libstdc++-v3/include/ext/stdio_sync_filebuf.h - gcc - Git at Google

 // 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
	// 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