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; |
Benjamin Peterson | b0c04cb | 2016-04-16 15:12:29 -0700 | [diff] [blame] | 105 | PyObject_GC_Del(obj); |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 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 { |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 122 | obj = PyObject_GC_New(PySliceObject, &PySlice_Type); |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 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 | |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 138 | _PyObject_GC_TRACK(obj); |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 139 | return (PyObject *) obj; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 140 | } |
| 141 | |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 142 | PyObject * |
| 143 | _PySlice_FromIndices(Py_ssize_t istart, Py_ssize_t istop) |
| 144 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 145 | PyObject *start, *end, *slice; |
| 146 | start = PyLong_FromSsize_t(istart); |
| 147 | if (!start) |
| 148 | return NULL; |
| 149 | end = PyLong_FromSsize_t(istop); |
| 150 | if (!end) { |
| 151 | Py_DECREF(start); |
| 152 | return NULL; |
| 153 | } |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 154 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 155 | slice = PySlice_New(start, end, NULL); |
| 156 | Py_DECREF(start); |
| 157 | Py_DECREF(end); |
| 158 | return slice; |
Thomas Wouters | 49fd7fa | 2006-04-21 10:40:58 +0000 | [diff] [blame] | 159 | } |
| 160 | |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 161 | int |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 162 | PySlice_GetIndices(PyObject *_r, Py_ssize_t length, |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 163 | 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] | 164 | { |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 165 | PySliceObject *r = (PySliceObject*)_r; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 166 | /* XXX support long ints */ |
| 167 | if (r->step == Py_None) { |
| 168 | *step = 1; |
| 169 | } else { |
| 170 | if (!PyLong_Check(r->step)) return -1; |
| 171 | *step = PyLong_AsSsize_t(r->step); |
| 172 | } |
| 173 | if (r->start == Py_None) { |
| 174 | *start = *step < 0 ? length-1 : 0; |
| 175 | } else { |
| 176 | if (!PyLong_Check(r->start)) return -1; |
| 177 | *start = PyLong_AsSsize_t(r->start); |
| 178 | if (*start < 0) *start += length; |
| 179 | } |
| 180 | if (r->stop == Py_None) { |
| 181 | *stop = *step < 0 ? -1 : length; |
| 182 | } else { |
| 183 | if (!PyLong_Check(r->stop)) return -1; |
| 184 | *stop = PyLong_AsSsize_t(r->stop); |
| 185 | if (*stop < 0) *stop += length; |
| 186 | } |
| 187 | if (*stop > length) return -1; |
| 188 | if (*start >= length) return -1; |
| 189 | if (*step == 0) return -1; |
| 190 | return 0; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 191 | } |
| 192 | |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 193 | int |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 194 | PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length, |
Mark Dickinson | e6fc740 | 2010-08-06 18:55:26 +0000 | [diff] [blame] | 195 | Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, |
| 196 | Py_ssize_t *slicelength) |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 197 | { |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame] | 198 | PySliceObject *r = (PySliceObject*)_r; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 199 | /* this is harder to get right than you might think */ |
Michael W. Hudson | 173f11d | 2002-11-05 15:28:51 +0000 | [diff] [blame] | 200 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 201 | Py_ssize_t defstart, defstop; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 202 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 203 | if (r->step == Py_None) { |
| 204 | *step = 1; |
| 205 | } |
| 206 | else { |
| 207 | if (!_PyEval_SliceIndex(r->step, step)) return -1; |
| 208 | if (*step == 0) { |
