| LEFT | RIGHT |
|---|---|
| 1 /* Range object implementation */ | 1 /* Range object implementation */ |
| 2 | 2 |
| 3 #include "Python.h" | 3 #include "Python.h" |
| 4 #include "structmember.h" | 4 #include "structmember.h" |
| 5 | 5 |
| 6 /* Support objects whose length is > PY_SSIZE_T_MAX. | 6 /* Support objects whose length is > PY_SSIZE_T_MAX. |
| 7 | 7 |
| 8 This could be sped up for small PyLongs if they fit in an Py_ssize_t. | 8 This could be sped up for small PyLongs if they fit in an Py_ssize_t. |
| 9 This only matters on Win64. Though we could use PY_LONG_LONG which | 9 This only matters on Win64. Though we could use PY_LONG_LONG which |
| 10 would presumably help perf. | 10 would presumably help perf. |
| 11 */ | 11 */ |
| 12 | 12 |
| 13 typedef struct { | 13 typedef struct { |
| 14 PyObject_HEAD | 14 PyObject_HEAD |
| 15 PyObject *start; | 15 PyObject *start; |
| 16 PyObject *stop; | 16 PyObject *stop; |
| 17 PyObject *step; | 17 PyObject *step; |
| 18 PyObject *length; | 18 PyObject *length; |
| 19 } rangeobject; | 19 } rangeobject; |
| 20 | 20 |
| 21 /* Helper function for validating step. Always returns a new reference or | 21 /* Helper function for validating step. Always returns a new reference or |
| 22 NULL on error. | 22 NULL on error. |
| 23 */ | 23 */ |
| 24 static PyObject * | 24 static PyObject * |
| 25 validate_step(PyObject *step) | 25 validate_step(PyObject *step) |
| 26 { | 26 { |
| 27 /* No step specified, use a step of 1. */ | 27 /* No step specified, use a step of 1. */ |
| 28 if (!step) | 28 if (!step) |
| 29 return PyLong_FromLong(1); | 29 return PyLong_FromLong(1); |
| 30 | 30 |
| 31 step = PyNumber_Index(step); | 31 step = PyNumber_Index(step); |
| 32 if (step) { | 32 if (step) { |
| 33 Py_ssize_t istep = PyNumber_AsSsize_t(step, NULL); | 33 Py_ssize_t istep = PyNumber_AsSsize_t(step, NULL); |
| 34 if (istep == -1 && PyErr_Occurred()) { | 34 if (istep == -1 && PyErr_Occurred()) { |
| 35 /* Ignore OverflowError, we know the value isn't 0. */ | 35 /* Ignore OverflowError, we know the value isn't 0. */ |
| 36 PyErr_Clear(); | 36 PyErr_Clear(); |
| 37 } | 37 } |
| 38 else if (istep == 0) { | 38 else if (istep == 0) { |
| 39 PyErr_SetString(PyExc_ValueError, | 39 PyErr_SetString(PyExc_ValueError, |
| 40 "range() arg 3 must not be zero"); | 40 "range() arg 3 must not be zero"); |
| 41 Py_CLEAR(step); | 41 Py_CLEAR(step); |
| 42 } | 42 } |
| 43 } | 43 } |
| 44 | 44 |
| 45 return step; | 45 return step; |
| 46 } | 46 } |
| 47 | 47 |
| 48 static PyObject* range_compute_length(PyObject *start, | 48 static PyObject* range_compute_length(PyObject *start, |
| 49 PyObject *stop, PyObject *step); | 49 PyObject *stop, PyObject *step); |
| 50 | 50 |
| 51 /* XXX(nnorwitz): should we error check if the user passes any empty ranges? | 51 /* XXX(nnorwitz): should we error check if the user passes any empty ranges? |
| 52 range(-10) | 52 range(-10) |
| 53 range(0, -5) | 53 range(0, -5) |
| 54 range(0, 5, -1) | 54 range(0, 5, -1) |
| 55 */ | 55 */ |
| 56 static PyObject * | 56 static PyObject * |
| 57 range_new(PyTypeObject *type, PyObject *args, PyObject *kw) | 57 range_new(PyTypeObject *type, PyObject *args, PyObject *kw) |
| 58 { | 58 { |
| 59 rangeobject *obj = NULL; | 59 rangeobject *obj = NULL; |
