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-rw-r--r--Doc/library/stdtypes.rst9
-rw-r--r--Lib/test/test_memoryview.py26
-rw-r--r--Misc/NEWS.d/next/Core_and_Builtins/2024-10-14-13-28-16.gh-issue-125420.hNKixM.rst2
-rw-r--r--Objects/clinic/memoryobject.c.h48
-rw-r--r--Objects/memoryobject.c87
5 files changed, 171 insertions, 1 deletions
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 4f4fc9f..f4e635d 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -4149,6 +4149,15 @@ copying.
.. versionchanged:: 3.5
The source format is no longer restricted when casting to a byte view.
+ .. method:: index(value, start=0, stop=sys.maxsize, /)
+
+ Return the index of the first occurrence of *value* (at or after
+ index *start* and before index *stop*).
+
+ Raises a :exc:`ValueError` if *value* cannot be found.
+
+ .. versionadded:: next
+
There are also several readonly attributes available:
.. attribute:: obj
diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py
index 2d4bf5f..8f07828 100644
--- a/Lib/test/test_memoryview.py
+++ b/Lib/test/test_memoryview.py
@@ -15,6 +15,7 @@ import copy
import pickle
import struct
+from itertools import product
from test.support import import_helper
@@ -58,6 +59,31 @@ class AbstractMemoryTests:
for tp in self._types:
self.check_getitem_with_type(tp)
+ def test_index(self):
+ for tp in self._types:
+ b = tp(self._source)
+ m = self._view(b) # may be a sub-view
+ l = m.tolist()
+ k = 2 * len(self._source)
+
+ for chi in self._source:
+ if chi in l:
+ self.assertEqual(m.index(chi), l.index(chi))
+ else:
+ self.assertRaises(ValueError, m.index, chi)
+
+ for start, stop in product(range(-k, k), range(-k, k)):
+ index = -1
+ try:
+ index = l.index(chi, start, stop)
+ except ValueError:
+ pass
+
+ if index == -1:
+ self.assertRaises(ValueError, m.index, chi, start, stop)
+ else:
+ self.assertEqual(m.index(chi, start, stop), index)
+
def test_iter(self):
for tp in self._types:
b = tp(self._source)
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-10-14-13-28-16.gh-issue-125420.hNKixM.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-10-14-13-28-16.gh-issue-125420.hNKixM.rst
new file mode 100644
index 0000000..6ed8231
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-10-14-13-28-16.gh-issue-125420.hNKixM.rst
@@ -0,0 +1,2 @@
+Add :meth:`memoryview.index` to :class:`memoryview` objects. Patch by
+Bénédikt Tran.
diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
index 185d781..9b8a233 100644
--- a/Objects/clinic/memoryobject.c.h
+++ b/Objects/clinic/memoryobject.c.h
@@ -418,4 +418,50 @@ skip_optional_pos:
exit:
return return_value;
}
-/*[clinic end generated code: output=0a93f08110630633 input=a9049054013a1b77]*/
+
+PyDoc_STRVAR(memoryview_index__doc__,
+"index($self, value, start=0, stop=sys.maxsize, /)\n"
+"--\n"
+"\n"
+"Return the index of the first occurrence of a value.\n"
+"\n"
+"Raises ValueError if the value is not present.");
+
+#define MEMORYVIEW_INDEX_METHODDEF \
+ {"index", _PyCFunction_CAST(memoryview_index), METH_FASTCALL, memoryview_index__doc__},
+
+static PyObject *
+memoryview_index_impl(PyMemoryViewObject *self, PyObject *value,
+ Py_ssize_t start, Py_ssize_t stop);
+
+static PyObject *
+memoryview_index(PyMemoryViewObject *self, PyObject *const *args, Py_ssize_t nargs)
+{
+ PyObject *return_value = NULL;
+ PyObject *value;
+ Py_ssize_t start = 0;
+ Py_ssize_t stop = PY_SSIZE_T_MAX;
+
+ if (!_PyArg_CheckPositional("index", nargs, 1, 3)) {
+ goto exit;
+ }
+ value = args[0];
+ if (nargs < 2) {
+ goto skip_optional;
+ }
+ if (!_PyEval_SliceIndexNotNone(args[1], &start)) {
+ goto exit;
+ }
+ if (nargs < 3) {
+ goto skip_optional;
+ }
+ if (!_PyEval_SliceIndexNotNone(args[2], &stop)) {
+ goto exit;
+ }
+skip_optional:
+ return_value = memoryview_index_impl(self, value, start, stop);
+
+exit:
+ return return_value;
+}
+/*[clinic end generated code: output=2742d371dba7314f input=a9049054013a1b77]*/
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index 25634f9..345aa79 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -2749,6 +2749,92 @@ static PySequenceMethods memory_as_sequence = {
/**************************************************************************/
+/* Lookup */
+/**************************************************************************/
+
+/*[clinic input]
+memoryview.index
+
+ value: object
+ start: slice_index(accept={int}) = 0
+ stop: slice_index(accept={int}, c_default="PY_SSIZE_T_MAX") = sys.maxsize
+ /
+
+Return the index of the first occurrence of a value.