| 209 | PyErr_SetString(PyExc_ValueError, |
| 210 | "slice step cannot be zero"); |
| 211 | return -1; |
| 212 | } |
Mark Dickinson | e6fc740 | 2010-08-06 18:55:26 +0000 | [diff] [blame] | 213 | /* Here *step might be -PY_SSIZE_T_MAX-1; in this case we replace it |
| 214 | * with -PY_SSIZE_T_MAX. This doesn't affect the semantics, and it |
| 215 | * guards against later undefined behaviour resulting from code that |
| 216 | * does "step = -step" as part of a slice reversal. |
| 217 | */ |
| 218 | if (*step < -PY_SSIZE_T_MAX) |
| 219 | *step = -PY_SSIZE_T_MAX; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 220 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 221 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 222 | defstart = *step < 0 ? length-1 : 0; |
| 223 | defstop = *step < 0 ? -1 : length; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 224 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 225 | if (r->start == Py_None) { |
| 226 | *start = defstart; |
| 227 | } |
| 228 | else { |
| 229 | if (!_PyEval_SliceIndex(r->start, start)) return -1; |
| 230 | if (*start < 0) *start += length; |
| 231 | if (*start < 0) *start = (*step < 0) ? -1 : 0; |
| 232 | if (*start >= length) |
| 233 | *start = (*step < 0) ? length - 1 : length; |
| 234 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 235 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 236 | if (r->stop == Py_None) { |
| 237 | *stop = defstop; |
| 238 | } |
| 239 | else { |
| 240 | if (!_PyEval_SliceIndex(r->stop, stop)) return -1; |
| 241 | if (*stop < 0) *stop += length; |
| 242 | if (*stop < 0) *stop = (*step < 0) ? -1 : 0; |
| 243 | if (*stop >= length) |
| 244 | *stop = (*step < 0) ? length - 1 : length; |
| 245 | } |
Michael W. Hudson | 173f11d | 2002-11-05 15:28:51 +0000 | [diff] [blame] | 246 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 247 | if ((*step < 0 && *stop >= *start) |
| 248 | || (*step > 0 && *start >= *stop)) { |
| 249 | *slicelength = 0; |
| 250 | } |
| 251 | else if (*step < 0) { |
| 252 | *slicelength = (*stop-*start+1)/(*step)+1; |
| 253 | } |
| 254 | else { |
| 255 | *slicelength = (*stop-*start-1)/(*step)+1; |
| 256 | } |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 257 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 258 | return 0; |
Michael W. Hudson | 5efaf7e | 2002-06-11 10:55:12 +0000 | [diff] [blame] | 259 | } |
| 260 | |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 261 | static PyObject * |
| 262 | slice_new(PyTypeObject *type, PyObject *args, PyObject *kw) |
| 263 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 264 | PyObject *start, *stop, *step; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 265 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 266 | start = stop = step = NULL; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 267 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 268 | if (!_PyArg_NoKeywords("slice()", kw)) |
| 269 | return NULL; |
Georg Brandl | 02c4287 | 2005-08-26 06:42:30 +0000 | [diff] [blame] | 270 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 271 | if (!PyArg_UnpackTuple(args, "slice", 1, 3, &start, &stop, &step)) |
| 272 | return NULL; |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 273 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 274 | /* This swapping of stop and start is to maintain similarity with |
| 275 | range(). */ |
| 276 | if (stop == NULL) { |
| 277 | stop = start; |
| 278 | start = NULL; |
| 279 | } |
| 280 | return PySlice_New(start, stop, step); |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 281 | } |
| 282 | |
| 283 | PyDoc_STRVAR(slice_doc, |
Chris Jerdonek | 83fe2e1 | 2012-10-07 14:48:36 -0700 | [diff] [blame] | 284 | "slice(stop)\n\ |
| 285 | slice(start, stop[, step])\n\ |
Guido van Rossum | bea18cc | 2002-06-14 20:41:17 +0000 | [diff] [blame] | 286 | \n\ |
| 287 | Create a slice object. This is used for extended slicing (e.g. a[0:10:2])."); |
