blob: d59e3699345576bbd0513b73d5593850cee69ac6 [file] [log] [blame]
// Protocol Buffers - Google's data interchange format
// Copyright 2023 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#include "upb/lex/strtod.h"
#include <stdlib.h>
#include <string.h>
// Must be last.
#include "upb/port/def.inc"
// Determine the locale-specific radix character by calling sprintf() to print
// the number 1.5, then stripping off the digits. As far as I can tell, this
// is the only portable, thread-safe way to get the C library to divulge the
// locale's radix character. No, localeconv() is NOT thread-safe.
static int GetLocaleRadix(char *data, size_t capacity) {
char temp[16];
const int size = snprintf(temp, sizeof(temp), "%.1f", 1.5);
UPB_ASSERT(temp[0] == '1');
UPB_ASSERT(temp[size - 1] == '5');
UPB_ASSERT(size < capacity);
temp[size - 1] = '\0';
strcpy(data, temp + 1);
return size - 2;
}
// Populates a string identical to *input except that the character pointed to
// by pos (which should be '.') is replaced with the locale-specific radix.
static void LocalizeRadix(const char *input, const char *pos, char *output) {
const int len1 = pos - input;
char radix[8];
const int len2 = GetLocaleRadix(radix, sizeof(radix));
memcpy(output, input, len1);
memcpy(output + len1, radix, len2);
strcpy(output + len1 + len2, input + len1 + 1);
}
double _upb_NoLocaleStrtod(const char *str, char **endptr) {
// We cannot simply set the locale to "C" temporarily with setlocale()
// as this is not thread-safe. Instead, we try to parse in the current
// locale first. If parsing stops at a '.' character, then this is a
// pretty good hint that we're actually in some other locale in which
// '.' is not the radix character.
char *temp_endptr;
double result = strtod(str, &temp_endptr);
if (endptr != NULL) *endptr = temp_endptr;
if (*temp_endptr != '.') return result;
// Parsing halted on a '.'. Perhaps we're in a different locale? Let's
// try to replace the '.' with a locale-specific radix character and
// try again.
char localized[80];
LocalizeRadix(str, temp_endptr, localized);
char *localized_endptr;
result = strtod(localized, &localized_endptr);
if ((localized_endptr - &localized[0]) > (temp_endptr - str)) {
// This attempt got further, so replacing the decimal must have helped.
// Update endptr to point at the right location.
if (endptr != NULL) {
// size_diff is non-zero if the localized radix has multiple bytes.
int size_diff = strlen(localized) - strlen(str);
*endptr = (char *)str + (localized_endptr - &localized[0] - size_diff);
}
}
return result;
}