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 <limits>
36 #include <string>
37
38 #include <google/protobuf/stubs/logging.h>
39 #include <google/protobuf/stubs/common.h>
40
41 namespace google {
42 namespace protobuf {
43 namespace io {
44
45 // ----------------------------------------------------------------------
46 // NoLocaleStrtod()
47 // This code will make you cry.
48 // ----------------------------------------------------------------------
49
50 namespace {
51
52 // Returns a string identical to *input except that the character pointed to
53 // by radix_pos (which should be '.') is replaced with the locale-specific
54 // radix character.
LocalizeRadix(const char * input,const char * radix_pos)55 string LocalizeRadix(const char* input, const char* radix_pos) {
56 // Determine the locale-specific radix character by calling sprintf() to
57 // print the number 1.5, then stripping off the digits. As far as I can
58 // tell, this is the only portable, thread-safe way to get the C library
59 // to divuldge the locale's radix character. No, localeconv() is NOT
60 // thread-safe.
61 char temp[16];
62 int size = sprintf(temp, "%.1f", 1.5);
63 GOOGLE_CHECK_EQ(temp[0], '1');
64 GOOGLE_CHECK_EQ(temp[size-1], '5');
65 GOOGLE_CHECK_LE(size, 6);
66
67 // Now replace the '.' in the input with it.
68 string result;
69 result.reserve(strlen(input) + size - 3);
70 result.append(input, radix_pos);
71 result.append(temp + 1, size - 2);
72 result.append(radix_pos + 1);
73 return result;
74 }
75
76 } // namespace
77
NoLocaleStrtod(const char * text,char ** original_endptr)78 double NoLocaleStrtod(const char* text, char** original_endptr) {
79 // We cannot simply set the locale to "C" temporarily with setlocale()
80 // as this is not thread-safe. Instead, we try to parse in the current
81 // locale first. If parsing stops at a '.' character, then this is a
82 // pretty good hint that we're actually in some other locale in which
83 // '.' is not the radix character.
84
85 char* temp_endptr;
86 double result = strtod(text, &temp_endptr);
87 if (original_endptr != NULL) *original_endptr = temp_endptr;
88 if (*temp_endptr != '.') return result;
89
90 // Parsing halted on a '.'. Perhaps we're in a different locale? Let's
91 // try to replace the '.' with a locale-specific radix character and
92 // try again.
93 string localized = LocalizeRadix(text, temp_endptr);
94 const char* localized_cstr = localized.c_str();
95 char* localized_endptr;
96 result = strtod(localized_cstr, &localized_endptr);
97 if ((localized_endptr - localized_cstr) >
98 (temp_endptr - text)) {
99 // This attempt got further, so replacing the decimal must have helped.
100 // Update original_endptr to point at the right location.
101 if (original_endptr != NULL) {
102 // size_diff is non-zero if the localized radix has multiple bytes.
103 int size_diff = localized.size() - strlen(text);
104 // const_cast is necessary to match the strtod() interface.
105 *original_endptr = const_cast<char*>(
106 text + (localized_endptr - localized_cstr - size_diff));
107 }
108 }
109
110 return result;
111 }
112
SafeDoubleToFloat(double value)113 float SafeDoubleToFloat(double value) {
114 if (value > std::numeric_limits<float>::max()) {
115 return std::numeric_limits<float>::infinity();
116 } else if (value < -std::numeric_limits<float>::max()) {
117 return -std::numeric_limits<float>::infinity();
118 } else {
119 return static_cast<float>(value);
120 }
121 }
122
123 } // namespace io
124 } // namespace protobuf
125 } // namespace google
126