Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 1 | /* |
| 2 | Written by Jim Hugunin and Chris Chase. |
| 3 | |
Guido van Rossum | e449af7 | 1996-10-11 16:25:41 +0000 | [diff] [blame] | 4 | This includes both the singular ellipsis object and slice objects. |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 5 | |
| 6 | Guido, feel free to do whatever you want in the way of copyrights |
| 7 | for this file. |
| 8 | */ |
| 9 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 10 | /* |
Guido van Rossum | e449af7 | 1996-10-11 16:25:41 +0000 | [diff] [blame] | 11 | Py_Ellipsis encodes the '...' rubber index token. It is similar to |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 12 | the Py_NoneStruct in that there is no way to create other objects of |
| 13 | this type and there is exactly one in existence. |
| 14 | */ |
| 15 | |
| 16 | #include "Python.h" |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 17 | #include "structmember.h" |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 18 | |
| 19 | static PyObject * |
Benjamin Peterson | c4607ae | 2011-07-29 18:19:43 -0500 | [diff] [blame] | 20 | ellipsis_new(PyTypeObject *type, PyObject *args, PyObject *kwargs) |
| 21 | { |
| 22 | if (PyTuple_GET_SIZE(args) || (kwargs && PyDict_Size(kwargs))) { |
| 23 | PyErr_SetString(PyExc_TypeError, "EllipsisType takes no arguments"); |
| 24 | return NULL; |
| 25 | } |
| 26 | Py_INCREF(Py_Ellipsis); |
| 27 | return Py_Ellipsis; |
| 28 | } |
| 29 | |
| 30 | static PyObject * |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 31 | ellipsis_repr(PyObject *op) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 32 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 33 | return PyUnicode_FromString("Ellipsis"); |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 34 | } |
| 35 | |
Alexandre Vassalotti | c49477b | 2013-11-24 02:53:45 -0800 | [diff] [blame] | 36 | static PyObject * |
| 37 | ellipsis_reduce(PyObject *op) |
| 38 | { |
| 39 | return PyUnicode_FromString("Ellipsis"); |
| 40 | } |
| 41 | |
| 42 | static PyMethodDef ellipsis_methods[] = { |
| 43 | {"__reduce__", (PyCFunction)ellipsis_reduce, METH_NOARGS, NULL}, |
| 44 | {NULL, NULL} |
| 45 | }; |
| 46 | |
Benjamin Peterson | fd838e6 | 2009-04-20 02:09:13 +0000 | [diff] [blame] | 47 | PyTypeObject PyEllipsis_Type = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 48 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 49 | "ellipsis", /* tp_name */ |
| 50 | 0, /* tp_basicsize */ |
| 51 | 0, /* tp_itemsize */ |
| 52 | 0, /*never called*/ /* tp_dealloc */ |
| 53 | 0, /* tp_print */ |
| 54 | 0, /* tp_getattr */ |
| 55 | 0, /* tp_setattr */ |
| 56 | 0, /* tp_reserved */ |
| 57 | ellipsis_repr, /* tp_repr */ |
| 58 | 0, /* tp_as_number */ |
| 59 | 0, /* tp_as_sequence */ |
| 60 | 0, /* tp_as_mapping */ |
| 61 | 0, /* tp_hash */ |
| 62 | 0, /* tp_call */ |
| 63 | 0, /* tp_str */ |
| 64 | PyObject_GenericGetAttr, /* tp_getattro */ |
| 65 | 0, /* tp_setattro */ |
| 66 | 0, /* tp_as_buffer */ |
| 67 | Py_TPFLAGS_DEFAULT, /* tp_flags */ |
Benjamin Peterson | c4607ae | 2011-07-29 18:19:43 -0500 | [diff] [blame] | 68 | 0, /* tp_doc */ |
| 69 | 0, /* tp_traverse */ |
| 70 | 0, /* tp_clear */ |
| 71 | 0, /* tp_richcompare */ |
| 72 | 0, /* tp_weaklistoffset */ |
| 73 | 0, /* tp_iter */ |
| 74 | 0, /* tp_iternext */ |
Alexandre Vassalotti | c49477b | 2013-11-24 02:53:45 -0800 | [diff] [blame] | 75 | ellipsis_methods, /* tp_methods */ |
Benjamin Peterson | c4607ae | 2011-07-29 18:19:43 -0500 | [diff] [blame] | 76 | 0, /* tp_members */ |
| 77 | 0, /* tp_getset */ |
| 78 | 0, /* tp_base */ |
| 79 | 0, /* tp_dict */ |
| 80 | 0, /* tp_descr_get */ |
| 81 | 0, /* tp_descr_set */ |
| 82 | 0, /* tp_dictoffset */ |
| 83 | 0, /* tp_init */ |
| 84 | 0, /* tp_alloc */ |
| 85 | ellipsis_new, /* tp_new */ |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 86 | }; |
| 87 | |
Guido van Rossum | e449af7 | 1996-10-11 16:25:41 +0000 | [diff] [blame] | 88 | PyObject _Py_EllipsisObject = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 89 | _PyObject_EXTRA_INIT |
