/*

  * Copyright (c) 1999

  * Silicon Graphics Computer Systems, Inc.

  *

  * Copyright (c) 1999

  * Boris Fomitchev

  *

  * This material is provided "as is", with absolutely no warranty expressed

  * or implied. Any use is at your own risk.

  *

  * Permission to use or copy this software for any purpose is hereby granted

  * without fee, provided the above notices are retained on all copies.

  * Permission to modify the code and to distribute modified code is granted,

  * provided the above notices are retained, and a notice that the code was

  * modified is included with the above copyright notice.

  *

  */

 #ifndef _STLP_INTERNAL_STREAMBUF

 #define _STLP_INTERNAL_STREAMBUF

 #ifndef _STLP_IOS_BASE_H

 #  include <stl/_ios_base.h>      // Needed for ios_base bitfield members.

 #endif                            // <ios_base> includes <iosfwd>.

 _STLP_BEGIN_NAMESPACE

 //----------------------------------------------------------------------

 // Class basic_streambuf<>, the base class of the streambuf hierarchy.

 // A basic_streambuf<> manages an input (get) area and an output (put)

 // area.  Each is described by three pointers: a beginning, an end, and a

 // current position.  basic_streambuf<> contains some very simple member

 // functions that manipulate those six pointers, but almost all of the real

 // functionality gets delegated to protected virtual member functions.

 // All of the public member functions are inline, and most of the protected

 // member functions are virtual.

 // Although basic_streambuf<> is not abstract, it is useful only as a base

 // class.  Its virtual member functions have default definitions such that

 // reading from a basic_streambuf<> will always yield EOF, and writing to a

 // basic_streambuf<> will always fail.

 // The second template parameter, _Traits, defaults to char_traits<_CharT>.

 // The default is declared in header <iosfwd>, and it isn't declared here

 // because C++ language rules do not allow it to be declared twice.

 template <class _CharT, class _Traits>

 class basic_streambuf {

   friend class basic_istream<_CharT, _Traits>;

   friend class basic_ostream<_CharT, _Traits>;

 public:                         // Typedefs.

   typedef _CharT                     char_type;

   typedef typename _Traits::int_type int_type;

   typedef typename _Traits::pos_type pos_type;

   typedef typename _Traits::off_type off_type;

   typedef _Traits                    traits_type;

 private:                        // Data members.

   char_type* _M_gbegin;         // Beginning of get area

   char_type* _M_gnext;          // Current position within the get area

   char_type* _M_gend;           // End of get area

   char_type* _M_pbegin;         // Beginning of put area

   char_type* _M_pnext;          // Current position within the put area

   char_type* _M_pend;           // End of put area

   locale _M_locale;             // The streambuf's locale object

 //public:                         // Extension: locking, for thread safety.

 //  _STLP_mutex _M_lock;

 public:                         // Destructor.

   virtual ~basic_streambuf();

 protected:                      // The default constructor.

   basic_streambuf()

 #if defined (_STLP_MSVC) && (_STLP_MSVC < 1300) && defined (_STLP_USE_STATIC_LIB)

     //We make it inline to avoid unresolved symbol.

     : _M_gbegin(0), _M_gnext(0), _M_gend(0),

       _M_pbegin(0), _M_pnext(0), _M_pend(0),

       _M_locale()

   {}

 #else

   ;

 #endif

 protected:                      // Protected interface to the get area.

   char_type* eback() const { return _M_gbegin; } // Beginning

   char_type* gptr()  const { return _M_gnext; }  // Current position

   char_type* egptr() const { return _M_gend; }   // End

   void gbump(int __n) { _M_gnext += __n; }

   void setg(char_type* __gbegin, char_type* __gnext, char_type* __gend) {

     _M_gbegin = __gbegin;

     _M_gnext  = __gnext;

     _M_gend   = __gend;

   }

 public:

   // An alternate public interface to the above functions

   // which allows us to avoid using templated friends which

   // are not supported on some compilers.

   char_type* _M_eback() const { return eback(); }

   char_type* _M_gptr()  const { return gptr(); }

   char_type* _M_egptr() const { return egptr(); }

   void _M_gbump(int __n)      { gbump(__n); }

   void _M_setg(char_type* __gbegin, char_type* __gnext, char_type* __gend)

   { this->setg(__gbegin, __gnext, __gend); }

 protected:                      // Protected interface to the put area

   char_type* pbase() const { return _M_pbegin; } // Beginning

   char_type* pptr()  const { return _M_pnext; }  // Current position

   char_type* epptr() const { return _M_pend; }   // End

   void pbump(int __n) { _M_pnext += __n; }

   void setp(char_type* __pbegin, char_type* __pend) {

     _M_pbegin = __pbegin;

     _M_pnext  = __pbegin;

     _M_pend   = __pend;

   }

 protected:                      // Virtual buffer management functions.

   virtual basic_streambuf<_CharT, _Traits>* setbuf(char_type*, streamsize);

   // Alters the stream position, using an integer offset.  In this

   // class seekoff does nothing; subclasses are expected to override it.

   virtual pos_type seekoff(off_type, ios_base::seekdir,

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

   // Alters the stream position, using a previously obtained streampos.  In

   // this class seekpos does nothing; subclasses are expected to override it.

   virtual pos_type

   seekpos(pos_type, ios_base::openmode = ios_base::in | ios_base::out);

   // Synchronizes (i.e. flushes) the buffer.  All subclasses are expected to

   // override this virtual member function.

   virtual int sync();

 public:                         // Buffer management.

   basic_streambuf<_CharT, _Traits>* pubsetbuf(char_type* __s, streamsize __n)

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

   pos_type pubseekoff(off_type __offset, ios_base::seekdir __way,

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

   { return this->seekoff(__offset, __way, __mod); }

   pos_type pubseekpos(pos_type __sp,

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

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

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

 protected:                      // Virtual get area functions, as defined in

                                 // 17.5.2.4.3 and 17.5.2.4.4 of the standard.

