michael@0: /*
michael@0:  * Copyright (c) 1999
michael@0:  * Silicon Graphics Computer Systems, Inc.
michael@0:  *
michael@0:  * Copyright (c) 1999
michael@0:  * Boris Fomitchev
michael@0:  *
michael@0:  * This material is provided "as is", with absolutely no warranty expressed
michael@0:  * or implied. Any use is at your own risk.
michael@0:  *
michael@0:  * Permission to use or copy this software for any purpose is hereby granted
michael@0:  * without fee, provided the above notices are retained on all copies.
michael@0:  * Permission to modify the code and to distribute modified code is granted,
michael@0:  * provided the above notices are retained, and a notice that the code was
michael@0:  * modified is included with the above copyright notice.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: #include "stlport_prefix.h"
michael@0: 
michael@0: #ifdef _STLP_USE_UNIX_IO
michael@0: # include "details/fstream_unistd.cpp"
michael@0: #elif defined(_STLP_USE_STDIO_IO)
michael@0: # include "details/fstream_stdio.cpp"
michael@0: #elif defined(_STLP_USE_WIN32_IO)
michael@0: # include "details/fstream_win32io.cpp"
michael@0: #else
michael@0: #  error "Can't recognize IO scheme to use"
michael@0: #endif
michael@0: 
michael@0: _STLP_BEGIN_NAMESPACE
michael@0: 
michael@0: // fbp : let us map 1 MB maximum, just be sure not to trash VM
michael@0: #define MMAP_CHUNK 0x100000L
michael@0: 
michael@0: _Underflow< char, char_traits<char> >::int_type _STLP_CALL
michael@0: _Underflow< char, char_traits<char> >::_M_doit(basic_filebuf<char, char_traits<char> >* __this)
michael@0: {
michael@0:   typedef char_traits<char> traits_type;
michael@0:   typedef traits_type::int_type int_type;
michael@0: 
michael@0:   if (!__this->_M_in_input_mode) {
michael@0:     if (!__this->_M_switch_to_input_mode())
michael@0:       return traits_type::eof();
michael@0:   }
michael@0:   else if (__this->_M_in_putback_mode) {
michael@0:     __this->_M_exit_putback_mode();
michael@0:     if (__this->gptr() != __this->egptr()) {
michael@0:       int_type __c = traits_type::to_int_type(*__this->gptr());
michael@0:       return __c;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // If it's a disk file, and if the internal and external character
michael@0:   // sequences are guaranteed to be identical, then try to use memory
michael@0:   // mapped I/O.  Otherwise, revert to ordinary read.
michael@0:   if (__this->_M_base.__regular_file()
michael@0:       && __this->_M_always_noconv
michael@0:       && __this->_M_base._M_in_binary_mode()) {
michael@0:     // If we've mmapped part of the file already, then unmap it.
michael@0:     if (__this->_M_mmap_base)
michael@0:       __this->_M_base._M_unmap(__this->_M_mmap_base, __this->_M_mmap_len);
michael@0: 
michael@0:     // Determine the position where we start mapping.  It has to be
michael@0:     // a multiple of the page size.
michael@0:     streamoff __cur = __this->_M_base._M_seek(0, ios_base::cur);
michael@0:     streamoff __size = __this->_M_base._M_file_size();
michael@0:     if (__size > 0 && __cur >= 0 && __cur < __size) {
michael@0:       streamoff __offset = (__cur / __this->_M_base.__page_size()) * __this->_M_base.__page_size();
michael@0:       streamoff __remainder = __cur - __offset;
michael@0: 
michael@0:       __this->_M_mmap_len = __size - __offset;
michael@0: 
michael@0:       if (__this->_M_mmap_len > MMAP_CHUNK)
michael@0:         __this->_M_mmap_len = MMAP_CHUNK;
michael@0: 
michael@0:       if ((__this->_M_mmap_base = __this->_M_base._M_mmap(__offset, __this->_M_mmap_len)) != 0) {
michael@0:         __this->setg(__STATIC_CAST(char*, __this->_M_mmap_base),
michael@0:                      __STATIC_CAST(char*, __this->_M_mmap_base) + __STATIC_CAST(ptrdiff_t, __remainder),
michael@0:                      __STATIC_CAST(char*, __this->_M_mmap_base) + __STATIC_CAST(ptrdiff_t, __this->_M_mmap_len));
michael@0:         return traits_type::to_int_type(*__this->gptr());
michael@0:       }
michael@0:       else
michael@0:         __this->_M_mmap_len = 0;
michael@0:     }
michael@0:     else {
michael@0:       __this->_M_mmap_base = 0;
michael@0:       __this->_M_mmap_len = 0;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return __this->_M_underflow_aux();
michael@0: }
michael@0: 
michael@0: //----------------------------------------------------------------------
michael@0: // Force instantiation of filebuf and fstream classes.
michael@0: #if !defined(_STLP_NO_FORCE_INSTANTIATE)
michael@0: 
michael@0: template class basic_filebuf<char, char_traits<char> >;
michael@0: template class basic_ifstream<char, char_traits<char> >;
michael@0: template class basic_ofstream<char, char_traits<char> >;
michael@0: template class basic_fstream<char, char_traits<char> >;
michael@0: 
michael@0: #  if !defined (_STLP_NO_WCHAR_T)
michael@0: template class _Underflow<wchar_t, char_traits<wchar_t> >;
michael@0: template class basic_filebuf<wchar_t, char_traits<wchar_t> >;
michael@0: template class basic_ifstream<wchar_t, char_traits<wchar_t> >;
michael@0: template class basic_ofstream<wchar_t, char_traits<wchar_t> >;
michael@0: template class basic_fstream<wchar_t, char_traits<wchar_t> >;
michael@0: #  endif /* _STLP_NO_WCHAR_T */
michael@0: 
michael@0: #endif
michael@0: 
michael@0: _STLP_END_NAMESPACE