| 60 PyObject *start = NULL, *stop = NULL, *step = NULL, *length = NULL; | 60 PyObject *start = NULL, *stop = NULL, *step = NULL, *length = NULL; |
| 61 | 61 |
| 62 if (!_PyArg_NoKeywords("range()", kw)) | 62 if (!_PyArg_NoKeywords("range()", kw)) |
| 63 return NULL; | 63 return NULL; |
| 64 | 64 |
| 65 if (PyTuple_Size(args) <= 1) { | 65 if (PyTuple_Size(args) <= 1) { |
| 66 if (!PyArg_UnpackTuple(args, "range", 1, 1, &stop)) | 66 if (!PyArg_UnpackTuple(args, "range", 1, 1, &stop)) |
| 67 goto Fail; | 67 goto Fail; |
| 68 stop = PyNumber_Index(stop); | 68 stop = PyNumber_Index(stop); |
| 69 if (!stop) | 69 if (!stop) |
| 70 goto Fail; | 70 goto Fail; |
| 71 start = PyLong_FromLong(0); | 71 start = PyLong_FromLong(0); |
| 72 step = PyLong_FromLong(1); | 72 step = PyLong_FromLong(1); |
| 73 if (!start || !step) | 73 if (!start || !step) |
| 74 goto Fail; | 74 goto Fail; |
| 75 } | 75 } |
| 76 else { | 76 else { |
| 77 if (!PyArg_UnpackTuple(args, "range", 2, 3, | 77 if (!PyArg_UnpackTuple(args, "range", 2, 3, |
| 78 &start, &stop, &step)) | 78 &start, &stop, &step)) |
| 79 goto Fail; | 79 goto Fail; |
| 80 | 80 |
| 81 /* Convert borrowed refs to owned refs */ | 81 /* Convert borrowed refs to owned refs */ |
| 82 start = PyNumber_Index(start); | 82 start = PyNumber_Index(start); |
| 83 stop = PyNumber_Index(stop); | 83 stop = PyNumber_Index(stop); |
| 84 step = validate_step(step); | 84 step = validate_step(step); |
| 85 if (!start || !stop || !step) | 85 if (!start || !stop || !step) |
| 86 goto Fail; | 86 goto Fail; |
| 87 } | 87 } |
| 88 | 88 |
| 89 length = range_compute_length(start, stop, step); | 89 length = range_compute_length(start, stop, step); |
| 90 if (length == NULL) | 90 if (length == NULL) |
| 91 goto Fail; | 91 goto Fail; |
| 92 obj = PyObject_New(rangeobject, &PyRange_Type); | 92 obj = PyObject_New(rangeobject, &PyRange_Type); |
| 93 if (obj == NULL) | 93 if (obj == NULL) |
| 94 goto Fail; | 94 goto Fail; |
| 95 obj->start = start; | 95 obj->start = start; |
| 96 obj->stop = stop; | 96 obj->stop = stop; |
| 97 obj->step = step; | 97 obj->step = step; |
| 98 obj->length = length; | 98 obj->length = length; |
| 99 return (PyObject *) obj; | 99 return (PyObject *) obj; |
| 100 | 100 |
| 101 Fail: | 101 Fail: |
| 102 Py_XDECREF(start); | 102 Py_XDECREF(start); |
| 103 Py_XDECREF(stop); | 103 Py_XDECREF(stop); |
| 104 Py_XDECREF(step); | 104 Py_XDECREF(step); |
| 105 Py_XDECREF(length); | 105 Py_XDECREF(length); |
| 106 return NULL; | 106 return NULL; |
| 107 } | 107 } |
| 108 | 108 |
| 109 PyDoc_STRVAR(range_doc, | 109 PyDoc_STRVAR(range_doc, |
| 110 "range([start,] stop[, step]) -> range object\n\ | 110 "range([start,] stop[, step]) -> range object\n\ |
| 111 \n\ | 111 \n\ |
| 112 Return an arithmetic progression of numbers from start " | 112 Returns a virtual sequence of numbers from start to stop by step."); |
| 113 "to stop (exclusive) by step."); | |
| 114 | 113 |
| 115 static void | 114 static void |
| 116 range_dealloc(rangeobject *r) | 115 range_dealloc(rangeobject *r) |
| 117 { | 116 { |
| 118 Py_DECREF(r->start); | 117 Py_DECREF(r->start); |
| 119 Py_DECREF(r->stop); | 118 Py_DECREF(r->stop); |
| 120 Py_DECREF(r->step); | 119 Py_DECREF(r->step); |
| 121 Py_DECREF(r->length); | 120 Py_DECREF(r->length); |
| 122 PyObject_Del(r); | 121 PyObject_Del(r); |