| 288 | |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 289 | static void |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 290 | slice_dealloc(PySliceObject *r) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 291 | { |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 292 | _PyObject_GC_UNTRACK(r); |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 293 | Py_DECREF(r->step); |
| 294 | Py_DECREF(r->start); |
| 295 | Py_DECREF(r->stop); |
Antoine Pitrou | f34a0cd | 2011-11-18 20:14:34 +0100 | [diff] [blame] | 296 | if (slice_cache == NULL) |
| 297 | slice_cache = r; |
| 298 | else |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 299 | PyObject_GC_Del(r); |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 300 | } |
| 301 | |
| 302 | static PyObject * |
Fred Drake | 45cfbcc | 2000-07-09 06:21:27 +0000 | [diff] [blame] | 303 | slice_repr(PySliceObject *r) |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 304 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 305 | 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] | 306 | } |
| 307 | |
Guido van Rossum | 6f79937 | 2001-09-20 20:46:19 +0000 | [diff] [blame] | 308 | static PyMemberDef slice_members[] = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 309 | {"start", T_OBJECT, offsetof(PySliceObject, start), READONLY}, |
| 310 | {"stop", T_OBJECT, offsetof(PySliceObject, stop), READONLY}, |
| 311 | {"step", T_OBJECT, offsetof(PySliceObject, step), READONLY}, |
| 312 | {0} |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 313 | }; |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 314 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 315 | /* Helper function to convert a slice argument to a PyLong, and raise TypeError |
| 316 | with a suitable message on failure. */ |
| 317 | |
| 318 | static PyObject* |
| 319 | evaluate_slice_index(PyObject *v) |
| 320 | { |
| 321 | if (PyIndex_Check(v)) { |
| 322 | return PyNumber_Index(v); |
| 323 | } |
| 324 | else { |
| 325 | PyErr_SetString(PyExc_TypeError, |
| 326 | "slice indices must be integers or " |
| 327 | "None or have an __index__ method"); |
| 328 | return NULL; |
| 329 | } |
| 330 | } |
| 331 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 332 | /* Compute slice indices given a slice and length. Return -1 on failure. Used |
| 333 | by slice.indices and rangeobject slicing. Assumes that `len` is a |
| 334 | nonnegative instance of PyLong. */ |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 335 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 336 | int |
| 337 | _PySlice_GetLongIndices(PySliceObject *self, PyObject *length, |
| 338 | PyObject **start_ptr, PyObject **stop_ptr, |
| 339 | PyObject **step_ptr) |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 340 | { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 341 | PyObject *start=NULL, *stop=NULL, *step=NULL; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 342 | PyObject *upper=NULL, *lower=NULL; |
| 343 | int step_is_negative, cmp_result; |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 344 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 345 | /* Convert step to an integer; raise for zero step. */ |
| 346 | if (self->step == Py_None) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 347 | step = PyLong_FromLong(1L); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 348 | if (step == NULL) |
| 349 | goto error; |
| 350 | step_is_negative = 0; |
| 351 | } |
| 352 | else { |
| 353 | int step_sign; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 354 | step = evaluate_slice_index(self->step); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 355 | if (step == NULL) |
| 356 | goto error; |
| 357 | step_sign = _PyLong_Sign(step); |
| 358 | if (step_sign == 0) { |
| 359 | PyErr_SetString(PyExc_ValueError, |
| 360 | "slice step cannot be zero"); |
| 361 | goto error; |
| 362 | } |
