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Refactor to remove duplicated nan/inf parsing code in

Browse source 
pystrtod.c, floatobject.c and dtoa.c.
This commit is contained in:
Mark Dickinson 2009-05-20 22:05:25 +00:00
parent 4db6ff683d
commit bd16edd305
5 changed files with 85 additions and 125 deletions
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2
Include/pystrtod.h
View file

@ -21,6 +21,8 @@ PyAPI_FUNC(char *) PyOS_double_to_string(double val,
int flags,
int *type);
PyAPI_FUNC(double) _Py_parse_inf_or_nan(const char *p, char **endptr);
/* PyOS_double_to_string's "flags" parameter can be set to 0 or more of: */
#define Py_DTSF_SIGN 0x01 /* always add the sign */

10
Lib/test/test_float.py
View file

@ -532,6 +532,11 @@ def test_inf_from_str(self):
self.assertRaises(ValueError, float, "-INFI")
self.assertRaises(ValueError, float, "infinitys")
self.assertRaises(ValueError, float, "++Inf")
self.assertRaises(ValueError, float, "-+inf")
self.assertRaises(ValueError, float, "+-infinity")
self.assertRaises(ValueError, float, "--Infinity")
def test_inf_as_str(self):
self.assertEqual(repr(1e300 * 1e300), "inf")
self.assertEqual(repr(-1e300 * 1e300), "-inf")
@ -563,6 +568,11 @@ def test_nan_from_str(self):
self.assertRaises(ValueError, float, "+na")
self.assertRaises(ValueError, float, "-na")
self.assertRaises(ValueError, float, "++nan")
self.assertRaises(ValueError, float, "-+NAN")
self.assertRaises(ValueError, float, "+-NaN")
self.assertRaises(ValueError, float, "--nAn")
def test_nan_as_str(self):
self.assertEqual(repr(1e300 * 1e300 * 0), "nan")
self.assertEqual(repr(-1e300 * 1e300 * 0), "nan")

49
Objects/floatobject.c
View file

@ -1157,20 +1157,6 @@ Return a hexadecimal representation of a floating-point number.\n\
>>> 3.14159.hex()\n\
'0x1.921f9f01b866ep+1'");
/* Case-insensitive locale-independent string match used for nan and inf
detection. t should be lower-case and null-terminated. Return a nonzero
result if the first strlen(t) characters of s match t and 0 otherwise. */
static int
case_insensitive_match(const char *s, const char *t)
{
while(*t && Py_TOLOWER(*s) == *t) {
s++;
t++;
}
return *t ? 0 : 1;
}
/* Convert a hexadecimal string to a float. */
static PyObject *
@ -1180,7 +1166,7 @@ float_fromhex(PyObject *cls, PyObject *arg)
double x;
long exp, top_exp, lsb, key_digit;
char *s, *coeff_start, *s_store, *coeff_end, *exp_start, *s_end;
int half_eps, digit, round_up, sign=1;
int half_eps, digit, round_up, negate=0;
Py_ssize_t length, ndigits, fdigits, i;
/*
@ -1237,33 +1223,24 @@ float_fromhex(PyObject *cls, PyObject *arg)
* Parse the string *
********************/
/* leading whitespace and optional sign */
/* leading whitespace */
while (Py_ISSPACE(*s))
s++;
if (*s == '-') {
s++;
sign = -1;
}
else if (*s == '+')
s++;
/* infinities and nans */
if (*s == 'i' || *s == 'I') {
if (!case_insensitive_match(s+1, "nf"))
goto parse_error;
s += 3;
x = Py_HUGE_VAL;
if (case_insensitive_match(s, "inity"))
s += 5;
x = _Py_parse_inf_or_nan(s, &coeff_end);
if (coeff_end != s) {
s = coeff_end;
goto finished;
}
if (*s == 'n' || *s == 'N') {
if (!case_insensitive_match(s+1, "an"))
goto parse_error;
s += 3;
x = Py_NAN;
goto finished;
/* optional sign */
if (*s == '-') {
s++;
negate = 1;
}
else if (*s == '+')
s++;
/* [0x] */
s_store = s;
@ -1400,7 +1377,7 @@ float_fromhex(PyObject *cls, PyObject *arg)
s++;
if (s != s_end)
goto parse_error;
result_as_float = Py_BuildValue("(d)", sign * x);
result_as_float = Py_BuildValue("(d)", negate ? -x : x);
if (result_as_float == NULL)
return NULL;
result = PyObject_CallObject(cls, result_as_float);

