1 /*
2 * Copyright (c) 2009-2022, Google LLC
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Google LLC nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "upb/lex/strtod.h"
29
30 #include <stdlib.h>
31 #include <string.h>
32
33 // Must be last.
34 #include "upb/port/def.inc"
35
36 // Determine the locale-specific radix character by calling sprintf() to print
37 // the number 1.5, then stripping off the digits. As far as I can tell, this
38 // is the only portable, thread-safe way to get the C library to divulge the
39 // locale's radix character. No, localeconv() is NOT thread-safe.
40
GetLocaleRadix(char * data,size_t capacity)41 static int GetLocaleRadix(char *data, size_t capacity) {
42 char temp[16];
43 const int size = snprintf(temp, sizeof(temp), "%.1f", 1.5);
44 UPB_ASSERT(temp[0] == '1');
45 UPB_ASSERT(temp[size - 1] == '5');
46 UPB_ASSERT(size < capacity);
47 temp[size - 1] = '\0';
48 strcpy(data, temp + 1);
49 return size - 2;
50 }
51
52 // Populates a string identical to *input except that the character pointed to
53 // by pos (which should be '.') is replaced with the locale-specific radix.
54
LocalizeRadix(const char * input,const char * pos,char * output)55 static void LocalizeRadix(const char *input, const char *pos, char *output) {
56 const int len1 = pos - input;
57
58 char radix[8];
59 const int len2 = GetLocaleRadix(radix, sizeof(radix));
60
61 memcpy(output, input, len1);
62 memcpy(output + len1, radix, len2);
63 strcpy(output + len1 + len2, input + len1 + 1);
64 }
65
_upb_NoLocaleStrtod(const char * str,char ** endptr)66 double _upb_NoLocaleStrtod(const char *str, char **endptr) {
67 // We cannot simply set the locale to "C" temporarily with setlocale()
68 // as this is not thread-safe. Instead, we try to parse in the current
69 // locale first. If parsing stops at a '.' character, then this is a
70 // pretty good hint that we're actually in some other locale in which
71 // '.' is not the radix character.
72
73 char *temp_endptr;
74 double result = strtod(str, &temp_endptr);
75 if (endptr != NULL) *endptr = temp_endptr;
76 if (*temp_endptr != '.') return result;
77
78 // Parsing halted on a '.'. Perhaps we're in a different locale? Let's
79 // try to replace the '.' with a locale-specific radix character and
80 // try again.
81
82 char localized[80];
83 LocalizeRadix(str, temp_endptr, localized);
84 char *localized_endptr;
85 result = strtod(localized, &localized_endptr);
86 if ((localized_endptr - &localized[0]) > (temp_endptr - str)) {
87 // This attempt got further, so replacing the decimal must have helped.
88 // Update endptr to point at the right location.
89 if (endptr != NULL) {
90 // size_diff is non-zero if the localized radix has multiple bytes.
91 int size_diff = strlen(localized) - strlen(str);
92 *endptr = (char *)str + (localized_endptr - &localized[0] - size_diff);
93 }
94 }
95
96 return result;
97 }
98