| 363 | step_is_negative = step_sign < 0; |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 364 | } |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 365 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 366 | /* Find lower and upper bounds for start and stop. */ |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 367 | if (step_is_negative) { |
| 368 | lower = PyLong_FromLong(-1L); |
| 369 | if (lower == NULL) |
| 370 | goto error; |
| 371 | |
| 372 | upper = PyNumber_Add(length, lower); |
| 373 | if (upper == NULL) |
| 374 | goto error; |
| 375 | } |
| 376 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 377 | lower = PyLong_FromLong(0L); |
| 378 | if (lower == NULL) |
| 379 | goto error; |
| 380 | |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 381 | upper = length; |
| 382 | Py_INCREF(upper); |
| 383 | } |
| 384 | |
| 385 | /* Compute start. */ |
| 386 | if (self->start == Py_None) { |
| 387 | start = step_is_negative ? upper : lower; |
| 388 | Py_INCREF(start); |
| 389 | } |
| 390 | else { |
| 391 | start = evaluate_slice_index(self->start); |
| 392 | if (start == NULL) |
| 393 | goto error; |
| 394 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 395 | if (_PyLong_Sign(start) < 0) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 396 | /* start += length */ |
| 397 | PyObject *tmp = PyNumber_Add(start, length); |
| 398 | Py_DECREF(start); |
| 399 | start = tmp; |
| 400 | if (start == NULL) |
| 401 | goto error; |
| 402 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 403 | cmp_result = PyObject_RichCompareBool(start, lower, Py_LT); |
| 404 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 405 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 406 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 407 | Py_INCREF(lower); |
| 408 | Py_DECREF(start); |
| 409 | start = lower; |
| 410 | } |
| 411 | } |
| 412 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 413 | cmp_result = PyObject_RichCompareBool(start, upper, Py_GT); |
| 414 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 415 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 416 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 417 | Py_INCREF(upper); |
| 418 | Py_DECREF(start); |
| 419 | start = upper; |
| 420 | } |
| 421 | } |
| 422 | } |
| 423 | |
| 424 | /* Compute stop. */ |
| 425 | if (self->stop == Py_None) { |
| 426 | stop = step_is_negative ? lower : upper; |
| 427 | Py_INCREF(stop); |
| 428 | } |
| 429 | else { |
| 430 | stop = evaluate_slice_index(self->stop); |
| 431 | if (stop == NULL) |
| 432 | goto error; |
| 433 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 434 | if (_PyLong_Sign(stop) < 0) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 435 | /* stop += length */ |
| 436 | PyObject *tmp = PyNumber_Add(stop, length); |
| 437 | Py_DECREF(stop); |
| 438 | stop = tmp; |
| 439 | if (stop == NULL) |
| 440 | goto error; |
| 441 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 442 | cmp_result = PyObject_RichCompareBool(stop, lower, Py_LT); |
| 443 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 444 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 445 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 446 | Py_INCREF(lower); |
| 447 | Py_DECREF(stop); |
| 448 | stop = lower; |
| 449 | } |
| 450 | } |
| 451 | else { |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 452 | cmp_result = PyObject_RichCompareBool(stop, upper, Py_GT); |
| 453 | if (cmp_result < 0) |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 454 | goto error; |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 455 | if (cmp_result) { |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 456 | Py_INCREF(upper); |
| 457 | Py_DECREF(stop); |
| 458 | stop = upper; |
| 459 | } |
| 460 | } |
| 461 | } |
| 462 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 463 | *start_ptr = start; |
| 464 | *stop_ptr = stop; |
| 465 | *step_ptr = step; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 466 | Py_DECREF(upper); |
| 467 | Py_DECREF(lower); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 468 | return 0; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 469 | |
