mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-11-24 04:17:38 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

gh-140149: Use PyBytesWriter in _build_concatenated_bytes() (#140150)

Browse source 
Use PyBytesWriter in action_helpers.c _build_concatenated_bytes().
3x faster bytes concat in the parser.

Co-authored-by: Victor Stinner <vstinner@python.org>
This commit is contained in:
Maurycy Pawłowski-Wieroński 2025-10-16 19:24:34 +02:00 • committed by GitHub
parent 5f357f3b0d
commit 459d493ce3
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
2 changed files with 35 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Misc/NEWS.d/next/Core_and_Builtins/2025-10-15-17-12-32.gh-issue-140149.cy1m3d.rst Normal file
View file

@ -0,0 +1,2 @@
Speed up parsing bytes literals concatenation by using PyBytesWriter API and
a single memory allocation (about 3x faster).

39
Parser/action_helpers.c
View file

@ -1612,19 +1612,46 @@ _build_concatenated_bytes(Parser *p, asdl_expr_seq *strings, int lineno,
Py_ssize_t len = asdl_seq_LEN(strings);
assert(len > 0);
PyObject* res = Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);
/* Bytes literals never get a kind, but just for consistency
since they are represented as Constant nodes, we'll mirror
the same behavior as unicode strings for determining the
kind. */
PyObject* kind = asdl_seq_GET(strings, 0)->v.Constant.kind;
PyObject *kind = asdl_seq_GET(strings, 0)->v.Constant.kind;
Py_ssize_t total = 0;
for (Py_ssize_t i = 0; i < len; i++) {
expr_ty elem = asdl_seq_GET(strings, i);
PyBytes_Concat(&res, elem->v.Constant.value);
PyObject *bytes = elem->v.Constant.value;
Py_ssize_t part = PyBytes_GET_SIZE(bytes);
if (part > PY_SSIZE_T_MAX - total) {
PyErr_NoMemory();
return NULL;
}
total += part;
}
if (!res || _PyArena_AddPyObject(arena, res) < 0) {
Py_XDECREF(res);
PyBytesWriter *writer = PyBytesWriter_Create(total);
if (writer == NULL) {
return NULL;
}
char *out = PyBytesWriter_GetData(writer);
for (Py_ssize_t i = 0; i < len; i++) {
expr_ty elem = asdl_seq_GET(strings, i);
PyObject *bytes = elem->v.Constant.value;
Py_ssize_t part = PyBytes_GET_SIZE(bytes);
if (part > 0) {
memcpy(out, PyBytes_AS_STRING(bytes), part);
out += part;
}
}
PyObject *res = PyBytesWriter_Finish(writer);
if (res == NULL) {
return NULL;
}
if (_PyArena_AddPyObject(arena, res) < 0) {
Py_DECREF(res);
return NULL;
}
return _PyAST_Constant(res, kind, lineno, col_offset, end_lineno, end_col_offset, p->arena);