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 #include <google/protobuf/stubs/strutil.h>
42
43 namespace google {
44 namespace protobuf {
45 namespace io {
46
47 // This approximately 0x1.ffffffp127, but we don't use 0x1.ffffffp127 because
48 // it won't compile in MSVC.
49 const double MAX_FLOAT_AS_DOUBLE_ROUNDED = 3.4028235677973366e+38;
50
SafeDoubleToFloat(double value)51 float SafeDoubleToFloat(double value) {
52 // static_cast<float> on a number larger than float can result in illegal
53 // instruction error, so we need to manually convert it to infinity or max.
54 if (value > std::numeric_limits<float>::max()) {
55 // Max float value is about 3.4028234664E38 when represented as a double.
56 // However, when printing float as text, it will be rounded as
57 // 3.4028235e+38. If we parse the value of 3.4028235e+38 from text and
58 // compare it to 3.4028234664E38, we may think that it is larger, but
59 // actually, any number between these two numbers could only be represented
60 // as the same max float number in float, so we should treat them the same
61 // as max float.
62 if (value <= MAX_FLOAT_AS_DOUBLE_ROUNDED) {
63 return std::numeric_limits<float>::max();
64 }
65 return std::numeric_limits<float>::infinity();
66 } else if (value < -std::numeric_limits<float>::max()) {
67 if (value >= -MAX_FLOAT_AS_DOUBLE_ROUNDED) {
68 return -std::numeric_limits<float>::max();
69 }
70 return -std::numeric_limits<float>::infinity();
71 } else {
72 return static_cast<float>(value);
73 }
74 }
75
NoLocaleStrtod(const char * str,char ** endptr)76 double NoLocaleStrtod(const char* str, char** endptr) {
77 return google::protobuf::internal::NoLocaleStrtod(str, endptr);
78 }
79
80 } // namespace io
81 } // namespace protobuf
82 } // namespace google
83