Internal plumbing changes for float parsing:
- 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
parent
35f1c9470a
commit
6d65df1e8a
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@ -162,7 +162,7 @@ PyFloat_FromDouble(double fval)
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PyObject *
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PyFloat_FromString(PyObject *v)
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{
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const char *s, *last, *end, *sp;
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const char *s, *last, *end;
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double x;
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char buffer[256]; /* for errors */
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char *s_buffer = NULL;
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@ -186,76 +186,40 @@ PyFloat_FromString(PyObject *v)
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"float() argument must be a string or a number");
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return NULL;
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}
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last = s + len;
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while (*s && isspace(Py_CHARMASK(*s)))
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s++;
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if (*s == '\0') {
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PyErr_SetString(PyExc_ValueError, "empty string for float()");
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goto error;
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}
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sp = s;
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/* We don't care about overflow or underflow. If the platform supports
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* them, infinities and signed zeroes (on underflow) are fine.
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* However, strtod can return 0 for denormalized numbers. Note that
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* whether strtod sets errno on underflow is not defined, so we can't
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* key off errno.
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*/
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/* We don't care about overflow or underflow. If the platform
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* supports them, infinities and signed zeroes (on underflow) are
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* fine. */
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errno = 0;
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PyFPE_START_PROTECT("strtod", goto error)
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x = PyOS_ascii_strtod(s, (char **)&end);
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PyFPE_END_PROTECT(x)
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errno = 0;
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/* Believe it or not, Solaris 2.6 can move end *beyond* the null
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byte at the end of the string, when the input is inf(inity). */
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if (end > last)
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end = last;
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/* Check for inf and nan. This is done late because it rarely happens. */
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if (end == s) {
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char *p = (char*)sp;
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int sign = 1;
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if (*p == '-') {
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sign = -1;
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p++;
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if (errno == ENOMEM)
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PyErr_NoMemory();
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else {
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PyOS_snprintf(buffer, sizeof(buffer),
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"invalid literal for float(): %.200s", s);
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PyErr_SetString(PyExc_ValueError, buffer);
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}
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if (*p == '+') {
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p++;
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}
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if (PyOS_strnicmp(p, "inf", 4) == 0) {
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if (s_buffer != NULL)
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PyMem_FREE(s_buffer);
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Py_RETURN_INF(sign);
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}
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if (PyOS_strnicmp(p, "infinity", 9) == 0) {
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if (s_buffer != NULL)
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PyMem_FREE(s_buffer);
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Py_RETURN_INF(sign);
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}
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#ifdef Py_NAN
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if(PyOS_strnicmp(p, "nan", 4) == 0) {
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if (s_buffer != NULL)
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PyMem_FREE(s_buffer);
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Py_RETURN_NAN;
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}
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#endif
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PyOS_snprintf(buffer, sizeof(buffer),
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"invalid literal for float(): %.200s", s);
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PyErr_SetString(PyExc_ValueError, buffer);
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goto error;
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}
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/* Since end != s, the platform made *some* kind of sense out
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of the input. Trust it. */
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while (*end && isspace(Py_CHARMASK(*end)))
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end++;
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if (*end != '\0') {
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PyOS_snprintf(buffer, sizeof(buffer),
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"invalid literal for float(): %.200s", s);
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PyErr_SetString(PyExc_ValueError, buffer);
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goto error;
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}
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else if (end != last) {
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PyErr_SetString(PyExc_ValueError,
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"null byte in argument for float()");
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if (end != last) {
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if (*end == '\0')
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PyErr_SetString(PyExc_ValueError,
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"null byte in argument for float()");
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else {
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PyOS_snprintf(buffer, sizeof(buffer),
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"invalid literal for float(): %.200s", s);
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PyErr_SetString(PyExc_ValueError, buffer);
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}
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goto error;
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}
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result = PyFloat_FromDouble(x);
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@ -94,6 +94,10 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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decimal_point_pos = NULL;
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/* Set errno to zero, so that we can distinguish zero results
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and underflows */
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errno = 0;
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/* We process any leading whitespace and the optional sign manually,
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then pass the remainder to the system strtod. This ensures that
