Subversion Repositories scarts

// Stream buffer classes -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005

// 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 2, 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.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

//

// ISO C++ 14882: 27.5  Stream buffers

//

/** @file streambuf

 *  This is a Standard C++ Library header.

 */

#ifndef _GLIBXX_STREAMBUF

#define _GLIBXX_STREAMBUF 1

#pragma GCC system_header

#include <bits/c++config.h>

#include <iosfwd>

#include <bits/localefwd.h>

#include <bits/ios_base.h>

namespace std

{

  /**

   *  @if maint

   *  Does stuff.

   *  @endif

  */

  template<typename _CharT, typename _Traits>

    streamsize

    __copy_streambufs(basic_streambuf<_CharT, _Traits>* __sbin,

                      basic_streambuf<_CharT, _Traits>* __sbout);

  /**

   *  @brief  The actual work of input and output (interface).

   *

   *  This is a base class.  Derived stream buffers each control a

   *  pair of character sequences:  one for input, and one for output.

   *

   *  Section [27.5.1] of the standard describes the requirements and

   *  behavior of stream buffer classes.  That section (three paragraphs)

   *  is reproduced here, for simplicity and accuracy.

   *

   *  -# Stream buffers can impose various constraints on the sequences

   *     they control.  Some constraints are:

   *     - The controlled input sequence can be not readable.

   *     - The controlled output sequence can be not writable.

   *     - The controlled sequences can be associated with the contents of

   *       other representations for character sequences, such as external

   *       files.

   *     - The controlled sequences can support operations @e directly to or

   *       from associated sequences.

   *     - The controlled sequences can impose limitations on how the

   *       program can read characters from a sequence, write characters to

   *       a sequence, put characters back into an input sequence, or alter

   *       the stream position.

   *     .

   *  -# Each sequence is characterized by three pointers which, if non-null,

   *     all point into the same @c charT array object.  The array object

   *     represents, at any moment, a (sub)sequence of characters from the

   *     sequence.  Operations performed on a sequence alter the values

   *     stored in these pointers, perform reads and writes directly to or

   *     from associated sequences, and alter "the stream position" and

   *     conversion state as needed to maintain this subsequence relationship.

   *     The three pointers are:

   *     - the <em>beginning pointer</em>, or lowest element address in the

   *       array (called @e xbeg here);

   *     - the <em>next pointer</em>, or next element address that is a

   *       current candidate for reading or writing (called @e xnext here);

   *     - the <em>end pointer</em>, or first element address beyond the

   *       end of the array (called @e xend here).

   *     .

   *  -# The following semantic constraints shall always apply for any set

   *     of three pointers for a sequence, using the pointer names given

   *     immediately above:

   *     - If @e xnext is not a null pointer, then @e xbeg and @e xend shall

   *       also be non-null pointers into the same @c charT array, as

   *       described above; otherwise, @e xbeg and @e xend shall also be null.

   *     - If @e xnext is not a null pointer and @e xnext < @e xend for an

   *       output sequence, then a <em>write position</em> is available.

   *       In this case, @e *xnext shall be assignable as the next element

   *       to write (to put, or to store a character value, into the sequence).

   *     - If @e xnext is not a null pointer and @e xbeg < @e xnext for an

   *       input sequence, then a <em>putback position</em> is available.

   *       In this case, @e xnext[-1] shall have a defined value and is the

   *       next (preceding) element to store a character that is put back

   *       into the input sequence.

   *     - If @e xnext is not a null pointer and @e xnext< @e xend for an

   *       input sequence, then a <em>read position</em> is available.

   *       In this case, @e *xnext shall have a defined value and is the

   *       next element to read (to get, or to obtain a character value,

   *       from the sequence).

  */

  template<typename _CharT, typename _Traits>

    class basic_streambuf

    {

    public:

      //@{

      /**

       *  These are standard types.  They permit a standardized way of

       *  referring to names of (or names dependant on) the template

       *  parameters, which are specific to the implementation.

      */

      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;

      //@}

      //@{

      /**

       *  @if maint

       *  This is a non-standard type.