| 123 } | 122 } |
| 124 | 123 |
| 124 /* Return number of items in range (lo, hi, step), when arguments are | |
| 125 * PyInt or PyLong objects. step > 0 required. Return a value < 0 if | |
| 126 * & only if the true value is too large to fit in a signed long. | |
| 127 * Arguments MUST return 1 with either PyLong_Check() or | |
| 128 * PyLong_Check(). Return -1 when there is an error. | |
| 129 */ | |
| 125 static PyObject * | 130 static PyObject * |
| 126 range_compute_length(PyObject *start, PyObject *stop, PyObject *step) | 131 range_compute_length(PyObject *start, PyObject *stop, PyObject *step) |
| 127 { | 132 { |
| 128 /* ------------------------------------------------------------- | 133 /* ------------------------------------------------------------- |
| 129 Algorithm is equal to that of get_len_of_range(), but it operates | 134 Algorithm is equal to that of get_len_of_range(), but it operates |
| 130 on PyObjects (which are assumed to be PyLong or PyInt objects). | 135 on PyObjects (which are assumed to be PyLong or PyInt objects). |
| 131 ---------------------------------------------------------------*/ | 136 ---------------------------------------------------------------*/ |
| 132 int cmp_result, cmp_call; | 137 int cmp_result, cmp_call; |
| 133 PyObject *lo, *hi; | 138 PyObject *lo, *hi; |
| 134 PyObject *diff = NULL; | 139 PyObject *diff = NULL; |
| 135 PyObject *one = NULL; | 140 PyObject *one = NULL; |
| 136 PyObject *tmp1 = NULL, *tmp2 = NULL, *result; | 141 PyObject *tmp1 = NULL, *tmp2 = NULL, *result; |
| 137 /* holds sub-expression evaluations */ | 142 /* holds sub-expression evaluations */ |
| 138 | 143 |
| 139 PyObject *zero = PyLong_FromLong(0); | 144 PyObject *zero = PyLong_FromLong(0); |
| 140 if (zero == NULL) | 145 if (zero == NULL) |
| 141 return NULL; | 146 return NULL; |
| 142 cmp_call = PyObject_Cmp(step, zero, &cmp_result); | 147 cmp_call = PyObject_Cmp(step, zero, &cmp_result); |
| 143 Py_DECREF(zero); | 148 Py_DECREF(zero); |
| 144 if (cmp_call == -1) | 149 if (cmp_call == -1) |
| 145 return NULL; | 150 return NULL; |
| 146 | 151 |
| 147 assert(cmp_result != 0); | 152 assert(cmp_result != 0); |
| 148 if (cmp_result > 0) { | 153 if (cmp_result > 0) { |
| 149 lo = start; | 154 lo = start; |
| 150 hi = stop; | 155 hi = stop; |
| 151 Py_INCREF(step); | 156 Py_INCREF(step); |
| 152 } else { | 157 } else { |
| 153 lo = stop; | 158 lo = stop; |
| 154 hi = start; | 159 hi = start; |
| 155 step = PyNumber_Negative(step); | 160 step = PyNumber_Negative(step); |
| 156 if (!step) | 161 if (!step) |
| 157 goto Fail; | 162 goto Fail; |
| 158 } | 163 } |
| 159 | 164 |
| 160 /* if (lo >= hi), return length of 0. */ | 165 /* if (lo >= hi), return length of 0. */ |
| 161 if (PyObject_Compare(lo, hi) >= 0) { | 166 if (PyObject_Compare(lo, hi) >= 0) { |
| 162 Py_XDECREF(step); | 167 Py_XDECREF(step); |
| 163 return PyLong_FromLong(0); | 168 return PyLong_FromLong(0); |
| 164 } | 169 } |
| 165 | 170 |
| 166 if ((one = PyLong_FromLong(1L)) == NULL) | 171 if ((one = PyLong_FromLong(1L)) == NULL) |
| 167 goto Fail; | 172 goto Fail; |
| 168 | 173 |
| 169 if ((tmp1 = PyNumber_Subtract(hi, lo)) == NULL) | 174 if ((tmp1 = PyNumber_Subtract(hi, lo)) == NULL) |
| 170 goto Fail; | 175 goto Fail; |
| 171 | 176 |
