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Issue #27867: Function PySlice_GetIndicesEx() is deprecated and replaced with
a macro if Py_LIMITED_API is not set or set to the value between 0x03050400 and 0x03060000 (not including) or 0x03060100 or higher. Added functions PySlice_Unpack() and PySlice_AdjustIndices().
2 parents a8df847 + 512c57c commit 6e08baf

6 files changed

Lines changed: 119 additions & 26 deletions

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‎Doc/c-api/slice.rst‎

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@@ -56,3 +56,40 @@ Slice Objects
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.. versionchanged:: 3.2
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The parameter type for the *slice* parameter was ``PySliceObject*``
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before.
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.. versionchanged:: 3.6.1
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If ``Py_LIMITED_API`` is not set or set to the value between ``0x03050400``
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and ``0x03060000`` (not including) or ``0x03060100`` or higher
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:c:func:`!PySlice_GetIndicesEx` is implemented as a macro using
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:c:func:`PySlice_Unpack` and :c:func:`PySlice_AdjustIndices`.
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Arguments *start*, *stop* and *step* are evaluated more than once.
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.. deprecated:: 3.6.1
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If ``Py_LIMITED_API`` is set to the value less than ``0x03050400`` or
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between ``0x03060000`` and ``0x03060100`` (not including)
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:c:func:`!PySlice_GetIndicesEx` is a deprecated function.
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.. c:function:: int PySlice_Unpack(PyObject *slice, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
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Extract the start, stop and step data members from a slice object as
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C integers. Silently reduce values larger than ``PY_SSIZE_T_MAX`` to
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``PY_SSIZE_T_MAX``, silently boost the start and stop values less than
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``-PY_SSIZE_T_MAX-1`` to ``-PY_SSIZE_T_MAX-1``, and silently boost the step
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values less than ``-PY_SSIZE_T_MAX`` to ``-PY_SSIZE_T_MAX``.
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Return ``-1`` on error, ``0`` on success.
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.. versionadded:: 3.6.1
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.. c:function:: Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
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Adjust start/end slice indices assuming a sequence of the specified length.
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Out of bounds indices are clipped in a manner consistent with the handling
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of normal slices.
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Return the length of the slice. Always successful. Doesn't call Python
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code.
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.. versionadded:: 3.6.1

‎Doc/whatsnew/3.7.rst‎

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@@ -128,10 +128,17 @@ Build and C API Changes
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is now of type ``const char *`` rather of ``char *``.
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(Contributed by Serhiy Storchaka in :issue:`28769`.)
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* Added functions :c:func:`PySlice_Unpack` and :c:func:`PySlice_AdjustIndices`.
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(Contributed by Serhiy Storchaka in :issue:`27867`.)
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Deprecated
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==========
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- Function :c:func:`PySlice_GetIndicesEx` is deprecated and replaced with
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a macro if ``Py_LIMITED_API`` is not set or set to the value between
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``0x03050400`` and ``0x03060000`` (not including) or ``0x03060100`` or
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higher. (Contributed by Serhiy Storchaka in :issue:`27867`.)
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Removed

‎Include/sliceobject.h‎

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@@ -41,8 +41,20 @@ PyAPI_FUNC(int) _PySlice_GetLongIndices(PySliceObject *self, PyObject *length,
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PyAPI_FUNC(int) PySlice_GetIndices(PyObject *r, Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step);
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PyAPI_FUNC(int) PySlice_GetIndicesEx(PyObject *r, Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop,
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Py_ssize_t *step, Py_ssize_t *slicelength);
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Py_ssize_t *start, Py_ssize_t *stop,
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Py_ssize_t *step, Py_ssize_t *slicelength) Py_DEPRECATED(3.7);
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#if !defined(Py_LIMITED_API) || (Py_LIMITED_API+0 >= 0x03050400 && Py_LIMITED_API+0 < 0x03060000) || Py_LIMITED_API+0 >= 0x03060100
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#define PySlice_GetIndicesEx(slice, length, start, stop, step, slicelen) ( \
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PySlice_Unpack((slice), (start), (stop), (step)) < 0 ? -1 : \
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((*slicelen = PySlice_AdjustIndices((length), (start), (stop), *(step))), \
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0))
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PyAPI_FUNC(int) PySlice_Unpack(PyObject *slice,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step);
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PyAPI_FUNC(Py_ssize_t) PySlice_AdjustIndices(Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop,
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Py_ssize_t step);
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#endif
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#ifdef __cplusplus
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}

