559 lines
16 KiB
C++
559 lines
16 KiB
C++
// File based streams -*- C++ -*-
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// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
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// Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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//
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// ISO C++ 14882: 27.8 File-based streams
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//
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/** @file fstream
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* This is a Standard C++ Library header. You should @c #include this header
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* in your programs, rather than any of the "st[dl]_*.h" implementation files.
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*/
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#ifndef _CPP_FSTREAM
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#define _CPP_FSTREAM 1
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#pragma GCC system_header
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#include <istream>
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#include <ostream>
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#include <locale> // For codecvt
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#include <bits/basic_file.h>
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#include <bits/gthr.h>
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namespace std
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{
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template<typename _CharT, typename _Traits>
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class basic_filebuf : public basic_streambuf<_CharT, _Traits>
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{
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public:
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// Types:
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typedef _CharT char_type;
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typedef _Traits traits_type;
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typedef typename traits_type::int_type int_type;
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typedef typename traits_type::pos_type pos_type;
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typedef typename traits_type::off_type off_type;
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// Non-standard Types:
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typedef basic_streambuf<char_type, traits_type> __streambuf_type;
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typedef basic_filebuf<char_type, traits_type> __filebuf_type;
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typedef __basic_file<char> __file_type;
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typedef typename traits_type::state_type __state_type;
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typedef codecvt<char_type, char, __state_type> __codecvt_type;
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typedef typename __codecvt_type::result __res_type;
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typedef ctype<char_type> __ctype_type;
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friend class ios_base; // For sync_with_stdio.
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protected:
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// Data Members:
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// MT lock inherited from libio or other low-level io library.
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__c_lock _M_lock;
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// External buffer.
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__file_type _M_file;
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// Current and beginning state type for codecvt.
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__state_type _M_state_cur;
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__state_type _M_state_beg;
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// Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.
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bool _M_buf_allocated;
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// XXX Needed?
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bool _M_last_overflowed;
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// The position in the buffer corresponding to the external file
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// pointer.
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char_type* _M_filepos;
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public:
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// Constructors/destructor:
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basic_filebuf();
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virtual
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~basic_filebuf()
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{
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this->close();
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_M_last_overflowed = false;
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}
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// Members:
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bool
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is_open() const { return _M_file.is_open(); }
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__filebuf_type*
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open(const char* __s, ios_base::openmode __mode);
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__filebuf_type*
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close();
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protected:
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void
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_M_allocate_internal_buffer();
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void
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_M_destroy_internal_buffer();
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// Overridden virtual functions:
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virtual streamsize
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showmanyc();
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// Stroustrup, 1998, p. 628
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// underflow() and uflow() functions are called to get the next
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// charater from the real input source when the buffer is empty.
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// Buffered input uses underflow()
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// The only difference between underflow() and uflow() is that the
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// latter bumps _M_in_cur after the read. In the sync_with_stdio
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// case, this is important, as we need to unget the read character in
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// the underflow() case in order to maintain synchronization. So
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// instead of calling underflow() from uflow(), we create a common
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// subroutine to do the real work.
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int_type
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_M_underflow_common(bool __bump);
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virtual int_type
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underflow() { return _M_underflow_common(false); }
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virtual int_type
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uflow() { return _M_underflow_common(true); }
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virtual int_type
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pbackfail(int_type __c = _Traits::eof());
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// NB: For what the standard expects of the overflow function,
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// see _M_really_overflow(), below. Because basic_streambuf's
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// sputc/sputn call overflow directly, and the complications of
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// this implementation's setting of the initial pointers all
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// equal to _M_buf when initializing, it seems essential to have
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// this in actuality be a helper function that checks for the
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// eccentricities of this implementation, and then call
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// overflow() if indeed the buffer is full.
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virtual int_type
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overflow(int_type __c = _Traits::eof());
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// Stroustrup, 1998, p 648
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// The overflow() function is called to transfer characters to the
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// real output destination when the buffer is full. A call to
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// overflow(c) outputs the contents of the buffer plus the
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// character c.
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// 27.5.2.4.5
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// Consume some sequence of the characters in the pending sequence.
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int_type
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_M_really_overflow(int_type __c = _Traits::eof());
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// Convert internal byte sequence to external, char-based
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// sequence via codecvt.
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void
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_M_convert_to_external(char_type*, streamsize, streamsize&, streamsize&);
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virtual __streambuf_type*
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setbuf(char_type* __s, streamsize __n);
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virtual pos_type
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seekoff(off_type __off, ios_base::seekdir __way,
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ios_base::openmode __mode = ios_base::in | ios_base::out);
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virtual pos_type
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seekpos(pos_type __pos,
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ios_base::openmode __mode = ios_base::in | ios_base::out);
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virtual int
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sync()
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{
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bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
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// Make sure that the internal buffer resyncs its idea of
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// the file position with the external file.
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if (__testput)
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{
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// Need to restore current position after the write.
