Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

gh-96538: Move some type-checking out of bisect.bisect() loops (GH-96539)

This commit is contained in:
Dennis Sweeney 2022-09-05 01:02:29 -04:00 committed by GitHub
parent a0ad63e70e
commit 9e35d05422
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 143 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Misc/NEWS.d/next/Library/2022-09-03-18-39-05.gh-issue-96538.W156-D.rst Normal file
View File

@ -0,0 +1 @@
Speed up ``bisect.bisect()`` functions by taking advantage of type-stability.

158
Modules/_bisectmodule.c
View File

@ -25,6 +25,26 @@ get_bisect_state(PyObject *module)
return (bisect_state *)state;
}
static ssizeargfunc
get_sq_item(PyObject *s)
{
// The parts of PySequence_GetItem that we only need to do once
PyTypeObject *tp = Py_TYPE(s);
PySequenceMethods *m = tp->tp_as_sequence;
if (m && m->sq_item) {
return m->sq_item;
}
const char *msg;
if (tp->tp_as_mapping && tp->tp_as_mapping->mp_subscript) {
msg = "%.200s is not a sequence";
}
else {
msg = "'%.200s' object does not support indexing";
}
PyErr_Format(PyExc_TypeError, msg, tp->tp_name);
return NULL;
}
static inline Py_ssize_t
internal_bisect_right(PyObject *list, PyObject *item, Py_ssize_t lo, Py_ssize_t hi,
PyObject* key)
@ -42,32 +62,85 @@ internal_bisect_right(PyObject *list, PyObject *item, Py_ssize_t lo, Py_ssize_t
if (hi < 0)
return -1;
}
ssizeargfunc sq_item = get_sq_item(list);
if (sq_item == NULL) {
return -1;
}
if (Py_EnterRecursiveCall("in _bisect.bisect_right") < 0) {
return -1;
}
PyTypeObject *tp = Py_TYPE(item);
richcmpfunc compare = tp->tp_richcompare;
while (lo < hi) {
/* The (size_t)cast ensures that the addition and subsequent division
are performed as unsigned operations, avoiding difficulties from
signed overflow. (See issue 13496.) */
mid = ((size_t)lo + hi) / 2;
litem = PySequence_GetItem(list, mid);
if (litem == NULL)
return -1;
assert(mid >= 0);
// PySequence_GetItem, but we already checked the types.
litem = sq_item(list, mid);
assert((PyErr_Occurred() == NULL) ^ (litem == NULL));
if (litem == NULL) {
goto error;
}
if (key != Py_None) {
PyObject *newitem = PyObject_CallOneArg(key, litem);
if (newitem == NULL) {
Py_DECREF(litem);
return -1;
goto error;
}
Py_SETREF(litem, newitem);
}
res = PyObject_RichCompareBool(item, litem, Py_LT);
/* if item < key(list[mid]):
* hi = mid
* else:
* lo = mid + 1
*/
if (compare != NULL && Py_IS_TYPE(litem, tp)) {
// A fast path for comparing objects of the same type
PyObject *res_obj = compare(item, litem, Py_LT);
if (res_obj == Py_True) {
Py_DECREF(res_obj);
Py_DECREF(litem);
hi = mid;
continue;
}
if (res_obj == Py_False) {
Py_DECREF(res_obj);
Py_DECREF(litem);
lo = mid + 1;
continue;
}
if (res_obj == NULL) {
goto error;
}
if (res_obj == Py_NotImplemented) {
Py_DECREF(res_obj);
compare = NULL;
res = PyObject_RichCompareBool(item, litem, Py_LT);
}
else {
res = PyObject_IsTrue(res_obj);
}
}
else {
// A default path for comparing arbitrary objects
res = PyObject_RichCompareBool(item, litem, Py_LT);
}
if (res < 0) {
goto error;
}
Py_DECREF(litem);
if (res < 0)
return -1;
if (res)
hi = mid;
else
lo = mid + 1;
}
Py_LeaveRecursiveCall();
return lo;
error:
Py_LeaveRecursiveCall();
Py_XDECREF(litem);
return -1;
}
/*[clinic input]
@ -168,32 +241,85 @@ internal_bisect_left(PyObject *list, PyObject *item, Py_ssize_t lo, Py_ssize_t h
if (hi < 0)
return -1;
}
ssizeargfunc sq_item = get_sq_item(list);
if (sq_item == NULL) {
return -1;
}
if (Py_EnterRecursiveCall("in _bisect.bisect_left") < 0) {
return -1;
}
PyTypeObject *tp = Py_TYPE(item);
richcmpfunc compare = tp->tp_richcompare;
while (lo < hi) {
/* The (size_t)cast ensures that the addition and subsequent division
are performed as unsigned operations, avoiding difficulties from
signed overflow. (See issue 13496.) */
mid = ((size_t)lo + hi) / 2;
litem = PySequence_GetItem(list, mid);
if (litem == NULL)
return -1;
assert(mid >= 0);
// PySequence_GetItem, but we already checked the types.
litem = sq_item(list, mid);
assert((PyErr_Occurred() == NULL) ^ (litem == NULL));
if (litem == NULL) {
goto error;
}
if (key != Py_None) {
PyObject *newitem = PyObject_CallOneArg(key, litem);
if (newitem == NULL) {
Py_DECREF(litem);
return -1;
goto error;
}
Py_SETREF(litem, newitem);
}
res = PyObject_RichCompareBool(litem, item, Py_LT);
/* if key(list[mid]) < item:
* lo = mid + 1
* else:
* hi = mid
*/
if (compare != NULL && Py_IS_TYPE(litem, tp)) {
// A fast path for comparing objects of the same type
PyObject *res_obj = compare(litem, item, Py_LT);
if (res_obj == Py_True) {
Py_DECREF(res_obj);
Py_DECREF(litem);
lo = mid + 1;
continue;
}
if (res_obj == Py_False) {
Py_DECREF(res_obj);
Py_DECREF(litem);
hi = mid;
continue;
}
if (res_obj == NULL) {
goto error;
}
if (res_obj == Py_NotImplemented) {
Py_DECREF(res_obj);
compare = NULL;
res = PyObject_RichCompareBool(litem, item, Py_LT);
}
else {
res = PyObject_IsTrue(res_obj);
}
}
else {
// A default path for comparing arbitrary objects
res = PyObject_RichCompareBool(litem, item, Py_LT);
}
if (res < 0) {
goto error;
}
Py_DECREF(litem);
if (res < 0)
return -1;
if (res)
lo = mid + 1;
else
hi = mid;
}
Py_LeaveRecursiveCall();
return lo;
error:
Py_LeaveRecursiveCall();
Py_XDECREF(litem);
return -1;
}