1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 // * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 // * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 // * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31 #include <google/protobuf/io/strtod.h>
32
33 #include <cstdio>
34 #include <cstring>
35 #include <string>
36
37 #include <google/protobuf/stubs/common.h>
38
39 namespace google {
40 namespace protobuf {
41 namespace io {
42
43 // ----------------------------------------------------------------------
44 // NoLocaleStrtod()
45 // This code will make you cry.
46 // ----------------------------------------------------------------------
47
48 namespace {
49
50 // Returns a string identical to *input except that the character pointed to
51 // by radix_pos (which should be '.') is replaced with the locale-specific
52 // radix character.
LocalizeRadix(const char * input,const char * radix_pos)53 string LocalizeRadix(const char* input, const char* radix_pos) {
54 // Determine the locale-specific radix character by calling sprintf() to
55 // print the number 1.5, then stripping off the digits. As far as I can
56 // tell, this is the only portable, thread-safe way to get the C library
57 // to divuldge the locale's radix character. No, localeconv() is NOT
58 // thread-safe.
59 char temp[16];
60 int size = sprintf(temp, "%.1f", 1.5);
61 GOOGLE_CHECK_EQ(temp[0], '1');
62 GOOGLE_CHECK_EQ(temp[size-1], '5');
63 GOOGLE_CHECK_LE(size, 6);
64
65 // Now replace the '.' in the input with it.
66 string result;
67 result.reserve(strlen(input) + size - 3);
68 result.append(input, radix_pos);
69 result.append(temp + 1, size - 2);
70 result.append(radix_pos + 1);
71 return result;
72 }
73
74 } // namespace
75
NoLocaleStrtod(const char * text,char ** original_endptr)76 double NoLocaleStrtod(const char* text, char** original_endptr) {
77 // We cannot simply set the locale to "C" temporarily with setlocale()
78 // as this is not thread-safe. Instead, we try to parse in the current
79 // locale first. If parsing stops at a '.' character, then this is a
80 // pretty good hint that we're actually in some other locale in which
81 // '.' is not the radix character.
82
83 char* temp_endptr;
84 double result = strtod(text, &temp_endptr);
85 if (original_endptr != NULL) *original_endptr = temp_endptr;
86 if (*temp_endptr != '.') return result;
87
88 // Parsing halted on a '.'. Perhaps we're in a different locale? Let's
89 // try to replace the '.' with a locale-specific radix character and
90 // try again.
91 string localized = LocalizeRadix(text, temp_endptr);
92 const char* localized_cstr = localized.c_str();
93 char* localized_endptr;
94 result = strtod(localized_cstr, &localized_endptr);
95 if ((localized_endptr - localized_cstr) >
96 (temp_endptr - text)) {
97 // This attempt got further, so replacing the decimal must have helped.
98 // Update original_endptr to point at the right location.
99 if (original_endptr != NULL) {
100 // size_diff is non-zero if the localized radix has multiple bytes.
101 int size_diff = localized.size() - strlen(text);
102 // const_cast is necessary to match the strtod() interface.
103 *original_endptr = const_cast<char*>(
104 text + (localized_endptr - localized_cstr - size_diff));
105 }
106 }
107
108 return result;
109 }
110
111 } // namespace io
112 } // namespace protobuf
113 } // namespace google
114