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
99template class basic_filebuf<char, char_traits<char> >;
100template class basic_ifstream<char, char_traits<char> >;
101template class basic_ofstream<char, char_traits<char> >;
102template class basic_fstream<char, char_traits<char> >;
103
104#  if !defined (_STLP_NO_WCHAR_T)
105template class _Underflow<wchar_t, char_traits<wchar_t> >;
106template class basic_filebuf<wchar_t, char_traits<wchar_t> >;
107template class basic_ifstream<wchar_t, char_traits<wchar_t> >;
108template class basic_ofstream<wchar_t, char_traits<wchar_t> >;
109template class basic_fstream<wchar_t, char_traits<wchar_t> >;
110#  endif /* _STLP_NO_WCHAR_T */
111
112#endif
113
114_STLP_END_NAMESPACE
115