| 172 if ((diff = PyNumber_Subtract(tmp1, one)) == NULL) | 177 if ((diff = PyNumber_Subtract(tmp1, one)) == NULL) |
| 173 goto Fail; | 178 goto Fail; |
| 174 | 179 |
| 175 if ((tmp2 = PyNumber_FloorDivide(diff, step)) == NULL) | 180 if ((tmp2 = PyNumber_FloorDivide(diff, step)) == NULL) |
| 176 goto Fail; | 181 goto Fail; |
| 177 | 182 |
| 178 if ((result = PyNumber_Add(tmp2, one)) == NULL) | 183 if ((result = PyNumber_Add(tmp2, one)) == NULL) |
| 179 goto Fail; | 184 goto Fail; |
| 180 | 185 |
| 181 Py_DECREF(tmp2); | 186 Py_DECREF(tmp2); |
| 182 Py_DECREF(diff); | 187 Py_DECREF(diff); |
| 183 Py_DECREF(step); | 188 Py_DECREF(step); |
| 184 Py_DECREF(tmp1); | 189 Py_DECREF(tmp1); |
| 185 Py_DECREF(one); | 190 Py_DECREF(one); |
| 186 return result; | 191 return result; |
| 187 | 192 |
| 188 Fail: | 193 Fail: |
| 189 Py_XDECREF(tmp2); | 194 Py_XDECREF(tmp2); |
| 190 Py_XDECREF(diff); | 195 Py_XDECREF(diff); |
| 191 Py_XDECREF(step); | 196 Py_XDECREF(step); |
| 192 Py_XDECREF(tmp1); | 197 Py_XDECREF(tmp1); |
| 193 Py_XDECREF(one); | 198 Py_XDECREF(one); |
| 194 return NULL; | 199 return NULL; |
| 195 } | 200 } |
| 196 | 201 |
| 197 static Py_ssize_t | 202 static Py_ssize_t |
| 198 range_length(rangeobject *r) | 203 range_length(rangeobject *r) |
| 199 { | 204 { |
| 200 return PyLong_AsSsize_t(r->length); | 205 return PyLong_AsSsize_t(r->length); |
| 201 } | 206 } |
| 202 | 207 |
| 203 | 208 |
| 204 static PyObject * | 209 static PyObject * |
| 205 range_repr(rangeobject *r) | 210 range_repr(rangeobject *r) |
| 206 { | 211 { |
| 207 Py_ssize_t istep; | 212 Py_ssize_t istep; |
| 208 | 213 |
| 209 /* Check for special case values for printing. We don't always | 214 /* Check for special case values for printing. We don't always |
| 210 need the step value. We don't care about errors | 215 need the step value. We don't care about errors |
| 211 (it means overflow), so clear the errors. */ | 216 (it means overflow), so clear the errors. */ |
| 212 istep = PyNumber_AsSsize_t(r->step, NULL); | 217 istep = PyNumber_AsSsize_t(r->step, NULL); |
| 213 if (istep != 1 || (istep == -1 && PyErr_Occurred())) { | 218 if (istep != 1 || (istep == -1 && PyErr_Occurred())) { |
| 214 PyErr_Clear(); | 219 PyErr_Clear(); |
| 215 } | 220 } |
| 216 | 221 |
| 217 if (istep == 1) | 222 if (istep == 1) |
| 218 return PyUnicode_FromFormat("range(%R, %R)", r->start, r->stop); | 223 return PyUnicode_FromFormat("range(%R, %R)", r->start, r->stop); |
| 219 else | 224 else |
| 220 return PyUnicode_FromFormat("range(%R, %R, %R)", | 225 return PyUnicode_FromFormat("range(%R, %R, %R)", |
| 221 r->start, r->stop, r->step); | 226 r->start, r->stop, r->step); |
| 222 } | 227 } |
| 223 | 228 |
| 224 static PyMemberDef range_members[] = { | 229 static PyMemberDef range_members[] = { |
| 225 {"start", T_OBJECT, offsetof(rangeobject, start), READONLY}, | 230 {"start", T_OBJECT, offsetof(rangeobject, start), READONLY}, |
| 226 {"stop", T_OBJECT, offsetof(rangeobject, stop), READONLY}, | 231 {"stop", T_OBJECT, offsetof(rangeobject, stop), READONLY}, |
| 227 {"step", T_OBJECT, offsetof(rangeobject, step), READONLY}, | 232 {"step", T_OBJECT, offsetof(rangeobject, step), READONLY}, |
| 228 {0} | 233 {0} |
| 229 }; | 234 }; |
| 230 | 235 |
| 236 static PySequenceMethods range_as_sequence = { | |
