williamr@2: /*
williamr@2:  * Copyright (c) 1999
williamr@2:  * Silicon Graphics Computer Systems, Inc.
williamr@2:  *
williamr@4:  * Copyright (c) 1999
williamr@2:  * Boris Fomitchev
williamr@2:  *
williamr@2:  * This material is provided "as is", with absolutely no warranty expressed
williamr@2:  * or implied. Any use is at your own risk.
williamr@2:  *
williamr@4:  * Permission to use or copy this software for any purpose is hereby granted
williamr@2:  * without fee, provided the above notices are retained on all copies.
williamr@2:  * Permission to modify the code and to distribute modified code is granted,
williamr@2:  * provided the above notices are retained, and a notice that the code was
williamr@2:  * modified is included with the above copyright notice.
williamr@2:  *
williamr@4:  */
williamr@2: #ifndef _STLP_INTERNAL_STREAMBUF
williamr@2: #define _STLP_INTERNAL_STREAMBUF
williamr@2: 
williamr@2: #ifndef _STLP_IOS_BASE_H
williamr@4: #  include <stl/_ios_base.h>      // Needed for ios_base bitfield members.
williamr@4: #endif                            // <ios_base> includes <iosfwd>.
williamr@2: 
williamr@2: _STLP_BEGIN_NAMESPACE
williamr@2: 
williamr@2: //----------------------------------------------------------------------
williamr@2: // Class basic_streambuf<>, the base class of the streambuf hierarchy.
williamr@2: 
williamr@2: // A basic_streambuf<> manages an input (get) area and an output (put)
williamr@2: // area.  Each is described by three pointers: a beginning, an end, and a
williamr@2: // current position.  basic_streambuf<> contains some very simple member
williamr@2: // functions that manipulate those six pointers, but almost all of the real
williamr@2: // functionality gets delegated to protected virtual member functions.
williamr@2: // All of the public member functions are inline, and most of the protected
williamr@2: // member functions are virtual.
williamr@2: 
williamr@2: // Although basic_streambuf<> is not abstract, it is useful only as a base
williamr@2: // class.  Its virtual member functions have default definitions such that
williamr@2: // reading from a basic_streambuf<> will always yield EOF, and writing to a
williamr@2: // basic_streambuf<> will always fail.
williamr@2: 
williamr@2: // The second template parameter, _Traits, defaults to char_traits<_CharT>.
williamr@2: // The default is declared in header <iosfwd>, and it isn't declared here
williamr@4: // because C++ language rules do not allow it to be declared twice.
williamr@2: 
williamr@2: template <class _CharT, class _Traits>
williamr@4: class basic_streambuf {
williamr@2:   friend class basic_istream<_CharT, _Traits>;
williamr@2:   friend class basic_ostream<_CharT, _Traits>;
williamr@2: 
williamr@2: public:                         // Typedefs.
williamr@2:   typedef _CharT                     char_type;
williamr@2:   typedef typename _Traits::int_type int_type;
williamr@2:   typedef typename _Traits::pos_type pos_type;
williamr@2:   typedef typename _Traits::off_type off_type;
williamr@2:   typedef _Traits                    traits_type;
williamr@2: 
williamr@2: private:                        // Data members.
williamr@2: 
williamr@2:   char_type* _M_gbegin;         // Beginning of get area
williamr@2:   char_type* _M_gnext;          // Current position within the get area
williamr@2:   char_type* _M_gend;           // End of get area
williamr@2: 
williamr@2:   char_type* _M_pbegin;         // Beginning of put area
williamr@2:   char_type* _M_pnext;          // Current position within the put area
williamr@2:   char_type* _M_pend;           // End of put area
williamr@2: 
williamr@2:   locale _M_locale;             // The streambuf's locale object
williamr@2: 
williamr@4: //public:                         // Extension: locking, for thread safety.
williamr@4: //  _STLP_mutex _M_lock;
williamr@2: 
williamr@2: public:                         // Destructor.
