/* -*- Mode: C; c-file-style: "python" -*- */

#include <Python.h>

#include <locale.h>

/**

* PyOS_ascii_strtod:

* @nptr: the string to convert to a numeric value.

* @endptr: if non-%NULL, it returns the character after

* the last character used in the conversion.

*

* Converts a string to a #gdouble value.

* This function behaves like the standard strtod() function

* does in the C locale. It does this without actually

* changing the current locale, since that would not be

* thread-safe.

*

* This function is typically used when reading configuration

* files or other non-user input that should be locale independent.

* To handle input from the user you should normally use the

* locale-sensitive system strtod() function.

*

* If the correct value would cause overflow, plus or minus %HUGE_VAL

* is returned (according to the sign of the value), and %ERANGE is

* stored in %errno. If the correct value would cause underflow,

* zero is returned and %ERANGE is stored in %errno.

* If memory allocation fails, %ENOMEM is stored in %errno.

*

* This function resets %errno before calling strtod() so that

* you can reliably detect overflow and underflow.

*

* Return value: the #gdouble value.

**/

#ifndef PY_NO_SHORT_FLOAT_REPR

double

_PyOS_ascii_strtod(const char *nptr, char **endptr)

{

double result;

_Py_SET_53BIT_PRECISION_HEADER;

assert(nptr != NULL);

/* Set errno to zero, so that we can distinguish zero results

and underflows */

errno = 0;

_Py_SET_53BIT_PRECISION_START;

result = _Py_dg_strtod(nptr, endptr);

_Py_SET_53BIT_PRECISION_END;

return result;

}

#else

/*

Use system strtod; since strtod is locale aware, we may

have to first fix the decimal separator.

Note that unlike _Py_dg_strtod, the system strtod may not always give

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)

{

char *fail_pos;

double val = -1.0;

struct lconv *locale_data;

const char *decimal_point;

size_t decimal_point_len;

const char *p, *decimal_point_pos;

const char *end = NULL; /* Silence gcc */

const char *digits_pos = NULL;

int negate = 0;

assert(nptr != NULL);

fail_pos = NULL;

locale_data = localeconv();

decimal_point = locale_data->decimal_point;

decimal_point_len = strlen(decimal_point);

assert(decimal_point_len != 0);

decimal_point_pos = NULL;

/* Set errno to zero, so that we can distinguish zero results

and underflows */

errno = 0;

/* We process the optional sign manually, then pass the remainder to

the system strtod. This ensures that the result of an underflow

has the correct sign. (bug #1725) */

p = nptr;

/* Process leading sign, if present */

if (*p == '-') {

negate = 1;

p++;

}

else if (*p == '+') {

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'))

goto invalid_string;

/* Check that what's left begins with a digit or decimal point */

if (!Py_ISDIGIT(*p) && *p != '.')

goto invalid_string;

digits_pos = p;

if (decimal_point[0] != '.' ||

decimal_point[1] != 0)

{

/* Look for a '.' in the input; if present, it'll need to be

swapped for the current locale's decimal point before we

call strtod. On the other hand, if we find the current

locale's decimal point then the input is invalid. */

while (Py_ISDIGIT(*p))

p++;

if (*p == '.')

{

decimal_point_pos = p++;

/* locate end of number */

while (Py_ISDIGIT(*p))

p++;

if (*p == 'e' || *p == 'E')

p++;

if (*p == '+' || *p == '-')

p++;

while (Py_ISDIGIT(*p))

p++;

end = p;

}

else if (strncmp(p, decimal_point, decimal_point_len) == 0)

/* Python bug #1417699 */

goto invalid_string;

/* For the other cases, we need not convert the decimal

point */

}

if (decimal_point_pos) {

char *copy, *c;

/* Create a copy of the input, with the '.' converted to the

locale-specific decimal point */

copy = (char *)PyMem_MALLOC(end - digits_pos +

1 + decimal_point_len);

if (copy == NULL) {

*endptr = (char *)nptr;

errno = ENOMEM;

return val;

