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bpo-35845: Add order={'C', 'F', 'A'} parameter to memoryview.tobytes(). (#11730)

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Stefan Krah 2019-02-02 18:57:41 +01:00 committed by GitHub
parent 4860f01ac0
commit d08ea70464
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4 changed files with 59 additions and 10 deletions
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9
Doc/library/stdtypes.rst
View file

@ -3600,7 +3600,7 @@ copying.
Previous versions compared the raw memory disregarding the item format
and the logical array structure.
.. method:: tobytes()
.. method:: tobytes(order=None)
Return the data in the buffer as a bytestring. This is equivalent to
calling the :class:`bytes` constructor on the memoryview. ::
@ -3616,6 +3616,13 @@ copying.
supports all format strings, including those that are not in
:mod:`struct` module syntax.
.. versionadded:: 3.8
*Order* can be {'C', 'F', 'A'}. When *order* is 'C' or 'F', the data
of the original array is converted to C or Fortran order. For contiguous
views, 'A' returns an exact copy of the physical memory. In particular,
in-memory Fortran order is preserved. For non-contiguous views, the
data is converted to C first. *order=None* is the same as *order='C'*.
.. method:: hex()
Return a string object containing two hexadecimal digits for each

15
Lib/test/test_buffer.py
View file

@ -893,6 +893,15 @@ def verify(self, result, *, obj,
y = ndarray(initlst, shape=shape, flags=ro, format=fmt)
self.assertEqual(memoryview(y), memoryview(result))
contig_bytes = memoryview(result).tobytes()
self.assertEqual(contig_bytes, contig)
contig_bytes = memoryview(result).tobytes(order=None)
self.assertEqual(contig_bytes, contig)
contig_bytes = memoryview(result).tobytes(order='C')
self.assertEqual(contig_bytes, contig)
# To 'F'
contig = py_buffer_to_contiguous(result, 'F', PyBUF_FULL_RO)
self.assertEqual(len(contig), nmemb * itemsize)
@ -905,6 +914,9 @@ def verify(self, result, *, obj,
format=fmt)
self.assertEqual(memoryview(y), memoryview(result))
contig_bytes = memoryview(result).tobytes(order='F')
self.assertEqual(contig_bytes, contig)
# To 'A'
contig = py_buffer_to_contiguous(result, 'A', PyBUF_FULL_RO)
self.assertEqual(len(contig), nmemb * itemsize)
@ -917,6 +929,9 @@ def verify(self, result, *, obj,
y = ndarray(initlst, shape=shape, flags=f|ro, format=fmt)
self.assertEqual(memoryview(y), memoryview(result))
contig_bytes = memoryview(result).tobytes(order='A')
self.assertEqual(contig_bytes, contig)
if is_memoryview_format(fmt):
try:
m = memoryview(result)

1
Misc/NEWS.d/next/Library/2019-02-02-00-04-01.bpo-35845.1jx2wk.rst Normal file
View file

@ -0,0 +1 @@
Add 'order' parameter to memoryview.tobytes().

44
Objects/memoryobject.c
View file

@ -2120,22 +2120,39 @@ memory_tolist(PyMemoryViewObject *mv, PyObject *noargs)
}
static PyObject *
memory_tobytes(PyMemoryViewObject *self, PyObject *dummy)
memory_tobytes(PyMemoryViewObject *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"order", NULL};
Py_buffer *src = VIEW_ADDR(self);
PyObject *bytes = NULL;
char *order = NULL;
char ord = 'C';
PyObject *bytes;
CHECK_RELEASED(self);
if (MV_C_CONTIGUOUS(self->flags)) {
return PyBytes_FromStringAndSize(src->buf, src->len);
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|z", kwlist, &order)) {
return NULL;
}
if (order) {
if (strcmp(order, "F") == 0) {
ord = 'F';
}
else if (strcmp(order, "A") == 0) {
ord = 'A';
}
else if (strcmp(order, "C") != 0) {
PyErr_SetString(PyExc_ValueError,
"order must be 'C', 'F' or 'A'");
return NULL;
}
}
bytes = PyBytes_FromStringAndSize(NULL, src->len);
if (bytes == NULL)
return NULL;
if (buffer_to_contiguous(PyBytes_AS_STRING(bytes), src, 'C') < 0) {
if (PyBuffer_ToContiguous(PyBytes_AS_STRING(bytes), src, src->len, ord) < 0) {
Py_DECREF(bytes);
return NULL;
}
@ -2156,10 +2173,15 @@ memory_hex(PyMemoryViewObject *self, PyObject *dummy)
return _Py_strhex(src->buf, src->len);
}
bytes = memory_tobytes(self, dummy);
bytes = PyBytes_FromStringAndSize(NULL, src->len);
if (bytes == NULL)
return NULL;
if (PyBuffer_ToContiguous(PyBytes_AS_STRING(bytes), src, src->len, 'C') < 0) {
Py_DECREF(bytes);
return NULL;
}
ret = _Py_strhex(PyBytes_AS_STRING(bytes), PyBytes_GET_SIZE(bytes));
Py_DECREF(bytes);
@ -3061,9 +3083,13 @@ PyDoc_STRVAR(memory_release_doc,
\n\
Release the underlying buffer exposed by the memoryview object.");
PyDoc_STRVAR(memory_tobytes_doc,
"tobytes($self, /)\n--\n\
"tobytes($self, /, order=None)\n--\n\
\n\
Return the data in the buffer as a byte string.");
Return the data in the buffer as a byte string. Order can be {'C', 'F', 'A'}.\n\
When order is 'C' or 'F', the data of the original array is converted to C or\n\
Fortran order. For contiguous views, 'A' returns an exact copy of the physical\n\
memory. In particular, in-memory Fortran order is preserved. For non-contiguous\n\
views, the data is converted to C first. order=None is the same as order='C'.");
PyDoc_STRVAR(memory_hex_doc,
"hex($self, /)\n--\n\
\n\
@ -3083,7 +3109,7 @@ Return a readonly version of the memoryview.");
static PyMethodDef memory_methods[] = {
{"release", (PyCFunction)memory_release, METH_NOARGS, memory_release_doc},
{"tobytes", (PyCFunction)memory_tobytes, METH_NOARGS, memory_tobytes_doc},
{"tobytes", (PyCFunction)memory_tobytes, METH_VARARGS|METH_KEYWORDS, memory_tobytes_doc},
{"hex", (PyCFunction)memory_hex, METH_NOARGS, memory_hex_doc},
{"tolist", (PyCFunction)memory_tolist, METH_NOARGS, memory_tolist_doc},
{"cast", (PyCFunction)(void(*)(void))memory_cast, METH_VARARGS|METH_KEYWORDS, memory_cast_doc},