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Changed PySequence_List() and PySequence_Tuple() to support

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"indefinite length" sequences.  These should still have a length, but
the length is only used as a hint -- the actual length of the sequence
is determined by the item that raises IndexError, which may be either
smaller or larger than what len() returns.  (This is a novelty; map(),
filter() and reduce() only allow the actual length to be larger than
what len() returns, not shorter.  I'll fix that shortly.)
This commit is contained in:
Guido van Rossum 1998-07-10 16:22:44 +00:00
parent df901dfdea
commit bfc725bf64
1 changed files with 38 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

61
Objects/abstract.c
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@ -1005,30 +1005,12 @@ PySequence_Tuple(v)
if (PyList_Check(v)) if (PyList_Check(v))
return PyList_AsTuple(v); return PyList_AsTuple(v);
if (PyString_Check(v)) { /* There used to be code for strings here, but tuplifying strings is
int n = PyString_Size(v); not a common activity, so I nuked it. Down with code bloat! */
PyObject *t = PyTuple_New(n);
if (t != NULL) {
int i;
char *p = PyString_AsString(v);
for (i = 0; i < n; i++) {
PyObject *item =
PyString_FromStringAndSize(p+i, 1);
if (item == NULL) {
Py_DECREF(t);
t = NULL;
break;
}
PyTuple_SetItem(t, i, item);
}
}
return t;
}
/* Generic sequence object */ /* Generic sequence object */
m = v->ob_type->tp_as_sequence; m = v->ob_type->tp_as_sequence;
if (m && m->sq_item) { if (m && m->sq_item) {
/* XXX Should support indefinite-length sequences */
int i; int i;
PyObject *t; PyObject *t;
int n = PySequence_Length(v); int n = PySequence_Length(v);
@ -1037,15 +1019,29 @@ PySequence_Tuple(v)
t = PyTuple_New(n); t = PyTuple_New(n);
if (t == NULL) if (t == NULL)
return NULL; return NULL;
for (i = 0; i < n; i++) { for (i = 0; ; i++) {
PyObject *item = (*m->sq_item)(v, i); PyObject *item = (*m->sq_item)(v, i);
if (item == NULL) { if (item == NULL) {
if (PyErr_ExceptionMatches(PyExc_IndexError))
PyErr_Clear();
else {
Py_DECREF(t); Py_DECREF(t);
t = NULL; t = NULL;
}
break; break;
} }
PyTuple_SetItem(t, i, item); if (i >= n) {
if (n < 500)
n += 10;
else
n += 100;
if (_PyTuple_Resize(&t, n, 0) != 0)
break;
} }
PyTuple_SET_ITEM(t, i, item);
}
if (i < n && t != NULL)
_PyTuple_Resize(&t, i, 0);
return t; return t;
} }
@ -1061,7 +1057,6 @@ PySequence_List(v)
m = v->ob_type->tp_as_sequence; m = v->ob_type->tp_as_sequence;
if (m && m->sq_item) { if (m && m->sq_item) {
/* XXX Should support indefinite-length sequences */
int i; int i;
PyObject *l; PyObject *l;
int n = PySequence_Length(v); int n = PySequence_Length(v);
@ -1070,14 +1065,30 @@ PySequence_List(v)
l = PyList_New(n); l = PyList_New(n);
if (l == NULL) if (l == NULL)
return NULL; return NULL;
for (i = 0; i < n; i++) { for (i = 0; ; i++) {
PyObject *item = (*m->sq_item)(v, i); PyObject *item = (*m->sq_item)(v, i);
if (item == NULL) { if (item == NULL) {
if (PyErr_ExceptionMatches(PyExc_IndexError))
PyErr_Clear();
else {
Py_DECREF(l);
l = NULL;
}
break;
}
if (i < n)
PyList_SET_ITEM(l, i, item);
else if (PyList_Append(l, item) < 0) {
Py_DECREF(l); Py_DECREF(l);
l = NULL; l = NULL;
break; break;
} }
PyList_SetItem(l, i, item); }
if (i < n && l != NULL) {
if (PyList_SetSlice(l, i, n, (PyObject *)NULL) != 0) {
Py_DECREF(l);
l = NULL;
}
} }
return l; return l;
} }