}

c = copy;

memcpy(c, digits_pos, decimal_point_pos - digits_pos);

c += decimal_point_pos - digits_pos;

memcpy(c, decimal_point, decimal_point_len);

c += decimal_point_len;

memcpy(c, decimal_point_pos + 1,

end - (decimal_point_pos + 1));

c += end - (decimal_point_pos + 1);

*c = 0;

val = strtod(copy, &fail_pos);

if (fail_pos)

{

if (fail_pos > decimal_point_pos)

fail_pos = (char *)digits_pos +

(fail_pos - copy) -

(decimal_point_len - 1);

else

fail_pos = (char *)digits_pos +

(fail_pos - copy);

}

PyMem_FREE(copy);

}

else {

val = strtod(digits_pos, &fail_pos);

}

if (fail_pos == digits_pos)

goto invalid_string;

got_val:

if (negate && fail_pos != nptr)

val = -val;

*endptr = fail_pos;

return val;

invalid_string:

*endptr = (char*)nptr;

errno = EINVAL;

return -1.0;

}

#endif

/* PyOS_ascii_strtod is DEPRECATED in Python 3.1 */

double

PyOS_ascii_strtod(const char *nptr, char **endptr)

{

char *fail_pos;

const char *p;

double x;

if (PyErr_WarnEx(PyExc_DeprecationWarning,

"PyOS_ascii_strtod and PyOS_ascii_atof are "

"deprecated. Use PyOS_string_to_double "

"instead.", 1) < 0)

return -1.0;

/* _PyOS_ascii_strtod already does everything that we want,

except that it doesn't parse leading whitespace */

p = nptr;

while (Py_ISSPACE(*p))

p++;

x = _PyOS_ascii_strtod(p, &fail_pos);

if (fail_pos == p)

fail_pos = (char *)nptr;

if (endptr)

*endptr = (char *)fail_pos;

return x;

}

/* PyOS_ascii_strtod is DEPRECATED in Python 3.1 */

double

PyOS_ascii_atof(const char *nptr)

{

return PyOS_ascii_strtod(nptr, NULL);

}

/* PyOS_string_to_double is the recommended replacement for the deprecated

PyOS_ascii_strtod and PyOS_ascii_atof functions. It converts a

null-terminated byte string s (interpreted as a string of ASCII characters)

to a float. The string should not have leading or trailing whitespace (in

contrast, PyOS_ascii_strtod allows leading whitespace but not trailing

whitespace). The conversion is independent of the current locale.

If endptr is NULL, try to convert the whole string. Raise ValueError and

return -1.0 if the string is not a valid representation of a floating-point

number.

If endptr is non-NULL, try to convert as much of the string as possible.

If no initial segment of the string is the valid representation of a

floating-point number then *endptr is set to point to the beginning of the

string, -1.0 is returned and again ValueError is raised.

On overflow (e.g., when trying to convert '1e500' on an IEEE 754 machine),

if overflow_exception is NULL then +-Py_HUGE_VAL is returned, and no Python

exception is raised. Otherwise, overflow_exception should point to a

a Python exception, this exception will be raised, -1.0 will be returned,

and *endptr will point just past the end of the converted value.

If any other failure occurs (for example lack of memory), -1.0 is returned

and the appropriate Python exception will have been set.

*/

double

PyOS_string_to_double(const char *s,

char **endptr,

PyObject *overflow_exception)

{

double x, result=-1.0;

char *fail_pos;

errno = 0;

PyFPE_START_PROTECT("PyOS_string_to_double", return -1.0)

x = _PyOS_ascii_strtod(s, &fail_pos);

PyFPE_END_PROTECT(x)

if (errno == ENOMEM) {

PyErr_NoMemory();

fail_pos = (char *)s;

}

else if (!endptr && (fail_pos == s || *fail_pos != '\0'))

PyErr_Format(PyExc_ValueError,

"could not convert string to float: "

"%.200s", s);

else if (fail_pos == s)

PyErr_Format(PyExc_ValueError,

"could not convert string to float: "

"%.200s", s);

else if (errno == ERANGE && fabs(x) >= 1.0 && overflow_exception)

