From f39edd9bb503f149ee01d0efa6cc17c7ed7e6968 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Fri, 12 Sep 2025 15:19:17 +0200 Subject: [PATCH] gh-129813, PEP 782: Use PyBytesWriter in _PyBytes_FromList() Use the new public PyBytesWriter API in: * _PyBytes_FromHex() * _PyBytes_FromBuffer() * _PyBytes_FromList() * _PyBytes_FromTuple() * _PyBytes_FromIterator() Add _PyBytesWriter_ResizeAndUpdatePointer() and _PyBytesWriter_GetAllocated() helper functions. --- Objects/bytesobject.c | 137 ++++++++++++++++++++++++------------------ 1 file changed, 78 insertions(+), 59 deletions(-) diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c index fc9e1bef80f037..415fd8c548b3d2 100644 --- a/Objects/bytesobject.c +++ b/Objects/bytesobject.c @@ -36,6 +36,9 @@ class bytes "PyBytesObject *" "&PyBytes_Type" /* Forward declaration */ Py_LOCAL_INLINE(Py_ssize_t) _PyBytesWriter_GetSize(_PyBytesWriter *writer, char *str); +static void* _PyBytesWriter_ResizeAndUpdatePointer(PyBytesWriter *writer, + Py_ssize_t size, void *data); +static Py_ssize_t _PyBytesWriter_GetAllocated(PyBytesWriter *writer); #define CHARACTERS _Py_SINGLETON(bytes_characters) @@ -2535,17 +2538,13 @@ bytes_fromhex_impl(PyTypeObject *type, PyObject *string) PyObject* _PyBytes_FromHex(PyObject *string, int use_bytearray) { - char *buf; Py_ssize_t hexlen, invalid_char; unsigned int top, bot; const Py_UCS1 *str, *start, *end; - _PyBytesWriter writer; + PyBytesWriter *writer = NULL; Py_buffer view; view.obj = NULL; - _PyBytesWriter_Init(&writer); - writer.use_bytearray = use_bytearray; - if (PyUnicode_Check(string)) { hexlen = PyUnicode_GET_LENGTH(string); @@ -2581,10 +2580,16 @@ _PyBytes_FromHex(PyObject *string, int use_bytearray) } /* This overestimates if there are spaces */ - buf = _PyBytesWriter_Alloc(&writer, hexlen / 2); - if (buf == NULL) { + if (use_bytearray) { + writer = _PyBytesWriter_CreateByteArray(hexlen / 2); + } + else { + writer = PyBytesWriter_Create(hexlen / 2); + } + if (writer == NULL) { goto release_buffer; } + char *buf = PyBytesWriter_GetData(writer); start = str; end = str + hexlen; @@ -2623,7 +2628,7 @@ _PyBytes_FromHex(PyObject *string, int use_bytearray) if (view.obj != NULL) { PyBuffer_Release(&view); } - return _PyBytesWriter_Finish(&writer, buf); + return PyBytesWriter_FinishWithPointer(writer, buf); error: if (invalid_char == -1) { @@ -2634,7 +2639,7 @@ _PyBytes_FromHex(PyObject *string, int use_bytearray) "non-hexadecimal number found in " "fromhex() arg at position %zd", invalid_char); } - _PyBytesWriter_Dealloc(&writer); + PyBytesWriter_Discard(writer); release_buffer: if (view.obj != NULL) { @@ -2861,23 +2866,25 @@ bytes_new_impl(PyTypeObject *type, PyObject *x, const char *encoding, static PyObject* _PyBytes_FromBuffer(PyObject *x) { - PyObject *new; Py_buffer view; - if (PyObject_GetBuffer(x, &view, PyBUF_FULL_RO) < 0) return NULL; - new = PyBytes_FromStringAndSize(NULL, view.len); - if (!new) + PyBytesWriter *writer = PyBytesWriter_Create(view.len); + if (writer == NULL) { goto fail; - if (PyBuffer_ToContiguous(((PyBytesObject *)new)->ob_sval, - &view, view.len, 'C') < 0) + } + + if (PyBuffer_ToContiguous(PyBytesWriter_GetData(writer), + &view, view.len, 'C') < 0) { goto fail; + } + PyBuffer_Release(&view); - return new; + return PyBytesWriter_Finish(writer); fail: - Py_XDECREF(new); + PyBytesWriter_Discard(writer); PyBuffer_Release(&view); return NULL; } @@ -2885,23 +2892,18 @@ _PyBytes_FromBuffer(PyObject *x) static PyObject* _PyBytes_FromList(PyObject *x) { - Py_ssize_t i, size = PyList_GET_SIZE(x); - Py_ssize_t value; - char *str; - PyObject *item; - _PyBytesWriter writer; - - _PyBytesWriter_Init(&writer); - str = _PyBytesWriter_Alloc(&writer, size); - if (str == NULL) + Py_ssize_t size = PyList_GET_SIZE(x); + PyBytesWriter *writer = PyBytesWriter_Create(size); + if (writer == NULL) { return NULL; - writer.overallocate = 1; - size = writer.allocated; + } + char *str = PyBytesWriter_GetData(writer); + size = _PyBytesWriter_GetAllocated(writer); - for (i = 0; i < PyList_GET_SIZE(x); i++) { - item = PyList_GET_ITEM(x, i); + for (Py_ssize_t i = 0; i < PyList_GET_SIZE(x); i++) { + PyObject *item = PyList_GET_ITEM(x, i); Py_INCREF(item); - value = PyNumber_AsSsize_t(item, NULL); + Py_ssize_t value = PyNumber_AsSsize_t(item, NULL); Py_DECREF(item); if (value == -1 && PyErr_Occurred()) goto error; @@ -2913,33 +2915,33 @@ _PyBytes_FromList(PyObject *x) } if (i >= size) { - str = _PyBytesWriter_Resize(&writer, str, size+1); - if (str == NULL) - return NULL; - size = writer.allocated; + str = _PyBytesWriter_ResizeAndUpdatePointer(writer, size + 1, str); + if (str == NULL) { + goto error; + } + size = _PyBytesWriter_GetAllocated(writer); } *str++ = (char) value; } - return _PyBytesWriter_Finish(&writer, str); + return PyBytesWriter_FinishWithPointer(writer, str); - error: - _PyBytesWriter_Dealloc(&writer); +error: + PyBytesWriter_Discard(writer); return NULL; } static PyObject* _PyBytes_FromTuple(PyObject *x) { - PyObject *bytes; Py_ssize_t i, size = PyTuple_GET_SIZE(x); Py_ssize_t value; - char *str; PyObject *item; - bytes = PyBytes_FromStringAndSize(NULL, size); - if (bytes == NULL) + PyBytesWriter *writer = PyBytesWriter_Create(size); + if (writer == NULL) { return NULL; - str = ((PyBytesObject *)bytes)->ob_sval; + } + char *str = PyBytesWriter_GetData(writer); for (i = 0; i < size; i++) { item = PyTuple_GET_ITEM(x, i); @@ -2954,31 +2956,29 @@ _PyBytes_FromTuple(PyObject *x) } *str++ = (char) value; } - return bytes; + return PyBytesWriter_Finish(writer); error: - Py_DECREF(bytes); + PyBytesWriter_Discard(writer); return NULL; } static PyObject * _PyBytes_FromIterator(PyObject *it, PyObject *x) { - char *str; Py_ssize_t i, size; - _PyBytesWriter writer; /* For iterator version, create a bytes object and resize as needed */ size = PyObject_LengthHint(x, 64); if (size == -1 && PyErr_Occurred()) return NULL; - _PyBytesWriter_Init(&writer); - str = _PyBytesWriter_Alloc(&writer, size); - if (str == NULL) + PyBytesWriter *writer = PyBytesWriter_Create(size); + if (writer == NULL) { return NULL; - writer.overallocate = 1; - size = writer.allocated; + } + char *str = PyBytesWriter_GetData(writer); + size = _PyBytesWriter_GetAllocated(writer); /* Run the iterator to exhaustion */ for (i = 0; ; i++) { @@ -3008,18 +3008,18 @@ _PyBytes_FromIterator(PyObject *it, PyObject *x) /* Append the byte */ if (i >= size) { - str = _PyBytesWriter_Resize(&writer, str, size+1); - if (str == NULL) - return NULL; - size = writer.allocated; + str = _PyBytesWriter_ResizeAndUpdatePointer(writer, size + 1, str); + if (str == NULL) { + goto error; + } + size = _PyBytesWriter_GetAllocated(writer); } *str++ = (char) value; } - - return _PyBytesWriter_Finish(&writer, str); + return PyBytesWriter_FinishWithPointer(writer, str); error: - _PyBytesWriter_Dealloc(&writer); + PyBytesWriter_Discard(writer); return NULL; } @@ -3987,6 +3987,13 @@ PyBytesWriter_GetSize(PyBytesWriter *writer) } +static Py_ssize_t +_PyBytesWriter_GetAllocated(PyBytesWriter *writer) +{ + return byteswriter_allocated(writer); +} + + int PyBytesWriter_Resize(PyBytesWriter *writer, Py_ssize_t size) { @@ -4002,6 +4009,18 @@ PyBytesWriter_Resize(PyBytesWriter *writer, Py_ssize_t size) } +static void* +_PyBytesWriter_ResizeAndUpdatePointer(PyBytesWriter *writer, Py_ssize_t size, + void *data) +{ + Py_ssize_t pos = (char*)data - byteswriter_data(writer); + if (PyBytesWriter_Resize(writer, size) < 0) { + return NULL; + } + return byteswriter_data(writer) + pos; +} + + int PyBytesWriter_Grow(PyBytesWriter *writer, Py_ssize_t size) {