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off_type __off = _M_out_cur - _M_out_end;
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_M_really_overflow(); // _M_file.sync() will be called within
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if (__off)
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_M_file.seekoff(__off, ios_base::cur);
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}
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else
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_M_file.sync();
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_M_last_overflowed = false;
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return 0;
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}
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virtual void
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imbue(const locale& __loc);
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virtual streamsize
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xsgetn(char_type* __s, streamsize __n)
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{
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streamsize __ret = 0;
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// Clear out pback buffer before going on to the real deal...
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if (_M_pback_init)
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{
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while (__ret < __n && _M_in_cur < _M_in_end)
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{
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*__s = *_M_in_cur;
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++__ret;
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++__s;
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++_M_in_cur;
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}
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_M_pback_destroy();
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}
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if (__ret < __n)
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__ret += __streambuf_type::xsgetn(__s, __n - __ret);
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return __ret;
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}
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virtual streamsize
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xsputn(const char_type* __s, streamsize __n)
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{
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_M_pback_destroy();
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return __streambuf_type::xsputn(__s, __n);
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}
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void
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_M_output_unshift();
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// These three functions are used to clarify internal buffer
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// maintenance. After an overflow, or after a seekoff call that
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// started at beg or end, or possibly when the stream becomes
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// unbuffered, and a myrid other obscure corner cases, the
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// internal buffer does not truly reflect the contents of the
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// external buffer. At this point, for whatever reason, it is in
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// an indeterminate state.
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void
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_M_set_indeterminate(void)
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{
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if (_M_mode & ios_base::in)
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this->setg(_M_buf, _M_buf, _M_buf);
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if (_M_mode & ios_base::out)
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this->setp(_M_buf, _M_buf);
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_M_filepos = _M_buf;
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}
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void
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_M_set_determinate(off_type __off)
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{
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bool __testin = _M_mode & ios_base::in;
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bool __testout = _M_mode & ios_base::out;
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if (__testin)
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this->setg(_M_buf, _M_buf, _M_buf + __off);
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if (__testout)
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this->setp(_M_buf, _M_buf + __off);
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_M_filepos = _M_buf + __off;
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}
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bool
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_M_is_indeterminate(void)
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{
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bool __ret = false;
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// Don't return true if unbuffered.
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if (_M_buf)
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{
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if (_M_mode & ios_base::in)
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__ret = _M_in_beg == _M_in_cur && _M_in_cur == _M_in_end;
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if (_M_mode & ios_base::out)
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__ret = _M_out_beg == _M_out_cur && _M_out_cur == _M_out_end;
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}
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return __ret;
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}
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};
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// 27.8.1.5 Template class basic_ifstream
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/**
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* Derivation of general input streams, specific to files.
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*/
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template<typename _CharT, typename _Traits>
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class basic_ifstream : public basic_istream<_CharT, _Traits>
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{
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public:
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// Types:
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typedef _CharT char_type;
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typedef _Traits traits_type;
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typedef typename traits_type::int_type int_type;
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typedef typename traits_type::pos_type pos_type;
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typedef typename traits_type::off_type off_type;
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// Non-standard types:
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typedef basic_filebuf<char_type, traits_type> __filebuf_type;
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typedef basic_istream<char_type, traits_type> __istream_type;
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private:
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__filebuf_type _M_filebuf;
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public:
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// Constructors/Destructors:
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/** Default constructor. Create an input file stream. */
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basic_ifstream()
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: __istream_type(NULL), _M_filebuf()
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{ this->init(&_M_filebuf); }
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/**
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* @brief Create an input file stream.
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* @param s Null terminated string specifying filename.
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* @param mode Open file in specified mode (see std::ios_base).
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*
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* Tip: When using std::string to hold the filename, you must use
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* .c_str() before passing it to this constructor.
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*/
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explicit
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basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)
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: __istream_type(NULL), _M_filebuf()
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{
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this->init(&_M_filebuf);
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this->open(__s, __mode);
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}
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~basic_ifstream()
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{ }
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// Members:
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/**
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* @brief Get a pointer to the file stream's buffer.
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* @return Pointer to basic_filebuf.
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*/
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__filebuf_type*
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rdbuf() const
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{ return const_cast<__filebuf_type*>(&_M_filebuf); }
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bool
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is_open() { return _M_filebuf.is_open(); }
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void
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open(const char* __s, ios_base::openmode __mode = ios_base::in)
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{
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if (!_M_filebuf.open(__s, __mode | ios_base::in))
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this->setstate(ios_base::failbit);
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}
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/** Close the file. */
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void
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close()
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{
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if (!_M_filebuf.close())
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this->setstate(ios_base::failbit);
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}
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};
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// 27.8.1.8 Template class basic_ofstream
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/**
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* Derivation of general output streams, specific to files.