PyErr_Format(overflow_exception,

"value too large to convert to float: "

"%.200s", s);

else

result = x;

if (endptr != NULL)

*endptr = fail_pos;

return result;

}

/* Given a string that may have a decimal point in the current

locale, change it back to a dot. Since the string cannot get

longer, no need for a maximum buffer size parameter. */

Py_LOCAL_INLINE(void)

change_decimal_from_locale_to_dot(char* buffer)

{

struct lconv *locale_data = localeconv();

const char *decimal_point = locale_data->decimal_point;

if (decimal_point[0] != '.' || decimal_point[1] != 0) {

size_t decimal_point_len = strlen(decimal_point);

if (*buffer == '+' || *buffer == '-')

buffer++;

while (Py_ISDIGIT(*buffer))

buffer++;

if (strncmp(buffer, decimal_point, decimal_point_len) == 0) {

*buffer = '.';

buffer++;

if (decimal_point_len > 1) {

/* buffer needs to get smaller */

size_t rest_len = strlen(buffer +

(decimal_point_len - 1));

memmove(buffer,

buffer + (decimal_point_len - 1),

rest_len);

buffer[rest_len] = 0;

}

}

}

}

/* From the C99 standard, section 7.19.6:

The exponent always contains at least two digits, and only as many more digits

as necessary to represent the exponent.

*/

#define MIN_EXPONENT_DIGITS 2

/* Ensure that any exponent, if present, is at least MIN_EXPONENT_DIGITS

in length. */

Py_LOCAL_INLINE(void)

ensure_minimum_exponent_length(char* buffer, size_t buf_size)

{

char *p = strpbrk(buffer, "eE");

if (p && (*(p + 1) == '-' || *(p + 1) == '+')) {

char *start = p + 2;

int exponent_digit_cnt = 0;

int leading_zero_cnt = 0;

int in_leading_zeros = 1;

int significant_digit_cnt;

/* Skip over the exponent and the sign. */

p += 2;

/* Find the end of the exponent, keeping track of leading

zeros. */

while (*p && Py_ISDIGIT(*p)) {

if (in_leading_zeros && *p == '0')

++leading_zero_cnt;

if (*p != '0')

in_leading_zeros = 0;

++p;

++exponent_digit_cnt;

}

significant_digit_cnt = exponent_digit_cnt - leading_zero_cnt;

if (exponent_digit_cnt == MIN_EXPONENT_DIGITS) {

/* If there are 2 exactly digits, we're done,

regardless of what they contain */

}

else if (exponent_digit_cnt > MIN_EXPONENT_DIGITS) {

int extra_zeros_cnt;

/* There are more than 2 digits in the exponent. See

if we can delete some of the leading zeros */

if (significant_digit_cnt < MIN_EXPONENT_DIGITS)

significant_digit_cnt = MIN_EXPONENT_DIGITS;

extra_zeros_cnt = exponent_digit_cnt -

significant_digit_cnt;

/* Delete extra_zeros_cnt worth of characters from the

front of the exponent */

assert(extra_zeros_cnt >= 0);

/* Add one to significant_digit_cnt to copy the

trailing 0 byte, thus setting the length */

memmove(start,

start + extra_zeros_cnt,

significant_digit_cnt + 1);

}

else {

/* If there are fewer than 2 digits, add zeros

until there are 2, if there's enough room */

int zeros = MIN_EXPONENT_DIGITS - exponent_digit_cnt;

if (start + zeros + exponent_digit_cnt + 1

< buffer + buf_size) {

memmove(start + zeros, start,

exponent_digit_cnt + 1);

memset(start, '0', zeros);

}

}

}

}

/* Remove trailing zeros after the decimal point from a numeric string; also

remove the decimal point if all digits following it are zero. The numeric

string must end in '\0', and should not have any leading or trailing

whitespace. Assumes that the decimal point is '.'. */

Py_LOCAL_INLINE(void)

remove_trailing_zeros(char *buffer)

{

char *old_fraction_end, *new_fraction_end, *end, *p;

p = buffer;

if (*p == '-' || *p == '+')

/* Skip leading sign, if present */

++p;

while (Py_ISDIGIT(*p))

++p;

/* if there's no decimal point there's nothing to do */

if (*p++ != '.')

return;

/* scan any digits after the point */

while (Py_ISDIGIT(*p))

++p;

old_fraction_end = p;

/* scan up to ending '\0' */

while (*p != '\0')

p++;

/* +1 to make sure that we move the null byte as well */

end = p+1;

/* scan back from fraction_end, looking for removable zeros */

p = old_fraction_end;

while (*(p-1) == '0')

--p;

/* and remove point if we've got that far */

if (*(p-1) == '.')

