view Python/structmember.c @ 22613:ddc9543c76a0 legacy-trunk

Introduce two new flag bits that can be set in a PyMethodDef method descriptor, as used for the tp_methods slot of a type. These new flag bits are both optional, and mutually exclusive. Most methods will not use either. These flags are used to create special method types which exist in the same namespace as normal methods without having to use tedious construction code to insert the new special method objects in the type's tp_dict after PyType_Ready() has been called. If METH_CLASS is specified, the method will represent a class method like that returned by the classmethod() built-in. If METH_STATIC is specified, the method will represent a static method like that returned by the staticmethod() built-in. These flags may not be used in the PyMethodDef table for modules since these special method types are not meaningful in that case; a ValueError will be raised if these flags are found in that context.
author Fred Drake <fdrake@acm.org>
date Thu, 28 Mar 2002 05:33:33 +0000
parents ef6f692c76e2
children 86fdf8fe7f17
line wrap: on
line source


/* Map C struct members to Python object attributes */

#include "Python.h"

#include "structmember.h"

static PyObject *
listmembers(struct memberlist *mlist)
{
	int i, n;
	PyObject *v;
	for (n = 0; mlist[n].name != NULL; n++)
		;
	v = PyList_New(n);
	if (v != NULL) {
		for (i = 0; i < n; i++)
			PyList_SetItem(v, i,
				       PyString_FromString(mlist[i].name));
		if (PyErr_Occurred()) {
			Py_DECREF(v);
			v = NULL;
		}
		else {
			PyList_Sort(v);
		}
	}
	return v;
}

PyObject *
PyMember_Get(char *addr, struct memberlist *mlist, char *name)
{
	struct memberlist *l;

	if (strcmp(name, "__members__") == 0)
		return listmembers(mlist);
	for (l = mlist; l->name != NULL; l++) {
		if (strcmp(l->name, name) == 0) {
			PyMemberDef copy;
			copy.name = l->name;
			copy.type = l->type;
			copy.offset = l->offset;
			copy.flags = l->flags;
			copy.doc = NULL;
			return PyMember_GetOne(addr, &copy);
		}
	}
	PyErr_SetString(PyExc_AttributeError, name);
	return NULL;
}

PyObject *
PyMember_GetOne(char *addr, PyMemberDef *l)
{
	PyObject *v;
	if ((l->flags & READ_RESTRICTED) &&
	    PyEval_GetRestricted()) {
		PyErr_SetString(PyExc_RuntimeError, "restricted attribute");
		return NULL;
	}
	addr += l->offset;
	switch (l->type) {
	case T_BYTE:
		v = PyInt_FromLong(
			(long) (((*(char*)addr & 0xff) ^ 0x80) - 0x80));
		break;
	case T_UBYTE:
		v = PyInt_FromLong((long) *(char*)addr & 0xff);
		break;
	case T_SHORT:
		v = PyInt_FromLong((long) *(short*)addr);
		break;
	case T_USHORT:
		v = PyInt_FromLong((long) *(unsigned short*)addr);
		break;
	case T_INT:
		v = PyInt_FromLong((long) *(int*)addr);
		break;
	case T_UINT:
		v = PyInt_FromLong((long) *(unsigned int*)addr);
		break;
	case T_LONG:
		v = PyInt_FromLong(*(long*)addr);
		break;
	case T_ULONG:
		v = PyLong_FromDouble((double) *(unsigned long*)addr);
		break;
	case T_FLOAT:
		v = PyFloat_FromDouble((double)*(float*)addr);
		break;
	case T_DOUBLE:
		v = PyFloat_FromDouble(*(double*)addr);
		break;
	case T_STRING:
		if (*(char**)addr == NULL) {
			Py_INCREF(Py_None);
			v = Py_None;
		}
		else
			v = PyString_FromString(*(char**)addr);
		break;
	case T_STRING_INPLACE:
		v = PyString_FromString((char*)addr);
		break;
#ifdef macintosh
	case T_PSTRING:
		if (*(char**)addr == NULL) {
			Py_INCREF(Py_None);
			v = Py_None;
		}
		else
			v = PyString_FromStringAndSize(
				(*(char**)addr)+1,
				**(unsigned char**)addr);
		break;
	case T_PSTRING_INPLACE:
		v = PyString_FromStringAndSize(
			((char*)addr)+1,
			*(unsigned char*)addr);
		break;
#endif /* macintosh */
	case T_CHAR:
		v = PyString_FromStringAndSize((char*)addr, 1);
		break;
	case T_OBJECT:
		v = *(PyObject **)addr;
		if (v == NULL)
			v = Py_None;
		Py_INCREF(v);
		break;
	case T_OBJECT_EX:
		v = *(PyObject **)addr;
		if (v == NULL)
			PyErr_SetString(PyExc_AttributeError, l->name);
		Py_XINCREF(v);
		break;
	default:
		PyErr_SetString(PyExc_SystemError, "bad memberdescr type");
		v = NULL;
	}
	return v;
}

