/* -*- Mode: C; c-file-style: "python" -*- */ | |
#include <Python.h> | |
#include <locale.h> | |
/* 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; | |
} | |
/* _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. */ | |
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. | |
* @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; | |
if (*endptr == nptr) | |
/* string might represent an inf or nan */ | |
result = _Py_parse_inf_or_nan(nptr, endptr); | |
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. | |
*/ | |
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; | |
/* 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; | |
/* 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++; | |
} | |
/* 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; | |
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 2.7 and 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 2.7 and 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 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>] | |
where either of the <zeros> pieces could be empty, and there's a | |
decimal point that could appear either in <digits> or in the | |
leading or trailing <zeros>. | |
Imagine an infinite 'virtual' string vdigits, consisting of the | |
string 'digits' (starting at index 0) padded on both the left and | |
right with infinite strings of zeros. We want to output a slice | |
vdigits[vdigits_start : vdigits_end] | |
of this virtual string. Thus if vdigits_start < 0 then we'll end | |
up producing some leading zeros; if vdigits_end > digits_len there | |
will be trailing zeros in the output. The next section of code | |
determines whether to use an exponent or not, figures out the | |
position 'decpt' of the decimal point, and computes 'vdigits_start' | |
and 'vdigits_end'. */ | |
vdigits_end = digits_len; | |
switch (format_code) { | |
case 'e': | |
use_exp = 1; | |
vdigits_end = precision; | |
break; | |
case 'f': | |
vdigits_end = decpt + precision; | |
break; | |
case 'g': | |
if (decpt <= -4 || decpt > | |
(add_dot_0_if_integer ? precision-1 : precision)) | |
use_exp = 1; | |
if (use_alt_formatting) | |
vdigits_end = precision; | |
break; | |
case 'r': | |
/* convert to exponential format at 1e16. We used to convert | |
at 1e17, but that gives odd-looking results for some values | |
when a 16-digit 'shortest' repr is padded with bogus zeros. | |
For example, repr(2e16+8) would give 20000000000000010.0; | |
the true value is 20000000000000008.0. */ | |
if (decpt <= -4 || decpt > 16) | |
use_exp = 1; | |
break; | |
default: | |
PyErr_BadInternalCall(); | |
goto exit; | |
} | |
/* if using an exponent, reset decimal point position to 1 and adjust | |
exponent accordingly.*/ | |
if (use_exp) { | |
exp = decpt - 1; | |
decpt = 1; | |
} | |
/* ensure vdigits_start < decpt <= vdigits_end, or vdigits_start < | |
decpt < vdigits_end if add_dot_0_if_integer and no exponent */ | |
vdigits_start = decpt <= 0 ? decpt-1 : 0; | |
if (!use_exp && add_dot_0_if_integer) | |
vdigits_end = vdigits_end > decpt ? vdigits_end : decpt + 1; | |
else | |
vdigits_end = vdigits_end > decpt ? vdigits_end : decpt; | |
/* double check inequalities */ | |
assert(vdigits_start <= 0 && | |
0 <= digits_len && | |
digits_len <= vdigits_end); | |
/* decimal point should be in (vdigits_start, vdigits_end] */ | |
assert(vdigits_start < decpt && decpt <= vdigits_end); | |
/* Compute an upper bound how much memory we need. This might be a few | |
chars too long, but no big deal. */ | |
bufsize = | |
/* sign, decimal point and trailing 0 byte */ | |
3 + | |