| 90 | 1, &PyEllipsis_Type |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 91 | }; |
| 92 | |
| 93 | |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 94 | /* Slice object implementation */ |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 95 | |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 96 | /* Using a cache is very effective since typically only a single slice is |
| 97 | * created and then deleted again |
| 98 | */ |
| 99 | static PySliceObject *slice_cache = NULL; |
| 100 | void PySlice_Fini(void) |
| 101 | { |
| 102 | PySliceObject *obj = slice_cache; |
| 103 | if (obj != NULL) { |
| 104 | slice_cache = NULL; |
| 105 | PyObject_Del(obj); |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | /* start, stop, and step are python objects with None indicating no |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 110 | index is present. |
| 111 | */ |
| 112 | |
| 113 | PyObject * |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 114 | PySlice_New(PyObject *start, PyObject *stop, PyObject *step) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 115 | { |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 116 | PySliceObject *obj; |
| 117 | if (slice_cache != NULL) { |
| 118 | obj = slice_cache; |
| 119 | slice_cache = NULL; |
| 120 | _Py_NewReference((PyObject *)obj); |
| 121 | } else { |
| 122 | obj = PyObject_New(PySliceObject, &PySlice_Type); |
| 123 | if (obj == NULL) |
| 124 | return NULL; |
| 125 | } |
Guido van Rossum | adf5410 | 2000-12-14 15:09:46 +0000 | [diff] [blame] | 126 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 127 | if (step == NULL) step = Py_None; |
| 128 | Py_INCREF(step); |
| 129 | if (start == NULL) start = Py_None; |
| 130 | Py_INCREF(start); |
| 131 | if (stop == NULL) stop = Py_None; |
| 132 | Py_INCREF(stop); |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 133 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 134 | obj->step = step; |
| 135 | obj->start = start; |
| 136 | obj->stop = stop; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 137 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 138 | return (PyObject *) obj; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 139 | } |
| 140 | |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 141 | PyObject * |
| 142 | _PySlice_FromIndices(Py_ssize_t istart, Py_ssize_t istop) |
| 143 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 144 | PyObject *start, *end, *slice; |
| 145 | start = PyLong_FromSsize_t(istart); |
| 146 | if (!start) |
| 147 | return NULL; |
| 148 | end = PyLong_FromSsize_t(istop); |
| 149 | if (!end) { |
| 150 | Py_DECREF(start); |
| 151 | return NULL; |
| 152 | } |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 153 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 154 | slice = PySlice_New(start, end, NULL); |
| 155 | Py_DECREF(start); |
| 156 | Py_DECREF(end); |
| 157 | return slice; |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 158 | } |
| 159 | |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 160 | int |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 161 | PySlice_GetIndices(PyObject *_r, Py_ssize_t length, |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 162 | Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 163 | { |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 164 | PySliceObject *r = (PySliceObject*)_r; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 165 | /* XXX support long ints */ |
| 166 | if (r->step == Py_None) { |
| 167 | *step = 1; |
| 168 | } else { |
| 169 | if (!PyLong_Check(r->step)) return -1; |
| 170 | *step = PyLong_AsSsize_t(r->step); |
| 171 | } |
| 172 | if (r->start == Py_None) { |
| 173 | *start = *step < 0 ? length-1 : 0; |
| 174 | } else { |
| 175 | if (!PyLong_Check(r->start)) return -1; |
| 176 | *start = PyLong_AsSsize_t(r->start); |
| 177 | if (*start < 0) *start += length; |
| 178 | } |
| 179 | if (r->stop == Py_None) { |
| 180 | *stop = *step < 0 ? -1 : length; |
| 181 | } else { |
| 182 | if (!PyLong_Check(r->stop)) return -1; |
| 183 | *stop = PyLong_AsSsize_t(r->stop); |
| 184 | if (*stop < 0) *stop += length; |