| 237 (lenfunc)range_length, /* sq_length */ | |
| 238 0, /* sq_concat */ | |
| 239 0, /* sq_repeat */ | |
| 240 0, /* sq_item */ | |
| 241 0, /* sq_slice */ | |
| 242 0, /* sq_ass_item */ | |
| 243 0, /* sq_ass_slice */ | |
| 244 0, /* sq_contains */ | |
| 245 }; | |
| 246 | |
| 231 static PyObject * range_iter(PyObject *seq); | 247 static PyObject * range_iter(PyObject *seq); |
| 232 static PyObject * range_reverse(PyObject *seq); | 248 static PyObject * range_reverse(PyObject *seq); |
| 233 | 249 |
| 234 PyDoc_STRVAR(reverse_doc, | 250 PyDoc_STRVAR(reverse_doc, |
| 235 "Returns a reverse iterator."); | 251 "Returns a reverse iterator."); |
| 236 | |
| 237 static PySequenceMethods range_as_sequence = { | |
| 238 (lenfunc)range_length, /* sq_length */ | |
| 239 0, /* sq_concat */ | |
| 240 0, /* sq_repeat */ | |
| 241 0, /* sq_item */ | |
| 242 0, /* sq_slice */ | |
| 243 0, /* sq_ass_item */ | |
| 244 0, /* sq_ass_slice */ | |
| 245 0, /* sq_contains */ | |
| 246 0, /* sq_inplace_concat */ | |
| 247 0, /* sq_inplace_repeat */ | |
| 248 }; | |
| 249 | 252 |
| 250 static PyMethodDef range_methods[] = { | 253 static PyMethodDef range_methods[] = { |
| 251 {"__reversed__", (PyCFunction)range_reverse, METH_NOARGS, | 254 {"__reversed__", (PyCFunction)range_reverse, METH_NOARGS, |
| 252 reverse_doc}, | 255 reverse_doc}, |
| 253 {NULL, NULL} /* sentinel */ | 256 {NULL, NULL} /* sentinel */ |
| 254 }; | 257 }; |
| 255 | 258 |
| 256 PyTypeObject PyRange_Type = { | 259 PyTypeObject PyRange_Type = { |
| 257 PyVarObject_HEAD_INIT(&PyType_Type, 0) | 260 PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 258 "range", /* Name of this type */ | 261 "range", /* Name of this type */ |
| 259 sizeof(rangeobject), /* Basic object size */ | 262 sizeof(rangeobject), /* Basic object size */ |
| 260 0, /* Item size for varobject */ | 263 0, /* Item size for varobject */ |
| 261 (destructor)range_dealloc, /* tp_dealloc */ | 264 (destructor)range_dealloc, /* tp_dealloc */ |
| 262 0, /* tp_print */ | 265 0, /* tp_print */ |
| 263 0, /* tp_getattr */ | 266 0, /* tp_getattr */ |
| 264 0, /* tp_setattr */ | 267 0, /* tp_setattr */ |
| 265 0, /* tp_compare */ | 268 0, /* tp_compare */ |
| 266 (reprfunc)range_repr, /* tp_repr */ | 269 (reprfunc)range_repr, /* tp_repr */ |
| 267 0, /* tp_as_number */ | 270 0, /* tp_as_number */ |
| 268 &range_as_sequence, /* tp_as_sequence */ | 271 &range_as_sequence, /* tp_as_sequence */ |
| 269 0, /* tp_as_mapping */ | 272 0, /* tp_as_mapping */ |
| 270 0, /* tp_hash */ | 273 0, /* tp_hash */ |
| 271 0, /* tp_call */ | 274 0, /* tp_call */ |
| 272 0, /* tp_str */ | 275 0, /* tp_str */ |
| 273 PyObject_GenericGetAttr, /* tp_getattro */ | 276 PyObject_GenericGetAttr, /* tp_getattro */ |
| 274 0, /* tp_setattro */ | 277 0, /* tp_setattro */ |
| 275 0, /* tp_as_buffer */ | 278 0, /* tp_as_buffer */ |
| 276 Py_TPFLAGS_DEFAULT, /* tp_flags */ | 279 Py_TPFLAGS_DEFAULT, /* tp_flags */ |
| 277 range_doc, /* tp_doc */ | 280 range_doc, /* tp_doc */ |
| 278 0, /* tp_traverse */ | 281 0, /* tp_traverse */ |
| 279 0, /* tp_clear */ | 282 0, /* tp_clear */ |
| 280 0, /* tp_richcompare */ | 283 0, /* tp_richcompare */ |
| 281 0, /* tp_weaklistoffset */ | 284 0, /* tp_weaklistoffset */ |
| 282 range_iter, /* tp_iter */ | 285 range_iter, /* tp_iter */ |
