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SF bug 433228: repr(list) woes when len(list) big.

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Gave Python linear-time repr() implementations for dicts, lists, strings.
This means, e.g., that repr(range(50000)) is no longer 50x slower than
pprint.pprint() in 2.2 <wink>.

I don't consider this a bugfix candidate, as it's a performance boost.

Added _PyString_Join() to the internal string API.  If we want that in the
public API, fine, but then it requires runtime error checks instead of
asserts.
This commit is contained in:
Tim Peters 2001-06-16 05:11:17 +00:00
parent 239508cd10
commit a7259597f1
5 changed files with 193 additions and 56 deletions
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68
Objects/listobject.c
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@ -246,26 +246,68 @@ list_print(PyListObject *op, FILE *fp, int flags)
static PyObject *
list_repr(PyListObject *v)
{
PyObject *s, *comma;
int i;
PyObject *s, *temp;
PyObject *pieces = NULL, *result = NULL;
i = Py_ReprEnter((PyObject*)v);
if (i != 0) {
if (i > 0)
return PyString_FromString("[...]");
return NULL;
return i > 0 ? PyString_FromString("[...]") : NULL;
}
if (v->ob_size == 0) {
result = PyString_FromString("[]");
goto Done;
}
pieces = PyList_New(0);
if (pieces == NULL)
goto Done;
/* Do repr() on each element. Note that this may mutate the list,
so must refetch the list size on each iteration. */
for (i = 0; i < v->ob_size; ++i) {
int status;
s = PyObject_Repr(v->ob_item[i]);
if (s == NULL)
goto Done;
status = PyList_Append(pieces, s);
Py_DECREF(s); /* append created a new ref */
if (status < 0)
goto Done;
}
/* Add "[]" decorations to the first and last items. */
assert(PyList_GET_SIZE(pieces) > 0);
s = PyString_FromString("[");
comma = PyString_FromString(", ");
for (i = 0; i < v->ob_size && s != NULL; i++) {
if (i > 0)
PyString_Concat(&s, comma);
PyString_ConcatAndDel(&s, PyObject_Repr(v->ob_item[i]));
}
Py_XDECREF(comma);
PyString_ConcatAndDel(&s, PyString_FromString("]"));
if (s == NULL)
goto Done;
temp = PyList_GET_ITEM(pieces, 0);
PyString_ConcatAndDel(&s, temp);
PyList_SET_ITEM(pieces, 0, s);
if (s == NULL)
goto Done;
s = PyString_FromString("]");
if (s == NULL)
goto Done;
temp = PyList_GET_ITEM(pieces, PyList_GET_SIZE(pieces) - 1);
PyString_ConcatAndDel(&temp, s);
PyList_SET_ITEM(pieces, PyList_GET_SIZE(pieces) - 1, temp);
if (temp == NULL)
goto Done;
/* Paste them all together with ", " between. */
s = PyString_FromString(", ");
if (s == NULL)
goto Done;
result = _PyString_Join(s, pieces);
Py_DECREF(s);
Done:
Py_XDECREF(pieces);
Py_ReprLeave((PyObject *)v);
return s;
return result;
}
static int