ref: 689109303467790df972f16918ee48a490c53f56
dir: /sys/src/cmd/python/Objects/enumobject.c/
/* enumerate object */ #include "Python.h" typedef struct { PyObject_HEAD long en_index; /* current index of enumeration */ PyObject* en_sit; /* secondary iterator of enumeration */ PyObject* en_result; /* result tuple */ } enumobject; static PyObject * enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds) { enumobject *en; PyObject *seq = NULL; static char *kwlist[] = {"sequence", 0}; if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:enumerate", kwlist, &seq)) return NULL; en = (enumobject *)type->tp_alloc(type, 0); if (en == NULL) return NULL; en->en_index = 0; en->en_sit = PyObject_GetIter(seq); if (en->en_sit == NULL) { Py_DECREF(en); return NULL; } en->en_result = PyTuple_Pack(2, Py_None, Py_None); if (en->en_result == NULL) { Py_DECREF(en); return NULL; } return (PyObject *)en; } static void enum_dealloc(enumobject *en) { PyObject_GC_UnTrack(en); Py_XDECREF(en->en_sit); Py_XDECREF(en->en_result); en->ob_type->tp_free(en); } static int enum_traverse(enumobject *en, visitproc visit, void *arg) { Py_VISIT(en->en_sit); Py_VISIT(en->en_result); return 0; } static PyObject * enum_next(enumobject *en) { PyObject *next_index; PyObject *next_item; PyObject *result = en->en_result; PyObject *it = en->en_sit; if (en->en_index == LONG_MAX) { PyErr_SetString(PyExc_OverflowError, "enumerate() is limited to LONG_MAX items"); return NULL; } next_item = (*it->ob_type->tp_iternext)(it); if (next_item == NULL) return NULL; next_index = PyInt_FromLong(en->en_index); if (next_index == NULL) { Py_DECREF(next_item); return NULL; } en->en_index++; if (result->ob_refcnt == 1) { Py_INCREF(result); Py_DECREF(PyTuple_GET_ITEM(result, 0)); Py_DECREF(PyTuple_GET_ITEM(result, 1)); } else { result = PyTuple_New(2); if (result == NULL) { Py_DECREF(next_index); Py_DECREF(next_item); return NULL; } } PyTuple_SET_ITEM(result, 0, next_index); PyTuple_SET_ITEM(result, 1, next_item); return result; } PyDoc_STRVAR(enum_doc, "enumerate(iterable) -> iterator for index, value of iterable\n" "\n" "Return an enumerate object. iterable must be an other object that supports\n" "iteration. The enumerate object yields pairs containing a count (from\n" "zero) and a value yielded by the iterable argument. enumerate is useful\n" "for obtaining an indexed list: (0, seq[0]), (1, seq[1]), (2, seq[2]), ..."); PyTypeObject PyEnum_Type = { PyObject_HEAD_INIT(&PyType_Type) 0, /* ob_size */ "enumerate", /* tp_name */ sizeof(enumobject), /* tp_basicsize */ 0, /* tp_itemsize */ /* methods */ (destructor)enum_dealloc, /* tp_dealloc */ 0, /* tp_print */ 0, /* tp_getattr */ 0, /* tp_setattr */ 0, /* tp_compare */ 0, /* tp_repr */ 0, /* tp_as_number */ 0, /* tp_as_sequence */ 0, /* tp_as_mapping */ 0, /* tp_hash */ 0, /* tp_call */ 0, /* tp_str */ PyObject_GenericGetAttr, /* tp_getattro */ 0, /* tp_setattro */ 0, /* tp_as_buffer */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_BASETYPE, /* tp_flags */ enum_doc, /* tp_doc */ (traverseproc)enum_traverse, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ PyObject_SelfIter, /* tp_iter */ (iternextfunc)enum_next, /* tp_iternext */ 0, /* tp_methods */ 0, /* tp_members */ 0, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ 