Boost C++ Libraries

libs/filesystem/example/mbpath.cpp

//  Boost.Filesystem mbpath.cpp  ---------------------------------------------//

//  (c) Copyright Beman Dawes 2005

//  Use, modification, and distribution is subject to 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)

//  See Boost.Filesystem home page at http://www.boost.org/libs/filesystem

#include <boost/filesystem/config.hpp>
#ifdef BOOST_FILESYSTEM_NARROW_ONLY
#error This compiler or standard library does not support wide-character strings or paths
#endif

#include "mbpath.hpp"
#include <boost/system/system_error.hpp>
#include <boost/scoped_array.hpp>

namespace fs = boost::filesystem;

namespace {

// ISO C calls this "the locale-specific native environment":
std::locale loc("");

const std::codecvt< wchar_t, char, std::mbstate_t >*
    cvt(&std::use_facet< std::codecvt< wchar_t, char, std::mbstate_t > >(loc));

} // namespace

namespace user {

mbpath_traits::external_string_type
mbpath_traits::to_external(const mbpath& ph, const internal_string_type& src)
{
    std::size_t work_size(cvt->max_length() * (src.size() + 1));
    boost::scoped_array< char > work(new char[work_size]);
    std::mbstate_t state;
    const internal_string_type::value_type* from_next;
    external_string_type::value_type* to_next;
    if (cvt->out(
            state, src.c_str(), src.c_str() + src.size(), from_next, work.get(),
            work.get() + work_size, to_next) != std::codecvt_base::ok)
        boost::throw_exception< fs::basic_filesystem_error< mbpath > >(
            fs::basic_filesystem_error< mbpath >(
                "user::mbpath::to_external conversion error",
                ph, boost::system::error_code(EINVAL, boost::system::errno_ecat)));
    *to_next = '\0';
    return external_string_type(work.get());
}

mbpath_traits::internal_string_type
mbpath_traits::to_internal(const external_string_type& src)
{
    std::size_t work_size(src.size() + 1);
    boost::scoped_array< wchar_t > work(new wchar_t[work_size]);
    std::mbstate_t state;
    const external_string_type::value_type* from_next;
    internal_string_type::value_type* to_next;
    if (cvt->in(
            state, src.c_str(), src.c_str() + src.size(), from_next, work.get(),
            work.get() + work_size, to_next) != std::codecvt_base::ok)
        boost::throw_exception< fs::basic_filesystem_error< mbpath > >(
            fs::basic_filesystem_error< mbpath >(
                "user::mbpath::to_internal conversion error",
                boost::system::error_code(EINVAL, boost::system::errno_ecat)));
    *to_next = L'\0';
    return internal_string_type(work.get());
}

void mbpath_traits::imbue(const std::locale& new_loc)
{
    loc = new_loc;
    cvt = &std::use_facet< std::codecvt< wchar_t, char, std::mbstate_t > >(loc);
}

} // namespace user