| 470 | error: |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 471 | *start_ptr = *stop_ptr = *step_ptr = NULL; |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 472 | Py_XDECREF(start); |
| 473 | Py_XDECREF(stop); |
| 474 | Py_XDECREF(step); |
| 475 | Py_XDECREF(upper); |
| 476 | Py_XDECREF(lower); |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 477 | return -1; |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 478 | } |
| 479 | |
Mark Dickinson | ffdb2c2 | 2012-11-17 19:18:10 +0000 | [diff] [blame] | 480 | /* Implementation of slice.indices. */ |
| 481 | |
| 482 | static PyObject* |
| 483 | slice_indices(PySliceObject* self, PyObject* len) |
| 484 | { |
| 485 | PyObject *start, *stop, *step; |
| 486 | PyObject *length; |
| 487 | int error; |
| 488 | |
| 489 | /* Convert length to an integer if necessary; raise for negative length. */ |
| 490 | length = PyNumber_Index(len); |
| 491 | if (length == NULL) |
| 492 | return NULL; |
| 493 | |
| 494 | if (_PyLong_Sign(length) < 0) { |
| 495 | PyErr_SetString(PyExc_ValueError, |
| 496 | "length should not be negative"); |
| 497 | Py_DECREF(length); |
| 498 | return NULL; |
| 499 | } |
| 500 | |
| 501 | error = _PySlice_GetLongIndices(self, length, &start, &stop, &step); |
| 502 | Py_DECREF(length); |
| 503 | if (error == -1) |
| 504 | return NULL; |
| 505 | else |
| 506 | return Py_BuildValue("(NNN)", start, stop, step); |
| 507 | } |
Mark Dickinson | c8a6967 | 2012-11-10 14:52:10 +0000 | [diff] [blame] | 508 | |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 509 | PyDoc_STRVAR(slice_indices_doc, |
| 510 | "S.indices(len) -> (start, stop, stride)\n\ |
| 511 | \n\ |
| 512 | Assuming a sequence of length len, calculate the start and stop\n\ |
| 513 | indices, and the stride length of the extended slice described by\n\ |
| 514 | S. Out of bounds indices are clipped in a manner consistent with the\n\ |
| 515 | handling of normal slices."); |
| 516 | |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 517 | static PyObject * |
| 518 | slice_reduce(PySliceObject* self) |
| 519 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 520 | 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] | 521 | } |
| 522 | |
| 523 | PyDoc_STRVAR(reduce_doc, "Return state information for pickling."); |
| 524 | |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 525 | static PyMethodDef slice_methods[] = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 526 | {"indices", (PyCFunction)slice_indices, |
| 527 | METH_O, slice_indices_doc}, |
| 528 | {"__reduce__", (PyCFunction)slice_reduce, |
| 529 | METH_NOARGS, reduce_doc}, |
| 530 | {NULL, NULL} |
Michael W. Hudson | f0d777c | 2002-07-19 15:47:06 +0000 | [diff] [blame] | 531 | }; |
| 532 | |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 533 | static PyObject * |
| 534 | slice_richcompare(PyObject *v, PyObject *w, int op) |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 535 | { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 536 | PyObject *t1; |
| 537 | PyObject *t2; |
| 538 | PyObject *res; |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 539 | |
Brian Curtin | dfc80e3 | 2011-08-10 20:28:54 -0500 | [diff] [blame] | 540 | if (!PySlice_Check(v) || !PySlice_Check(w)) |
| 541 | Py_RETURN_NOTIMPLEMENTED; |
Thomas Wouters | 3e57b52 | 2007-08-28 23:07:26 +0000 | [diff] [blame] | 542 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 543 | if (v == w) { |
| 544 | /* XXX Do we really need this shortcut? |
| 545 | There's a unit test for it, but is that fair? */ |
| 546 | switch (op) { |
| 547 | case Py_EQ: |
| 548 | case Py_LE: |
| 549 | case Py_GE: |
| 550 | res = Py_True; |
| 551 | break; |
| 552 | default: |
| 553 | res = Py_False; |
| 554 | break; |
| 555 | } |
| 556 | Py_INCREF(res); |
| 557 | return res; |
| 558 | } |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 559 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 560 | t1 = PyTuple_New(3); |