--p;

new_fraction_end = p;

memmove(new_fraction_end, old_fraction_end, end-old_fraction_end);

}

/* Ensure that buffer has a decimal point in it. The decimal point will not

be in the current locale, it will always be '.'. Don't add a decimal point

if an exponent is present. Also, convert to exponential notation where

adding a '.0' would produce too many significant digits (see issue 5864).

Returns a pointer to the fixed buffer, or NULL on failure.

*/

Py_LOCAL_INLINE(char *)

ensure_decimal_point(char* buffer, size_t buf_size, int precision)

{

int digit_count, insert_count = 0, convert_to_exp = 0;

char *chars_to_insert, *digits_start;

/* search for the first non-digit character */

char *p = buffer;

if (*p == '-' || *p == '+')

/* Skip leading sign, if present. I think this could only

ever be '-', but it can't hurt to check for both. */

++p;

digits_start = p;

while (*p && Py_ISDIGIT(*p))

++p;

digit_count = Py_SAFE_DOWNCAST(p - digits_start, Py_ssize_t, int);

if (*p == '.') {

if (Py_ISDIGIT(*(p+1))) {

/* Nothing to do, we already have a decimal

point and a digit after it */

}

else {

/* We have a decimal point, but no following

digit. Insert a zero after the decimal. */

/* can't ever get here via PyOS_double_to_string */

assert(precision == -1);

++p;

chars_to_insert = "0";

insert_count = 1;

}

}

else if (!(*p == 'e' || *p == 'E')) {

/* Don't add ".0" if we have an exponent. */

if (digit_count == precision) {

/* issue 5864: don't add a trailing .0 in the case

where the '%g'-formatted result already has as many

significant digits as were requested. Switch to

exponential notation instead. */

convert_to_exp = 1;

/* no exponent, no point, and we shouldn't land here

for infs and nans, so we must be at the end of the

string. */

assert(*p == '\0');

}

else {

assert(precision == -1 || digit_count < precision);

chars_to_insert = ".0";

insert_count = 2;

}

}

if (insert_count) {

size_t buf_len = strlen(buffer);

if (buf_len + insert_count + 1 >= buf_size) {

/* If there is not enough room in the buffer

for the additional text, just skip it. It's

not worth generating an error over. */

}

else {

memmove(p + insert_count, p,

buffer + strlen(buffer) - p + 1);

memcpy(p, chars_to_insert, insert_count);

}

}

if (convert_to_exp) {

int written;

size_t buf_avail;

p = digits_start;

/* insert decimal point */

assert(digit_count >= 1);

memmove(p+2, p+1, digit_count); /* safe, but overwrites nul */

p[1] = '.';

p += digit_count+1;

assert(p <= buf_size+buffer);

buf_avail = buf_size+buffer-p;

if (buf_avail == 0)

return NULL;

/* Add exponent. It's okay to use lower case 'e': we only

arrive here as a result of using the empty format code or

repr/str builtins and those never want an upper case 'E' */

written = PyOS_snprintf(p, buf_avail, "e%+.02d", digit_count-1);

if (!(0 <= written &&

written < Py_SAFE_DOWNCAST(buf_avail, size_t, int)))

/* output truncated, or something else bad happened */

return NULL;

remove_trailing_zeros(buffer);

}

return buffer;

}

/* see FORMATBUFLEN in unicodeobject.c */

#define FLOAT_FORMATBUFLEN 120

/**

* PyOS_ascii_formatd:

* @buffer: A buffer to place the resulting string in

* @buf_size: The length of the buffer.