       *  @endif

      */

      typedef basic_streambuf<char_type, traits_type>   __streambuf_type;

      //@}

      friend class basic_ios<char_type, traits_type>;

      friend class basic_istream<char_type, traits_type>;

      friend class basic_ostream<char_type, traits_type>;

      friend class istreambuf_iterator<char_type, traits_type>;

      friend class ostreambuf_iterator<char_type, traits_type>;

      friend streamsize

      __copy_streambufs<>(__streambuf_type* __sbin,

                          __streambuf_type* __sbout);

      template<typename _CharT2, typename _Traits2>

        friend basic_istream<_CharT2, _Traits2>&

        operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*);

      template<typename _CharT2, typename _Traits2, typename _Alloc>

        friend basic_istream<_CharT2, _Traits2>&

        operator>>(basic_istream<_CharT2, _Traits2>&,

                   basic_string<_CharT2, _Traits2, _Alloc>&);

      template<typename _CharT2, typename _Traits2, typename _Alloc>

        friend basic_istream<_CharT2, _Traits2>&

        getline(basic_istream<_CharT2, _Traits2>&,

                basic_string<_CharT2, _Traits2, _Alloc>&, _CharT2);

    protected:

      //@{

      /**

       *  @if maint

       *  This is based on _IO_FILE, just reordered to be more consistent,

       *  and is intended to be the most minimal abstraction for an

       *  internal buffer.

       *  -  get == input == read

       *  -  put == output == write

       *  @endif

      */

      char_type*                _M_in_beg;     // Start of get area. 

      char_type*                _M_in_cur;     // Current read area. 

      char_type*                _M_in_end;     // End of get area. 

      char_type*                _M_out_beg;    // Start of put area. 

      char_type*                _M_out_cur;    // Current put area. 

      char_type*                _M_out_end;    // End of put area.

      /**

       *  @if maint

       *  Current locale setting.

       *  @endif

      */

      locale                    _M_buf_locale;

  public:

      /// Destructor deallocates no buffer space.

      virtual

      ~basic_streambuf()

      { }

      // [27.5.2.2.1] locales

      /**

       *  @brief  Entry point for imbue().

       *  @param  loc  The new locale.

       *  @return  The previous locale.

       *

       *  Calls the derived imbue(loc).

      */

      locale

      pubimbue(const locale &__loc)

      {

        locale __tmp(this->getloc());

        this->imbue(__loc);

        _M_buf_locale = __loc;

        return __tmp;

      }

      /**

       *  @brief  Locale access.

       *  @return  The current locale in effect.

       *

       *  If pubimbue(loc) has been called, then the most recent @c loc

       *  is returned.  Otherwise the global locale in effect at the time

       *  of construction is returned.

      */

      locale

      getloc() const

      { return _M_buf_locale; }

      // [27.5.2.2.2] buffer management and positioning

      //@{

      /**

       *  @brief  Entry points for derived buffer functions.

       *

       *  The public versions of @c pubfoo dispatch to the protected

       *  derived @c foo member functions, passing the arguments (if any)

       *  and returning the result unchanged.

      */

      __streambuf_type*

      pubsetbuf(char_type* __s, streamsize __n)

      { return this->setbuf(__s, __n); }

      pos_type

      pubseekoff(off_type __off, ios_base::seekdir __way,

                 ios_base::openmode __mode = ios_base::in | ios_base::out)

      { return this->seekoff(__off, __way, __mode); }

      pos_type

      pubseekpos(pos_type __sp,

                 ios_base::openmode __mode = ios_base::in | ios_base::out)

      { return this->seekpos(__sp, __mode); }

      int

      pubsync() { return this->sync(); }

      //@}

      // [27.5.2.2.3] get area

      /**

       *  @brief  Looking ahead into the stream.

       *  @return  The number of characters available.

       *

       *  If a read position is available, returns the number of characters

       *  available for reading before the buffer must be refilled.

       *  Otherwise returns the derived @c showmanyc().

