[Python-checkins] cpython (2.7): support pep 3118 format strings for ctypes objects with nontrivial shapes
benjamin.peterson
python-checkins at python.org
Sun May 18 00:07:45 CEST 2014
http://hg.python.org/cpython/rev/44dac2e7fcb8
changeset: 90736:44dac2e7fcb8
branch: 2.7
user: Benjamin Peterson <benjamin at python.org>
date: Sat May 17 14:57:10 2014 -0700
summary:
support pep 3118 format strings for ctypes objects with nontrivial shapes (closes #10744)
Patch from Matti Picus.
files:
Lib/ctypes/test/test_pep3118.py | 15 +++-
Misc/NEWS | 3 +
Modules/_ctypes/_ctypes.c | 62 +++++++++++++++++---
Modules/_ctypes/ctypes.h | 3 +
Modules/_ctypes/stgdict.c | 7 ++-
5 files changed, 75 insertions(+), 15 deletions(-)
diff --git a/Lib/ctypes/test/test_pep3118.py b/Lib/ctypes/test/test_pep3118.py
--- a/Lib/ctypes/test/test_pep3118.py
+++ b/Lib/ctypes/test/test_pep3118.py
@@ -92,6 +92,10 @@
class aUnion(Union):
_fields_ = [("a", c_int)]
+class StructWithArrays(Structure):
+ _fields_ = [("x", c_long * 3 * 2), ("y", Point * 4)]
+
+
class Incomplete(Structure):
pass
@@ -141,10 +145,10 @@
## arrays and pointers
- (c_double * 4, "(4)<d", (4,), c_double),
- (c_float * 4 * 3 * 2, "(2,3,4)<f", (2,3,4), c_float),
- (POINTER(c_short) * 2, "(2)&<h", (2,), POINTER(c_short)),
- (POINTER(c_short) * 2 * 3, "(3,2)&<h", (3,2,), POINTER(c_short)),
+ (c_double * 4, "<d", (4,), c_double),
+ (c_float * 4 * 3 * 2, "<f", (2,3,4), c_float),
+ (POINTER(c_short) * 2, "&<h", (2,), POINTER(c_short)),
+ (POINTER(c_short) * 2 * 3, "&<h", (3,2,), POINTER(c_short)),
(POINTER(c_short * 2), "&(2)<h", None, POINTER(c_short)),
## structures and unions
@@ -156,6 +160,9 @@
(EmptyStruct, "T{}", None, EmptyStruct),
# the pep does't support unions
(aUnion, "B", None, aUnion),
+ # structure with sub-arrays
+ (StructWithArrays, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}", None, StructWithArrays),
+ (StructWithArrays * 3, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}", (3,), StructWithArrays),
## pointer to incomplete structure
(Incomplete, "B", None, Incomplete),
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -49,6 +49,9 @@
Library
-------
+- Issue #10744: Fix PEP 3118 format strings on ctypes objects with a nontrivial
+ shape.
+
- Issue #7776: Backport Fix ``Host:'' header and reconnection when using
http.client.HTTPConnection.set_tunnel() from Python 3. Patch by Nikolaus
Rath.
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -322,6 +322,48 @@
}
/*
+ Allocate a memory block for a pep3118 format string, adding
+ the given prefix (if non-null), an additional shape prefix, and a suffix.
+ Returns NULL on failure, with the error indicator set. If called with
+ a suffix of NULL the error indicator must already be set.
