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| 1 | +/* |
| 2 | +Written by Jim Hugunin and Chris Chase. |
| 3 | +
|
| 4 | +This includes both the singular ellipses object and slice objects. |
| 5 | +
|
| 6 | +Guido, feel free to do whatever you want in the way of copyrights |
| 7 | +for this file. |
| 8 | +*/ |
| 9 | + |
| 10 | +/* |
| 11 | +Py_Ellipses encodes the '...' rubber index token. It is similar to |
| 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" |
| 17 | + |
| 18 | +static PyObject * |
| 19 | +ellipses_repr(op) |
| 20 | + PyObject *op; |
| 21 | +{ |
| 22 | + return PyString_FromString("..."); |
| 23 | +} |
| 24 | + |
| 25 | +static PyTypeObject PyEllipses_Type = { |
| 26 | + PyObject_HEAD_INIT(&PyType_Type) |
| 27 | + 0, |
| 28 | + "ellipses", |
| 29 | + 0, |
| 30 | + 0, |
| 31 | + 0, /*tp_dealloc*/ /*never called*/ |
| 32 | + 0, /*tp_print*/ |
| 33 | + 0, /*tp_getattr*/ |
| 34 | + 0, /*tp_setattr*/ |
| 35 | + 0, /*tp_compare*/ |
| 36 | + (reprfunc)ellipses_repr, /*tp_repr*/ |
| 37 | + 0, /*tp_as_number*/ |
| 38 | + 0, /*tp_as_sequence*/ |
| 39 | + 0, /*tp_as_mapping*/ |
| 40 | + 0, /*tp_hash */ |
| 41 | +}; |
| 42 | + |
| 43 | +PyObject _Py_EllipsesObject = { |
| 44 | + PyObject_HEAD_INIT(&PyEllipses_Type) |
| 45 | +}; |
| 46 | + |
| 47 | + |
| 48 | +/* Slice object implementation |
| 49 | +
|
| 50 | + start, stop, and step are python objects with None indicating no |
| 51 | + index is present. |
| 52 | +*/ |
| 53 | + |
| 54 | +PyObject * |
| 55 | +PySlice_New(start, stop, step) |
| 56 | + PyObject *start; |
| 57 | + PyObject *stop; |
| 58 | + PyObject *step; |
| 59 | +{ |
| 60 | + PySliceObject *obj = |
| 61 | + (PySliceObject *) PyObject_NEW(PySliceObject, &PySlice_Type); |
| 62 | + |
| 63 | + if (step == NULL) step = Py_None; |
| 64 | + Py_INCREF(step); |
| 65 | + if (start == NULL) start = Py_None; |
| 66 | + Py_INCREF(start); |
| 67 | + if (stop == NULL) stop = Py_None; |
| 68 | + Py_INCREF(stop); |
| 69 | + |
| 70 | + obj->step = step; |
| 71 | + obj->start = start; |
| 72 | + obj->stop = stop; |
| 73 | + |
| 74 | + return (PyObject *) obj; |
| 75 | +} |
| 76 | + |
| 77 | +int |
| 78 | +PySlice_GetIndices(r, length, start, stop, step) |
| 79 | + PySliceObject *r; |
| 80 | + int length; |
| 81 | + int *start; |
| 82 | + int *stop; |
| 83 | + int *step; |
| 84 | +{ |
| 85 | + if (r->step == Py_None) { |
| 86 | + *step = 1; |
| 87 | + } else { |
| 88 | + if (!PyInt_Check(r->step)) return -1; |
| 89 | + *step = PyInt_AsLong(r->step); |
| 90 | + } |
| 91 | + if (r->start == Py_None) { |
| 92 | + *start = *step < 0 ? length-1 : 0; |
| 93 | + } else { |
| 94 | + if (!PyInt_Check(r->start)) return -1; |
| 95 | + *start = PyInt_AsLong(r->start); |
| 96 | + if (*start < 0) *start += length; |
| 97 | + } |
| 98 | + if (r->stop == Py_None) { |