      */

      streamsize

      in_avail()

      {

        const streamsize __ret = this->egptr() - this->gptr();

        return __ret ? __ret : this->showmanyc();

      }

      /**

       *  @brief  Getting the next character.

       *  @return  The next character, or eof.

       *

       *  Calls @c sbumpc(), and if that function returns

       *  @c traits::eof(), so does this function.  Otherwise, @c sgetc().

      */

      int_type

      snextc()

      {

        int_type __ret = traits_type::eof();

        if (__builtin_expect(!traits_type::eq_int_type(this->sbumpc(),

                                                       __ret), true))

          __ret = this->sgetc();

        return __ret;

      }

      /**

       *  @brief  Getting the next character.

       *  @return  The next character, or eof.

       *

       *  If the input read position is available, returns that character

       *  and increments the read pointer, otherwise calls and returns

       *  @c uflow().

      */

      int_type

      sbumpc()

      {

        int_type __ret;

        if (__builtin_expect(this->gptr() < this->egptr(), true))

          {

            __ret = traits_type::to_int_type(*this->gptr());

            this->gbump(1);

          }

        else

          __ret = this->uflow();

        return __ret;

      }

      /**

       *  @brief  Getting the next character.

       *  @return  The next character, or eof.

       *

       *  If the input read position is available, returns that character,

       *  otherwise calls and returns @c underflow().  Does not move the

       *  read position after fetching the character.

      */

      int_type

      sgetc()

      {

        int_type __ret;

        if (__builtin_expect(this->gptr() < this->egptr(), true))

          __ret = traits_type::to_int_type(*this->gptr());

        else

          __ret = this->underflow();

        return __ret;

      }

      /**

       *  @brief  Entry point for xsgetn.

       *  @param  s  A buffer area.

       *  @param  n  A count.

       *

       *  Returns xsgetn(s,n).  The effect is to fill @a s[0] through

       *  @a s[n-1] with characters from the input sequence, if possible.

      */

      streamsize

      sgetn(char_type* __s, streamsize __n)

      { return this->xsgetn(__s, __n); }

      // [27.5.2.2.4] putback

      /**

       *  @brief  Pushing characters back into the input stream.

       *  @param  c  The character to push back.

       *  @return  The previous character, if possible.

       *

       *  Similar to sungetc(), but @a c is pushed onto the stream instead

       *  of "the previous character".  If successful, the next character

       *  fetched from the input stream will be @a c.

      */

      int_type

      sputbackc(char_type __c)

      {

        int_type __ret;

        const bool __testpos = this->eback() < this->gptr();

        if (__builtin_expect(!__testpos ||

                             !traits_type::eq(__c, this->gptr()[-1]), false))

          __ret = this->pbackfail(traits_type::to_int_type(__c));

        else

          {

            this->gbump(-1);

            __ret = traits_type::to_int_type(*this->gptr());

          }

        return __ret;

      }

      /**

       *  @brief  Moving backwards in the input stream.

       *  @return  The previous character, if possible.

       *

       *  If a putback position is available, this function decrements the

       *  input pointer and returns that character.  Otherwise, calls and

       *  returns pbackfail().  The effect is to "unget" the last character

       *  "gotten".

      */

      int_type

      sungetc()

      {

        int_type __ret;

        if (__builtin_expect(this->eback() < this->gptr(), true))

          {

            this->gbump(-1);

            __ret = traits_type::to_int_type(*this->gptr());

          }

        else

          __ret = this->pbackfail();

        return __ret;

      }

      // [27.5.2.2.5] put area

      /**

       *  @brief  Entry point for all single-character output functions.

       *  @param  c  A character to output.

       *  @return  @a c, if possible.

       *

       *  One of two public output functions.

       *

       *  If a write position is available for the output sequence (i.e.,

       *  the buffer is not full), stores @a c in that position, increments

       *  the position, and returns @c traits::to_int_type(c).  If a write

       *  position is not available, returns @c overflow(c).

