1 /* 2 * Copyright (c) 1999 3 * Silicon Graphics Computer Systems, Inc. 4 * 5 * Copyright (c) 1999 6 * Boris Fomitchev 7 * 8 * This material is provided "as is", with absolutely no warranty expressed 9 * or implied. Any use is at your own risk. 10 * 11 * Permission to use or copy this software for any purpose is hereby granted 12 * without fee, provided the above notices are retained on all copies. 13 * Permission to modify the code and to distribute modified code is granted, 14 * provided the above notices are retained, and a notice that the code was 15 * modified is included with the above copyright notice. 16 * 17 */ 18 19 #include "stlport_prefix.h" 20 21 #ifdef _STLP_USE_UNIX_IO 22 # include "details/fstream_unistd.cpp" 23 #elif defined(_STLP_USE_STDIO_IO) 24 # include "details/fstream_stdio.cpp" 25 #elif defined(_STLP_USE_WIN32_IO) 26 # include "details/fstream_win32io.cpp" 27 #else 28 # error "Can't recognize IO scheme to use" 29 #endif 30 31 _STLP_BEGIN_NAMESPACE 32 33 // fbp : let us map 1 MB maximum, just be sure not to trash VM 34 #define MMAP_CHUNK 0x100000L 35 36 _Underflow< char, char_traits<char> >::int_type _STLP_CALL 37 _Underflow< char, char_traits<char> >::_M_doit(basic_filebuf<char, char_traits<char> >* __this) 38 { 39 typedef char_traits<char> traits_type; 40 typedef traits_type::int_type int_type; 41 42 if (!__this->_M_in_input_mode) { 43 if (!__this->_M_switch_to_input_mode()) 44 return traits_type::eof(); 45 } 46 else if (__this->_M_in_putback_mode) { 47 __this->_M_exit_putback_mode(); 48 if (__this->gptr() != __this->egptr()) { 49 int_type __c = traits_type::to_int_type(*__this->gptr()); 50 return __c; 51 } 52 } 53 54 // If it's a disk file, and if the internal and external character 55 // sequences are guaranteed to be identical, then try to use memory 56 // mapped I/O. Otherwise, revert to ordinary read. 57 if (__this->_M_base.__regular_file() 58 && __this->_M_always_noconv 59 && __this->_M_base._M_in_binary_mode()) { 60 // If we've mmapped part of the file already, then unmap it. 61 if (__this->_M_mmap_base) 62 __this->_M_base._M_unmap(__this->_M_mmap_base, __this->_M_mmap_len); 63 64 // Determine the position where we start mapping. It has to be 65 // a multiple of the page size. 66 streamoff __cur = __this->_M_base._M_seek(0, ios_base::cur); 67 streamoff __size = __this->_M_base._M_file_size(); 68 if (__size > 0 && __cur >= 0 && __cur < __size) { 69 streamoff __offset = (__cur / __this->_M_base.__page_size()) * __this->_M_base.__page_size(); 70 streamoff __remainder = __cur - __offset; 71 72 __this->_M_mmap_len = __size - __offset; 73 74 if (__this->_M_mmap_len > MMAP_CHUNK) 75 __this->_M_mmap_len = MMAP_CHUNK; 76 77 if ((__this->_M_mmap_base = __this->_M_base._M_mmap(__offset, __this->_M_mmap_len)) != 0) { 78 __this->setg(__STATIC_CAST(char*, __this->_M_mmap_base), 79 __STATIC_CAST(char*, __this->_M_mmap_base) + __STATIC_CAST(ptrdiff_t, __remainder), 80 __STATIC_CAST(char*, __this->_M_mmap_base) + __STATIC_CAST(ptrdiff_t, __this->_M_mmap_len)); 81 return traits_type::to_int_type(*__this->gptr()); 82 } 83 else 84 __this->_M_mmap_len = 0; 85 } 86 else { 87 __this->_M_mmap_base = 0; 88 __this->_M_mmap_len = 0; 89 } 90 } 91 92 return __this->_M_underflow_aux(); 93 } 94 95 //---------------------------------------------------------------------- 96 // Force instantiation of filebuf and fstream classes. 97 #if !defined(_STLP_NO_FORCE_INSTANTIATE) 98 99 template class basic_filebuf<char, char_traits<char> >; 100 template class basic_ifstream<char, char_traits<char> >; 101 template class basic_ofstream<char, char_traits<char> >; 102 template class basic_fstream<char, char_traits<char> >; 103 104 # if !defined (_STLP_NO_WCHAR_T) 105 template class _Underflow<wchar_t, char_traits<wchar_t> >; 106 template class basic_filebuf<wchar_t, char_traits<wchar_t> >; 107 template class basic_ifstream<wchar_t, char_traits<wchar_t> >; 108 template class basic_ofstream<wchar_t, char_traits<wchar_t> >; 109 template class basic_fstream<wchar_t, char_traits<wchar_t> >; 110 # endif /* _STLP_NO_WCHAR_T */ 111 112 #endif 113 114 _STLP_END_NAMESPACE 115