‎Misc/NEWS‎

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@@ -623,6 +623,11 @@ Windows
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C API
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-----
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- Issue #27867: Function PySlice_GetIndicesEx() is deprecated and replaced with
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a macro if Py_LIMITED_API is not set or set to the value between 0x03050400
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and 0x03060000 (not including) or 0x03060100 or higher. Added functions
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PySlice_Unpack() and PySlice_AdjustIndices().
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- Issue #29083: Fixed the declaration of some public API functions.
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PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in
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limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and

‎Objects/sliceobject.c‎

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@@ -191,15 +191,12 @@ PySlice_GetIndices(PyObject *_r, Py_ssize_t length,
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}
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int
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PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
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Py_ssize_t *slicelength)
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PySlice_Unpack(PyObject *_r,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
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{
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PySliceObject *r = (PySliceObject*)_r;
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/* this is harder to get right than you might think */
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Py_ssize_t defstart, defstop;
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if (r->step == Py_None) {
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*step = 1;
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}
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*step = -PY_SSIZE_T_MAX;
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}
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defstart = *step < 0 ? length-1 : 0;
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defstop = *step < 0 ? -1 : length;
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if (r->start == Py_None) {
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*start = defstart;
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*start = *step < 0 ? PY_SSIZE_T_MAX-1 : 0;;
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}
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else {
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if (!_PyEval_SliceIndex(r->start, start)) return -1;
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if (*start < 0) *start += length;
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if (*start < 0) *start = (*step < 0) ? -1 : 0;
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if (*start >= length)
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*start = (*step < 0) ? length - 1 : length;
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}
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if (r->stop == Py_None) {
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*stop = defstop;
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*stop = *step < 0 ? -PY_SSIZE_T_MAX : PY_SSIZE_T_MAX;
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}
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else {
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if (!_PyEval_SliceIndex(r->stop, stop)) return -1;
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if (*stop < 0) *stop += length;
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if (*stop < 0) *stop = (*step < 0) ? -1 : 0;
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if (*stop >= length)
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*stop = (*step < 0) ? length - 1 : length;
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}
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if ((*step < 0 && *stop >= *start)
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|| (*step > 0 && *start >= *stop)) {
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*slicelength = 0;
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return 0;
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}
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Py_ssize_t
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PySlice_AdjustIndices(Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
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{
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/* this is harder to get right than you might think */
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assert(step != 0);
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assert(step >= -PY_SSIZE_T_MAX);
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if (*start < 0) {
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*start += length;
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if (*start < 0) {
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*start = (step < 0) ? -1 : 0;
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}
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}
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else if (*step < 0) {
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*slicelength = (*stop-*start+1)/(*step)+1;
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else if (*start >= length) {
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*start = (step < 0) ? length - 1 : length;
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}
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if (*stop < 0) {
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*stop += length;
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if (*stop < 0) {
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*stop = (step < 0) ? -1 : 0;
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}
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}
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else if (*stop >= length) {
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*stop = (step < 0) ? length - 1 : length;
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}
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if (step < 0) {
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if (*stop < *start) {
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return (*start - *stop - 1) / (-step) + 1;
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}
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}
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else {
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*slicelength = (*stop-*start-1)/(*step)+1;
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if (*start < *stop) {
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return (*stop - *start - 1) / step + 1;
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}
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}
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return 0;
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}
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#undef PySlice_GetIndicesEx
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int
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PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length,
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Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
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Py_ssize_t *slicelength)
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{
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if (PySlice_Unpack(_r, start, stop, step) < 0)
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return -1;
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*slicelength = PySlice_AdjustIndices(length, start, stop, *step);
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return 0;
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}
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‎PC/python3.def‎

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PySet_Pop=python37.PySet_Pop
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PySet_Size=python37.PySet_Size
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PySet_Type=python37.PySet_Type DATA
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PySlice_AdjustIndices=python37.PySlice_AdjustIndices
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PySlice_GetIndices=python37.PySlice_GetIndices
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PySlice_GetIndicesEx=python37.PySlice_GetIndicesEx
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PySlice_New=python37.PySlice_New
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PySlice_Type=python37.PySlice_Type DATA
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PySlice_Unpack=python37.PySlice_Unpack
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PySortWrapper_Type=python37.PySortWrapper_Type DATA
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PyState_AddModule=python37.PyState_AddModule
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PyState_FindModule=python37.PyState_FindModule

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