Benjamin Peterson | 2963fe0 | 2011-10-17 13:09:27 -0400 | [diff] [blame] | 561 | if (t1 == NULL) |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 562 | return NULL; |
Benjamin Peterson | 2963fe0 | 2011-10-17 13:09:27 -0400 | [diff] [blame] | 563 | t2 = PyTuple_New(3); |
| 564 | if (t2 == NULL) { |
| 565 | Py_DECREF(t1); |
| 566 | return NULL; |
| 567 | } |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 568 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 569 | PyTuple_SET_ITEM(t1, 0, ((PySliceObject *)v)->start); |
| 570 | PyTuple_SET_ITEM(t1, 1, ((PySliceObject *)v)->stop); |
| 571 | PyTuple_SET_ITEM(t1, 2, ((PySliceObject *)v)->step); |
| 572 | PyTuple_SET_ITEM(t2, 0, ((PySliceObject *)w)->start); |
| 573 | PyTuple_SET_ITEM(t2, 1, ((PySliceObject *)w)->stop); |
| 574 | PyTuple_SET_ITEM(t2, 2, ((PySliceObject *)w)->step); |
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 | res = PyObject_RichCompare(t1, t2, op); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 577 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 578 | PyTuple_SET_ITEM(t1, 0, NULL); |
| 579 | PyTuple_SET_ITEM(t1, 1, NULL); |
| 580 | PyTuple_SET_ITEM(t1, 2, NULL); |
| 581 | PyTuple_SET_ITEM(t2, 0, NULL); |
| 582 | PyTuple_SET_ITEM(t2, 1, NULL); |
| 583 | PyTuple_SET_ITEM(t2, 2, NULL); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 584 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 585 | Py_DECREF(t1); |
| 586 | Py_DECREF(t2); |
Guido van Rossum | 47b9ff6 | 2006-08-24 00:41:19 +0000 | [diff] [blame] | 587 | |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 588 | return res; |
Guido van Rossum | a1351fb | 2001-03-20 12:41:34 +0000 | [diff] [blame] | 589 | } |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 590 | |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 591 | static int |
| 592 | slice_traverse(PySliceObject *v, visitproc visit, void *arg) |
| 593 | { |
| 594 | Py_VISIT(v->start); |
| 595 | Py_VISIT(v->stop); |
| 596 | Py_VISIT(v->step); |
| 597 | return 0; |
| 598 | } |
| 599 | |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 600 | PyTypeObject PySlice_Type = { |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 601 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 602 | "slice", /* Name of this type */ |
| 603 | sizeof(PySliceObject), /* Basic object size */ |
| 604 | 0, /* Item size for varobject */ |
| 605 | (destructor)slice_dealloc, /* tp_dealloc */ |
| 606 | 0, /* tp_print */ |
| 607 | 0, /* tp_getattr */ |
| 608 | 0, /* tp_setattr */ |
| 609 | 0, /* tp_reserved */ |
| 610 | (reprfunc)slice_repr, /* tp_repr */ |
| 611 | 0, /* tp_as_number */ |
| 612 | 0, /* tp_as_sequence */ |
| 613 | 0, /* tp_as_mapping */ |
Benjamin Peterson | 23d05c1 | 2010-10-17 20:13:05 +0000 | [diff] [blame] | 614 | PyObject_HashNotImplemented, /* tp_hash */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 615 | 0, /* tp_call */ |
| 616 | 0, /* tp_str */ |
| 617 | PyObject_GenericGetAttr, /* tp_getattro */ |
| 618 | 0, /* tp_setattro */ |
| 619 | 0, /* tp_as_buffer */ |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 620 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 621 | slice_doc, /* tp_doc */ |
Benjamin Peterson | 2b601d3 | 2016-04-16 14:47:12 -0700 | [diff] [blame] | 622 | (traverseproc)slice_traverse, /* tp_traverse */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 623 | 0, /* tp_clear */ |
| 624 | slice_richcompare, /* tp_richcompare */ |
| 625 | 0, /* tp_weaklistoffset */ |
| 626 | 0, /* tp_iter */ |
| 627 | 0, /* tp_iternext */ |
| 628 | slice_methods, /* tp_methods */ |
| 629 | slice_members, /* tp_members */ |
| 630 | 0, /* tp_getset */ |
| 631 | 0, /* tp_base */ |
| 632 | 0, /* tp_dict */ |
| 633 | 0, /* tp_descr_get */ |
| 634 | 0, /* tp_descr_set */ |
| 635 | 0, /* tp_dictoffset */ |
| 636 | 0, /* tp_init */ |
| 637 | 0, /* tp_alloc */ |
| 638 | slice_new, /* tp_new */ |
Guido van Rossum | f2d125b | 1996-07-30 16:45:48 +0000 | [diff] [blame] | 639 | }; |