320 lines
8.6 KiB
C++
320 lines
8.6 KiB
C++
// Iostreams wrapper for stdio FILE* -*- C++ -*-
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// Copyright (C) 2003-2018 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 3, 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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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file ext/stdio_sync_filebuf.h
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* This file is a GNU extension to the Standard C++ Library.
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*/
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#ifndef _STDIO_SYNC_FILEBUF_H
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#define _STDIO_SYNC_FILEBUF_H 1
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#pragma GCC system_header
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#include <streambuf>
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#include <unistd.h>
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#include <cstdio>
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#include <bits/c++io.h> // For __c_file
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#include <bits/move.h> // For __exchange
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#ifdef _GLIBCXX_USE_WCHAR_T
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#include <cwchar>
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#endif
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @brief Provides a layer of compatibility for C.
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* @ingroup io
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*
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* This GNU extension provides extensions for working with standard
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* C FILE*'s. It must be instantiated by the user with the type of
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* character used in the file stream, e.g., stdio_filebuf<char>.
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*/
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template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
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class stdio_sync_filebuf : public std::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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private:
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typedef std::basic_streambuf<_CharT, _Traits> __streambuf_type;
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// Underlying stdio FILE
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std::__c_file* _M_file;
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// Last character gotten. This is used when pbackfail is
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// called from basic_streambuf::sungetc()
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int_type _M_unget_buf;
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public:
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explicit
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stdio_sync_filebuf(std::__c_file* __f)
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: _M_file(__f), _M_unget_buf(traits_type::eof())
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{ }
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#if __cplusplus >= 201103L
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stdio_sync_filebuf(stdio_sync_filebuf&& __fb) noexcept
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: __streambuf_type(std::move(__fb)),
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_M_file(__fb._M_file), _M_unget_buf(__fb._M_unget_buf)
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{
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__fb._M_file = nullptr;
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__fb._M_unget_buf = traits_type::eof();
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}
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stdio_sync_filebuf&
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operator=(stdio_sync_filebuf&& __fb) noexcept
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{
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__streambuf_type::operator=(__fb);
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_M_file = std::__exchange(__fb._M_file, nullptr);
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_M_unget_buf = std::__exchange(__fb._M_unget_buf, traits_type::eof());
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return *this;
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}
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void
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swap(stdio_sync_filebuf& __fb)
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{
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__streambuf_type::swap(__fb);
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std::swap(_M_file, __fb._M_file);
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std::swap(_M_unget_buf, __fb._M_unget_buf);
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}
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#endif
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/**
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* @return The underlying FILE*.
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*
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* This function can be used to access the underlying C file pointer.
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* Note that there is no way for the library to track what you do
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* with the file, so be careful.
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*/
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std::__c_file*
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file() { return this->_M_file; }
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protected:
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int_type
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syncgetc();
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int_type
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syncungetc(int_type __c);
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int_type
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syncputc(int_type __c);
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virtual int_type
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underflow()
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{
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int_type __c = this->syncgetc();
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return this->syncungetc(__c);
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}
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virtual int_type
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uflow()
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{
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// Store the gotten character in case we need to unget it.
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_M_unget_buf = this->syncgetc();
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return _M_unget_buf;
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}
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virtual int_type
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pbackfail(int_type __c = traits_type::eof())
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{
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int_type __ret;
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const int_type __eof = traits_type::eof();
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// Check if the unget or putback was requested
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if (traits_type::eq_int_type(__c, __eof)) // unget
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{
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if (!traits_type::eq_int_type(_M_unget_buf, __eof))
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__ret = this->syncungetc(_M_unget_buf);
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else // buffer invalid, fail.
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__ret = __eof;
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}
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else // putback
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__ret = this->syncungetc(__c);
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// The buffered character is no longer valid, discard it.