+
+Raises ValueError if the value is not present.
+[clinic start generated code]*/
+
+static PyObject *
+memoryview_index_impl(PyMemoryViewObject *self, PyObject *value,
+ Py_ssize_t start, Py_ssize_t stop)
+/*[clinic end generated code: output=e0185e3819e549df input=0697a0165bf90b5a]*/
+{
+ const Py_buffer *view = &self->view;
+ CHECK_RELEASED(self);
+
+ if (view->ndim == 0) {
+ PyErr_SetString(PyExc_TypeError, "invalid lookup on 0-dim memory");
+ return NULL;
+ }
+
+ if (view->ndim == 1) {
+ Py_ssize_t n = view->shape[0];
+
+ if (start < 0) {
+ start = Py_MAX(start + n, 0);
+ }
+
+ if (stop < 0) {
+ stop = Py_MAX(stop + n, 0);
+ }
+
+ stop = Py_MIN(stop, n);
+ assert(stop >= 0);
+ assert(stop <= n);
+
+ start = Py_MIN(start, stop);
+ assert(0 <= start);
+ assert(start <= stop);
+
+ PyObject *obj = _PyObject_CAST(self);
+ for (Py_ssize_t index = start; index < stop; index++) {
+ // Note: while memoryviews can be mutated during iterations
+ // when calling the == operator, their shape cannot. As such,
+ // it is safe to assume that the index remains valid for the
+ // entire loop.
+ assert(index < n);
+
+ PyObject *item = memory_item(obj, index);
+ if (item == NULL) {
+ return NULL;
+ }
+ if (item == value) {
+ Py_DECREF(item);
+ return PyLong_FromSsize_t(index);
+ }
+ int contained = PyObject_RichCompareBool(item, value, Py_EQ);
+ Py_DECREF(item);
+ if (contained > 0) { // more likely than 'contained < 0'
+ return PyLong_FromSsize_t(index);
+ }
+ else if (contained < 0) {
+ return NULL;
+ }
+ }
+
+ PyErr_SetString(PyExc_ValueError, "memoryview.index(x): x not found");
+ return NULL;
+ }
+
+ PyErr_SetString(PyExc_NotImplementedError,
+ "multi-dimensional lookup is not implemented");
+ return NULL;
+
+}
+
+
+/**************************************************************************/
/* Comparisons */
/**************************************************************************/
@@ -3284,6 +3370,7 @@ static PyMethodDef memory_methods[] = {
MEMORYVIEW_CAST_METHODDEF
MEMORYVIEW_TOREADONLY_METHODDEF
MEMORYVIEW__FROM_FLAGS_METHODDEF
+ MEMORYVIEW_INDEX_METHODDEF
{"__enter__", memory_enter, METH_NOARGS, NULL},
{"__exit__", memory_exit, METH_VARARGS, memory_exit_doc},
{"__class_getitem__", Py_GenericAlias, METH_O|METH_CLASS, PyDoc_STR("See PEP 585")},
generated by cgit v0.12 at 2025-03-19 21:29:53 (GMT)