*(unsigned int*)addr);
  84                 break;
  85         case T_LONG:
  86                 v = PyInt_FromLong(*(long*)addr);
  87                 break;
  88         case T_ULONG:
  89                 v = PyLong_FromUnsignedLong(*(unsigned long*)addr);
  90                 break;
  91         case T_PYSSIZET:
  92                 v = PyInt_FromSsize_t(*(Py_ssize_t*)addr);
  93                 break;
  94         case T_FLOAT:
  95                 v = PyFloat_FromDouble((double)*(float*)addr);
  96                 break;
  97         case T_DOUBLE:
  98                 v = PyFloat_FromDouble(*(double*)addr);
  99                 break;
 100         case T_STRING:
 101                 if (*(char**)addr == NULL) {
 102                         Py_INCREF(Py_None);
 103                         v = Py_None;
 104                 }
 105                 else
 106                         v = PyString_FromString(*(char**)addr);
 107                 break;
 108         case T_STRING_INPLACE:
 109                 v = PyString_FromString((char*)addr);
 110                 break;
 111         case T_CHAR:
 112                 v = PyString_FromStringAndSize((char*)addr, 1);
 113                 break;
 114         case T_OBJECT:
 115                 v = *(PyObject **)addr;
 116                 if (v == NULL)
 117                         v = Py_None;
 118                 Py_INCREF(v);
 119                 break;
 120         case T_OBJECT_EX:
 121                 v = *(PyObject **)addr;
 122                 if (v == NULL)
 123                         PyErr_SetString(PyExc_AttributeError, l->name);
 124                 Py_XINCREF(v);
 125                 break;
 126 #ifdef HAVE_LONG_LONG
 127         case T_LONGLONG:
 128                 v = PyLong_FromLongLong(*(PY_LONG_LONG *)addr);
 129                 break;
 130         case T_ULONGLONG:
 131                 v = PyLong_FromUnsignedLongLong(*(unsigned PY_LONG_LONG *)addr);
 132                 break;
 133 #endif /* HAVE_LONG_LONG */
 134         default:
 135                 PyErr_SetString(PyExc_SystemError, "bad memberdescr type");
 136                 v = NULL;
 137         }
 138         return v;
 139 }
 140
 141 int
 142 PyMember_Set(char *addr, struct memberlist *mlist, const char *name, PyObject *v)
 143 {
 144         struct memberlist *l;
 145
 146         for (l = mlist; l->name != NULL; l++) {
 147                 if (strcmp(l->name, name) == 0) {
 148                         PyMemberDef copy;
 149                         copy.name = l->name;
 150                         copy.type = l->type;
 151                         copy.offset = l->offset;
 152                         copy.flags = l->flags;
 153                         copy.doc = NULL;
 154                         return PyMember_SetOne(addr, &copy, v);
 155                 }
 156         }
 157
 158         PyErr_SetString(PyExc_AttributeError, name);
 159         return -1;
 160 }
 161
 162 #define WARN(msg)                                       \
 163     do {                                                \
 164         if (PyErr_Warn(PyExc_RuntimeWarning, msg) < 0)  \
 165                 return -1;                              \
 166     } while (0)
 167
 168 int
 169 PyMember_SetOne(char *addr, PyMemberDef *l, PyObject *v)
 170 {
 171         PyObject *oldv;
 172
 173         addr += l->offset;
 174
 175         if ((l->flags & READONLY) || l->type == T_STRING)
 176         {
 177                 PyErr_SetString(PyExc_TypeError, "readonly attribute");
 178                 return -1;
 179         }
 180         if ((l->flags & PY_WRITE_RESTRICTED) && PyEval_GetRestricted()) {
 181                 PyErr_SetString(PyExc_RuntimeError, "restricted attribute");
 182                 return -1;
 183         }
 184         if (v == NULL) {
 185                 if (l->type == T_OBJECT_EX) {
 186                         /* Check if the attribute is set. */
 187                         if (*(PyObject **)addr == NULL) {
 188                                 PyErr_SetString(PyExc_AttributeError, l->name);
 189                                 return -1;
 190                         }
 191                 }
 192                 else if (l->type != T_OBJECT) {
 193                         PyErr_SetString(PyExc_TypeError,
 194                                         "can't delete numeric/char attribute");
 195                         return -1;
 196                 }
 197         }
 198         switch (l->type) {
 199         case T_BOOL:{
 200                 if (!PyBool_Check(v)) {
 201                         PyErr_SetString(PyExc_TypeError,
 202                                         "attribute value type must be bool");
 203                         return -1;
 204                 }
 205                 if (v == Py_True)
 206                         *(char*)addr = (char) 1;
 207                 else
 208                         *(char*)addr = (char) 0;
 209                 break;
 210                 }
 211         case T_BYTE:{
 212                 long long_val = PyInt_AsLong(v);
 213                 if ((long_val == -1) && PyErr_Occurred())
 214                         return -1;
 215                 *(char*)addr = (char)long_val;
 216                 /* XXX: For compatibility, only warn about truncations
 217                    for now. */
 218                 if ((long_val > CHAR_MAX) || (long_val < CHAR_MIN))
 219                         WARN("Truncation of value to char");
 220                 break;
 221                 }
 222         case T_UBYTE:{
 223                 long long_val = PyInt_AsLong(v);
 224                 if ((long_val == -1) && PyErr_Occurred())
 225                         return -1;
 226                 *(unsigned char*)addr = (unsigned char)long_val;
 227                 if ((long_val > UCHAR_MAX) || (long_val < 0))
 228                         WARN("Truncation of value to unsigned char");
 229                 break;
 230                 }