      */

      int_type

      sputc(char_type __c)

      {

        int_type __ret;

        if (__builtin_expect(this->pptr() < this->epptr(), true))

          {

            *this->pptr() = __c;

            this->pbump(1);

            __ret = traits_type::to_int_type(__c);

          }

        else

          __ret = this->overflow(traits_type::to_int_type(__c));

        return __ret;

      }

      /**

       *  @brief  Entry point for all single-character output functions.

       *  @param  s  A buffer read area.

       *  @param  n  A count.

       *

       *  One of two public output functions.

       *

       *

       *  Returns xsputn(s,n).  The effect is to write @a s[0] through

       *  @a s[n-1] to the output sequence, if possible.

      */

      streamsize

      sputn(const char_type* __s, streamsize __n)

      { return this->xsputn(__s, __n); }

    protected:

      /**

       *  @brief  Base constructor.

       *

       *  Only called from derived constructors, and sets up all the

       *  buffer data to zero, including the pointers described in the

       *  basic_streambuf class description.  Note that, as a result,

       *  - the class starts with no read nor write positions available,

       *  - this is not an error

      */

      basic_streambuf()

      : _M_in_beg(0), _M_in_cur(0), _M_in_end(0),

      _M_out_beg(0), _M_out_cur(0), _M_out_end(0),

      _M_buf_locale(locale())

      { }

      // [27.5.2.3.1] get area access

      //@{

      /**

       *  @brief  Access to the get area.

       *

       *  These functions are only available to other protected functions,

       *  including derived classes.

       *

       *  - eback() returns the beginning pointer for the input sequence

       *  - gptr() returns the next pointer for the input sequence

       *  - egptr() returns the end pointer for the input sequence

      */

      char_type*

      eback() const { return _M_in_beg; }

      char_type*

      gptr()  const { return _M_in_cur;  }

      char_type*

      egptr() const { return _M_in_end; }

      //@}

      /**

       *  @brief  Moving the read position.

       *  @param  n  The delta by which to move.

       *

       *  This just advances the read position without returning any data.

      */

      void

      gbump(int __n) { _M_in_cur += __n; }

      /**

       *  @brief  Setting the three read area pointers.

       *  @param  gbeg  A pointer.

       *  @param  gnext  A pointer.

       *  @param  gend  A pointer.

       *  @post  @a gbeg == @c eback(), @a gnext == @c gptr(), and

       *         @a gend == @c egptr()

      */

      void

      setg(char_type* __gbeg, char_type* __gnext, char_type* __gend)

      {

        _M_in_beg = __gbeg;

        _M_in_cur = __gnext;

        _M_in_end = __gend;

      }

      // [27.5.2.3.2] put area access

      //@{

      /**

       *  @brief  Access to the put area.

       *

       *  These functions are only available to other protected functions,

       *  including derived classes.

       *

       *  - pbase() returns the beginning pointer for the output sequence

       *  - pptr() returns the next pointer for the output sequence

       *  - epptr() returns the end pointer for the output sequence

      */

      char_type*

      pbase() const { return _M_out_beg; }

      char_type*

      pptr() const { return _M_out_cur; }

      char_type*

      epptr() const { return _M_out_end; }

      //@}

      /**

       *  @brief  Moving the write position.

       *  @param  n  The delta by which to move.

       *

       *  This just advances the write position without returning any data.

      */

      void

      pbump(int __n) { _M_out_cur += __n; }

      /**

       *  @brief  Setting the three write area pointers.

       *  @param  pbeg  A pointer.

       *  @param  pend  A pointer.

       *  @post  @a pbeg == @c pbase(), @a pbeg == @c pptr(), and

       *         @a pend == @c epptr()

      */

      void

      setp(char_type* __pbeg, char_type* __pend)

      {

        _M_out_beg = _M_out_cur = __pbeg;

        _M_out_end = __pend;

      }

      // [27.5.2.4] virtual functions

      // [27.5.2.4.1] locales

      /**

       *  @brief  Changes translations.

       *  @param  loc  A new locale.