| 185 | } |
| 186 | if (*stop > length) return -1; |
| 187 | if (*start >= length) return -1; |
| 188 | if (*step == 0) return -1; |
| 189 | return 0; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 190 | } |
| 191 | |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 192 | int |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 193 | PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length, |
Mark Dickinson | e6fc740 | 2010-08-06 18:55:26 +0000 | [diff] [blame] | 194 | Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, |
| 195 | Py_ssize_t *slicelength) |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 196 | { |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 197 | PySliceObject *r = (PySliceObject*)_r; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 198 | /* this is harder to get right than you might think */ |
Michael W. Hudson | 173f11d | 2002-11-05 15:28:51 +0000 | [diff] [blame] | 199 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 200 | Py_ssize_t defstart, defstop; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 201 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 202 | if (r->step == Py_None) { |
| 203 | *step = 1; |
| 204 | } |
| 205 | else { |
| 206 | if (!_PyEval_SliceIndex(r->step, step)) return -1; |
| 207 | if (*step == 0) { |
| 208 | PyErr_SetString(PyExc_ValueError, |
| 209 | "slice step cannot be zero"); |
| 210 | return -1; |
| 211 | } |
Mark Dickinson | e6fc740 | 2010-08-06 18:55:26 +0000 | [diff] [blame] | 212 | /* Here *step might be -PY_SSIZE_T_MAX-1; in this case we replace it |
| 213 | * with -PY_SSIZE_T_MAX. This doesn't affect the semantics, and it |
| 214 | * guards against later undefined behaviour resulting from code that |
| 215 | * does "step = -step" as part of a slice reversal. |
| 216 | */ |
| 217 | if (*step < -PY_SSIZE_T_MAX) |
| 218 | *step = -PY_SSIZE_T_MAX; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 219 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 220 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 221 | defstart = *step < 0 ? length-1 : 0; |
| 222 | defstop = *step < 0 ? -1 : length; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 223 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 224 | if (r->start == Py_None) { |
| 225 | *start = defstart; |
| 226 | } |
| 227 | else { |
| 228 | if (!_PyEval_SliceIndex(r->start, start)) return -1; |
| 229 | if (*start < 0) *start += length; |
| 230 | if (*start < 0) *start = (*step < 0) ? -1 : 0; |
| 231 | if (*start >= length) |
| 232 | *start = (*step < 0) ? length - 1 : length; |
| 233 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 234 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 235 | if (r->stop == Py_None) { |
| 236 | *stop = defstop; |
| 237 | } |
| 238 | else { |
| 239 | if (!_PyEval_SliceIndex(r->stop, stop)) return -1; |
| 240 | if (*stop < 0) *stop += length; |
| 241 | if (*stop < 0) *stop = (*step < 0) ? -1 : 0; |
| 242 | if (*stop >= length) |
| 243 | *stop = (*step < 0) ? length - 1 : length; |
| 244 | } |
Michael W. Hudson | 173f11d | 2002-11-05 15:28:51 +0000 | [diff] [blame] | 245 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 246 | if ((*step < 0 && *stop >= *start) |
| 247 | || (*step > 0 && *start >= *stop)) { |
| 248 | *slicelength = 0; |
| 249 | } |
| 250 | else if (*step < 0) { |
| 251 | *slicelength = (*stop-*start+1)/(*step)+1; |
| 252 | } |
| 253 | else { |
| 254 | *slicelength = (*stop-*start-1)/(*step)+1; |
| 255 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 256 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 257 | return 0; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 258 | } |
| 259 | |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 260 | static PyObject * |
| 261 | slice_new(PyTypeObject *type, PyObject *args, PyObject *kw) |
| 262 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 263 | PyObject *start, *stop, *step; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 264 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 265 | start = stop = step = NULL; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 266 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 267 | if (!_PyArg_NoKeywords("slice()", kw)) |
