11.2.0/ext/stdio_sync_filebuf.h

// Iostreams wrapper for stdio FILE* -*- C++ -*-

// Copyright (C) 2003-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file ext/stdio_sync_filebuf.h
 *  This file is a GNU extension to the Standard C++ Library.
 */

#ifndef _STDIO_SYNC_FILEBUF_H
#define _STDIO_SYNC_FILEBUF_H 1

#pragma GCC system_header

#include <streambuf>
#include <cstdio>
#include <bits/c++io.h>  // For __c_file
#include <bits/move.h>   // For __exchange

#ifdef _GLIBCXX_USE_WCHAR_T
#include <cwchar>
#endif

namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**
   *  @brief Provides a layer of compatibility for C.
   *  @ingroup io
   *
   *  This GNU extension provides extensions for working with standard
   *  C FILE*'s.  It must be instantiated by the user with the type of
   *  character used in the file stream, e.g., stdio_filebuf<char>.
  */
  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
    class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits>
    {
    public:
      // Types:
      typedef _CharT                                    char_type;
      typedef _Traits                                   traits_type;
      typedef typename traits_type::int_type            int_type;
      typedef typename traits_type::pos_type            pos_type;
      typedef typename traits_type::off_type            off_type;

    private:
      typedef std::basic_streambuf<_CharT, _Traits> __streambuf_type;

      // Underlying stdio FILE
      std::__c_file* _M_file;

      // Last character gotten. This is used when pbackfail is
      // called from basic_streambuf::sungetc()
      int_type _M_unget_buf;

    public:
      explicit
      stdio_sync_filebuf(std::__c_file* __f)
      : _M_file(__f), _M_unget_buf(traits_type::eof())
      { }

#if __cplusplus >= 201103L
      stdio_sync_filebuf(stdio_sync_filebuf&& __fb) noexcept
      : __streambuf_type(std::move(__fb)),
      _M_file(__fb._M_file), _M_unget_buf(__fb._M_unget_buf)
      {
        __fb._M_file = nullptr;
        __fb._M_unget_buf = traits_type::eof();
      }

      stdio_sync_filebuf&
      operator=(stdio_sync_filebuf&& __fb) noexcept
      {
        __streambuf_type::operator=(__fb);
        _M_file = std::__exchange(__fb._M_file, nullptr);
        _M_unget_buf = std::__exchange(__fb._M_unget_buf, traits_type::eof());
        return *this;
      }

      void
      swap(stdio_sync_filebuf& __fb)
      {
        __streambuf_type::swap(__fb);
        std::swap(_M_file, __fb._M_file);
        std::swap(_M_unget_buf, __fb._M_unget_buf);
      }
#endif

      /**
       *  @return  The underlying FILE*.
       *
       *  This function can be used to access the underlying C file pointer.
       *  Note that there is no way for the library to track what you do
       *  with the file, so be careful.
       */
      std::__c_file*
      file() { return this->_M_file; }

    protected:
      int_type
      syncgetc();

      int_type
      syncungetc(int_type __c);

      int_type
      syncputc(int_type __c);

      virtual int_type
      underflow()
      {
        int_type __c = this->syncgetc();
        return this->syncungetc(__c);
      }

      virtual int_type
      uflow()
      {
        // Store the gotten character in case we need to unget it.
        _M_unget_buf = this->syncgetc();
        return _M_unget_buf;
      }

      virtual int_type
      pbackfail(int_type __c = traits_type::eof())
      {
        int_type __ret;
        const int_type __eof = traits_type::eof();

        // Check if the unget or putback was requested
        if (traits_type::eq_int_type(__c, __eof)) // unget
          {
            if (!traits_type::eq_int_type(_M_unget_buf, __eof))
              __ret = this->syncungetc(_M_unget_buf);
            else // buffer invalid, fail.
              __ret = __eof;
          }
        else // putback
          __ret = this->syncungetc(__c);