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_M_unget_buf = __eof;
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return __ret;
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}
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virtual std::streamsize
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xsgetn(char_type* __s, std::streamsize __n);
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virtual int_type
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overflow(int_type __c = traits_type::eof())
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{
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int_type __ret;
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if (traits_type::eq_int_type(__c, traits_type::eof()))
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{
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if (std::fflush(_M_file))
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__ret = traits_type::eof();
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else
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__ret = traits_type::not_eof(__c);
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}
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else
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__ret = this->syncputc(__c);
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return __ret;
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}
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virtual std::streamsize
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xsputn(const char_type* __s, std::streamsize __n);
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virtual int
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sync()
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{ return std::fflush(_M_file); }
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virtual std::streampos
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seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
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std::ios_base::openmode = std::ios_base::in | std::ios_base::out)
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{
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std::streampos __ret(std::streamoff(-1));
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int __whence;
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if (__dir == std::ios_base::beg)
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__whence = SEEK_SET;
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else if (__dir == std::ios_base::cur)
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__whence = SEEK_CUR;
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else
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__whence = SEEK_END;
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#ifdef _GLIBCXX_USE_LFS
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if (!fseeko64(_M_file, __off, __whence))
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__ret = std::streampos(ftello64(_M_file));
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#else
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if (!fseek(_M_file, __off, __whence))
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__ret = std::streampos(std::ftell(_M_file));
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#endif
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return __ret;
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}
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virtual std::streampos
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seekpos(std::streampos __pos,
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std::ios_base::openmode __mode =
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std::ios_base::in | std::ios_base::out)
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{ return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
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};
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template<>
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inline stdio_sync_filebuf<char>::int_type
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stdio_sync_filebuf<char>::syncgetc()
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{ return std::getc(_M_file); }
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template<>
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inline stdio_sync_filebuf<char>::int_type
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stdio_sync_filebuf<char>::syncungetc(int_type __c)
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{ return std::ungetc(__c, _M_file); }
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template<>
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inline stdio_sync_filebuf<char>::int_type
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stdio_sync_filebuf<char>::syncputc(int_type __c)
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{ return std::putc(__c, _M_file); }
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template<>
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inline std::streamsize
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stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
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{
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std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
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if (__ret > 0)
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_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
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else
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_M_unget_buf = traits_type::eof();
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return __ret;
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}
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template<>
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inline std::streamsize
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stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
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{ return std::fwrite(__s, 1, __n, _M_file); }
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#ifdef _GLIBCXX_USE_WCHAR_T
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template<>
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inline stdio_sync_filebuf<wchar_t>::int_type
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stdio_sync_filebuf<wchar_t>::syncgetc()
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{ return std::getwc(_M_file); }
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template<>
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inline stdio_sync_filebuf<wchar_t>::int_type
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stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
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{ return std::ungetwc(__c, _M_file); }
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template<>
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inline stdio_sync_filebuf<wchar_t>::int_type
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stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
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{ return std::putwc(__c, _M_file); }
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template<>
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inline std::streamsize
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stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
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{
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std::streamsize __ret = 0;
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const int_type __eof = traits_type::eof();
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while (__n--)
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{
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int_type __c = this->syncgetc();
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if (traits_type::eq_int_type(__c, __eof))
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break;
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__s[__ret] = traits_type::to_char_type(__c);
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++__ret;
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}
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if (__ret > 0)
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_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
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else
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_M_unget_buf = traits_type::eof();
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return __ret;
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}
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template<>
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inline std::streamsize
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stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
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std::streamsize __n)
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{
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std::streamsize __ret = 0;
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const int_type __eof = traits_type::eof();
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while (__n--)
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{
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if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
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break;
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++__ret;
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}
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return __ret;
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}
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#endif
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#if _GLIBCXX_EXTERN_TEMPLATE
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extern template class stdio_sync_filebuf<char>;
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#ifdef _GLIBCXX_USE_WCHAR_T
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extern template class stdio_sync_filebuf<wchar_t>;
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#endif
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#endif
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace
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#endif
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