       *

       *  Translations done during I/O which depend on the current locale

       *  are changed by this call.  The standard adds, "Between invocations

       *  of this function a class derived from streambuf can safely cache

       *  results of calls to locale functions and to members of facets

       *  so obtained."

       *

       *  @note  Base class version does nothing.

      */

      virtual void

      imbue(const locale&)

      { }

      // [27.5.2.4.2] buffer management and positioning

      /**

       *  @brief  Maniuplates the buffer.

       *

       *  Each derived class provides its own appropriate behavior.  See

       *  the next-to-last paragraph of

       *  http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for

       *  more on this function.

       *

       *  @note  Base class version does nothing, returns @c this.

      */

      virtual basic_streambuf<char_type,_Traits>*

      setbuf(char_type*, streamsize)

      { return this; }

      /**

       *  @brief  Alters the stream positions.

       *

       *  Each derived class provides its own appropriate behavior.

       *  @note  Base class version does nothing, returns a @c pos_type

       *         that represents an invalid stream position.

      */

      virtual pos_type

      seekoff(off_type, ios_base::seekdir,

              ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)

      { return pos_type(off_type(-1)); }

      /**

       *  @brief  Alters the stream positions.

       *

       *  Each derived class provides its own appropriate behavior.

       *  @note  Base class version does nothing, returns a @c pos_type

       *         that represents an invalid stream position.

      */

      virtual pos_type

      seekpos(pos_type,

              ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)

      { return pos_type(off_type(-1)); }

      /**

       *  @brief  Synchronizes the buffer arrays with the controlled sequences.

       *  @return  -1 on failure.

       *

       *  Each derived class provides its own appropriate behavior,

       *  including the definition of "failure".

       *  @note  Base class version does nothing, returns zero.

      */

      virtual int

      sync() { return 0; }

      // [27.5.2.4.3] get area

      /**

       *  @brief  Investigating the data available.

       *  @return  An estimate of the number of characters available in the

       *           input sequence, or -1.

       *

       *  "If it returns a positive value, then successive calls to

       *  @c underflow() will not return @c traits::eof() until at least that

       *  number of characters have been supplied.  If @c showmanyc()

       *  returns -1, then calls to @c underflow() or @c uflow() will fail."

       *  [27.5.2.4.3]/1

       *

       *  @note  Base class version does nothing, returns zero.

       *  @note  The standard adds that "the intention is not only that the

       *         calls [to underflow or uflow] will not return @c eof() but

       *         that they will return "immediately".

       *  @note  The standard adds that "the morphemes of @c showmanyc are

       *         "es-how-many-see", not "show-manic".

      */

      virtual streamsize

      showmanyc() { return 0; }

      /**

       *  @brief  Multiple character extraction.

       *  @param  s  A buffer area.

       *  @param  n  Maximum number of characters to assign.

       *  @return  The number of characters assigned.

       *

       *  Fills @a s[0] through @a s[n-1] with characters from the input

       *  sequence, as if by @c sbumpc().  Stops when either @a n characters

       *  have been copied, or when @c traits::eof() would be copied.

       *

       *  It is expected that derived classes provide a more efficient

       *  implementation by overriding this definition.

      */

      virtual streamsize

      xsgetn(char_type* __s, streamsize __n);

      /**

       *  @brief  Fetches more data from the controlled sequence.

       *  @return  The first character from the <em>pending sequence</em>.

       *

       *  Informally, this function is called when the input buffer is

       *  exhausted (or does not exist, as buffering need not actually be

       *  done).  If a buffer exists, it is "refilled".  In either case, the

       *  next available character is returned, or @c traits::eof() to

       *  indicate a null pending sequence.

       *

       *  For a formal definiton of the pending sequence, see a good text

       *  such as Langer & Kreft, or [27.5.2.4.3]/7-14.

       *

       *  A functioning input streambuf can be created by overriding only

       *  this function (no buffer area will be used).  For an example, see

       *  http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#6

       *

       *  @note  Base class version does nothing, returns eof().

      */

      virtual int_type

      underflow()

      { return traits_type::eof(); }

      /**

       *  @brief  Fetches more data from the controlled sequence.

