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Internal plumbing changes for float parsing:

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- check for nans and infs within PyOS_ascii_strtod
 - simplify parsing in PyFloat_FromString, and handle out-of-memory
   errors properly
This commit is contained in:
Mark Dickinson 2009-04-26 15:30:47 +00:00
parent 35f1c9470a
commit 6d65df1e8a
2 changed files with 78 additions and 87 deletions
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78
Objects/floatobject.c
View file

@ -162,7 +162,7 @@ PyFloat_FromDouble(double fval)
PyObject *
PyFloat_FromString(PyObject *v)
{
const char *s, *last, *end, *sp;
const char *s, *last, *end;
double x;
char buffer[256]; /* for errors */
char *s_buffer = NULL;
@ -186,76 +186,40 @@ PyFloat_FromString(PyObject *v)
"float() argument must be a string or a number");
return NULL;
}
last = s + len;
while (*s && isspace(Py_CHARMASK(*s)))
s++;
if (*s == '\0') {
PyErr_SetString(PyExc_ValueError, "empty string for float()");
goto error;
}
sp = s;
/* We don't care about overflow or underflow. If the platform supports
* them, infinities and signed zeroes (on underflow) are fine.
* However, strtod can return 0 for denormalized numbers. Note that
* whether strtod sets errno on underflow is not defined, so we can't
* key off errno.
*/
/* We don't care about overflow or underflow. If the platform
* supports them, infinities and signed zeroes (on underflow) are
* fine. */
errno = 0;
PyFPE_START_PROTECT("strtod", goto error)
x = PyOS_ascii_strtod(s, (char **)&end);
PyFPE_END_PROTECT(x)
errno = 0;
/* Believe it or not, Solaris 2.6 can move end *beyond* the null
byte at the end of the string, when the input is inf(inity). */
if (end > last)
end = last;
/* Check for inf and nan. This is done late because it rarely happens. */
if (end == s) {
char *p = (char*)sp;
int sign = 1;
if (*p == '-') {
sign = -1;
p++;
if (errno == ENOMEM)
PyErr_NoMemory();
else {
PyOS_snprintf(buffer, sizeof(buffer),
"invalid literal for float(): %.200s", s);
PyErr_SetString(PyExc_ValueError, buffer);
}
if (*p == '+') {
p++;
}
if (PyOS_strnicmp(p, "inf", 4) == 0) {
if (s_buffer != NULL)
PyMem_FREE(s_buffer);
Py_RETURN_INF(sign);
}
if (PyOS_strnicmp(p, "infinity", 9) == 0) {
if (s_buffer != NULL)
PyMem_FREE(s_buffer);
Py_RETURN_INF(sign);
}
#ifdef Py_NAN
if(PyOS_strnicmp(p, "nan", 4) == 0) {
if (s_buffer != NULL)
PyMem_FREE(s_buffer);
Py_RETURN_NAN;
}
#endif
PyOS_snprintf(buffer, sizeof(buffer),
"invalid literal for float(): %.200s", s);
PyErr_SetString(PyExc_ValueError, buffer);
goto error;
}
/* Since end != s, the platform made *some* kind of sense out
of the input. Trust it. */
while (*end && isspace(Py_CHARMASK(*end)))
end++;
if (*end != '\0') {
PyOS_snprintf(buffer, sizeof(buffer),
"invalid literal for float(): %.200s", s);
PyErr_SetString(PyExc_ValueError, buffer);
goto error;
}
else if (end != last) {
PyErr_SetString(PyExc_ValueError,
"null byte in argument for float()");
if (end != last) {
if (*end == '\0')
PyErr_SetString(PyExc_ValueError,
"null byte in argument for float()");
else {
PyOS_snprintf(buffer, sizeof(buffer),
"invalid literal for float(): %.200s", s);
PyErr_SetString(PyExc_ValueError, buffer);
}
goto error;
}
result = PyFloat_FromDouble(x);