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
_M_doit(basic_filebuf<char,char_traits<char>> * __this)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