        // The buffered character is no longer valid, discard it.
        _M_unget_buf = __eof;
        return __ret;
      }

      virtual std::streamsize
      xsgetn(char_type* __s, std::streamsize __n);

      virtual int_type
      overflow(int_type __c = traits_type::eof())
      {
        int_type __ret;
        if (traits_type::eq_int_type(__c, traits_type::eof()))
          {
            if (std::fflush(_M_file))
              __ret = traits_type::eof();
            else
              __ret = traits_type::not_eof(__c);
          }
        else
          __ret = this->syncputc(__c);
        return __ret;
      }

      virtual std::streamsize
      xsputn(const char_type* __s, std::streamsize __n);

      virtual int
      sync()
      { return std::fflush(_M_file); }

      virtual std::streampos
      seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
              std::ios_base::openmode = std::ios_base::in | std::ios_base::out)
      {
        std::streampos __ret(std::streamoff(-1));
        int __whence;
        if (__dir == std::ios_base::beg)
          __whence = SEEK_SET;
        else if (__dir == std::ios_base::cur)
          __whence = SEEK_CUR;
        else
          __whence = SEEK_END;
#ifdef _GLIBCXX_USE_LFS
        if (!fseeko64(_M_file, __off, __whence))
          __ret = std::streampos(ftello64(_M_file));
#else
        if (!fseek(_M_file, __off, __whence))
          __ret = std::streampos(std::ftell(_M_file));
#endif
        return __ret;
      }

      virtual std::streampos
      seekpos(std::streampos __pos,
              std::ios_base::openmode __mode =
              std::ios_base::in | std::ios_base::out)
      { return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
    };

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncgetc()
    { return std::getc(_M_file); }

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncungetc(int_type __c)
    { return std::ungetc(__c, _M_file); }

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncputc(int_type __c)
    { return std::putc(__c, _M_file); }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
    {
      std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
      if (__ret > 0)
        _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
      else
        _M_unget_buf = traits_type::eof();
      return __ret;
    }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
    { return std::fwrite(__s, 1, __n, _M_file); }

#ifdef _GLIBCXX_USE_WCHAR_T
  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncgetc()
    { return std::getwc(_M_file); }

  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
    { return std::ungetwc(__c, _M_file); }

  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
    { return std::putwc(__c, _M_file); }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
    {
      std::streamsize __ret = 0;
      const int_type __eof = traits_type::eof();
      while (__n--)
        {
          int_type __c = this->syncgetc();
          if (traits_type::eq_int_type(__c, __eof))
            break;
          __s[__ret] = traits_type::to_char_type(__c);
          ++__ret;
        }

      if (__ret > 0)
        _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
      else
        _M_unget_buf = traits_type::eof();
      return __ret;
    }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
                                        std::streamsize __n)
    {
      std::streamsize __ret = 0;
      const int_type __eof = traits_type::eof();
      while (__n--)
        {
          if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
            break;
          ++__ret;
        }
      return __ret;
    }
#endif