| 268 | return NULL; |
Georg Brandl | 02c4287 | 2005-08-26 06:42:30 +0000 | [diff] [blame] | 269 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 270 | if (!PyArg_UnpackTuple(args, "slice", 1, 3, &start, &stop, &step)) |
| 271 | return NULL; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 272 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 273 | /* This swapping of stop and start is to maintain similarity with |
| 274 | range(). */ |
| 275 | if (stop == NULL) { |
| 276 | stop = start; |
| 277 | start = NULL; |
| 278 | } |
| 279 | return PySlice_New(start, stop, step); |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 280 | } |
| 281 | |
| 282 | PyDoc_STRVAR(slice_doc, |
Chris Jerdonek | 83fe2e1 | 2012-10-07 14:48:36 -0700 | [diff] [blame] | 283 | "slice(stop)\n\ |
| 284 | slice(start, stop[, step])\n\ |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 285 | \n\ |
| 286 | Create a slice object. This is used for extended slicing (e.g. a[0:10:2])."); |
| 287 | |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 288 | static void |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 289 | slice_dealloc(PySliceObject *r) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 290 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 291 | Py_DECREF(r->step); |
| 292 | Py_DECREF(r->start); |
| 293 | Py_DECREF(r->stop); |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 294 | if (slice_cache == NULL) |
| 295 | slice_cache = r; |
| 296 | else |
| 297 | PyObject_Del(r); |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 298 | } |
| 299 | |
| 300 | static PyObject * |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 301 | slice_repr(PySliceObject *r) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 302 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 303 | return PyUnicode_FromFormat("slice(%R, %R, %R)", r->start, r->stop, r->step); |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 304 | } |
| 305 | |
Guido van Rossum | 6f79937 | 2001-09-20 20:46:19 +0000 | [diff] [blame] | 306 | static PyMemberDef slice_members[] = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 307 | {"start", T_OBJECT, offsetof(PySliceObject, start), READONLY}, |
| 308 | {"stop", T_OBJECT, offsetof(PySliceObject, stop), READONLY}, |
| 309 | {"step", T_OBJECT, offsetof(PySliceObject, step), READONLY}, |
| 310 | {0} |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 311 | }; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 312 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 313 | /* Helper function to convert a slice argument to a PyLong, and raise TypeError |
| 314 | with a suitable message on failure. */ |
| 315 | |
| 316 | static PyObject* |
| 317 | evaluate_slice_index(PyObject *v) |
| 318 | { |
| 319 | if (PyIndex_Check(v)) { |
| 320 | return PyNumber_Index(v); |
| 321 | } |
| 322 | else { |
| 323 | PyErr_SetString(PyExc_TypeError, |
| 324 | "slice indices must be integers or " |
| 325 | "None or have an __index__ method"); |
| 326 | return NULL; |
| 327 | } |
| 328 | } |
| 329 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 330 | /* Compute slice indices given a slice and length. Return -1 on failure. Used |
| 331 | by slice.indices and rangeobject slicing. Assumes that `len` is a |
| 332 | nonnegative instance of PyLong. */ |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 333 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 334 | int |
| 335 | _PySlice_GetLongIndices(PySliceObject *self, PyObject *length, |
| 336 | PyObject **start_ptr, PyObject **stop_ptr, |
| 337 | PyObject **step_ptr) |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 338 | { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 339 | PyObject *start=NULL, *stop=NULL, *step=NULL; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 340 | PyObject *upper=NULL, *lower=NULL; |
