libs/filesystem/src/path_traits.cpp

   1 //  filesystem path_traits.cpp  --------------------------------------------------------//
   2
   3 //  Copyright Beman Dawes 2008, 2009
   4
   5 //  Distributed under the Boost Software License, Version 1.0.
   6 //  See http://www.boost.org/LICENSE_1_0.txt
   7
   8 //  Library home page: http://www.boost.org/libs/filesystem
   9
  10 //--------------------------------------------------------------------------------------//
  11
  12 #ifndef BOOST_SYSTEM_NO_DEPRECATED
  13 # define BOOST_SYSTEM_NO_DEPRECATED
  14 #endif
  15
  16 #include <boost/filesystem/config.hpp>
  17 #include <boost/filesystem/path_traits.hpp>
  18 #include <boost/system/system_error.hpp>
  19 #include <boost/scoped_array.hpp>
  20 #include <locale>   // for codecvt_base::result
  21 #include <cstring>  // for strlen
  22 #include <cwchar>   // for wcslen
  23
  24 namespace pt = boost::filesystem::path_traits;
  25 namespace fs = boost::filesystem;
  26 namespace bs = boost::system;
  27
  28 //--------------------------------------------------------------------------------------//
  29 //                                  configuration                                       //
  30 //--------------------------------------------------------------------------------------//
  31
  32 #ifndef BOOST_FILESYSTEM_CODECVT_BUF_SIZE
  33 # define BOOST_FILESYSTEM_CODECVT_BUF_SIZE 256
  34 #endif
  35
  36 namespace {
  37
  38   const std::size_t default_codecvt_buf_size = BOOST_FILESYSTEM_CODECVT_BUF_SIZE;
  39
  40
  41 //--------------------------------------------------------------------------------------//
  42 //                                                                                      //
  43 //  The public convert() functions do buffer management, and then forward to the        //
  44 //  convert_aux() functions for the actual call to the codecvt facet.                   //
  45 //                                                                                      //
  46 //--------------------------------------------------------------------------------------//
  47
  48 //--------------------------------------------------------------------------------------//
  49 //                      convert_aux const char* to wstring                             //
  50 //--------------------------------------------------------------------------------------//
  51
  52   void convert_aux(
  53                    const char* from,
  54                    const char* from_end,
  55                    wchar_t* to, wchar_t* to_end,
  56                    std::wstring & target,
  57                    const pt::codecvt_type & cvt)
  58   {
  59     //std::cout << std::hex
  60     //          << " from=" << std::size_t(from)
  61     //          << " from_end=" << std::size_t(from_end)
  62     //          << " to=" << std::size_t(to)
  63     //          << " to_end=" << std::size_t(to_end)
  64     //          << std::endl;
  65
  66     std::mbstate_t state  = std::mbstate_t();  // perhaps unneeded, but cuts bug reports
  67     const char* from_next;
  68     wchar_t* to_next;
  69
  70     std::codecvt_base::result res;
  71
  72     if ((res=cvt.in(state, from, from_end, from_next,
  73            to, to_end, to_next)) != std::codecvt_base::ok)
  74     {
  75       //std::cout << " result is " << static_cast<int>(res) << std::endl;
  76       BOOST_FILESYSTEM_THROW(bs::system_error(res, fs::codecvt_error_category(),
  77         "boost::filesystem::path codecvt to wstring"));
  78     }
  79     target.append(to, to_next);
  80   }
  81
  82 //--------------------------------------------------------------------------------------//
  83 //                      convert_aux const wchar_t* to string                           //
  84 //--------------------------------------------------------------------------------------//
  85
  86   void convert_aux(
  87                    const wchar_t* from,
  88                    const wchar_t* from_end,
  89                    char* to, char* to_end,
  90                    std::string & target,
  91                    const pt::codecvt_type & cvt)
  92   {
  93     //std::cout << std::hex
  94     //          << " from=" << std::size_t(from)
