summaryrefslogtreecommitdiffstats
path: root/Objects/rangeobject.c
blob: 8e8f77e610df4437df667acecb81f57643c971cc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170

/* Range object implementation */

#include "Python.h"

typedef struct {
	PyObject_HEAD
	long	start;
	long	step;
	long	len;
	long	index;
	int	used;	/* Set to 1 if called by range_getiter */	
} rangeobject;

PyObject *
PyRange_New(long start, long len, long step, int reps)
{
	rangeobject *obj;

	if (reps != 1) {
		PyErr_SetString(PyExc_ValueError,
			"PyRange_New's 'repetitions' argument must be 1");
		return NULL;
	}

	obj = PyObject_New(rangeobject, &PyRange_Type);
	if (obj == NULL)
		return NULL;

	if (len == 0) {
		start = 0;
		len = 0;
		step = 1;
	}
	else {
		long last = start + (len - 1) * step;
		if ((step > 0) ?
		    (last > (PyInt_GetMax() - step)) : 
		    (last < (-1 - PyInt_GetMax() - step))) {
			PyErr_SetString(PyExc_OverflowError,
					"integer addition");
			return NULL;
		}			
	}
	obj->start = start;
	obj->len   = len;
	obj->step  = step;
	obj->index = 0;
	obj->used = 0;	

	return (PyObject *) obj;
}

static PyObject *
range_item(rangeobject *r, int i)
{
	if (i < 0 || i >= r->len) {
		PyErr_SetString(PyExc_IndexError,
				"xrange object index out of range");
		return NULL;
	}
	return PyInt_FromLong(r->start + (i % r->len) * r->step);
}

static int
range_length(rangeobject *r)
{
	return r->len;
}

static PyObject *
range_repr(rangeobject *r)
{
	PyObject *rtn;
	
	if (r->start == 0 && r->step == 1)
		rtn = PyString_FromFormat("xrange(%ld)",
					  r->start + r->len * r->step);

	else if (r->step == 1)
		rtn = PyString_FromFormat("xrange(%ld, %ld)",
					  r->start,
					  r->start + r->len * r->step);

	else
		rtn = PyString_FromFormat("xrange(%ld, %ld, %ld)",
					  r->start,
					  r->start + r->len * r->step,
					  r->step);
	return rtn;
}

static PyObject *
range_getiter(rangeobject *r)
{
	rangeobject *obj;
	if (r->used == 0 || r->index >= r->len) { 
		Py_INCREF(r);
		r->used = 1;
		r->index = 0;
		return (PyObject *)r;
	}

	obj = PyObject_NEW(rangeobject, &PyRange_Type);
	if (obj == NULL)
		return NULL;

	obj->start = r->start;
	obj->len   = r->len;
	obj->step  = r->step;
	obj->index = 0;
	obj->used = 1;
	return (PyObject *) obj;
}

static PyObject *
range_next(rangeobject *r)
{
	if (r->index >= r->len) {
		PyErr_SetObject(PyExc_StopIteration, Py_None);
		return NULL;
	}
	return PyInt_FromLong(r->start + (r->index++) * r->step);
}

static PyMethodDef range_methods[] = {
        {"next",        (PyCFunction)range_next, METH_NOARGS,
         "it.next() -- get the next value, or raise StopIteration"},
        {NULL,          NULL}           /* sentinel */
};

static PySequenceMethods range_as_sequence = {
	(inquiry)range_length,	/* sq_length */
	0,			/* sq_concat */
	0,			/* sq_repeat */
	(intargfunc)range_item, /* sq_item */
	0,			/* sq_slice */
};

PyTypeObject PyRange_Type = {
	PyObject_HEAD_INIT(&PyType_Type)
	0,				/* Number of items for varobject */
	"xrange",			/* Name of this type */
	sizeof(rangeobject),		/* Basic object size */
	0,				/* Item size for varobject */
	(destructor)PyObject_Del,	/* tp_dealloc */
	0,				/* tp_print */
	0,				/* tp_getattr */
	0,				/* tp_setattr */
	0,				/* tp_compare */
	(reprfunc)range_repr,		/* tp_repr */
	0,				/* tp_as_number */
	&range_as_sequence,		/* tp_as_sequence */
	0,				/* tp_as_mapping */
	0,				/* tp_hash */
	0,				/* tp_call */
	0,				/* tp_str */
	PyObject_GenericGetAttr,	/* tp_getattro */
	0,				/* tp_setattro */
	0,				/* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,		/* tp_flags */
	0,				/* tp_doc */
	0,				/* tp_traverse */
	0,				/* tp_clear */
	0,				/* tp_richcompare */
	0,				/* tp_weaklistoffset */
	(getiterfunc)range_getiter,	/* tp_iter */
	(iternextfunc)range_next,	/* tp_iternext */
	range_methods,			/* tp_methods */	
};