| 341 | int step_is_negative, cmp_result; |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 342 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 343 | /* Convert step to an integer; raise for zero step. */ |
| 344 | if (self->step == Py_None) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 345 | step = PyLong_FromLong(1L); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 346 | if (step == NULL) |
| 347 | goto error; |
| 348 | step_is_negative = 0; |
| 349 | } |
| 350 | else { |
| 351 | int step_sign; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 352 | step = evaluate_slice_index(self->step); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 353 | if (step == NULL) |
| 354 | goto error; |
| 355 | step_sign = _PyLong_Sign(step); |
| 356 | if (step_sign == 0) { |
| 357 | PyErr_SetString(PyExc_ValueError, |
| 358 | "slice step cannot be zero"); |
| 359 | goto error; |
| 360 | } |
| 361 | step_is_negative = step_sign < 0; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 362 | } |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 363 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 364 | /* Find lower and upper bounds for start and stop. */ |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 365 | if (step_is_negative) { |
| 366 | lower = PyLong_FromLong(-1L); |
| 367 | if (lower == NULL) |
| 368 | goto error; |
| 369 | |
| 370 | upper = PyNumber_Add(length, lower); |
| 371 | if (upper == NULL) |
| 372 | goto error; |
| 373 | } |
| 374 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 375 | lower = PyLong_FromLong(0L); |
| 376 | if (lower == NULL) |
| 377 | goto error; |
| 378 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 379 | upper = length; |
| 380 | Py_INCREF(upper); |
| 381 | } |
| 382 | |
| 383 | /* Compute start. */ |
| 384 | if (self->start == Py_None) { |
| 385 | start = step_is_negative ? upper : lower; |
| 386 | Py_INCREF(start); |
| 387 | } |
| 388 | else { |
| 389 | start = evaluate_slice_index(self->start); |
| 390 | if (start == NULL) |
| 391 | goto error; |
| 392 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 393 | if (_PyLong_Sign(start) < 0) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 394 | /* start += length */ |
| 395 | PyObject *tmp = PyNumber_Add(start, length); |
| 396 | Py_DECREF(start); |
| 397 | start = tmp; |
| 398 | if (start == NULL) |
| 399 | goto error; |
| 400 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 401 | cmp_result = PyObject_RichCompareBool(start, lower, Py_LT); |
| 402 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 403 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 404 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 405 | Py_INCREF(lower); |
| 406 | Py_DECREF(start); |
| 407 | start = lower; |
| 408 | } |
| 409 | } |
| 410 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 411 | cmp_result = PyObject_RichCompareBool(start, upper, Py_GT); |
| 412 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 413 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 414 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 415 | Py_INCREF(upper); |
| 416 | Py_DECREF(start); |
| 417 | start = upper; |
| 418 | } |
| 419 | } |
| 420 | } |
| 421 | |
| 422 | /* Compute stop. */ |
| 423 | if (self->stop == Py_None) { |
| 424 | stop = step_is_negative ? lower : upper; |
| 425 | Py_INCREF(stop); |
| 426 | } |
| 427 | else { |
| 428 | stop = evaluate_slice_index(self->stop); |
| 429 | if (stop == NULL) |
| 430 | goto error; |
| 431 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 432 | if (_PyLong_Sign(stop) < 0) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 433 | /* stop += length */ |
| 434 | PyObject *tmp = PyNumber_Add(stop, length); |
| 435 | Py_DECREF(stop); |
| 436 | stop = tmp; |
| 437 | if (stop == NULL) |
| 438 | goto error; |
| 439 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 440 | cmp_result = PyObject_RichCompareBool(stop, lower, Py_LT); |
| 441 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 442 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 443 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 444 | Py_INCREF(lower); |
| 445 | Py_DECREF(stop); |
| 446 | stop = lower; |
