(Most of) SF patch 601369 (Christos Georgiou): obmalloc,structmodule:
64bit, big endian (issue 2 only).
This adds a bunch of memcpy calls via a temporary variable to avoid
alignment errors. That's needed for some platforms.
diff --git a/Modules/structmodule.c b/Modules/structmodule.c
index 093cd7b..d4f8d86 100644
--- a/Modules/structmodule.c
+++ b/Modules/structmodule.c
@@ -1,4 +1,3 @@
-
/* struct module -- pack values into and (out of) strings */
/* New version supporting byte order, alignment and size options,
@@ -482,6 +481,14 @@
*/
/* Native mode routines. ****************************************************/
+/* NOTE:
+ In all n[up]_<type> routines handling types larger than 1 byte, there is
+ *no* guarantee that the p pointer is properly aligned for each type,
+ therefore memcpy is called. An intermediate variable is used to
+ compensate for big-endian architectures.
+ Normally both the intermediate variable and the memcpy call will be
+ skipped by C optimisation in little-endian architectures (gcc >= 2.91
+ does this). */
static PyObject *
nu_char(const char *p, const formatdef *f)
@@ -504,38 +511,49 @@
static PyObject *
nu_short(const char *p, const formatdef *f)
{
- return PyInt_FromLong((long) *(short *)p);
+ short x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyInt_FromLong((long)x);
}
static PyObject *
nu_ushort(const char *p, const formatdef *f)
{
- return PyInt_FromLong((long) *(unsigned short *)p);
+ unsigned short x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyInt_FromLong((long)x);
}
static PyObject *
nu_int(const char *p, const formatdef *f)
{
- return PyInt_FromLong((long) *(int *)p);
+ int x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyInt_FromLong((long)x);
}
static PyObject *
nu_uint(const char *p, const formatdef *f)
{
- unsigned int x = *(unsigned int *)p;
+ unsigned int x;
+ memcpy((char *)&x, p, sizeof x);
return PyLong_FromUnsignedLong((unsigned long)x);
}
static PyObject *
nu_long(const char *p, const formatdef *f)
{
- return PyInt_FromLong(*(long *)p);
+ long x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyInt_FromLong(x);
}
static PyObject *
nu_ulong(const char *p, const formatdef *f)
{
- return PyLong_FromUnsignedLong(*(unsigned long *)p);
+ unsigned long x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyLong_FromUnsignedLong(x);
}
/* Native mode doesn't support q or Q unless the platform C supports
@@ -546,27 +564,26 @@
static PyObject *
nu_longlong(const char *p, const formatdef *f)
{
- /* p may not be properly aligned */
LONG_LONG x;
- memcpy(&x, p, sizeof(LONG_LONG));
+ memcpy((char *)&x, p, sizeof x);
return PyLong_FromLongLong(x);
}
static PyObject *
nu_ulonglong(const char *p, const formatdef *f)
{
- /* p may not be properly aligned */
unsigned LONG_LONG x;
- memcpy(&x, p, sizeof(unsigned LONG_LONG));
+ memcpy((char *)&x, p, sizeof x);
return PyLong_FromUnsignedLongLong(x);
}
+
#endif
static PyObject *
nu_float(const char *p, const formatdef *f)
{
float x;
- memcpy((char *)&x, p, sizeof(float));
+ memcpy((char *)&x, p, sizeof x);
return PyFloat_FromDouble((double)x);
}
@@ -574,14 +591,16 @@
nu_double(const char *p, const formatdef *f)
{
double x;
- memcpy((char *)&x, p, sizeof(double));
+ memcpy((char *)&x, p, sizeof x);
return PyFloat_FromDouble(x);
}
static PyObject *
nu_void_p(const char *p, const formatdef *f)
{
- return PyLong_FromVoidPtr(*(void **)p);
+ void *x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyLong_FromVoidPtr(x);
}
static int
@@ -630,15 +649,17 @@
np_short(char *p, PyObject *v, const formatdef *f)
{
long x;
+ short y;
if (get_long(v, &x) < 0)
return -1;
if (x < SHRT_MIN || x > SHRT_MAX){
PyErr_SetString(StructError,
"short format requires " STRINGIFY(SHRT_MIN)
- "<=number<=" STRINGIFY(SHRT_MAX));
+ "<=number<=" STRINGIFY(SHRT_MAX));
return -1;
}
- * (short *)p = (short)x;
+ y = (short)x;
+ memcpy(p, (char *)&y, sizeof y);
return 0;
}
@@ -646,6 +667,7 @@
np_ushort(char *p, PyObject *v, const formatdef *f)
{
long x;
+ unsigned short y;
if (get_long(v, &x) < 0)
return -1;
if (x < 0 || x > USHRT_MAX){
@@ -653,7 +675,8 @@
"short format requires 0<=number<=" STRINGIFY(USHRT_MAX));
return -1;
}
- * (unsigned short *)p = (unsigned short)x;
+ y = (unsigned short)x;
+ memcpy(p, (char *)&y, sizeof y);
return 0;
}
@@ -661,9 +684,11 @@
np_int(char *p, PyObject *v, const formatdef *f)
{
long x;
+ int y;
if (get_long(v, &x) < 0)
return -1;
- * (int *)p = x;
+ y = (int)x;
+ memcpy(p, (char *)&y, sizeof y);
return 0;
}
@@ -671,9 +696,11 @@
np_uint(char *p, PyObject *v, const formatdef *f)
{
unsigned long x;
+ unsigned int y;
if (get_ulong(v, &x) < 0)
return -1;
- * (unsigned int *)p = x;
+ y = (unsigned int)x;
+ memcpy(p, (char *)&y, sizeof y);
return 0;
}
@@ -683,7 +710,7 @@
long x;
if (get_long(v, &x) < 0)
return -1;
- * (long *)p = x;
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
@@ -693,7 +720,7 @@
unsigned long x;
if (get_ulong(v, &x) < 0)
return -1;
- * (unsigned long *)p = x;
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
@@ -705,7 +732,7 @@
LONG_LONG x;
if (get_longlong(v, &x) < 0)
return -1;
- memcpy(p, &x, sizeof(LONG_LONG));
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
@@ -715,7 +742,7 @@
unsigned LONG_LONG x;
if (get_ulonglong(v, &x) < 0)
return -1;
- memcpy(p, &x, sizeof(unsigned LONG_LONG));
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
#endif
@@ -729,7 +756,7 @@
"required argument is not a float");
return -1;
}
- memcpy(p, (char *)&x, sizeof(float));
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
@@ -757,7 +784,7 @@
"required argument is not an integer");
return -1;
}
- *(void **)p = x;
+ memcpy(p, (char *)&x, sizeof x);
return 0;
}
@@ -1217,7 +1244,7 @@
size += x;
if (x/itemsize != num || size < 0) {
PyErr_SetString(StructError,
- "total struct size too long");
+ "total struct size too long");
return -1;
}
}
@@ -1266,7 +1293,7 @@
if (args == NULL || !PyTuple_Check(args) ||
(n = PyTuple_Size(args)) < 1)
- {
+ {
PyErr_SetString(PyExc_TypeError,
"struct.pack requires at least one argument");
return NULL;