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_BYTE:
  65                 v = PyInt_FromLong(*(char*)addr);
  66                 break;
  67         case T_UBYTE:
  68                 v = PyLong_FromUnsignedLong(*(unsigned char*)addr);
  69                 break;
  70         case T_SHORT:
  71                 v = PyInt_FromLong(*(short*)addr);
  72                 break;
  73         case T_USHORT:
  74                 v = PyLong_FromUnsignedLong(*(unsigned short*)addr);
  75                 break;
  76         case T_INT:
  77                 v = PyInt_FromLong(*(int*)addr);
  78                 break;
  79         case T_UINT:
  80                 v = PyLong_FromUnsignedLong(*(unsigned int*)addr);
  81                 break;
  82         case T_LONG:
  83                 v = PyInt_FromLong(*(long*)addr);
  84                 break;
  85         case T_ULONG:
  86                 v = PyLong_FromUnsignedLong(*(unsigned long*)addr);
  87                 break;
  88         case T_PYSSIZET:
  89                 v = PyInt_FromSsize_t(*(Py_ssize_t*)addr);
  90                 break;
  91         case T_FLOAT:
  92                 v = PyFloat_FromDouble((double)*(float*)addr);
  93                 break;
  94         case T_DOUBLE:
  95                 v = PyFloat_FromDouble(*(double*)addr);
  96                 break;
  97         case T_STRING:
  98                 if (*(char**)addr == NULL) {
  99                         Py_INCREF(Py_None);
 100                         v = Py_None;
 101                 }
 102                 else
 103                         v = PyString_FromString(*(char**)addr);
 104                 break;
 105         case T_STRING_INPLACE:
 106                 v = PyString_FromString((char*)addr);
 107                 break;
 108         case T_CHAR:
 109                 v = PyString_FromStringAndSize((char*)addr, 1);
 110                 break;
 111         case T_OBJECT:
 112                 v = *(PyObject **)addr;
 113                 if (v == NULL)
 114                         v = Py_None;
 115                 Py_INCREF(v);
 116                 break;
 117         case T_OBJECT_EX:
 118                 v = *(PyObject **)addr;
 119                 if (v == NULL)
 120                         PyErr_SetString(PyExc_AttributeError, l->name);
 121                 Py_XINCREF(v);
 122                 break;
 123 #ifdef HAVE_LONG_LONG
 124         case T_LONGLONG:
 125                 v = PyLong_FromLongLong(*(PY_LONG_LONG *)addr);
 126                 break;
 127         case T_ULONGLONG:
 128                 v = PyLong_FromUnsignedLongLong(*(unsigned PY_LONG_LONG *)addr);
 129                 break;
 130 #endif /* HAVE_LONG_LONG */
 131         default:
 132                 PyErr_SetString(PyExc_SystemError, "bad memberdescr type");
 133                 v = NULL;
 134         }
 135         return v;
 136 }
 137
 138 int
 139 PyMember_Set(char *addr, struct memberlist *mlist, const char *name, PyObject *v)
 140 {
 141         struct memberlist *l;
 142
 143         for (l = mlist; l->name != NULL; l++) {
 144                 if (strcmp(l->name, name) == 0) {
 145                         PyMemberDef copy;
 146                         copy.name = l->name;
 147                         copy.type = l->type;
 148                         copy.offset = l->offset;
 149                         copy.flags = l->flags;
 150                         copy.doc = NULL;
 151                         return PyMember_SetOne(addr, &copy, v);
 152                 }
 153         }
 154
 155         PyErr_SetString(PyExc_AttributeError, name);
 156         return -1;
 157 }
 158
 159 #define WARN(msg)                                       \
 160     do {                                                \
 161         if (PyErr_Warn(PyExc_RuntimeWarning, msg) < 0)  \
 162                 return -1;                              \
 163     } while (0)
 164
 165 int
 166 PyMember_SetOne(char *addr, PyMemberDef *l, PyObject *v)
 167 {
 168         PyObject *oldv;
 169
 170         if ((l->flags & READONLY) || l->type == T_STRING)
 171         {
 172                 PyErr_SetString(PyExc_TypeError, "readonly attribute");
 173                 return -1;
 174         }
 175         if ((l->flags & WRITE_RESTRICTED) && PyEval_GetRestricted()) {
 176                 PyErr_SetString(PyExc_RuntimeError, "restricted attribute");
 177                 return -1;
 178         }
 179         if (v == NULL && l->type != T_OBJECT_EX && l->type != T_OBJECT) {
 180                 PyErr_SetString(PyExc_TypeError,
 181                                 "can't delete numeric/char attribute");
 182                 return -1;
 183         }
 184         addr += l->offset;
 185         switch (l->type) {
 186         case T_BYTE:{
 187                 long long_val = PyInt_AsLong(v);
 188                 if ((long_val == -1) && PyErr_Occurred())
 189                         return -1;
 190                 *(char*)addr = (char)long_val;
 191                 /* XXX: For compatibility, only warn about truncations
 192                    for now. */
 193                 if ((long_val > CHAR_MAX) || (long_val < CHAR_MIN))
 194                         WARN("Truncation of value to char");
 195                 break;
 196                 }
 197         case T_UBYTE:{
 198                 long long_val = PyInt_AsLong(v);
 199                 if ((long_val == -1) && PyErr_Occurred())
 200                         return -1;
 201                 *(unsigned char*)addr = (unsigned char)long_val;
 202                 if ((long_val > UCHAR_MAX) || (long_val < 0))
 203                         WARN("Truncation of value to unsigned char");
 204                 break;
 205                 }
 206         case T_SHORT:{
 207                 long long_val = PyInt_AsLong(v);
 208                 if ((long_val == -1) && PyErr_Occurred())