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*/
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template<typename _CharT, typename _Traits>
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class basic_ofstream : public basic_ostream<_CharT,_Traits>
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{
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public:
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// Types:
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typedef _CharT char_type;
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typedef _Traits traits_type;
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typedef typename traits_type::int_type int_type;
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typedef typename traits_type::pos_type pos_type;
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typedef typename traits_type::off_type off_type;
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// Non-standard types:
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typedef basic_filebuf<char_type, traits_type> __filebuf_type;
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typedef basic_ostream<char_type, traits_type> __ostream_type;
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private:
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__filebuf_type _M_filebuf;
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public:
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// Constructors:
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/** Default constructor for output file_stream. */
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basic_ofstream()
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: __ostream_type(NULL), _M_filebuf()
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{ this->init(&_M_filebuf); }
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/**
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* @brief Create an output stream.
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* @param s Null terminated string specifying filename.
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* @param mode Open file in specified mode (see std::ios_base).
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*
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* Tip: When using std::string to hold the filename, you must use
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* .c_str() before passing it to this constructor.
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*/
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explicit
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basic_ofstream(const char* __s,
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ios_base::openmode __mode = ios_base::out|ios_base::trunc)
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: __ostream_type(NULL), _M_filebuf()
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{
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this->init(&_M_filebuf);
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this->open(__s, __mode);
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}
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~basic_ofstream()
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{ }
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// Members:
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/**
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* @brief Get a pointer to the file stream's buffer.
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* @return Pointer to basic_filebuf.
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*/
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__filebuf_type*
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rdbuf() const
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{ return const_cast<__filebuf_type*>(&_M_filebuf); }
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/**
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* @brief Query to see if file stream is open.
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* @return True if stream is open.
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*/
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bool
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is_open() { return _M_filebuf.is_open(); }
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/**
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* @brief Specify a file to open for output.
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* @param s Null terminated string specifying filename.
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* @param mode Mode in which to open file (see std::ios_base).
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*
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* Tip: When using std::string to hold the filename, you must use
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* .c_str() before passing it to this constructor.
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*/
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void
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open(const char* __s,
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ios_base::openmode __mode = ios_base::out | ios_base::trunc)
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{
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if (!_M_filebuf.open(__s, __mode | ios_base::out))
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this->setstate(ios_base::failbit);
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}
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/** Close the file stream. */
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void
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close()
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{
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if (!_M_filebuf.close())
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this->setstate(ios_base::failbit);
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}
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};
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// 27.8.1.11 Template class basic_fstream
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/**
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* Derivation of general input/output streams, specific to files.
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*/
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template<typename _CharT, typename _Traits>
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class basic_fstream : public basic_iostream<_CharT, _Traits>
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{
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public:
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// Types:
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typedef _CharT char_type;
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typedef _Traits traits_type;
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typedef typename traits_type::int_type int_type;
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typedef typename traits_type::pos_type pos_type;
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typedef typename traits_type::off_type off_type;
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// Non-standard types:
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typedef basic_filebuf<char_type, traits_type> __filebuf_type;
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typedef basic_ios<char_type, traits_type> __ios_type;
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typedef basic_iostream<char_type, traits_type> __iostream_type;
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private:
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__filebuf_type _M_filebuf;
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public:
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// Constructors/destructor:
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/** Default constructor. Create a file stream. */
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basic_fstream()
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: __iostream_type(NULL), _M_filebuf()
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{ this->init(&_M_filebuf); }
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/**
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* @brief Create an input/output stream.
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* @param s Null terminated string specifying filename.
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* @param mode Open file in specified mode (see std::ios_base).
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*
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* Tip: When using std::string to hold the filename, you must use
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* .c_str() before passing it to this constructor.
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*/
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explicit
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basic_fstream(const char* __s,
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ios_base::openmode __mode = ios_base::in | ios_base::out)
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: __iostream_type(NULL), _M_filebuf()
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{
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this->init(&_M_filebuf);
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this->open(__s, __mode);
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}
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~basic_fstream()
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{ }
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// Members:
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/**
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* @brief Get a pointer to the file stream's buffer.
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* @return Pointer to basic_filebuf.
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*/
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__filebuf_type*
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rdbuf() const
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{ return const_cast<__filebuf_type*>(&_M_filebuf); }
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/**
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* @brief Query to see if file stream is open.
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* @return True if stream is open.
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*/
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bool
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is_open() { return _M_filebuf.is_open(); }
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/**
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* @brief Specify a file to open for input and/or output.
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* @param s Null terminated string specifying filename.
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* @param mode Mode in which to open file (see std::ios_base).
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*
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* Tip: When using std::string to hold the filename, you must use
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* .c_str() before passing it to this constructor.
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*/
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void
|
|
open(const char* __s,
|
|
ios_base::openmode __mode = ios_base::in | ios_base::out)
|
|
{
|
|
if (!_M_filebuf.open(__s, __mode))
|
|
setstate(ios_base::failbit);
|
|
}
|
|
|
|
/** Close the file stream. */
|
|
void
|
|
close()
|
|
{
|
|
if (!_M_filebuf.close())
|
|
setstate(ios_base::failbit);
|
|
}
|
|
};
|
|
} // namespace std
|
|
|
|
#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
|
|
# define export
|
|
#endif
|
|
#ifdef _GLIBCPP_FULLY_COMPLIANT_HEADERS
|
|
# include <bits/fstream.tcc>
|
|
#endif
|
|
|
|
#endif
|