| 99 | + *stop = *step < 0 ? -1 : length; |
| 100 | + } else { |
| 101 | + if (!PyInt_Check(r->stop)) return -1; |
| 102 | + *stop = PyInt_AsLong(r->stop); |
| 103 | + if (*stop < 0) *stop += length; |
| 104 | + } |
| 105 | + if (*stop > length) return -1; |
| 106 | + if (*start >= length) return -1; |
| 107 | + if (*step == 0) return -1; |
| 108 | + return 0; |
| 109 | +} |
| 110 | + |
| 111 | +static void |
| 112 | +slice_dealloc(r) |
| 113 | + PySliceObject *r; |
| 114 | +{ |
| 115 | + Py_DECREF(r->step); |
| 116 | + Py_DECREF(r->start); |
| 117 | + Py_DECREF(r->stop); |
| 118 | + PyMem_DEL(r); |
| 119 | +} |
| 120 | + |
| 121 | +static PyObject * |
| 122 | +slice_repr(r) |
| 123 | + PySliceObject *r; |
| 124 | +{ |
| 125 | + PyObject *s, *comma; |
| 126 | + |
| 127 | + s = PyString_FromString("slice("); |
| 128 | + comma = PyString_FromString(", "); |
| 129 | + PyString_ConcatAndDel(&s, PyObject_Repr(r->start)); |
| 130 | + PyString_Concat(&s, comma); |
| 131 | + PyString_ConcatAndDel(&s, PyObject_Repr(r->stop)); |
| 132 | + PyString_Concat(&s, comma); |
| 133 | + PyString_ConcatAndDel(&s, PyObject_Repr(r->step)); |
| 134 | + PyString_ConcatAndDel(&s, PyString_FromString(")")); |
| 135 | + Py_DECREF(comma); |
| 136 | + return s; |
| 137 | +} |
| 138 | + |
| 139 | + |
| 140 | +static PyObject *slice_getattr(self, name) |
| 141 | + PySliceObject *self; |
| 142 | + char *name; |
| 143 | +{ |
| 144 | + PyObject *ret; |
| 145 | + |
| 146 | + ret = NULL; |
| 147 | + if (strcmp(name, "start") == 0) { |
| 148 | + ret = self->start; |
| 149 | + } |
| 150 | + else if (strcmp(name, "stop") == 0) { |
| 151 | + ret = self->stop; |
| 152 | + } |
| 153 | + else if (strcmp(name, "step") == 0) { |
| 154 | + ret = self->step; |
| 155 | + } |
| 156 | + else if (strcmp(name, "__members__") == 0) { |
| 157 | + return Py_BuildValue("[sss]", |
| 158 | + "start", "stop", "step"); |
| 159 | + } |
| 160 | + else { |
| 161 | + PyErr_SetString(PyExc_AttributeError, name); |
| 162 | + return NULL; |
| 163 | + } |
| 164 | + Py_INCREF(ret); |
| 165 | + return ret; |
| 166 | +} |
| 167 | + |
| 168 | + |
| 169 | +PyTypeObject PySlice_Type = { |
| 170 | + PyObject_HEAD_INIT(&PyType_Type) |
| 171 | + 0, /* Number of items for varobject */ |
| 172 | + "slice", /* Name of this type */ |
| 173 | + sizeof(PySliceObject), /* Basic object size */ |
| 174 | + 0, /* Item size for varobject */ |
| 175 | + (destructor)slice_dealloc, /*tp_dealloc*/ |
| 176 | + 0, /*tp_print*/ |
| 177 | + (getattrfunc)slice_getattr, /*tp_getattr*/ |
| 178 | + 0, /*tp_setattr*/ |
| 179 | + 0, /*tp_compare*/ |
| 180 | + (reprfunc)slice_repr, /*tp_repr*/ |
| 181 | + 0, /*tp_as_number*/ |
| 182 | + 0, /*tp_as_sequence*/ |
| 183 | + 0, /*tp_as_mapping*/ |
| 184 | +}; |
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