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

// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009, 2010

// 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 <unistd.h>

#include <cstdio>

#include <bits/c++io.h>  // For __c_file

#ifdef _GLIBCXX_USE_WCHAR_T

#include <cwchar>

#endif

_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)

  /**

   *  @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:

      // Underlying stdio FILE

      std::__c_file* const _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())

      { }

      /**

       *  @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* const

      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

#endif