+ */
+char *
+_ctypes_alloc_format_string_with_shape(int ndim, const Py_ssize_t *shape,
+ const char *prefix, const char *suffix)
+{
+ char *new_prefix;
+ char *result;
+ char buf[32];
+ int prefix_len;
+ int k;
+
+ prefix_len = 32 * ndim + 3;
+ if (prefix)
+ prefix_len += strlen(prefix);
+ new_prefix = PyMem_Malloc(prefix_len);
+ if (new_prefix == NULL)
+ return NULL;
+ new_prefix[0] = '\0';
+ if (prefix)
+ strcpy(new_prefix, prefix);
+ if (ndim > 0) {
+ /* Add the prefix "(shape[0],shape[1],...,shape[ndim-1])" */
+ strcat(new_prefix, "(");
+ for (k = 0; k < ndim; ++k) {
+ if (k < ndim-1) {
+ sprintf(buf, "%"PY_FORMAT_SIZE_T"d,", shape[k]);
+ } else {
+ sprintf(buf, "%"PY_FORMAT_SIZE_T"d)", shape[k]);
+ }
+ strcat(new_prefix, buf);
+ }
+ }
+ result = _ctypes_alloc_format_string(new_prefix, suffix);
+ PyMem_Free(new_prefix);
+ return result;
+}
+
+/*
PyCStructType_Type - a meta type/class. Creating a new class using this one as
__metaclass__ will call the contructor StructUnionType_new. It replaces the
tp_dict member with a new instance of StgDict, and initializes the C
@@ -917,14 +959,21 @@
if (proto) {
StgDictObject *itemdict = PyType_stgdict(proto);
+ const char *current_format;
assert(itemdict);
/* If itemdict->format is NULL, then this is a pointer to an
incomplete type. We create a generic format string
'pointer to bytes' in this case. XXX Better would be to
fix the format string later...
*/
- stgdict->format = _ctypes_alloc_format_string("&",
- itemdict->format ? itemdict->format : "B");
+ current_format = itemdict->format ? itemdict->format : "B";
+ if (itemdict->shape != NULL) {
+ /* pointer to an array: the shape needs to be prefixed */
+ stgdict->format = _ctypes_alloc_format_string_with_shape(
+ itemdict->ndim, itemdict->shape, "&", current_format);
+ } else {
+ stgdict->format = _ctypes_alloc_format_string("&", current_format);
+ }
if (stgdict->format == NULL) {
Py_DECREF((PyObject *)stgdict);
return NULL;
@@ -1326,7 +1375,6 @@
long length;
Py_ssize_t itemsize, itemalign;
- char buf[32];
typedict = PyTuple_GetItem(args, 2);
if (!typedict)
@@ -1362,13 +1410,7 @@
}
assert(itemdict->format);
- if (itemdict->format[0] == '(') {
- sprintf(buf, "(%ld,", length);
- stgdict->format = _ctypes_alloc_format_string(buf, itemdict->format+1);
- } else {
- sprintf(buf, "(%ld)", length);
- stgdict->format = _ctypes_alloc_format_string(buf, itemdict->format);
- }
+ stgdict->format = _ctypes_alloc_format_string(NULL, itemdict->format);
if (stgdict->format == NULL) {
Py_DECREF((PyObject *)stgdict);
return NULL;
diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -434,6 +434,9 @@
extern PyObject *PyCData_FromBaseObj(PyObject *type, PyObject *base, Py_ssize_t index, char *adr);
extern char *_ctypes_alloc_format_string(const char *prefix, const char *suffix);
+extern char *_ctypes_alloc_format_string_with_shape(int ndim,
+ const Py_ssize_t *shape,
+ const char *prefix, const char *suffix);
extern int _ctypes_simple_instance(PyObject *obj);
diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -518,7 +518,12 @@
sprintf(buf, "%s:%s:", fieldfmt, fieldname);
ptr = stgdict->format;
- stgdict->format = _ctypes_alloc_format_string(stgdict->format, buf);
+ if (dict->shape != NULL) {
+ stgdict->format = _ctypes_alloc_format_string_with_shape(
+ dict->ndim, dict->shape, stgdict->format, buf);
+ } else {
+ stgdict->format = _ctypes_alloc_format_string(stgdict->format, buf);
+ }
PyMem_Free(ptr);
PyMem_Free(buf);
--
Repository URL: http://hg.python.org/cpython
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