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