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the result of an underflow has the correct sign. (bug #1725) */
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@ -107,27 +111,53 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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if (*p == '-') {
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negate = 1;
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p++;
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} else if (*p == '+') {
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}
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else if (*p == '+') {
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p++;
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}
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/* What's left should begin with a digit, a decimal point, or one of
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the letters i, I, n, N. It should not begin with 0x or 0X */
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if ((!ISDIGIT(*p) &&
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*p != '.' && *p != 'i' && *p != 'I' && *p != 'n' && *p != 'N')
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||
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(*p == '0' && (p[1] == 'x' || p[1] == 'X')))
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{
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if (endptr)
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*endptr = (char*)nptr;
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errno = EINVAL;
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return val;
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/* Parse infinities and nans */
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if (*p == 'i' || *p == 'I') {
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if (PyOS_strnicmp(p, "inf", 3) == 0) {
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val = Py_HUGE_VAL;
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if (PyOS_strnicmp(p+3, "inity", 5) == 0)
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fail_pos = (char *)p+8;
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else
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fail_pos = (char *)p+3;
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goto got_val;
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}
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else
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goto invalid_string;
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}
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digits_pos = p;
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#ifdef Py_NAN
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if (*p == 'n' || *p == 'N') {
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if (PyOS_strnicmp(p, "nan", 3) == 0) {
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val = Py_NAN;
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fail_pos = (char *)p+3;
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goto got_val;
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}
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else
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goto invalid_string;
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}
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#endif
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/* Some platform strtods accept hex floats; Python shouldn't (at the
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moment), so we check explicitly for strings starting with '0x'. */
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if (*p == '0' && (*(p+1) == 'x' || *(p+1) == 'X'))
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goto invalid_string;
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/* Check that what's left begins with a digit or decimal point */
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if (!ISDIGIT(*p) && *p != '.')
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goto invalid_string;
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digits_pos = p;
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if (decimal_point[0] != '.' ||
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decimal_point[1] != 0)
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{
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/* Look for a '.' in the input; if present, it'll need to be
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swapped for the current locale's decimal point before we
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call strtod. On the other hand, if we find the current
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locale's decimal point then the input is invalid. */
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while (ISDIGIT(*p))
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p++;
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@ -135,6 +165,7 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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{
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decimal_point_pos = p++;
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/* locate end of number */
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while (ISDIGIT(*p))
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p++;
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@ -147,27 +178,16 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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end = p;
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}
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else if (strncmp(p, decimal_point, decimal_point_len) == 0)
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{
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/* Python bug #1417699 */
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if (endptr)
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*endptr = (char*)nptr;
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errno = EINVAL;
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return val;
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}
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goto invalid_string;
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/* For the other cases, we need not convert the decimal
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point */
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}
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/* Set errno to zero, so that we can distinguish zero results
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and underflows */
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errno = 0;
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if (decimal_point_pos)
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{
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if (decimal_point_pos) {
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char *copy, *c;
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/* We need to convert the '.' to the locale specific decimal
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point */
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/* Create a copy of the input, with the '.' converted to the
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locale-specific decimal point */
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copy = (char *)PyMem_MALLOC(end - digits_pos +
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1 + decimal_point_len);
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if (copy == NULL) {
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@ -208,8 +228,9 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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}
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if (fail_pos == digits_pos)
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fail_pos = (char *)nptr;
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goto invalid_string;
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got_val:
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if (negate && fail_pos != nptr)
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val = -val;
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@ -217,6 +238,12 @@ PyOS_ascii_strtod(const char *nptr, char **endptr)
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*endptr = fail_pos;
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return val;
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invalid_string:
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if (endptr)
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*endptr = (char*)nptr;
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errno = EINVAL;
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return -1.0;
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}
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#endif
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