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220 lines
6.0 KiB
C
220 lines
6.0 KiB
C
/* PickleBuffer object implementation */
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#define PY_SSIZE_T_CLEAN
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#include "Python.h"
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#include <stddef.h>
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typedef struct {
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PyObject_HEAD
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/* The view exported by the original object */
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Py_buffer view;
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PyObject *weakreflist;
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} PyPickleBufferObject;
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/* C API */
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PyObject *
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PyPickleBuffer_FromObject(PyObject *base)
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{
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PyTypeObject *type = &PyPickleBuffer_Type;
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PyPickleBufferObject *self;
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self = (PyPickleBufferObject *) type->tp_alloc(type, 0);
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if (self == NULL) {
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return NULL;
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}
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self->view.obj = NULL;
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self->weakreflist = NULL;
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if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) {
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Py_DECREF(self);
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return NULL;
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}
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return (PyObject *) self;
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}
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const Py_buffer *
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PyPickleBuffer_GetBuffer(PyObject *obj)
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{
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PyPickleBufferObject *self = (PyPickleBufferObject *) obj;
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if (!PyPickleBuffer_Check(obj)) {
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PyErr_Format(PyExc_TypeError,
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"expected PickleBuffer, %.200s found",
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Py_TYPE(obj)->tp_name);
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return NULL;
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}
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if (self->view.obj == NULL) {
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PyErr_SetString(PyExc_ValueError,
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"operation forbidden on released PickleBuffer object");
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return NULL;
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}
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return &self->view;
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}
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int
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PyPickleBuffer_Release(PyObject *obj)
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{
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PyPickleBufferObject *self = (PyPickleBufferObject *) obj;
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if (!PyPickleBuffer_Check(obj)) {
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PyErr_Format(PyExc_TypeError,
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"expected PickleBuffer, %.200s found",
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Py_TYPE(obj)->tp_name);
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return -1;
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}
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PyBuffer_Release(&self->view);
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return 0;
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}
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static PyObject *
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picklebuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
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{
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PyPickleBufferObject *self;
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PyObject *base;
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char *keywords[] = {"", NULL};
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if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:PickleBuffer",
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keywords, &base)) {
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return NULL;
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}
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self = (PyPickleBufferObject *) type->tp_alloc(type, 0);
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if (self == NULL) {
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return NULL;
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}
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self->view.obj = NULL;
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self->weakreflist = NULL;
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if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) {
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Py_DECREF(self);
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return NULL;
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}
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return (PyObject *) self;
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}
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static int
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picklebuf_traverse(PyPickleBufferObject *self, visitproc visit, void *arg)
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{
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Py_VISIT(self->view.obj);
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return 0;
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}
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static int
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picklebuf_clear(PyPickleBufferObject *self)
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{
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PyBuffer_Release(&self->view);
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return 0;
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}
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static void
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picklebuf_dealloc(PyPickleBufferObject *self)
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{
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PyObject_GC_UnTrack(self);
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if (self->weakreflist != NULL)
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PyObject_ClearWeakRefs((PyObject *) self);
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PyBuffer_Release(&self->view);
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Py_TYPE(self)->tp_free((PyObject *) self);
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}
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/* Buffer API */
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static int
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picklebuf_getbuf(PyPickleBufferObject *self, Py_buffer *view, int flags)
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{
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if (self->view.obj == NULL) {
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PyErr_SetString(PyExc_ValueError,
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"operation forbidden on released PickleBuffer object");
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return -1;
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}
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return PyObject_GetBuffer(self->view.obj, view, flags);
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}
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static void
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picklebuf_releasebuf(PyPickleBufferObject *self, Py_buffer *view)
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{
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/* Since our bf_getbuffer redirects to the original object, this
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* implementation is never called. It only exists to signal that
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* buffers exported by PickleBuffer have non-trivial releasing
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* behaviour (see check in Python/getargs.c).
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*/
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}
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static PyBufferProcs picklebuf_as_buffer = {
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.bf_getbuffer = (getbufferproc) picklebuf_getbuf,
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.bf_releasebuffer = (releasebufferproc) picklebuf_releasebuf,
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};
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/* Methods */
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static PyObject *
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picklebuf_raw(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored))
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{
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if (self->view.obj == NULL) {
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PyErr_SetString(PyExc_ValueError,
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"operation forbidden on released PickleBuffer object");
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return NULL;
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}
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if (self->view.suboffsets != NULL
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|| !PyBuffer_IsContiguous(&self->view, 'A')) {
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PyErr_SetString(PyExc_BufferError,
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"cannot extract raw buffer from non-contiguous buffer");
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return NULL;
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}
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PyObject *m = PyMemoryView_FromObject((PyObject *) self);
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if (m == NULL) {
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return NULL;
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}
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PyMemoryViewObject *mv = (PyMemoryViewObject *) m;
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assert(mv->view.suboffsets == NULL);
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/* Mutate memoryview instance to make it a "raw" memoryview */
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mv->view.format = "B";
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mv->view.ndim = 1;
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mv->view.itemsize = 1;
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/* shape = (length,) */
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mv->view.shape = &mv->view.len;
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/* strides = (1,) */
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mv->view.strides = &mv->view.itemsize;
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/* Fix memoryview state flags */
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/* XXX Expose memoryobject.c's init_flags() instead? */
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mv->flags = _Py_MEMORYVIEW_C | _Py_MEMORYVIEW_FORTRAN;
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return m;
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}
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PyDoc_STRVAR(picklebuf_raw_doc,
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"raw($self, /)\n--\n\
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\n\
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Return a memoryview of the raw memory underlying this buffer.\n\
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Will raise BufferError is the buffer isn't contiguous.");
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static PyObject *
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picklebuf_release(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored))
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{
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PyBuffer_Release(&self->view);
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Py_RETURN_NONE;
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}
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PyDoc_STRVAR(picklebuf_release_doc,
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"release($self, /)\n--\n\
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\n\
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Release the underlying buffer exposed by the PickleBuffer object.");
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static PyMethodDef picklebuf_methods[] = {
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{"raw", (PyCFunction) picklebuf_raw, METH_NOARGS, picklebuf_raw_doc},
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{"release", (PyCFunction) picklebuf_release, METH_NOARGS, picklebuf_release_doc},
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{NULL, NULL}
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};
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PyTypeObject PyPickleBuffer_Type = {
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PyVarObject_HEAD_INIT(NULL, 0)
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.tp_name = "pickle.PickleBuffer",
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.tp_doc = "Wrapper for potentially out-of-band buffers",
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.tp_basicsize = sizeof(PyPickleBufferObject),
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.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
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.tp_new = picklebuf_new,
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.tp_dealloc = (destructor) picklebuf_dealloc,
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.tp_traverse = (traverseproc) picklebuf_traverse,
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.tp_clear = (inquiry) picklebuf_clear,
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.tp_weaklistoffset = offsetof(PyPickleBufferObject, weakreflist),
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.tp_as_buffer = &picklebuf_as_buffer,
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.tp_methods = picklebuf_methods,
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};
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