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Diffstat (limited to 'src/google/protobuf/io/strtod.cc')
-rw-r--r-- | src/google/protobuf/io/strtod.cc | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/src/google/protobuf/io/strtod.cc b/src/google/protobuf/io/strtod.cc new file mode 100644 index 0000000..cf0c6e1 --- /dev/null +++ b/src/google/protobuf/io/strtod.cc @@ -0,0 +1,113 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// http://code.google.com/p/protobuf/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include <google/protobuf/io/strtod.h> + +#include <cstdio> +#include <cstring> +#include <string> + +#include <google/protobuf/stubs/common.h> + +namespace google { +namespace protobuf { +namespace io { + +// ---------------------------------------------------------------------- +// NoLocaleStrtod() +// This code will make you cry. +// ---------------------------------------------------------------------- + +namespace { + +// Returns a string identical to *input except that the character pointed to +// by radix_pos (which should be '.') is replaced with the locale-specific +// radix character. +string LocalizeRadix(const char* input, const char* radix_pos) { + // Determine the locale-specific radix character by calling sprintf() to + // print the number 1.5, then stripping off the digits. As far as I can + // tell, this is the only portable, thread-safe way to get the C library + // to divuldge the locale's radix character. No, localeconv() is NOT + // thread-safe. + char temp[16]; + int size = sprintf(temp, "%.1f", 1.5); + GOOGLE_CHECK_EQ(temp[0], '1'); + GOOGLE_CHECK_EQ(temp[size-1], '5'); + GOOGLE_CHECK_LE(size, 6); + + // Now replace the '.' in the input with it. + string result; + result.reserve(strlen(input) + size - 3); + result.append(input, radix_pos); + result.append(temp + 1, size - 2); + result.append(radix_pos + 1); + return result; +} + +} // namespace + +double NoLocaleStrtod(const char* text, char** original_endptr) { + // We cannot simply set the locale to "C" temporarily with setlocale() + // as this is not thread-safe. Instead, we try to parse in the current + // locale first. If parsing stops at a '.' character, then this is a + // pretty good hint that we're actually in some other locale in which + // '.' is not the radix character. + + char* temp_endptr; + double result = strtod(text, &temp_endptr); + if (original_endptr != NULL) *original_endptr = temp_endptr; + if (*temp_endptr != '.') return result; + + // Parsing halted on a '.'. Perhaps we're in a different locale? Let's + // try to replace the '.' with a locale-specific radix character and + // try again. + string localized = LocalizeRadix(text, temp_endptr); + const char* localized_cstr = localized.c_str(); + char* localized_endptr; + result = strtod(localized_cstr, &localized_endptr); + if ((localized_endptr - localized_cstr) > + (temp_endptr - text)) { + // This attempt got further, so replacing the decimal must have helped. + // Update original_endptr to point at the right location. + if (original_endptr != NULL) { + // size_diff is non-zero if the localized radix has multiple bytes. + int size_diff = localized.size() - strlen(text); + // const_cast is necessary to match the strtod() interface. + *original_endptr = const_cast<char*>( + text + (localized_endptr - localized_cstr - size_diff)); + } + } + + return result; +} + +} // namespace io +} // namespace protobuf +} // namespace google |