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().
This commit is contained in:
Serhiy Storchaka 2017-01-25 13:27:44 +02:00
commit 6e08baf12d
6 changed files with 119 additions and 26 deletions

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

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@ -128,10 +128,17 @@ Build and C API Changes
is now of type ``const char *`` rather of ``char *``. is now of type ``const char *`` rather of ``char *``.
(Contributed by Serhiy Storchaka in :issue:`28769`.) (Contributed by Serhiy Storchaka in :issue:`28769`.)
* Added functions :c:func:`PySlice_Unpack` and :c:func:`PySlice_AdjustIndices`.
(Contributed by Serhiy Storchaka in :issue:`27867`.)
Deprecated Deprecated
========== ==========
- Function :c:func:`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. (Contributed by Serhiy Storchaka in :issue:`27867`.)
Removed Removed

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

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@ -623,6 +623,11 @@ Windows
C API C API
----- -----
- 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().
- Issue #29083: Fixed the declaration of some public API functions. - Issue #29083: Fixed the declaration of some public API functions.
PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in
limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and

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@ -191,15 +191,12 @@ PySlice_GetIndices(PyObject *_r, Py_ssize_t length,
} }
int int
PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length, PySlice_Unpack(PyObject *_r,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
Py_ssize_t *slicelength)
{ {
PySliceObject *r = (PySliceObject*)_r; PySliceObject *r = (PySliceObject*)_r;
/* this is harder to get right than you might think */ /* this is harder to get right than you might think */
Py_ssize_t defstart, defstop;
if (r->step == Py_None) { if (r->step == Py_None) {
*step = 1; *step = 1;
} }
@ -219,42 +216,75 @@ PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length,
*step = -PY_SSIZE_T_MAX; *step = -PY_SSIZE_T_MAX;
} }
defstart = *step < 0 ? length-1 : 0;
defstop = *step < 0 ? -1 : length;
if (r->start == Py_None) { if (r->start == Py_None) {
*start = defstart; *start = *step < 0 ? PY_SSIZE_T_MAX-1 : 0;;
} }
else { else {
if (!_PyEval_SliceIndex(r->start, start)) return -1; if (!_PyEval_SliceIndex(r->start, start)) return -1;
if (*start < 0) *start += length;
if (*start < 0) *start = (*step < 0) ? -1 : 0;
if (*start >= length)
*start = (*step < 0) ? length - 1 : length;
} }
if (r->stop == Py_None) { if (r->stop == Py_None) {
*stop = defstop; *stop = *step < 0 ? -PY_SSIZE_T_MAX : PY_SSIZE_T_MAX;
} }
else { else {
if (!_PyEval_SliceIndex(r->stop, stop)) return -1; if (!_PyEval_SliceIndex(r->stop, stop)) return -1;
if (*stop < 0) *stop += length;
if (*stop < 0) *stop = (*step < 0) ? -1 : 0;
if (*stop >= length)
*stop = (*step < 0) ? length - 1 : length;
} }
if ((*step < 0 && *stop >= *start) return 0;
|| (*step > 0 && *start >= *stop)) { }
*slicelength = 0;
Py_ssize_t
PySlice_AdjustIndices(Py_ssize_t length,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
{
/* this is harder to get right than you might think */
assert(step != 0);
assert(step >= -PY_SSIZE_T_MAX);
if (*start < 0) {
*start += length;
if (*start < 0) {
*start = (step < 0) ? -1 : 0;
}
} }
else if (*step < 0) { else if (*start >= length) {
*slicelength = (*stop-*start+1)/(*step)+1; *start = (step < 0) ? length - 1 : length;
}
if (*stop < 0) {
*stop += length;
if (*stop < 0) {
*stop = (step < 0) ? -1 : 0;
}
}
else if (*stop >= length) {
*stop = (step < 0) ? length - 1 : length;
}
if (step < 0) {
if (*stop < *start) {
return (*start - *stop - 1) / (-step) + 1;
}
} }
else { else {
*slicelength = (*stop-*start-1)/(*step)+1; if (*start < *stop) {
return (*stop - *start - 1) / step + 1;
}
} }
return 0;
}
#undef PySlice_GetIndicesEx
int
PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
Py_ssize_t *slicelength)
{
if (PySlice_Unpack(_r, start, stop, step) < 0)
return -1;
*slicelength = PySlice_AdjustIndices(length, start, stop, *step);
return 0; return 0;
} }

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@ -531,10 +531,12 @@ EXPORTS
PySet_Pop=python37.PySet_Pop PySet_Pop=python37.PySet_Pop
PySet_Size=python37.PySet_Size PySet_Size=python37.PySet_Size
PySet_Type=python37.PySet_Type DATA PySet_Type=python37.PySet_Type DATA
PySlice_AdjustIndices=python37.PySlice_AdjustIndices
PySlice_GetIndices=python37.PySlice_GetIndices PySlice_GetIndices=python37.PySlice_GetIndices
PySlice_GetIndicesEx=python37.PySlice_GetIndicesEx PySlice_GetIndicesEx=python37.PySlice_GetIndicesEx
PySlice_New=python37.PySlice_New PySlice_New=python37.PySlice_New
PySlice_Type=python37.PySlice_Type DATA PySlice_Type=python37.PySlice_Type DATA
PySlice_Unpack=python37.PySlice_Unpack
PySortWrapper_Type=python37.PySortWrapper_Type DATA PySortWrapper_Type=python37.PySortWrapper_Type DATA
PyState_AddModule=python37.PyState_AddModule PyState_AddModule=python37.PyState_AddModule
PyState_FindModule=python37.PyState_FindModule PyState_FindModule=python37.PyState_FindModule