#if _GLIBCXX_EXTERN_TEMPLATE
  extern template class stdio_sync_filebuf<char>;
#ifdef _GLIBCXX_USE_WCHAR_T
  extern template class stdio_sync_filebuf<wchar_t>;
#endif
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif
Revision:	1166
Committed:	Tue Oct 26 14:22:36 2021 UTC (4 years ago) by rossy
Content type:	text/x-chdr
File size:	8762 byte(s)
Log Message:	Daodan: Replace MinGW build env with an up-to-date MSYS2 env
#	Content
1	// Iostreams wrapper for stdio FILE* -- C++ --
2
3	// Copyright (C) 2003-2021 Free Software Foundation, Inc.
4	//
5	// This file is part of the GNU ISO C++ Library. This library is free
6	// software; you can redistribute it and/or modify it under the
7	// terms of the GNU General Public License as published by the
8	// Free Software Foundation; either version 3, or (at your option)
9	// any later version.
10
11	// This library is distributed in the hope that it will be useful,
12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	// GNU General Public License for more details.
15
16	// Under Section 7 of GPL version 3, you are granted additional
17	// permissions described in the GCC Runtime Library Exception, version
18	// 3.1, as published by the Free Software Foundation.
19
20	// You should have received a copy of the GNU General Public License and
21	// a copy of the GCC Runtime Library Exception along with this program;
22	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23	// <http://www.gnu.org/licenses/>.
24
25	/** @file ext/stdio_sync_filebuf.h
26	* This file is a GNU extension to the Standard C++ Library.
27	*/
28
29	#ifndef _STDIO_SYNC_FILEBUF_H
30	#define _STDIO_SYNC_FILEBUF_H 1
31
32	#pragma GCC system_header
33
34	#include <streambuf>
35	#include <cstdio>
36	#include <bits/c++io.h> // For __c_file
37	#include <bits/move.h> // For __exchange
38
39	#ifdef _GLIBCXX_USE_WCHAR_T
40	#include <cwchar>
41	#endif
42
43	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
44	{
45	_GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47	/**
48	* @brief Provides a layer of compatibility for C.
49	* @ingroup io
50	*
51	* This GNU extension provides extensions for working with standard
52	* C FILE*'s. It must be instantiated by the user with the type of
53	* character used in the file stream, e.g., stdio_filebuf<char>.
54	*/
55	template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
56	class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits>
57	{
58	public:
59	// Types:
60	typedef _CharT char_type;
61	typedef _Traits traits_type;
62	typedef typename traits_type::int_type int_type;
63	typedef typename traits_type::pos_type pos_type;
64	typedef typename traits_type::off_type off_type;
65
66	private:
67	typedef std::basic_streambuf<_CharT, _Traits> __streambuf_type;
68
69	// Underlying stdio FILE
70	std::__c_file* _M_file;
71
72	// Last character gotten. This is used when pbackfail is
73	// called from basic_streambuf::sungetc()
74	int_type _M_unget_buf;
75
76	public:
77	explicit
78	stdio_sync_filebuf(std::__c_file* __f)
79	: _M_file(__f), _M_unget_buf(traits_type::eof())
80	{ }
81
82	#if __cplusplus >= 201103L
83	stdio_sync_filebuf(stdio_sync_filebuf&& __fb) noexcept
84	: __streambuf_type(std::move(__fb)),
85	_M_file(__fb._M_file), _M_unget_buf(__fb._M_unget_buf)
86	{
87	__fb._M_file = nullptr;
88	__fb._M_unget_buf = traits_type::eof();
89	}
90
91	stdio_sync_filebuf&
92	operator=(stdio_sync_filebuf&& __fb) noexcept
93	{
94	__streambuf_type::operator=(__fb);
95	_M_file = std::__exchange(__fb._M_file, nullptr);
96	_M_unget_buf = std::__exchange(__fb._M_unget_buf, traits_type::eof());
97	return *this;
98	}
99
100	void
101	swap(stdio_sync_filebuf& __fb)
102	{
103	__streambuf_type::swap(__fb);
104	std::swap(_M_file, __fb._M_file);
105	std::swap(_M_unget_buf, __fb._M_unget_buf);
106	}
107	#endif
108
109	/**
110	* @return The underlying FILE*.
111	*
112	* This function can be used to access the underlying C file pointer.
113	* Note that there is no way for the library to track what you do
114	* with the file, so be careful.
115	*/
116	std::__c_file*
117	file() { return this->_M_file; }
118
119	protected:
120	int_type
121	syncgetc();
122
123	int_type
124	syncungetc(int_type __c);
125
126	int_type
127	syncputc(int_type __c);
128
129	virtual int_type
130	underflow()
131	{
132	int_type __c = this->syncgetc();
133	return this->syncungetc(__c);
134	}
135
136	virtual int_type
137	uflow()
138	{
139	// Store the gotten character in case we need to unget it.
140	_M_unget_buf = this->syncgetc();
141	return _M_unget_buf;
142	}
143
144	virtual int_type
145	pbackfail(int_type __c = traits_type::eof())