0, /* tp_descr_get */ 0, /* tp_descr_set */ 0, /* tp_dictoffset */ 0, /* tp_init */ PyType_GenericAlloc, /* tp_alloc */ enum_new, /* tp_new */ PyObject_GC_Del, /* tp_free */ }; /* Reversed Object ***************************************************************/ typedef struct { PyObject_HEAD Py_ssize_t index; PyObject* seq; } reversedobject; static PyObject * reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds) { Py_ssize_t n; PyObject *seq; reversedobject *ro; if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq)) return NULL; if (PyObject_HasAttrString(seq, "__reversed__")) return PyObject_CallMethod(seq, "__reversed__", NULL); if (!PySequence_Check(seq)) { PyErr_SetString(PyExc_TypeError, "argument to reversed() must be a sequence"); return NULL; } n = PySequence_Size(seq); if (n == -1) return NULL; ro = (reversedobject *)type->tp_alloc(type, 0); if (ro == NULL) return NULL; ro->index = n-1; Py_INCREF(seq); ro->seq = seq; return (PyObject *)ro; } static void reversed_dealloc(reversedobject *ro) { PyObject_GC_UnTrack(ro); Py_XDECREF(ro->seq); ro->ob_type->tp_free(ro); } static int reversed_traverse(reversedobject *ro, visitproc visit, void *arg) { Py_VISIT(ro->seq); return 0; } static PyObject * reversed_next(reversedobject *ro) { PyObject *item; Py_ssize_t index = ro->index; if (index >= 0) { item = PySequence_GetItem(ro->seq, index); if (item != NULL) { ro->index--; return item; } if (PyErr_ExceptionMatches(PyExc_IndexError) || PyErr_ExceptionMatches(PyExc_StopIteration)) PyErr_Clear(); } ro->index = -1; Py_CLEAR(ro->seq); return NULL; } PyDoc_STRVAR(reversed_doc, "reversed(sequence) -> reverse iterator over values of the sequence\n" "\n" "Return a reverse iterator"); static PyObject * reversed_len(reversedobject *ro) { Py_ssize_t position, seqsize; if (ro->seq == NULL) return PyInt_FromLong(0); seqsize = PySequence_Size(ro->seq); if (seqsize == -1) return NULL; position = ro->index + 1; return PyInt_FromSsize_t((seqsize < position) ? 0 : position); } PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it))."); static PyMethodDef reversediter_methods[] = { {"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc}, {NULL, NULL} /* sentinel */ }; PyTypeObject PyReversed_Type = { PyObject_HEAD_INIT(&PyType_Type) 0, /* ob_size */ "reversed", /* tp_name */ sizeof(reversedobject), /* tp_basicsize */ 0, /* tp_itemsize */ /* methods */ (destructor)reversed_dealloc, /* tp_dealloc */ 0, /* tp_print */ 0, /* tp_getattr */ 0, /* tp_setattr */ 0, /* tp_compare */ 0, /* tp_repr */ 0, /* tp_as_number */ 0, /* tp_as_sequence */ 0, /* tp_as_mapping */ 0, /* tp_hash */ 0, /* tp_call */ 0, /* tp_str */ PyObject_GenericGetAttr, /* tp_getattro */ 0, /* tp_setattro */ 0, /* tp_as_buffer */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_BASETYPE, /* tp_flags */ reversed_doc, /* tp_doc */ (traverseproc)reversed_traverse,/* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ PyObject_SelfIter, /* tp_iter */ (iternextfunc)reversed_next, /* tp_iternext */ reversediter_methods, /* tp_methods */ 0, /* tp_members */ 0, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ 0, /* tp_descr_get */ 0, /* tp_descr_set */ 0, /* tp_dictoffset */ 0, /* tp_init */ PyType_GenericAlloc, /* tp_alloc */ reversed_new, /* tp_new */ PyObject_GC_Del, /* tp_free */ };