 209                         return -1;
 210                 *(short*)addr = (short)long_val;
 211                 if ((long_val > SHRT_MAX) || (long_val < SHRT_MIN))
 212                         WARN("Truncation of value to short");
 213                 break;
 214                 }
 215         case T_USHORT:{
 216                 long long_val = PyInt_AsLong(v);
 217                 if ((long_val == -1) && PyErr_Occurred())
 218                         return -1;
 219                 *(unsigned short*)addr = (unsigned short)long_val;
 220                 if ((long_val > USHRT_MAX) || (long_val < 0))
 221                         WARN("Truncation of value to unsigned short");
 222                 break;
 223                 }
 224         case T_INT:{
 225                 long long_val = PyInt_AsLong(v);
 226                 if ((long_val == -1) && PyErr_Occurred())
 227                         return -1;
 228                 *(int *)addr = (int)long_val;
 229                 if ((long_val > INT_MAX) || (long_val < INT_MIN))
 230                         WARN("Truncation of value to int");
 231                 break;
 232                 }
 233         case T_UINT:{
 234                 unsigned long ulong_val = PyLong_AsUnsignedLong(v);
 235                 if ((ulong_val == (unsigned int)-1) && PyErr_Occurred()) {
 236                         /* XXX: For compatibility, accept negative int values
 237                            as well. */
 238                         PyErr_Clear();
 239                         ulong_val = PyLong_AsLong(v);
 240                         if ((ulong_val == (unsigned int)-1) && PyErr_Occurred())
 241                                 return -1;
 242                         *(unsigned int *)addr = (unsigned int)ulong_val;
 243                         WARN("Writing negative value into unsigned field");
 244                 } else
 245                         *(unsigned int *)addr = (unsigned int)ulong_val;
 246                 if (ulong_val > UINT_MAX)
 247                         WARN("Truncation of value to unsigned int");
 248                 break;
 249                 }
 250         case T_LONG:{
 251                 *(long*)addr = PyLong_AsLong(v);
 252                 if ((*(long*)addr == -1) && PyErr_Occurred())
 253                         return -1;
 254                 break;
 255                 }
 256         case T_ULONG:{
 257                 *(unsigned long*)addr = PyLong_AsUnsignedLong(v);
 258                 if ((*(unsigned long*)addr == (unsigned long)-1)
 259                     && PyErr_Occurred()) {
 260                         /* XXX: For compatibility, accept negative int values
 261                            as well. */
 262                         PyErr_Clear();
 263                         *(unsigned long*)addr = PyLong_AsLong(v);
 264                         if ((*(unsigned long*)addr == (unsigned int)-1)
 265                             && PyErr_Occurred())
 266                                 return -1;
 267                         WARN("Writing negative value into unsigned field");
 268                 }
 269                 break;
 270                 }
 271         case T_PYSSIZET:{
 272                 *(Py_ssize_t*)addr = PyInt_AsSsize_t(v);
 273                 if ((*(Py_ssize_t*)addr == (Py_ssize_t)-1)
 274                     && PyErr_Occurred())
 275                                 return -1;
 276                 break;
 277                 }
 278         case T_FLOAT:{
 279                 double double_val = PyFloat_AsDouble(v);
 280                 if ((double_val == -1) && PyErr_Occurred())
 281                         return -1;
 282                 *(float*)addr = (float)double_val;
 283                 break;
 284                 }
 285         case T_DOUBLE:
 286                 *(double*)addr = PyFloat_AsDouble(v);
 287                 if ((*(double*)addr == -1) && PyErr_Occurred())
 288                         return -1;
 289                 break;
 290         case T_OBJECT:
 291         case T_OBJECT_EX:
 292                 Py_XINCREF(v);
 293                 oldv = *(PyObject **)addr;
 294                 *(PyObject **)addr = v;
 295                 Py_XDECREF(oldv);
 296                 break;
 297         case T_CHAR:
 298                 if (PyString_Check(v) && PyString_Size(v) == 1) {
 299                         *(char*)addr = PyString_AsString(v)[0];
 300                 }
 301                 else {
 302                         PyErr_BadArgument();
 303                         return -1;
 304                 }
 305                 break;
 306 #ifdef HAVE_LONG_LONG
 307         case T_LONGLONG:{
 308                 PY_LONG_LONG value;
 309                 *(PY_LONG_LONG*)addr = value = PyLong_AsLongLong(v);
 310                 if ((value == -1) && PyErr_Occurred())
 311                         return -1;
 312                 break;
 313                 }
 314         case T_ULONGLONG:{
 315                 unsigned PY_LONG_LONG value;
 316                 /* ??? PyLong_AsLongLong accepts an int, but PyLong_AsUnsignedLongLong
 317                         doesn't ??? */
 318                 if (PyLong_Check(v))
 319                         *(unsigned PY_LONG_LONG*)addr = value = PyLong_AsUnsignedLongLong(v);
 320                 else
 321                         *(unsigned PY_LONG_LONG*)addr = value = PyInt_AsLong(v);
 322                 if ((value == (unsigned PY_LONG_LONG)-1) && PyErr_Occurred())
 323                         return -1;
 324                 break;
 325                 }
 326 #endif /* HAVE_LONG_LONG */
 327         default:
 328                 PyErr_Format(PyExc_SystemError,
 329                              "bad memberdescr type for %s", l->name);
 330                 return -1;
 331         }
 332         return 0;
 333 }