 231         case T_SHORT:{
 232                 long long_val = PyInt_AsLong(v);
 233                 if ((long_val == -1) && PyErr_Occurred())
 234                         return -1;
 235                 *(short*)addr = (short)long_val;
 236                 if ((long_val > SHRT_MAX) || (long_val < SHRT_MIN))
 237                         WARN("Truncation of value to short");
 238                 break;
 239                 }
 240         case T_USHORT:{
 241                 long long_val = PyInt_AsLong(v);
 242                 if ((long_val == -1) && PyErr_Occurred())
 243                         return -1;
 244                 *(unsigned short*)addr = (unsigned short)long_val;
 245                 if ((long_val > USHRT_MAX) || (long_val < 0))
 246                         WARN("Truncation of value to unsigned short");
 247                 break;
 248                 }
 249         case T_INT:{
 250                 long long_val = PyInt_AsLong(v);
 251                 if ((long_val == -1) && PyErr_Occurred())
 252                         return -1;
 253                 *(int *)addr = (int)long_val;
 254                 if ((long_val > INT_MAX) || (long_val < INT_MIN))
 255                         WARN("Truncation of value to int");
 256                 break;
 257                 }
 258         case T_UINT:{
 259                 unsigned long ulong_val = PyLong_AsUnsignedLong(v);
 260                 if ((ulong_val == (unsigned int)-1) && PyErr_Occurred()) {
 261                         /* XXX: For compatibility, accept negative int values
 262                            as well. */
 263                         PyErr_Clear();
 264                         ulong_val = PyLong_AsLong(v);
 265                         if ((ulong_val == (unsigned int)-1) && PyErr_Occurred())
 266                                 return -1;
 267                         *(unsigned int *)addr = (unsigned int)ulong_val;
 268                         WARN("Writing negative value into unsigned field");
 269                 } else
 270                         *(unsigned int *)addr = (unsigned int)ulong_val;
 271                 if (ulong_val > UINT_MAX)
 272                         WARN("Truncation of value to unsigned int");
 273                 break;
 274                 }
 275         case T_LONG:{
 276                 *(long*)addr = PyLong_AsLong(v);
 277                 if ((*(long*)addr == -1) && PyErr_Occurred())
 278                         return -1;
 279                 break;
 280                 }
 281         case T_ULONG:{
 282                 *(unsigned long*)addr = PyLong_AsUnsignedLong(v);
 283                 if ((*(unsigned long*)addr == (unsigned long)-1)
 284                     && PyErr_Occurred()) {
 285                         /* XXX: For compatibility, accept negative int values
 286                            as well. */
 287                         PyErr_Clear();
 288                         *(unsigned long*)addr = PyLong_AsLong(v);
 289                         if ((*(unsigned long*)addr == (unsigned int)-1)
 290                             && PyErr_Occurred())
 291                                 return -1;
 292                         WARN("Writing negative value into unsigned field");
 293                 }
 294                 break;
 295                 }
 296         case T_PYSSIZET:{
 297                 *(Py_ssize_t*)addr = PyInt_AsSsize_t(v);
 298                 if ((*(Py_ssize_t*)addr == (Py_ssize_t)-1)
 299                     && PyErr_Occurred())
 300                                 return -1;
 301                 break;
 302                 }
 303         case T_FLOAT:{
 304                 double double_val = PyFloat_AsDouble(v);
 305                 if ((double_val == -1) && PyErr_Occurred())
 306                         return -1;
 307                 *(float*)addr = (float)double_val;
 308                 break;
 309                 }
 310         case T_DOUBLE:
 311                 *(double*)addr = PyFloat_AsDouble(v);
 312                 if ((*(double*)addr == -1) && PyErr_Occurred())
 313                         return -1;
 314                 break;
 315         case T_OBJECT:
 316         case T_OBJECT_EX:
 317                 Py_XINCREF(v);
 318                 oldv = *(PyObject **)addr;
 319                 *(PyObject **)addr = v;
 320                 Py_XDECREF(oldv);
 321                 break;
 322         case T_CHAR:
 323                 if (PyString_Check(v) && PyString_Size(v) == 1) {
 324                         *(char*)addr = PyString_AsString(v)[0];
 325                 }
 326                 else {
 327                         PyErr_BadArgument();
 328                         return -1;
 329                 }
 330                 break;
 331 #ifdef HAVE_LONG_LONG
 332         case T_LONGLONG:{
 333                 PY_LONG_LONG value;
 334                 *(PY_LONG_LONG*)addr = value = PyLong_AsLongLong(v);
 335                 if ((value == -1) && PyErr_Occurred())
 336                         return -1;
 337                 break;
 338                 }
 339         case T_ULONGLONG:{
 340                 unsigned PY_LONG_LONG value;
 341                 /* ??? PyLong_AsLongLong accepts an int, but PyLong_AsUnsignedLongLong
 342                         doesn't ??? */
 343                 if (PyLong_Check(v))
 344                         *(unsigned PY_LONG_LONG*)addr = value = PyLong_AsUnsignedLongLong(v);
 345                 else
 346                         *(unsigned PY_LONG_LONG*)addr = value = PyInt_AsLong(v);
 347                 if ((value == (unsigned PY_LONG_LONG)-1) && PyErr_Occurred())
 348                         return -1;
 349                 break;
 350                 }
 351 #endif /* HAVE_LONG_LONG */
 352         default:
 353                 PyErr_Format(PyExc_SystemError,
 354                              "bad memberdescr type for %s", l->name);
 355                 return -1;
 356         }
 357         return 0;
 358 }