   // Returns a lower bound on the number of characters that we can read,

   // with underflow, before reaching end of file.  (-1 is a special value:

   // it means that underflow will fail.)  Most subclasses should probably

   // override this virtual member function.

   virtual streamsize showmanyc();

   // Reads up to __n characters.  Return value is the number of

   // characters read.

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

   // Called when there is no read position, i.e. when gptr() is null

   // or when gptr() >= egptr().  Subclasses are expected to override

   // this virtual member function.

   virtual int_type underflow();

   // Similar to underflow(), but used for unbuffered input.  Most

   // subclasses should probably override this virtual member function.

   virtual int_type uflow();

   // Called when there is no putback position, i.e. when gptr() is null

   // or when gptr() == eback().  All subclasses are expected to override

   // this virtual member function.

   virtual int_type pbackfail(int_type = traits_type::eof());

 protected:                      // Virtual put area functions, as defined in

                                 // 27.5.2.4.5 of the standard.

   // Writes up to __n characters.  Return value is the number of characters

   // written.

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

   // Extension: writes up to __n copies of __c.  Return value is the number

   // of characters written.

   virtual streamsize _M_xsputnc(char_type __c, streamsize __n);

   // Called when there is no write position.  All subclasses are expected to

   // override this virtual member function.

   virtual int_type overflow(int_type = traits_type::eof());

 public:                         // Public members for writing characters.

   // Write a single character.

   int_type sputc(char_type __c) {

     return ((_M_pnext < _M_pend) ? _Traits::to_int_type(*_M_pnext++ = __c)

       : this->overflow(_Traits::to_int_type(__c)));

   }

   // Write __n characters.

   streamsize sputn(const char_type* __s, streamsize __n)

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

   // Extension: write __n copies of __c.

   streamsize _M_sputnc(char_type __c, streamsize __n)

   { return this->_M_xsputnc(__c, __n); }

 private:                        // Helper functions.

   int_type _M_snextc_aux();

 public:                         // Public members for reading characters.

   streamsize in_avail() {

     return (_M_gnext < _M_gend) ? (_M_gend - _M_gnext) : this->showmanyc();

   }

   // Advance to the next character and return it.

   int_type snextc() {

   return ( _M_gend - _M_gnext > 1 ?

              _Traits::to_int_type(*++_M_gnext) :

              this->_M_snextc_aux());

   }

   // Return the current character and advance to the next.

   int_type sbumpc() {

     return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext++)

       : this->uflow();

   }

   // Return the current character without advancing to the next.

   int_type sgetc() {

     return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext)

       : this->underflow();

   }

   streamsize sgetn(char_type* __s, streamsize __n)

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

   int_type sputbackc(char_type __c) {

     return ((_M_gbegin < _M_gnext) && _Traits::eq(__c, *(_M_gnext - 1)))

       ? _Traits::to_int_type(*--_M_gnext)

       : this->pbackfail(_Traits::to_int_type(__c));

   }

   int_type sungetc() {

     return (_M_gbegin < _M_gnext)

       ? _Traits::to_int_type(*--_M_gnext)

       : this->pbackfail();

   }

 protected:                      // Virtual locale functions.

   // This is a hook, called by pubimbue() just before pubimbue()

   // sets the streambuf's locale to __loc.  Note that imbue should

   // not (and cannot, since it has no access to streambuf's private

   // members) set the streambuf's locale itself.

   virtual void imbue(const locale&);

 public:                         // Locale-related functions.

   locale pubimbue(const locale&);

   locale getloc() const { return _M_locale; }

 #if !defined (_STLP_NO_ANACHRONISMS)

   void stossc() { this->sbumpc(); }

 #endif

 #if defined (__MVS__) || defined (__OS400__)

 private: // Data members.

   char_type* _M_gbegin; // Beginning of get area

   char_type* _M_gnext; // Current position within the get area

   char_type* _M_gend; // End of get area

   char_type* _M_pbegin; // Beginning of put area

   char_type* _M_pnext; // Current position within the put area

   char_type* _M_pend; // End of put area

 #endif

 };

 #if defined (_STLP_USE_TEMPLATE_EXPORT)

 _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<char, char_traits<char> >;

 #  if !defined (_STLP_NO_WCHAR_T)

 _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<wchar_t, char_traits<wchar_t> >;

 #  endif // _STLP_NO_WCHAR_T

 #endif // _STLP_USE_TEMPLATE_EXPORT

 _STLP_END_NAMESPACE

 #if defined (_STLP_EXPOSE_STREAM_IMPLEMENTATION) && !defined (_STLP_LINK_TIME_INSTANTIATION)

 #  include <stl/_streambuf.c>

 #endif

 #endif

 // Local Variables:

 // mode:C++

 // End: