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      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.
     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 
     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 
    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