Fix for SF bug 110624: float literals behave inconsistently.
I fixed the specific complaint but left the (many) large issues untouched.
See the (very long) bug report discussion for why:
http://sourceforge.net/bugs/?func=detailbug&group_id=5470&bug_id=110624
Note that while I left the interface to the undocumented public API function
PyFloat_FromString alone, its 2nd argument is useless. From a comment block
in the code:
RED_FLAG 22-Sep-2000 tim
PyFloat_FromString's pend argument is braindead. Prior to this RED_FLAG,
1. If v was a regular string, *pend was set to point to its terminating
null byte. That's useless (the caller can find that without any
help from this function!).
2. If v was a Unicode string, or an object convertible to a character
buffer, *pend was set to point into stack trash (the auto temp
vector holding the character buffer). That was downright dangerous.
Since we can't change the interface of a public API function, pend is
still supported but now *officially* useless: if pend is not NULL,
*pend is set to NULL.
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 774996f..168cbcd 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -117,16 +117,33 @@
return (PyObject *) op;
}
+/**************************************************************************
+RED_FLAG 22-Sep-2000 tim
+PyFloat_FromString's pend argument is braindead. Prior to this RED_FLAG,
+
+1. If v was a regular string, *pend was set to point to its terminating
+ null byte. That's useless (the caller can find that without any
+ help from this function!).
+
+2. If v was a Unicode string, or an object convertible to a character
+ buffer, *pend was set to point into stack trash (the auto temp
+ vector holding the character buffer). That was downright dangerous.
+
+Since we can't change the interface of a public API function, pend is
+still supported but now *officially* useless: if pend is not NULL,
+*pend is set to NULL.
+**************************************************************************/
PyObject *
PyFloat_FromString(PyObject *v, char **pend)
{
- extern double strtod(const char *, char **);
const char *s, *last, *end;
double x;
- char buffer[256]; /* For errors */
- char s_buffer[256];
+ char buffer[256]; /* for errors */
+ char s_buffer[256]; /* for objects convertible to a char buffer */
int len;
+ if (pend)
+ *pend = NULL;
if (PyString_Check(v)) {
s = PyString_AS_STRING(v);
len = PyString_GET_SIZE(v);
@@ -134,10 +151,10 @@
else if (PyUnicode_Check(v)) {
if (PyUnicode_GET_SIZE(v) >= sizeof(s_buffer)) {
PyErr_SetString(PyExc_ValueError,
- "float() literal too large to convert");
+ "Unicode float() literal too long to convert");
return NULL;
}
- if (PyUnicode_EncodeDecimal(PyUnicode_AS_UNICODE(v),
+ if (PyUnicode_EncodeDecimal(PyUnicode_AS_UNICODE(v),
PyUnicode_GET_SIZE(v),
s_buffer,
NULL))
@@ -154,18 +171,30 @@
last = s + len;
while (*s && isspace(Py_CHARMASK(*s)))
s++;
- if (s[0] == '\0') {
+ if (*s == '\0') {
PyErr_SetString(PyExc_ValueError, "empty string for float()");
return NULL;
}
+ /* 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, where atof
+ * does not. So (alas!) we special-case a zero result. Note that
+ * whether strtod sets errno on underflow is not defined, so we can't
+ * key off errno.
+ */
+ x = strtod(s, (char **)&end);
errno = 0;
- PyFPE_START_PROTECT("PyFloat_FromString", return 0)
- x = strtod((char *)s, (char **)&end);
- PyFPE_END_PROTECT(x)
/* 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) */
+ byte at the end of the string, when the input is inf(inity). */
if (end > last)
end = last;
+ if (end == s) {
+ sprintf(buffer, "invalid literal for float(): %.200s", s);
+ PyErr_SetString(PyExc_ValueError, buffer);
+ return NULL;
+ }
+ /* 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') {
@@ -178,13 +207,12 @@
"null byte in argument for float()");
return NULL;
}
- else if (errno != 0) {
- sprintf(buffer, "float() literal too large: %.200s", s);
- PyErr_SetString(PyExc_ValueError, buffer);
- return NULL;
+ if (x == 0.0) {
+ /* See above -- may have been strtod being anal
+ about denorms. */
+ x = atof(s);
+ errno = 0; /* whether atof ever set errno is undefined */
}
- if (pend)
- *pend = (char *)end;
return PyFloat_FromDouble(x);
}