int
PyMember_Set(char *addr, struct memberlist *mlist, char *name, PyObject *v)
{
	struct memberlist *l;

	for (l = mlist; l->name != NULL; l++) {
		if (strcmp(l->name, name) == 0) {
			PyMemberDef copy;
			copy.name = l->name;
			copy.type = l->type;
			copy.offset = l->offset;
			copy.flags = l->flags;
			copy.doc = NULL;
			return PyMember_SetOne(addr, &copy, v);
		}
	}

	PyErr_SetString(PyExc_AttributeError, name);
	return -1;
}

int
PyMember_SetOne(char *addr, PyMemberDef *l, PyObject *v)
{
	PyObject *oldv;

	if ((l->flags & READONLY) || l->type == T_STRING
#ifdef macintosh
	    || l->type == T_PSTRING
#endif
		)
	{
		PyErr_SetString(PyExc_TypeError, "readonly attribute");
		return -1;
	}
	if ((l->flags & WRITE_RESTRICTED) && PyEval_GetRestricted()) {
		PyErr_SetString(PyExc_RuntimeError, "restricted attribute");
		return -1;
	}
	if (v == NULL && l->type != T_OBJECT_EX && l->type != T_OBJECT) {
		PyErr_SetString(PyExc_TypeError,
				"can't delete numeric/char attribute");
		return -1;
	}
	addr += l->offset;
	switch (l->type) {
	case T_BYTE:
	case T_UBYTE:
		if (!PyInt_Check(v)) {
			PyErr_BadArgument();
			return -1;
		}
		*(char*)addr = (char) PyInt_AsLong(v);
		break;
	case T_SHORT:
	case T_USHORT:
		if (!PyInt_Check(v)) {
			PyErr_BadArgument();
			return -1;
		}
		*(short*)addr = (short) PyInt_AsLong(v);
		break;
	case T_UINT:
	case T_INT:
		if (!PyInt_Check(v)) {
			PyErr_BadArgument();
			return -1;
		}
		*(int*)addr = (int) PyInt_AsLong(v);
		break;
	case T_LONG:
		if (!PyInt_Check(v)) {
			PyErr_BadArgument();
			return -1;
		}
		*(long*)addr = PyInt_AsLong(v);
		break;
	case T_ULONG:
		if (PyInt_Check(v))
			*(long*)addr = PyInt_AsLong(v);
		else if (PyLong_Check(v))
			*(long*)addr = PyLong_AsLong(v);
		else {
			PyErr_BadArgument();
			return -1;
		}
		break;
	case T_FLOAT:
		if (PyInt_Check(v))
			*(float*)addr =
				(float) PyInt_AsLong(v);
		else if (PyFloat_Check(v))
			*(float*)addr =
				(float) PyFloat_AsDouble(v);
		else {
			PyErr_BadArgument();
			return -1;
		}
		break;
	case T_DOUBLE:
		if (PyInt_Check(v))
			*(double*)addr = (double) PyInt_AsLong(v);
		else if (PyFloat_Check(v))
			*(double*)addr = PyFloat_AsDouble(v);
		else {
			PyErr_BadArgument();
			return -1;
		}
		break;
	case T_OBJECT:
	case T_OBJECT_EX:
		Py_XINCREF(v);
		oldv = *(PyObject **)addr;
		*(PyObject **)addr = v;
		Py_XDECREF(oldv);
		break;
	case T_CHAR:
		if (PyString_Check(v) && PyString_Size(v) == 1) {
			*(char*)addr = PyString_AsString(v)[0];
		}
		else {
			PyErr_BadArgument();
			return -1;
		}
		break;
	default:
		PyErr_Format(PyExc_SystemError,
			     "bad memberdescr type for %s", l->name);
		return -1;
	}
	return 0;
}