* @format: The printf()-style format to use for the

* code to use for converting.

* @d: The #gdouble to convert

*

* Converts a #gdouble to a string, using the '.' as

* decimal point. To format the number you pass in

* a printf()-style format string. Allowed conversion

* specifiers are 'e', 'E', 'f', 'F', 'g', 'G', and 'Z'.

*

* 'Z' is the same as 'g', except it always has a decimal and

* at least one digit after the decimal.

*

* Return value: The pointer to the buffer with the converted string.

* On failure returns NULL but does not set any Python exception.

**/

char *

_PyOS_ascii_formatd(char *buffer,

size_t buf_size,

const char *format,

double d,

int precision)

{

char format_char;

size_t format_len = strlen(format);

/* Issue 2264: code 'Z' requires copying the format. 'Z' is 'g', but

also with at least one character past the decimal. */

char tmp_format[FLOAT_FORMATBUFLEN];

/* The last character in the format string must be the format char */

format_char = format[format_len - 1];

if (format[0] != '%')

return NULL;

/* I'm not sure why this test is here. It's ensuring that the format

string after the first character doesn't have a single quote, a

lowercase l, or a percent. This is the reverse of the commented-out

test about 10 lines ago. */

if (strpbrk(format + 1, "'l%"))

return NULL;

/* Also curious about this function is that it accepts format strings

like "%xg", which are invalid for floats. In general, the

interface to this function is not very good, but changing it is

difficult because it's a public API. */

if (!(format_char == 'e' || format_char == 'E' ||

format_char == 'f' || format_char == 'F' ||

format_char == 'g' || format_char == 'G' ||

format_char == 'Z'))

return NULL;

/* Map 'Z' format_char to 'g', by copying the format string and

replacing the final char with a 'g' */

if (format_char == 'Z') {

if (format_len + 1 >= sizeof(tmp_format)) {

/* The format won't fit in our copy. Error out. In

practice, this will never happen and will be

detected by returning NULL */

return NULL;

}

strcpy(tmp_format, format);

tmp_format[format_len - 1] = 'g';

format = tmp_format;

}

/* Have PyOS_snprintf do the hard work */

PyOS_snprintf(buffer, buf_size, format, d);

/* Do various fixups on the return string */

/* Get the current locale, and find the decimal point string.

Convert that string back to a dot. */

change_decimal_from_locale_to_dot(buffer);

/* If an exponent exists, ensure that the exponent is at least

MIN_EXPONENT_DIGITS digits, providing the buffer is large enough

for the extra zeros. Also, if there are more than

MIN_EXPONENT_DIGITS, remove as many zeros as possible until we get

back to MIN_EXPONENT_DIGITS */

ensure_minimum_exponent_length(buffer, buf_size);

/* If format_char is 'Z', make sure we have at least one character

after the decimal point (and make sure we have a decimal point);

also switch to exponential notation in some edge cases where the

extra character would produce more significant digits that we

really want. */

if (format_char == 'Z')

buffer = ensure_decimal_point(buffer, buf_size, precision);

return buffer;

}

char *

PyOS_ascii_formatd(char *buffer,

size_t buf_size,

const char *format,

double d)

{

if (PyErr_WarnEx(PyExc_DeprecationWarning,

"PyOS_ascii_formatd is deprecated, "

"use PyOS_double_to_string instead", 1) < 0)

return NULL;

return _PyOS_ascii_formatd(buffer, buf_size, format, d, -1);

}

#ifdef PY_NO_SHORT_FLOAT_REPR

/* The fallback code to use if _Py_dg_dtoa is not available. */

PyAPI_FUNC(char *) PyOS_double_to_string(double val,

char format_code,

int precision,

int flags,

int *type)

{

char format[32];

Py_ssize_t bufsize;

char *buf;

int t, exp;

int upper = 0;