  95     //          << " from_end=" << std::size_t(from_end)
  96     //          << " to=" << std::size_t(to)
  97     //          << " to_end=" << std::size_t(to_end)
  98     //          << std::endl;
  99
 100     std::mbstate_t state  = std::mbstate_t();  // perhaps unneeded, but cuts bug reports
 101     const wchar_t* from_next;
 102     char* to_next;
 103
 104     std::codecvt_base::result res;
 105
 106     if ((res=cvt.out(state, from, from_end, from_next,
 107            to, to_end, to_next)) != std::codecvt_base::ok)
 108     {
 109       //std::cout << " result is " << static_cast<int>(res) << std::endl;
 110       BOOST_FILESYSTEM_THROW(bs::system_error(res, fs::codecvt_error_category(),
 111         "boost::filesystem::path codecvt to string"));
 112     }
 113     target.append(to, to_next);
 114   }
 115
 116 }  // unnamed namespace
 117
 118 //--------------------------------------------------------------------------------------//
 119 //                                   path_traits                                        //
 120 //--------------------------------------------------------------------------------------//
 121
 122 namespace boost { namespace filesystem { namespace path_traits {
 123
 124 //--------------------------------------------------------------------------------------//
 125 //                          convert const char* to wstring                              //
 126 //--------------------------------------------------------------------------------------//
 127
 128   BOOST_FILESYSTEM_DECL
 129   void convert(const char* from,
 130                 const char* from_end,    // 0 for null terminated MBCS
 131                 std::wstring & to,
 132                 const codecvt_type & cvt)
 133   {
 134     BOOST_ASSERT(from);
 135
 136     if (!from_end)  // null terminated
 137     {
 138       from_end = from + std::strlen(from);
 139     }
 140
 141     if (from == from_end) return;
 142
 143     std::size_t buf_size = (from_end - from) * 3;  // perhaps too large, but that's OK
 144
 145     //  dynamically allocate a buffer only if source is unusually large
 146     if (buf_size > default_codecvt_buf_size)
 147     {
 148       boost::scoped_array< wchar_t > buf(new wchar_t [buf_size]);
 149       convert_aux(from, from_end, buf.get(), buf.get()+buf_size, to, cvt);
 150     }
 151     else
 152     {
 153       wchar_t buf[default_codecvt_buf_size];
 154       convert_aux(from, from_end, buf, buf+default_codecvt_buf_size, to, cvt);
 155     }
 156   }
 157
 158 //--------------------------------------------------------------------------------------//
 159 //                         convert const wchar_t* to string                            //
 160 //--------------------------------------------------------------------------------------//
 161
 162   BOOST_FILESYSTEM_DECL
 163   void convert(const wchar_t* from,
 164                 const wchar_t* from_end,  // 0 for null terminated MBCS
 165                 std::string & to,
 166                 const codecvt_type & cvt)
 167   {
 168     BOOST_ASSERT(from);
 169
 170     if (!from_end)  // null terminated
 171     {
 172       from_end = from + std::wcslen(from);
 173     }
 174
 175     if (from == from_end) return;
 176
 177     //  The codecvt length functions may not be implemented, and I don't really
 178     //  understand them either. Thus this code is just a guess; if it turns
 179     //  out the buffer is too small then an error will be reported and the code
 180     //  will have to be fixed.
 181     std::size_t buf_size = (from_end - from) * 4;  // perhaps too large, but that's OK
 182     buf_size += 4;  // encodings like shift-JIS need some prefix space
 183
 184     //  dynamically allocate a buffer only if source is unusually large
 185     if (buf_size > default_codecvt_buf_size)
 186     {
 187       boost::scoped_array< char > buf(new char [buf_size]);
 188       convert_aux(from, from_end, buf.get(), buf.get()+buf_size, to, cvt);
 189     }
 190     else
 191     {
 192       char buf[default_codecvt_buf_size];
 193       convert_aux(from, from_end, buf, buf+default_codecvt_buf_size, to, cvt);
 194     }
 195   }
 196 }}} // namespace boost::filesystem::path_traits