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Raise ValueError when value being stored in a time_t variable will result in

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more than a second of precision.  Primarily affects ctime, localtime, and
gmtime.

Closes bug #919012 thanks to Tim Peters' code.

Tim suggests that the new funciton being introduced, _PyTime_DoubletoTimet(),
should be added to the internal C API and then used in datetime where
appropriate.  Not being done now for lack of time.
This commit is contained in:
Brett Cannon 2004-06-19 20:48:43 +00:00
parent cdc7923f6d
commit 298c380c74
1 changed files with 40 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

45
Modules/timemodule.c
View file

@ -84,6 +84,35 @@ static double floattime(void);
/* For Y2K check */
static PyObject *moddict;
/* Cast double x to time_t, but raise ValueError if x is too large
* to fit in a time_t. ValueError is set on return iff the return
* value is (time_t)-1 and PyErr_Occurred().
*/
static time_t
_PyTime_DoubleToTimet(double x)
{
time_t result;
double diff;
result = (time_t)x;
/* How much info did we lose? time_t may be an integral or
* floating type, and we don't know which. If it's integral,
* we don't know whether C truncates, rounds, returns the floor,
* etc. If we lost a second or more, the C rounding is
* unreasonable, or the input just doesn't fit in a time_t;
* call it an error regardless. Note that the original cast to
* time_t can cause a C error too, but nothing we can do to
* worm around that.
*/
diff = x - (double)result;
if (diff <= -1.0 || diff >= 1.0) {
PyErr_SetString(PyExc_ValueError,
"timestamp out of range for platform time_t");
result = (time_t)-1;
}
return result;
}
static PyObject *
time_time(PyObject *self, PyObject *args)
{
@ -231,11 +260,15 @@ tmtotuple(struct tm *p)
}
static PyObject *
time_convert(time_t when, struct tm * (*function)(const time_t *))
time_convert(double when, struct tm * (*function)(const time_t *))
{
struct tm *p;
time_t whent = _PyTime_DoubleToTimet(when);
if (whent == (time_t)-1 && PyErr_Occurred())
return NULL;
errno = 0;
p = function(&when);
p = function(&whent);
if (p == NULL) {
#ifdef EINVAL
if (errno == 0)
@ -254,7 +287,7 @@ time_gmtime(PyObject *self, PyObject *args)
when = floattime();
if (!PyArg_ParseTuple(args, "|d:gmtime", &when))
return NULL;
return time_convert((time_t)when, gmtime);
return time_convert(when, gmtime);
}
PyDoc_STRVAR(gmtime_doc,
@ -272,7 +305,7 @@ time_localtime(PyObject *self, PyObject *args)
when = floattime();
if (!PyArg_ParseTuple(args, "|d:localtime", &when))
return NULL;
return time_convert((time_t)when, localtime);
return time_convert(when, localtime);
}
PyDoc_STRVAR(localtime_doc,
@ -480,7 +513,9 @@ time_ctime(PyObject *self, PyObject *args)
else {
if (!PyArg_ParseTuple(args, "|d:ctime", &dt))
return NULL;
tt = (time_t)dt;
tt = _PyTime_DoubleToTimet(dt);
if (tt == (time_t)-1 && PyErr_Occurred())
return NULL;
}
p = ctime(&tt);
if (p == NULL) {