| 447 | } |
| 448 | } |
| 449 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 450 | cmp_result = PyObject_RichCompareBool(stop, upper, Py_GT); |
| 451 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 452 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 453 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 454 | Py_INCREF(upper); |
| 455 | Py_DECREF(stop); |
| 456 | stop = upper; |
| 457 | } |
| 458 | } |
| 459 | } |
| 460 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 461 | *start_ptr = start; |
| 462 | *stop_ptr = stop; |
| 463 | *step_ptr = step; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 464 | Py_DECREF(upper); |
| 465 | Py_DECREF(lower); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 466 | return 0; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 467 | |
| 468 | error: |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 469 | *start_ptr = *stop_ptr = *step_ptr = NULL; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 470 | Py_XDECREF(start); |
| 471 | Py_XDECREF(stop); |
| 472 | Py_XDECREF(step); |
| 473 | Py_XDECREF(upper); |
| 474 | Py_XDECREF(lower); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 475 | return -1; |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 476 | } |
| 477 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 478 | /* Implementation of slice.indices. */ |
| 479 | |
| 480 | static PyObject* |
| 481 | slice_indices(PySliceObject* self, PyObject* len) |
| 482 | { |
| 483 | PyObject *start, *stop, *step; |
| 484 | PyObject *length; |
| 485 | int error; |
| 486 | |
| 487 | /* Convert length to an integer if necessary; raise for negative length. */ |
| 488 | length = PyNumber_Index(len); |
| 489 | if (length == NULL) |
| 490 | return NULL; |
| 491 | |
| 492 | if (_PyLong_Sign(length) < 0) { |
| 493 | PyErr_SetString(PyExc_ValueError, |
| 494 | "length should not be negative"); |
| 495 | Py_DECREF(length); |
| 496 | return NULL; |
| 497 | } |
| 498 | |
| 499 | error = _PySlice_GetLongIndices(self, length, &start, &stop, &step); |
| 500 | Py_DECREF(length); |
| 501 | if (error == -1) |
| 502 | return NULL; |
| 503 | else |
| 504 | return Py_BuildValue("(NNN)", start, stop, step); |
| 505 | } |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 506 | |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 507 | PyDoc_STRVAR(slice_indices_doc, |
| 508 | "S.indices(len) -> (start, stop, stride)\n\ |
| 509 | \n\ |
| 510 | Assuming a sequence of length len, calculate the start and stop\n\ |
| 511 | indices, and the stride length of the extended slice described by\n\ |
| 512 | S. Out of bounds indices are clipped in a manner consistent with the\n\ |
| 513 | handling of normal slices."); |
| 514 | |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 515 | static PyObject * |
| 516 | slice_reduce(PySliceObject* self) |
| 517 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 518 | return Py_BuildValue("O(OOO)", Py_TYPE(self), self->start, self->stop, self->step); |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 519 | } |
| 520 | |
| 521 | PyDoc_STRVAR(reduce_doc, "Return state information for pickling."); |
| 522 | |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 523 | static PyMethodDef slice_methods[] = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 524 | {"indices", (PyCFunction)slice_indices, |
| 525 | METH_O, slice_indices_doc}, |
| 526 | {"__reduce__", (PyCFunction)slice_reduce, |
| 527 | METH_NOARGS, reduce_doc}, |
| 528 | {NULL, NULL} |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 529 | }; |
| 530 | |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 531 | static PyObject * |
| 532 | slice_richcompare(PyObject *v, PyObject *w, int op) |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 533 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 534 | PyObject *t1; |
| 535 | PyObject *t2; |
| 536 | PyObject *res; |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 537 | |
Brian Curtin | dfc80e3 | 2011-08-10 20:28:54 -0500 | [diff] [blame] | 538 | if (!PySlice_Check(v) || !PySlice_Check(w)) |
