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#include "jansson_private.h"
#include "strbuffer.h"
#include <assert.h>
#include <errno.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
/* need jansson_private_config.h to get the correct snprintf */
#ifdef HAVE_CONFIG_H
#include <jansson_private_config.h>
#endif
/*
- This code assumes that the decimal separator is exactly one
character.
- If setlocale() is called by another thread between the call to
get_decimal_point() and the call to sprintf() or strtod(), the
result may be wrong. setlocale() is not thread-safe and should
not be used this way. Multi-threaded programs should use
uselocale() instead.
*/
static char get_decimal_point() {
char buf[3];
sprintf(buf, "%#.0f", 1.0); // "1." in the current locale
return buf[1];
}
static void to_locale(strbuffer_t *strbuffer) {
char point;
char *pos;
point = get_decimal_point();
if (point == '.') {
/* No conversion needed */
return;
}
pos = strchr(strbuffer->value, '.');
if (pos)
*pos = point;
}
int jsonp_strtod(strbuffer_t *strbuffer, double *out) {
double value;
char *end;
to_locale(strbuffer);
errno = 0;
value = strtod(strbuffer->value, &end);
assert(end == strbuffer->value + strbuffer->length);
if ((value == HUGE_VAL || value == -HUGE_VAL) && errno == ERANGE) {
/* Overflow */
return -1;
}
*out = value;
return 0;
}
#if DTOA_ENABLED
/* see dtoa.c */
char *dtoa_r(double dd, int mode, int ndigits, int *decpt, int *sign, char **rve,
char *buf, size_t blen);
int jsonp_dtostr(char *buffer, size_t size, double value, int precision) {
/* adapted from `format_float_short()` in
* https://github.com/python/cpython/blob/2cf18a44303b6d84faa8ecffaecc427b53ae121e/Python/pystrtod.c#L969
*/
char digits[25];
char *digits_end;
int mode = precision == 0 ? 0 : 2;
int decpt, sign, exp_len, exp = 0, use_exp = 0;
int digits_len, vdigits_start, vdigits_end;
char *p;
if (dtoa_r(value, mode, precision, &decpt, &sign, &digits_end, digits, 25) == NULL) {
// digits is too short => should not happen
return -1;
}
digits_len = digits_end - digits;
if (decpt <= -4 || decpt > 16) {
use_exp = 1;
exp = decpt - 1;
decpt = 1;
}
vdigits_start = decpt <= 0 ? decpt - 1 : 0;
vdigits_end = digits_len;
if (!use_exp) {
/* decpt + 1 to add ".0" if value is an integer */
vdigits_end = vdigits_end > decpt ? vdigits_end : decpt + 1;
} else {
vdigits_end = vdigits_end > decpt ? vdigits_end : decpt;
}
if (
/* sign, decimal point and trailing 0 byte */
(size_t)(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)) > size) {
/* buffer is too short */
return -1;
}
p = buffer;
if (sign == 1) {
*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;
}
if (p[-1] == '.')
p--;
if (use_exp) {
*p++ = 'e';
exp_len = sprintf(p, "%d", exp);
p += exp_len;
}
*p = '\0';
return (int)(p - buffer);
}
#else /* DTOA_ENABLED == 0 */
static void from_locale(char *buffer) {
char point;
char *pos;
point = get_decimal_point();
if (point == '.') {
/* No conversion needed */
return;
}
pos = strchr(buffer, point);
if (pos)
*pos = '.';
}
int jsonp_dtostr(char *buffer, size_t size, double value, int precision) {
int ret;
char *start, *end;
size_t length;
if (precision == 0)
precision = 17;
ret = snprintf(buffer, size, "%.*g", precision, value);
if (ret < 0)
return -1;
length = (size_t)ret;
if (length >= size)
return -1;
from_locale(buffer);
/* Make sure there's a dot or 'e' in the output. Otherwise
a real is converted to an integer when decoding */
if (strchr(buffer, '.') == NULL && strchr(buffer, 'e') == NULL) {
if (length + 3 >= size) {
/* No space to append ".0" */
return -1;
}
buffer[length] = '.';
buffer[length + 1] = '0';
buffer[length + 2] = '\0';
length += 2;
}
/* Remove leading '+' from positive exponent. Also remove leading
zeros from exponents (added by some printf() implementations) */
start = strchr(buffer, 'e');
if (start) {
start++;
end = start + 1;
if (*start == '-')
start++;
while (*end == '0')
end++;
if (end != start) {
memmove(start, end, length - (size_t)(end - buffer));
length -= (size_t)(end - start);
}
}
return (int)length;
}
#endif
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