50
Python/dtoa.c
View file

@ -264,15 +264,6 @@ extern int strtod_diglim;
#define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))
#define Big1 0xffffffff
#ifndef NAN_WORD0
#define NAN_WORD0 0x7ff80000
#endif
#ifndef NAN_WORD1
#define NAN_WORD1 0
#endif
/* struct BCinfo is used to pass information from _Py_dg_strtod to bigcomp */
typedef struct BCinfo BCinfo;
@ -1026,25 +1017,6 @@ static const double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128,
#define Scale_Bit 0x10
#define n_bigtens 5
/* case insensitive string match, for recognising 'inf[inity]' and
'nan' strings. */
static int
match(const char **sp, char *t)
{
int c, d;
const char *s = *sp;
while((d = *t++)) {
if ((c = *++s) >= 'A' && c <= 'Z')
c += 'a' - 'A';
if (c != d)
return 0;
}
*sp = s + 1;
return 1;
}
#define ULbits 32
#define kshift 5
#define kmask 31
@ -1459,28 +1431,6 @@ _Py_dg_strtod(const char *s00, char **se)
}
if (!nd) {
if (!nz && !nz0) {
/* Check for Nan and Infinity */
if (!bc.dplen)
switch(c) {
case 'i':
case 'I':
if (match(&s,"nf")) {
--s;
if (!match(&s,"inity"))
++s;
word0(&rv) = 0x7ff00000;
word1(&rv) = 0;
goto ret;
}
break;
case 'n':
case 'N':
if (match(&s, "an")) {
word0(&rv) = NAN_WORD0;
word1(&rv) = NAN_WORD1;
goto ret;
}
}
ret0:
s = s00;
sign = 0;

99
Python/pystrtod.c
View file

@ -3,6 +3,57 @@
#include <Python.h>
#include <locale.h>
/* _Py_parse_inf_or_nan: Attempt to parse a string of the form "nan", "inf" or
"infinity", with an optional leading sign of "+" or "-". On success,
return the NaN or Infinity as a double and set *endptr to point just beyond
the successfully parsed portion of the string. On failure, return -1.0 and
set *endptr to point to the start of the string. */
static int
case_insensitive_match(const char *s, const char *t)
{
while(*t && Py_TOLOWER(*s) == *t) {
s++;
t++;
}
return *t ? 0 : 1;
}
double
_Py_parse_inf_or_nan(const char *p, char **endptr)
{
double retval;
const char *s;
int negate = 0;
s = p;
if (*s == '-') {
negate = 1;
s++;
}
else if (*s == '+') {
s++;
}
if (case_insensitive_match(s, "inf")) {
s += 3;
if (case_insensitive_match(s, "inity"))
s += 5;
retval = negate ? -Py_HUGE_VAL : Py_HUGE_VAL;
}
#ifdef Py_NAN
else if (case_insensitive_match(s, "nan")) {
s += 3;
retval = negate ? -Py_NAN : Py_NAN;
}
#endif
else {
s = p;
retval = -1.0;
}
*endptr = (char *)s;
return retval;
}
/**
* PyOS_ascii_strtod:
* @nptr: the string to convert to a numeric value.
@ -49,6 +100,10 @@ _PyOS_ascii_strtod(const char *nptr, char **endptr)
result = _Py_dg_strtod(nptr, endptr);
_Py_SET_53BIT_PRECISION_END;
if (*endptr == nptr)
/* string might represent and inf or nan */
result = _Py_parse_inf_or_nan(nptr, endptr);
return result;
}
@ -63,19 +118,6 @@ _PyOS_ascii_strtod(const char *nptr, char **endptr)
correctly rounded results.
*/
/* Case-insensitive string match used for nan and inf detection; t should be
lower-case. Returns 1 for a successful match, 0 otherwise. */
static int
case_insensitive_match(const char *s, const char *t)
{
while(*t && Py_TOLOWER(*s) == *t) {
s++;
t++;
}
return *t ? 0 : 1;
}
double
_PyOS_ascii_strtod(const char *nptr, char **endptr)
{
@ -101,6 +143,11 @@ _PyOS_ascii_strtod(const char *nptr, char **endptr)
decimal_point_pos = NULL;
/* Parse infinities and nans */
val = _Py_parse_inf_or_nan(nptr, endptr);
if (*endptr != nptr)
return val;
/* Set errno to zero, so that we can distinguish zero results
and underflows */
errno = 0;
@ -118,31 +165,6 @@ _PyOS_ascii_strtod(const char *nptr, char **endptr)
p++;
}
/* Parse infinities and nans */
if (*p == 'i' || *p == 'I') {
if (case_insensitive_match(p+1, "nf")) {
val = Py_HUGE_VAL;
if (case_insensitive_match(p+3, "inity"))
fail_pos = (char *)p+8;
else
fail_pos = (char *)p+3;
goto got_val;
}
else
goto invalid_string;
}
#ifdef Py_NAN
if (*p == 'n' || *p == 'N') {
if (case_insensitive_match(p+1, "an")) {
val = Py_NAN;
fail_pos = (char *)p+3;
goto got_val;
}
else
goto invalid_string;
}
#endif
/* Some platform strtods accept hex floats; Python shouldn't (at the
moment), so we check explicitly for strings starting with '0x'. */
if (*p == '0' && (*(p+1) == 'x' || *(p+1) == 'X'))
@ -231,7 +253,6 @@ _PyOS_ascii_strtod(const char *nptr, char **endptr)
if (fail_pos == digits_pos)
goto invalid_string;
got_val:
if (negate && fail_pos != nptr)
val = -val;
*endptr = fail_pos;