| 283 0, /* tp_iternext */ | 286 0, /* tp_iternext */ |
| 284 range_methods, /* tp_methods */ | 287 range_methods, /* tp_methods */ |
| 285 range_members, /* tp_members */ | 288 range_members, /* tp_members */ |
|
mvloewis
2008/05/02 20:17:20
Carrying forward from the previous patch set: this
| |
| 286 0, /* tp_getset */ | 289 0, /* tp_getset */ |
| 287 0, /* tp_base */ | 290 0, /* tp_base */ |
| 288 0, /* tp_dict */ | 291 0, /* tp_dict */ |
| 289 0, /* tp_descr_get */ | 292 0, /* tp_descr_get */ |
| 290 0, /* tp_descr_set */ | 293 0, /* tp_descr_set */ |
| 291 0, /* tp_dictoffset */ | 294 0, /* tp_dictoffset */ |
| 292 0, /* tp_init */ | 295 0, /* tp_init */ |
| 293 0, /* tp_alloc */ | 296 0, /* tp_alloc */ |
| 294 range_new, /* tp_new */ | 297 range_new, /* tp_new */ |
| 295 }; | 298 }; |
| 296 | 299 |
| 297 /*********************** range Iterator **************************/ | 300 /*********************** range Iterator **************************/ |
| 298 | 301 |
| 299 /* There are 2 types of iterators, one for C longs, the other for | 302 /* There are 2 types of iterators, one for C longs, the other for |
| 300 Python longs (ie, PyObjects). This should make iteration fast | 303 Python longs (ie, PyObjects). This should make iteration fast |
| 301 in the normal case, but possible for any numeric value. | 304 in the normal case, but possible for any numeric value. |
| 302 */ | 305 */ |
| 303 | 306 |
| 304 typedef struct { | 307 typedef struct { |
| 305 PyObject_HEAD | 308 PyObject_HEAD |
| 306 long index; | 309 long index; |
| 307 long start; | 310 long start; |
| 308 long step; | 311 long step; |
| 309 long len; | 312 long len; |
| 310 } rangeiterobject; | 313 } rangeiterobject; |
| 311 | 314 |
| 312 static PyObject * | 315 static PyObject * |
| 313 rangeiter_next(rangeiterobject *r) | 316 rangeiter_next(rangeiterobject *r) |
| 314 { | 317 { |
| 315 if (r->index < r->len) | 318 if (r->index < r->len) |
| 316 return PyLong_FromLong(r->start + (r->index++) * r->step); | 319 return PyLong_FromLong(r->start + (r->index++) * r->step); |
| 317 return NULL; | 320 return NULL; |
| 318 } | 321 } |
| 319 | 322 |
| 320 static PyObject * | 323 static PyObject * |
| 321 rangeiter_len(rangeiterobject *r) | 324 rangeiter_len(rangeiterobject *r) |
| 322 { | 325 { |
| 323 return PyLong_FromLong(r->len - r->index); | 326 return PyLong_FromLong(r->len - r->index); |
| 324 } | 327 } |
| 325 | 328 |
| 326 typedef struct { | 329 typedef struct { |
| 327 PyObject_HEAD | 330 PyObject_HEAD |
| 328 PyObject *index; | 331 PyObject *index; |
| 329 PyObject *start; | 332 PyObject *start; |
| 330 PyObject *step; | 333 PyObject *step; |
| 331 PyObject *length; | 334 PyObject *len; |
| 332 } longrangeiterobject; | 335 } longrangeiterobject; |
| 333 | 336 |
| 334 static PyObject * | 337 static PyObject * |
| 335 longrangeiter_len(longrangeiterobject *r, PyObject *no_args) | 338 longrangeiter_len(longrangeiterobject *r, PyObject *no_args) |
| 336 { | 339 { |
| 337 return PyNumber_Subtract(r->length, r->index); | 340 return PyNumber_Subtract(r->len, r->index); |
| 338 } | 341 } |
| 339 | 342 |
| 340 static PyObject *rangeiter_new(PyTypeObject *, PyObject *args, PyObject *kw); | 343 static PyObject *rangeiter_new(PyTypeObject *, PyObject *args, PyObject *kw); |
| 341 | 344 |
