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- /** nonfinite_serialization_archives.cpp
- *
- * Copyright (c) 2011 Paul A. Bristow
- *
- * Distributed under the Boost Software License, Version 1.0.
- * (See accompanying file LICENSE_1_0.txt
- * or copy at http://www.boost.org/LICENSE_1_0.txt)
- *
- * This very simple program illustrates how to use the
- * `boost/math/nonfinite_num_facets.hpp' to obtain C99
- * representation of infinity and NaN.
- * From the original Floating Point Utilities contribution by Johan Rade.
- * Floating Point Utility library has been accepted into Boost,
- * but the utilities are incorporated into Boost.Math library.
- *
- \file
- \brief A simple example of using non_finite_num facet for
- C99 standard output of infinity and NaN in serialization archives.
- \detail This example shows how to create a C99 non-finite locale,
- and imbue input and output streams with the non_finite_num put and get facets.
- This allow output and input of infinity and NaN in a Standard portable way,
- This permits 'loop-back' of output back into input (and portably across different system too).
- This is particularly useful when used with Boost.Seralization so that non-finite NaNs and infinity
- values in text and xml archives can be handled correctly and portably.
- */
- #ifdef _MSC_VER
- # pragma warning(disable : 4127) // conditional expression is constant.
- #endif
- #include <boost/archive/text_oarchive.hpp>
- using boost::archive::text_oarchive;
- #include <boost/archive/codecvt_null.hpp>
- using boost::archive::codecvt_null;
- using boost::archive::no_codecvt;
- #include <boost/math/special_functions/nonfinite_num_facets.hpp>
- using boost::math::nonfinite_num_get;
- using boost::math::nonfinite_num_put;
- #include <iostream>
- using std::cout;
- using std::endl;
- using std::cerr;
- #include <iomanip>
- using std::setw;
- using std::left;
- using std::right;
- using std::internal;
- #include <string>
- using std::string;
- #include <sstream>
- using std::istringstream;
- #include <fstream>
- using std::ofstream;
- #include <limits>
- using std::numeric_limits;
- #include <locale>
- using std::locale;
- /*
- Use with serialization archives.
- It is important that the same locale is used
- when an archive is saved and when it is loaded.
- Otherwise, loading the archive may fail.
- By default, archives are saved and loaded with a classic C locale with a
- `boost::archive::codecvt_null` facet added.
- Normally you do not have to worry about that.
- The constructors for the archive classes, as a side-effect,
- imbue the stream with such a locale.
- However, if you want to use the facets `nonfinite_num_put` and `nonfinite_num_get`
- with archives,`then you have to manage the locale manually.
- That is done by calling the archive constructor with the flag `boost::archive::no_codecvt`.
- Then the archive constructor will not imbue the stream with a new locale.
- The following code shows how to use `nonfinite_num_put` with a `text_oarchive`:
- */
- int main()
- {
- if((std::numeric_limits<double>::has_infinity == false) || (std::numeric_limits<double>::infinity() == 0))
- {
- std::cout << "Infinity not supported on this platform." << std::endl;
- return 0;
- }
- if((std::numeric_limits<double>::has_quiet_NaN == false) || (std::numeric_limits<double>::quiet_NaN() == 0))
- {
- std::cout << "NaN not supported on this platform." << std::endl;
- return 0;
- }
- locale default_locale(locale::classic(), new boost::archive::codecvt_null<char>);
- // codecvt_null so the archive constructor will not imbue the stream with a new locale.
- locale my_locale(default_locale, new nonfinite_num_put<char>);
- // Add nonfinite_num_put facet to locale.
- // Use a temporary folder /.temps (which contains "boost-no-inspect" so that it will not be inspected, and made 'hidden' too).
- ofstream ofs("./.temps/test.txt");
- ofs.imbue(my_locale);
- boost::archive::text_oarchive oa(ofs, no_codecvt);
- double x = numeric_limits<double>::infinity();
- oa & x;
- } // int main()
- /* The same method works with nonfinite_num_get and text_iarchive.
- If you use the trap_infinity and trap_nan flags with a serialization archive,
- then you must set the exception mask of the stream.
- Serialization archives do not check the stream state.
- */
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