| 539 | Py_RETURN_NOTIMPLEMENTED; |
Thomas Wouters | 3e57b52 | 2007-08-28 23:07:26 +0000 | [diff] [blame] | 540 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 541 | if (v == w) { |
| 542 | /* XXX Do we really need this shortcut? |
| 543 | There's a unit test for it, but is that fair? */ |
| 544 | switch (op) { |
| 545 | case Py_EQ: |
| 546 | case Py_LE: |
| 547 | case Py_GE: |
| 548 | res = Py_True; |
| 549 | break; |
| 550 | default: |
| 551 | res = Py_False; |
| 552 | break; |
| 553 | } |
| 554 | Py_INCREF(res); |
| 555 | return res; |
| 556 | } |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 557 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 558 | t1 = PyTuple_New(3); |
Benjamin Peterson | 2963fe0 | 2011-10-17 13:09:27 -0400 | [diff] [blame] | 559 | if (t1 == NULL) |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 560 | return NULL; |
Benjamin Peterson | 2963fe0 | 2011-10-17 13:09:27 -0400 | [diff] [blame] | 561 | t2 = PyTuple_New(3); |
| 562 | if (t2 == NULL) { |
| 563 | Py_DECREF(t1); |
| 564 | return NULL; |
| 565 | } |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 566 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 567 | PyTuple_SET_ITEM(t1, 0, ((PySliceObject *)v)->start); |
| 568 | PyTuple_SET_ITEM(t1, 1, ((PySliceObject *)v)->stop); |
| 569 | PyTuple_SET_ITEM(t1, 2, ((PySliceObject *)v)->step); |
| 570 | PyTuple_SET_ITEM(t2, 0, ((PySliceObject *)w)->start); |
| 571 | PyTuple_SET_ITEM(t2, 1, ((PySliceObject *)w)->stop); |
| 572 | PyTuple_SET_ITEM(t2, 2, ((PySliceObject *)w)->step); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 573 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 574 | res = PyObject_RichCompare(t1, t2, op); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 575 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 576 | PyTuple_SET_ITEM(t1, 0, NULL); |
| 577 | PyTuple_SET_ITEM(t1, 1, NULL); |
| 578 | PyTuple_SET_ITEM(t1, 2, NULL); |
| 579 | PyTuple_SET_ITEM(t2, 0, NULL); |
| 580 | PyTuple_SET_ITEM(t2, 1, NULL); |
| 581 | PyTuple_SET_ITEM(t2, 2, NULL); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 582 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 583 | Py_DECREF(t1); |
| 584 | Py_DECREF(t2); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 585 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 586 | return res; |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 587 | } |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 588 | |
| 589 | PyTypeObject PySlice_Type = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 590 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 591 | "slice", /* Name of this type */ |
| 592 | sizeof(PySliceObject), /* Basic object size */ |
| 593 | 0, /* Item size for varobject */ |
| 594 | (destructor)slice_dealloc, /* tp_dealloc */ |
| 595 | 0, /* tp_print */ |
| 596 | 0, /* tp_getattr */ |
| 597 | 0, /* tp_setattr */ |
| 598 | 0, /* tp_reserved */ |
| 599 | (reprfunc)slice_repr, /* tp_repr */ |
| 600 | 0, /* tp_as_number */ |
| 601 | 0, /* tp_as_sequence */ |
| 602 | 0, /* tp_as_mapping */ |
Benjamin Peterson | 23d05c1 | 2010-10-17 20:13:05 +0000 | [diff] [blame] | 603 | PyObject_HashNotImplemented, /* tp_hash */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 604 | 0, /* tp_call */ |
| 605 | 0, /* tp_str */ |
| 606 | PyObject_GenericGetAttr, /* tp_getattro */ |
| 607 | 0, /* tp_setattro */ |
| 608 | 0, /* tp_as_buffer */ |
| 609 | Py_TPFLAGS_DEFAULT, /* tp_flags */ |
| 610 | slice_doc, /* tp_doc */ |
| 611 | 0, /* tp_traverse */ |
| 612 | 0, /* tp_clear */ |
| 613 | slice_richcompare, /* tp_richcompare */ |
| 614 | 0, /* tp_weaklistoffset */ |
| 615 | 0, /* tp_iter */ |
| 616 | 0, /* tp_iternext */ |
| 617 | slice_methods, /* tp_methods */ |
| 618 | slice_members, /* tp_members */ |
| 619 | 0, /* tp_getset */ |
| 620 | 0, /* tp_base */ |
| 621 | 0, /* tp_dict */ |
| 622 | 0, /* tp_descr_get */ |
| 623 | 0, /* tp_descr_set */ |
| 624 | 0, /* tp_dictoffset */ |
| 625 | 0, /* tp_init */ |
| 626 | 0, /* tp_alloc */ |
| 627 | slice_new, /* tp_new */ |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 628 | }; |