| 342 PyDoc_STRVAR(length_hint_doc, | 345 PyDoc_STRVAR(length_hint_doc, |
| 343 "Private method returning an estimate of len(list(it))."); | 346 "Private method returning an estimate of len(list(it))."); |
| 344 | 347 |
| 345 static PyMethodDef rangeiter_methods[] = { | 348 static PyMethodDef rangeiter_methods[] = { |
| 346 {"__length_hint__", (PyCFunction)rangeiter_len, METH_NOARGS, | 349 {"__length_hint__", (PyCFunction)rangeiter_len, METH_NOARGS, |
| 347 length_hint_doc}, | 350 length_hint_doc}, |
| 348 {NULL, NULL} /* sentinel */ | 351 {NULL, NULL} /* sentinel */ |
| 349 }; | 352 }; |
| 350 | 353 |
| 351 PyTypeObject PyRangeIter_Type = { | 354 PyTypeObject PyRangeIter_Type = { |
| 352 PyVarObject_HEAD_INIT(&PyType_Type, 0) | 355 PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 353 "range_iterator", /* tp_name */ | 356 "range_iterator", /* tp_name */ |
| 354 sizeof(rangeiterobject), /* tp_basicsize */ | 357 sizeof(rangeiterobject), /* tp_basicsize */ |
| 355 0, /* tp_itemsize */ | 358 0, /* tp_itemsize */ |
| 356 /* methods */ | 359 /* methods */ |
| 357 (destructor)PyObject_Del, /* tp_dealloc */ | 360 (destructor)PyObject_Del, /* tp_dealloc */ |
| 358 0, /* tp_print */ | 361 0, /* tp_print */ |
| 359 0, /* tp_getattr */ | 362 0, /* tp_getattr */ |
| 360 0, /* tp_setattr */ | 363 0, /* tp_setattr */ |
| 361 0, /* tp_compare */ | 364 0, /* tp_compare */ |
| 362 0, /* tp_repr */ | 365 0, /* tp_repr */ |
| 363 0, /* tp_as_number */ | 366 0, /* tp_as_number */ |
| 364 0, /* tp_as_sequence */ | 367 0, /* tp_as_sequence */ |
| 365 0, /* tp_as_mapping */ | 368 0, /* tp_as_mapping */ |
| 366 0, /* tp_hash */ | 369 0, /* tp_hash */ |
| 367 0, /* tp_call */ | 370 0, /* tp_call */ |
| 368 0, /* tp_str */ | 371 0, /* tp_str */ |
| 369 PyObject_GenericGetAttr, /* tp_getattro */ | 372 PyObject_GenericGetAttr, /* tp_getattro */ |
| 370 0, /* tp_setattro */ | 373 0, /* tp_setattro */ |
| 371 0, /* tp_as_buffer */ | 374 0, /* tp_as_buffer */ |
| 372 Py_TPFLAGS_DEFAULT, /* tp_flags */ | 375 Py_TPFLAGS_DEFAULT, /* tp_flags */ |
| 373 0, /* tp_doc */ | 376 0, /* tp_doc */ |
| 374 0, /* tp_traverse */ | 377 0, /* tp_traverse */ |
| 375 0, /* tp_clear */ | 378 0, /* tp_clear */ |
| 376 0, /* tp_richcompare */ | 379 0, /* tp_richcompare */ |
| 377 0, /* tp_weaklistoffset */ | 380 0, /* tp_weaklistoffset */ |
| 378 PyObject_SelfIter, /* tp_iter */ | 381 PyObject_SelfIter, /* tp_iter */ |
| 379 (iternextfunc)rangeiter_next, /* tp_iternext */ | 382 (iternextfunc)rangeiter_next, /* tp_iternext */ |
| 380 rangeiter_methods, /* tp_methods */ | 383 rangeiter_methods, /* tp_methods */ |
| 381 0, /* tp_members */ | 384 0, /* tp_members */ |
| 382 0, /* tp_getset */ | 385 0, /* tp_getset */ |
| 383 0, /* tp_base */ | 386 0, /* tp_base */ |
| 384 0, /* tp_dict */ | 387 0, /* tp_dict */ |
| 385 0, /* tp_descr_get */ | 388 0, /* tp_descr_get */ |
| 386 0, /* tp_descr_set */ | 389 0, /* tp_descr_set */ |
| 387 0, /* tp_dictoffset */ | 390 0, /* tp_dictoffset */ |
| 388 0, /* tp_init */ | 391 0, /* tp_init */ |
| 389 0, /* tp_alloc */ | 392 0, /* tp_alloc */ |
| 390 rangeiter_new, /* tp_new */ | 393 rangeiter_new, /* tp_new */ |
| 391 }; | 394 }; |
| 392 | 395 |
| 393 /* Return number of items in range/xrange (lo, hi, step). step > 0 | 396 /* Return number of items in range/xrange (lo, hi, step). step > 0 |