146	{
147	int_type __ret;
148	const int_type __eof = traits_type::eof();
149
150	// Check if the unget or putback was requested
151	if (traits_type::eq_int_type(__c, __eof)) // unget
152	{
153	if (!traits_type::eq_int_type(_M_unget_buf, __eof))
154	__ret = this->syncungetc(_M_unget_buf);
155	else // buffer invalid, fail.
156	__ret = __eof;
157	}
158	else // putback
159	__ret = this->syncungetc(__c);
160
161	// The buffered character is no longer valid, discard it.
162	_M_unget_buf = __eof;
163	return __ret;
164	}
165
166	virtual std::streamsize
167	xsgetn(char_type* __s, std::streamsize __n);
168
169	virtual int_type
170	overflow(int_type __c = traits_type::eof())
171	{
172	int_type __ret;
173	if (traits_type::eq_int_type(__c, traits_type::eof()))
174	{
175	if (std::fflush(_M_file))
176	__ret = traits_type::eof();
177	else
178	__ret = traits_type::not_eof(__c);
179	}
180	else
181	__ret = this->syncputc(__c);
182	return __ret;
183	}
184
185	virtual std::streamsize
186	xsputn(const char_type* __s, std::streamsize __n);
187
188	virtual int
189	sync()
190	{ return std::fflush(_M_file); }
191
192	virtual std::streampos
193	seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
194	std::ios_base::openmode = std::ios_base::in \| std::ios_base::out)
195	{
196	std::streampos __ret(std::streamoff(-1));
197	int __whence;
198	if (__dir == std::ios_base::beg)
199	__whence = SEEK_SET;
200	else if (__dir == std::ios_base::cur)
201	__whence = SEEK_CUR;
202	else
203	__whence = SEEK_END;
204	#ifdef _GLIBCXX_USE_LFS
205	if (!fseeko64(_M_file, __off, __whence))
206	__ret = std::streampos(ftello64(_M_file));
207	#else
208	if (!fseek(_M_file, __off, __whence))
209	__ret = std::streampos(std::ftell(_M_file));
210	#endif
211	return __ret;
212	}
213
214	virtual std::streampos
215	seekpos(std::streampos __pos,
216	std::ios_base::openmode __mode =
217	std::ios_base::in \| std::ios_base::out)
218	{ return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
219	};
220
221	template<>
222	inline stdio_sync_filebuf<char>::int_type
223	stdio_sync_filebuf<char>::syncgetc()
224	{ return std::getc(_M_file); }
225
226	template<>
227	inline stdio_sync_filebuf<char>::int_type
228	stdio_sync_filebuf<char>::syncungetc(int_type __c)
229	{ return std::ungetc(__c, _M_file); }
230
231	template<>
232	inline stdio_sync_filebuf<char>::int_type
233	stdio_sync_filebuf<char>::syncputc(int_type __c)
234	{ return std::putc(__c, _M_file); }
235
236	template<>
237	inline std::streamsize
238	stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
239	{
240	std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
241	if (__ret > 0)
242	_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
243	else
244	_M_unget_buf = traits_type::eof();
245	return __ret;
246	}
247
248	template<>
249	inline std::streamsize
250	stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
251	{ return std::fwrite(__s, 1, __n, _M_file); }
252
253	#ifdef _GLIBCXX_USE_WCHAR_T
254	template<>
255	inline stdio_sync_filebuf<wchar_t>::int_type
256	stdio_sync_filebuf<wchar_t>::syncgetc()
257	{ return std::getwc(_M_file); }
258
259	template<>
260	inline stdio_sync_filebuf<wchar_t>::int_type
261	stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
262	{ return std::ungetwc(__c, _M_file); }
263
264	template<>
265	inline stdio_sync_filebuf<wchar_t>::int_type
266	stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
267	{ return std::putwc(__c, _M_file); }
268
269	template<>
270	inline std::streamsize
271	stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
272	{
273	std::streamsize __ret = 0;
274	const int_type __eof = traits_type::eof();
275	while (__n--)
276	{
277	int_type __c = this->syncgetc();
278	if (traits_type::eq_int_type(__c, __eof))
279	break;
280	__s[__ret] = traits_type::to_char_type(__c);
281	++__ret;
282	}
283
284	if (__ret > 0)
285	_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
286	else
287	_M_unget_buf = traits_type::eof();
288	return __ret;
289	}
290
291	template<>
292	inline std::streamsize
293	stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
294	std::streamsize __n)
295	{
296	std::streamsize __ret = 0;
297	const int_type __eof = traits_type::eof();
298	while (__n--)
299	{
300	if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
301	break;
302	++__ret;
303	}
304	return __ret;
305	}
306	#endif
307
308	#if _GLIBCXX_EXTERN_TEMPLATE
309	extern template class stdio_sync_filebuf<char>;
310	#ifdef _GLIBCXX_USE_WCHAR_T
311	extern template class stdio_sync_filebuf<wchar_t>;
312	#endif
313	#endif
314
315	_GLIBCXX_END_NAMESPACE_VERSION
316	} // namespace
317
318	#endif