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
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8//
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10// notice, this list of conditions and the following disclaimer.
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13// in the documentation and/or other materials provided with the
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18//
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20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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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
41namespace google {
42namespace protobuf {
43namespace io {
44
45// ----------------------------------------------------------------------
46// NoLocaleStrtod()
47//   This code will make you cry.
48// ----------------------------------------------------------------------
49
50namespace {
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.
55string 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
78double 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
113float 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