/* Validate format_code, and map upper and lower case */

switch (format_code) {

case 'e': /* exponent */

case 'f': /* fixed */

case 'g': /* general */

break;

case 'E':

upper = 1;

format_code = 'e';

break;

case 'F':

upper = 1;

format_code = 'f';

break;

case 'G':

upper = 1;

format_code = 'g';

break;

case 'r': /* repr format */

/* Supplied precision is unused, must be 0. */

if (precision != 0) {

PyErr_BadInternalCall();

return NULL;

}

/* The repr() precision (17 significant decimal digits) is the

minimal number that is guaranteed to have enough precision

so that if the number is read back in the exact same binary

value is recreated. This is true for IEEE floating point

by design, and also happens to work for all other modern

hardware. */

precision = 17;

format_code = 'g';

break;

default:

PyErr_BadInternalCall();

return NULL;

}

/* Here's a quick-and-dirty calculation to figure out how big a buffer

we need. In general, for a finite float we need:

1 byte for each digit of the decimal significand, and

1 for a possible sign

1 for a possible decimal point

2 for a possible [eE][+-]

1 for each digit of the exponent; if we allow 19 digits

total then we're safe up to exponents of 2**63.

1 for the trailing nul byte

This gives a total of 24 + the number of digits in the significand,

and the number of digits in the significand is:

for 'g' format: at most precision, except possibly

when precision == 0, when it's 1.

for 'e' format: precision+1

for 'f' format: precision digits after the point, at least 1

before. To figure out how many digits appear before the point

we have to examine the size of the number. If fabs(val) < 1.0

then there will be only one digit before the point. If

fabs(val) >= 1.0, then there are at most

1+floor(log10(ceiling(fabs(val))))

digits before the point (where the 'ceiling' allows for the

possibility that the rounding rounds the integer part of val

up). A safe upper bound for the above quantity is

1+floor(exp/3), where exp is the unique integer such that 0.5

<= fabs(val)/2**exp < 1.0. This exp can be obtained from

frexp.

So we allow room for precision+1 digits for all formats, plus an

extra floor(exp/3) digits for 'f' format.

*/

if (Py_IS_NAN(val) || Py_IS_INFINITY(val))

/* 3 for 'inf'/'nan', 1 for sign, 1 for '\0' */

bufsize = 5;

else {

bufsize = 25 + precision;

if (format_code == 'f' && fabs(val) >= 1.0) {

frexp(val, &exp);

bufsize += exp/3;

}

}

buf = PyMem_Malloc(bufsize);

if (buf == NULL) {

PyErr_NoMemory();

return NULL;

}

/* Handle nan and inf. */

if (Py_IS_NAN(val)) {

strcpy(buf, "nan");

t = Py_DTST_NAN;

} else if (Py_IS_INFINITY(val)) {

if (copysign(1., val) == 1.)

strcpy(buf, "inf");

else

strcpy(buf, "-inf");

t = Py_DTST_INFINITE;

} else {

t = Py_DTST_FINITE;

if (flags & Py_DTSF_ADD_DOT_0)

format_code = 'Z';

PyOS_snprintf(format, sizeof(format), "%%%s.%i%c",

(flags & Py_DTSF_ALT ? "#" : ""), precision,

format_code);

_PyOS_ascii_formatd(buf, bufsize, format, val, precision);

}

/* Add sign when requested. It's convenient (esp. when formatting

complex numbers) to include a sign even for inf and nan. */

if (flags & Py_DTSF_SIGN && buf[0] != '-') {

size_t len = strlen(buf);

/* the bufsize calculations above should ensure that we've got

space to add a sign */

assert((size_t)bufsize >= len+2);

memmove(buf+1, buf, len+1);

buf[0] = '+';

}

if (upper) {

/* Convert to upper case. */

char *p1;

for (p1 = buf; *p1; p1++)

*p1 = Py_TOUPPER(*p1);

}

if (type)

*type = t;

return buf;

}

#else

/* _Py_dg_dtoa is available. */

/* I'm using a lookup table here so that I don't have to invent a non-locale

specific way to convert to uppercase */

#define OFS_INF 0

#define OFS_NAN 1

#define OFS_E 2

/* The lengths of these are known to the code below, so don't change them */

static char *lc_float_strings[] = {

"inf",

"nan",

"e",

};

static char *uc_float_strings[] = {

"INF",

"NAN",

"E",

};

/* Convert a double d to a string, and return a PyMem_Malloc'd block of

memory contain the resulting string.