| 394 * required. Return a value < 0 if & only if the true value is too | 397 * required. Return a value < 0 if & only if the true value is too |
| 395 * large to fit in a signed long. | 398 * large to fit in a signed long. |
| 396 */ | 399 */ |
| 397 static long | 400 static long |
| 398 get_len_of_range(long lo, long hi, long step) | 401 get_len_of_range(long lo, long hi, long step) |
| 399 { | 402 { |
| 400 /* ------------------------------------------------------------- | 403 /* ------------------------------------------------------------- |
| 401 If lo >= hi, the range is empty. | 404 If lo >= hi, the range is empty. |
| 402 Else if n values are in the range, the last one is | 405 Else if n values are in the range, the last one is |
| 403 lo + (n-1)*step, which must be <= hi-1. Rearranging, | 406 lo + (n-1)*step, which must be <= hi-1. Rearranging, |
| 404 n <= (hi - lo - 1)/step + 1, so taking the floor of the RHS gives | 407 n <= (hi - lo - 1)/step + 1, so taking the floor of the RHS gives |
| 405 the proper value. Since lo < hi in this case, hi-lo-1 >= 0, so | 408 the proper value. Since lo < hi in this case, hi-lo-1 >= 0, so |
| 406 the RHS is non-negative and so truncation is the same as the | 409 the RHS is non-negative and so truncation is the same as the |
| 407 floor. Letting M be the largest positive long, the worst case | 410 floor. Letting M be the largest positive long, the worst case |
| 408 for the RHS numerator is hi=M, lo=-M-1, and then | 411 for the RHS numerator is hi=M, lo=-M-1, and then |
| 409 hi-lo-1 = M-(-M-1)-1 = 2*M. Therefore unsigned long has enough | 412 hi-lo-1 = M-(-M-1)-1 = 2*M. Therefore unsigned long has enough |
| 410 precision to compute the RHS exactly. | 413 precision to compute the RHS exactly. |
| 411 ---------------------------------------------------------------*/ | 414 ---------------------------------------------------------------*/ |
| 412 long n = 0; | 415 long n = 0; |
| 413 if (lo < hi) { | 416 if (lo < hi) { |
| 414 unsigned long uhi = (unsigned long)hi; | 417 unsigned long uhi = (unsigned long)hi; |
| 415 unsigned long ulo = (unsigned long)lo; | 418 unsigned long ulo = (unsigned long)lo; |
| 416 unsigned long diff = uhi - ulo - 1; | 419 unsigned long diff = uhi - ulo - 1; |
| 417 n = (long)(diff / (unsigned long)step + 1); | 420 n = (long)(diff / (unsigned long)step + 1); |
| 418 } | 421 } |
| 419 return n; | 422 return n; |
| 420 } | 423 } |
| 421 | 424 |
| 422 static PyObject * | 425 static PyObject * |
| 423 int_range_iter(long start, long stop, long step) | 426 int_range_iter(long start, long stop, long step) |
| 424 { | 427 { |
| 425 rangeiterobject *it = PyObject_New(rangeiterobject, &PyRangeIter_Type); | 428 rangeiterobject *it = PyObject_New(rangeiterobject, &PyRangeIter_Type); |
| 426 if (it == NULL) | 429 if (it == NULL) |
| 427 return NULL; | 430 return NULL; |
| 428 it->start = start; | 431 it->start = start; |
| 429 it->step = step; | 432 it->step = step; |
| 430 if (step > 0) | 433 if (step > 0) |
| 431 it->len = get_len_of_range(start, stop, step); | 434 it->len = get_len_of_range(start, stop, step); |
| 432 else | 435 else |
| 433 it->len = get_len_of_range(stop, start, -step); | 436 it->len = get_len_of_range(stop, start, -step); |