/* total digit count (including zero padding on both sides) */ | |
(vdigits_end - vdigits_start) + | |
/* exponent "e+100", max 3 numerical digits */ | |
(use_exp ? 5 : 0); | |
/* Now allocate the memory and initialize p to point to the start of | |
it. */ | |
buf = (char *)PyMem_Malloc(bufsize); | |
if (buf == NULL) { | |
PyErr_NoMemory(); | |
goto exit; | |
} | |
p = buf; | |
/* Add a negative sign if negative, and a plus sign if non-negative | |
and always_add_sign is true. */ | |
if (sign == 1) | |
*p++ = '-'; | |
else if (always_add_sign) | |
*p++ = '+'; | |
/* note that exactly one of the three 'if' conditions is true, | |
so we include exactly one decimal point */ | |
/* Zero padding on left of digit string */ | |
if (decpt <= 0) { | |
memset(p, '0', decpt-vdigits_start); | |
p += decpt - vdigits_start; | |
*p++ = '.'; | |
memset(p, '0', 0-decpt); | |
p += 0-decpt; | |
} | |
else { | |
memset(p, '0', 0-vdigits_start); | |
p += 0 - vdigits_start; | |
} | |
/* Digits, with included decimal point */ | |
if (0 < decpt && decpt <= digits_len) { | |
strncpy(p, digits, decpt-0); | |
p += decpt-0; | |
*p++ = '.'; | |
strncpy(p, digits+decpt, digits_len-decpt); | |
p += digits_len-decpt; | |
} | |
else { | |
strncpy(p, digits, digits_len); | |
p += digits_len; | |
} | |
/* And zeros on the right */ | |
if (digits_len < decpt) { | |
memset(p, '0', decpt-digits_len); | |
p += decpt-digits_len; | |
*p++ = '.'; | |
memset(p, '0', vdigits_end-decpt); | |
p += vdigits_end-decpt; | |
} | |
else { | |
memset(p, '0', vdigits_end-digits_len); | |
p += vdigits_end-digits_len; | |
} | |
/* Delete a trailing decimal pt unless using alternative formatting. */ | |
if (p[-1] == '.' && !use_alt_formatting) | |
p--; | |
/* Now that we've done zero padding, add an exponent if needed. */ | |
if (use_exp) { | |
*p++ = float_strings[OFS_E][0]; | |
exp_len = sprintf(p, "%+.02d", exp); | |
p += exp_len; | |
} | |
exit: | |
if (buf) { | |
*p = '\0'; | |
/* It's too late if this fails, as we've already stepped on | |
memory that isn't ours. But it's an okay debugging test. */ | |
assert(p-buf < bufsize); | |
} | |
if (digits) | |
_Py_dg_freedtoa(digits); | |
return buf; | |
} | |
PyAPI_FUNC(char *) PyOS_double_to_string(double val, | |
char format_code, | |
int precision, | |
int flags, | |
int *type) | |
{ | |
char **float_strings = lc_float_strings; | |
int mode; | |
/* Validate format_code, and map upper and lower case. Compute the | |
mode and make any adjustments as needed. */ | |
switch (format_code) { | |
/* exponent */ | |
case 'E': | |
float_strings = uc_float_strings; | |
format_code = 'e'; | |
/* Fall through. */ | |
case 'e': | |
mode = 2; | |
precision++; | |
break; | |
/* fixed */ | |
case 'F': | |
float_strings = uc_float_strings; | |
format_code = 'f'; | |
/* Fall through. */ | |
case 'f': | |
mode = 3; | |
break; | |
/* general */ | |
case 'G': | |
float_strings = uc_float_strings; | |
format_code = 'g'; | |
/* Fall through. */ | |
case 'g': | |
mode = 2; | |
/* precision 0 makes no sense for 'g' format; interpret as 1 */ | |
if (precision == 0) | |
precision = 1; | |
break; | |
/* repr format */ | |
case 'r': | |
mode = 0; | |
/* Supplied precision is unused, must be 0. */ | |
if (precision != 0) { | |
PyErr_BadInternalCall(); | |
return NULL; | |
} | |
break; | |
default: | |
PyErr_BadInternalCall(); | |
return NULL; | |
} | |
return format_float_short(val, format_code, mode, precision, | |
flags & Py_DTSF_SIGN, | |
flags & Py_DTSF_ADD_DOT_0, | |
flags & Py_DTSF_ALT, | |
float_strings, type); | |
} | |
#endif /* ifdef PY_NO_SHORT_FLOAT_REPR */ |