Arguments:

d is the double to be converted

format_code is one of 'e', 'f', 'g', 'r'. 'e', 'f' and 'g'

correspond to '%e', '%f' and '%g'; 'r' corresponds to repr.

mode is one of '0', '2' or '3', and is completely determined by

format_code: 'e' and 'g' use mode 2; 'f' mode 3, 'r' mode 0.

precision is the desired precision

always_add_sign is nonzero if a '+' sign should be included for positive

numbers

add_dot_0_if_integer is nonzero if integers in non-exponential form

should have ".0" added. Only applies to format codes 'r' and 'g'.

use_alt_formatting is nonzero if alternative formatting should be

used. Only applies to format codes 'e', 'f' and 'g'. For code 'g',

at most one of use_alt_formatting and add_dot_0_if_integer should

be nonzero.

type, if non-NULL, will be set to one of these constants to identify

the type of the 'd' argument:

Py_DTST_FINITE

Py_DTST_INFINITE

Py_DTST_NAN

Returns a PyMem_Malloc'd block of memory containing the resulting string,

or NULL on error. If NULL is returned, the Python error has been set.

*/

static char *

format_float_short(double d, char format_code,

int mode, Py_ssize_t precision,

int always_add_sign, int add_dot_0_if_integer,

int use_alt_formatting, char **float_strings, int *type)

{

char *buf = NULL;

char *p = NULL;

Py_ssize_t bufsize = 0;

char *digits, *digits_end;

int decpt_as_int, sign, exp_len, exp = 0, use_exp = 0;

Py_ssize_t decpt, digits_len, vdigits_start, vdigits_end;

_Py_SET_53BIT_PRECISION_HEADER;

/* _Py_dg_dtoa returns a digit string (no decimal point or exponent).

Must be matched by a call to _Py_dg_freedtoa. */

_Py_SET_53BIT_PRECISION_START;

digits = _Py_dg_dtoa(d, mode, precision, &decpt_as_int, &sign,

&digits_end);

_Py_SET_53BIT_PRECISION_END;

decpt = (Py_ssize_t)decpt_as_int;

if (digits == NULL) {

/* The only failure mode is no memory. */

PyErr_NoMemory();

goto exit;

}

assert(digits_end != NULL && digits_end >= digits);

digits_len = digits_end - digits;

if (digits_len && !Py_ISDIGIT(digits[0])) {

/* Infinities and nans here; adapt Gay's output,

so convert Infinity to inf and NaN to nan, and

ignore sign of nan. Then return. */

/* ignore the actual sign of a nan */

if (digits[0] == 'n' || digits[0] == 'N')

sign = 0;

/* We only need 5 bytes to hold the result "+inf\0" . */

bufsize = 5; /* Used later in an assert. */

buf = (char *)PyMem_Malloc(bufsize);

if (buf == NULL) {

PyErr_NoMemory();

goto exit;

}

p = buf;

if (sign == 1) {

*p++ = '-';

}

else if (always_add_sign) {

*p++ = '+';

}

if (digits[0] == 'i' || digits[0] == 'I') {

strncpy(p, float_strings[OFS_INF], 3);

p += 3;

if (type)

*type = Py_DTST_INFINITE;

}

else if (digits[0] == 'n' || digits[0] == 'N') {

strncpy(p, float_strings[OFS_NAN], 3);

p += 3;

if (type)

*type = Py_DTST_NAN;

}

else {

/* shouldn't get here: Gay's code should always return

something starting with a digit, an 'I', or 'N' */

strncpy(p, "ERR", 3);

p += 3;

assert(0);

}

goto exit;

}

/* The result must be finite (not inf or nan). */

if (type)

*type = Py_DTST_FINITE;

/* We got digits back, format them. We may need to pad 'digits'

either on the left or right (or both) with extra zeros, so in

general the resulting string has the form

[<sign>]<zeros><digits><zeros>[<exponent>]