       *  @return  The first character from the <em>pending sequence</em>.

       *

       *  Informally, this function does the same thing as @c underflow(),

       *  and in fact is required to call that function.  It also returns

       *  the new character, like @c underflow() does.  However, this

       *  function also moves the read position forward by one.

      */

      virtual int_type

      uflow()

      {

        int_type __ret = traits_type::eof();

        const bool __testeof = traits_type::eq_int_type(this->underflow(),

                                                        __ret);

        if (!__testeof)

          {

            __ret = traits_type::to_int_type(*this->gptr());

            this->gbump(1);

          }

        return __ret;

      }

      // [27.5.2.4.4] putback

      /**

       *  @brief  Tries to back up the input sequence.

       *  @param  c  The character to be inserted back into the sequence.

       *  @return  eof() on failure, "some other value" on success

       *  @post  The constraints of @c gptr(), @c eback(), and @c pptr()

       *         are the same as for @c underflow().

       *

       *  @note  Base class version does nothing, returns eof().

      */

      virtual int_type

      pbackfail(int_type /* __c */  = traits_type::eof())

      { return traits_type::eof(); }

      // Put area:

      /**

       *  @brief  Multiple character insertion.

       *  @param  s  A buffer area.

       *  @param  n  Maximum number of characters to write.

       *  @return  The number of characters written.

       *

       *  Writes @a s[0] through @a s[n-1] to the output sequence, as if

       *  by @c sputc().  Stops when either @a n characters have been

       *  copied, or when @c sputc() would return @c traits::eof().

       *

       *  It is expected that derived classes provide a more efficient

       *  implementation by overriding this definition.

      */

      virtual streamsize

      xsputn(const char_type* __s, streamsize __n);

      /**

       *  @brief  Consumes data from the buffer; writes to the

       *          controlled sequence.

       *  @param  c  An additional character to consume.

       *  @return  eof() to indicate failure, something else (usually

       *           @a c, or not_eof())

       *

       *  Informally, this function is called when the output buffer is full

       *  (or does not exist, as buffering need not actually be done).  If a

       *  buffer exists, it is "consumed", with "some effect" on the

       *  controlled sequence.  (Typically, the buffer is written out to the

       *  sequence verbatim.)  In either case, the character @a c is also

       *  written out, if @a c is not @c eof().

       *

       *  For a formal definiton of this function, see a good text

       *  such as Langer & Kreft, or [27.5.2.4.5]/3-7.

       *

       *  A functioning output streambuf can be created by overriding only

       *  this function (no buffer area will be used).

       *

       *  @note  Base class version does nothing, returns eof().

      */

      virtual int_type

      overflow(int_type /* __c */ = traits_type::eof())

      { return traits_type::eof(); }

#ifdef _GLIBCXX_DEPRECATED

    // Annex D.6

    public:

      /**

       *  @brief  Tosses a character.

       *

       *  Advances the read pointer, ignoring the character that would have

       *  been read.

       *

       *  See http://gcc.gnu.org/ml/libstdc++/2002-05/msg00168.html

       *

       *  @note  This function has been deprecated by the standard.  You

       *         must define @c _GLIBCXX_DEPRECATED to make this visible; see

       *         c++config.h.

      */

      void

      stossc()

      {

        if (this->gptr() < this->egptr())

          this->gbump(1);

        else

          this->uflow();

      }

#endif

    private:

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // Side effect of DR 50. 

      basic_streambuf(const __streambuf_type& __sb)

      : _M_in_beg(__sb._M_in_beg), _M_in_cur(__sb._M_in_cur),

      _M_in_end(__sb._M_in_end), _M_out_beg(__sb._M_out_beg),

      _M_out_cur(__sb._M_out_cur), _M_out_end(__sb._M_out_cur),

      _M_buf_locale(__sb._M_buf_locale)

      { }

      __streambuf_type&

      operator=(const __streambuf_type&) { return *this; };

    };

  // Explicit specialization declarations, defined in src/streambuf.cc.

  template<>