williamr@4:   virtual ~basic_streambuf();
williamr@2: 
williamr@2: protected:                      // The default constructor.
williamr@4:   basic_streambuf()
williamr@4: #if defined (_STLP_MSVC) && (_STLP_MSVC < 1300) && defined (_STLP_USE_STATIC_LIB)
williamr@4:     //We make it inline to avoid unresolved symbol.
williamr@4:     : _M_gbegin(0), _M_gnext(0), _M_gend(0),
williamr@4:       _M_pbegin(0), _M_pnext(0), _M_pend(0),
williamr@4:       _M_locale()
williamr@4:   {}
williamr@4: #else
williamr@4:   ;
williamr@4: #endif
williamr@2: 
williamr@2: protected:                      // Protected interface to the get area.
williamr@2:   char_type* eback() const { return _M_gbegin; } // Beginning
williamr@2:   char_type* gptr()  const { return _M_gnext; }  // Current position
williamr@2:   char_type* egptr() const { return _M_gend; }   // End
williamr@4: 
williamr@2:   void gbump(int __n) { _M_gnext += __n; }
williamr@2:   void setg(char_type* __gbegin, char_type* __gnext, char_type* __gend) {
williamr@2:     _M_gbegin = __gbegin;
williamr@2:     _M_gnext  = __gnext;
williamr@2:     _M_gend   = __gend;
williamr@2:   }
williamr@2: 
williamr@2: public:
williamr@2:   // An alternate public interface to the above functions
williamr@2:   // which allows us to avoid using templated friends which
williamr@2:   // are not supported on some compilers.
williamr@2:   char_type* _M_eback() const { return eback(); }
williamr@2:   char_type* _M_gptr()  const { return gptr(); }
williamr@2:   char_type* _M_egptr() const { return egptr(); }
williamr@2:   void _M_gbump(int __n)      { gbump(__n); }
williamr@2:   void _M_setg(char_type* __gbegin, char_type* __gnext, char_type* __gend)
williamr@4:   { this->setg(__gbegin, __gnext, __gend); }
williamr@2: 
williamr@2: protected:                      // Protected interface to the put area
williamr@2: 
williamr@2:   char_type* pbase() const { return _M_pbegin; } // Beginning
williamr@2:   char_type* pptr()  const { return _M_pnext; }  // Current position
williamr@2:   char_type* epptr() const { return _M_pend; }   // End
williamr@2: 
williamr@2:   void pbump(int __n) { _M_pnext += __n; }
williamr@2:   void setp(char_type* __pbegin, char_type* __pend) {
williamr@2:     _M_pbegin = __pbegin;
williamr@2:     _M_pnext  = __pbegin;
williamr@2:     _M_pend   = __pend;
williamr@2:   }
williamr@2: 
williamr@2: protected:                      // Virtual buffer management functions.
williamr@2: 
williamr@4:   virtual basic_streambuf<_CharT, _Traits>* setbuf(char_type*, streamsize);
williamr@2: 
williamr@2:   // Alters the stream position, using an integer offset.  In this
williamr@2:   // class seekoff does nothing; subclasses are expected to override it.
williamr@4:   virtual pos_type seekoff(off_type, ios_base::seekdir,
williamr@2:                            ios_base::openmode = ios_base::in | ios_base::out);
williamr@2: 
williamr@2:   // Alters the stream position, using a previously obtained streampos.  In
williamr@2:   // this class seekpos does nothing; subclasses are expected to override it.
williamr@4:   virtual pos_type
williamr@2:   seekpos(pos_type, ios_base::openmode = ios_base::in | ios_base::out);
williamr@2: 
williamr@4:   // Synchronizes (i.e. flushes) the buffer.  All subclasses are expected to
williamr@2:   // override this virtual member function.
williamr@4:   virtual int sync();
williamr@2: 
williamr@2: 
williamr@2: public:                         // Buffer management.
williamr@4:   basic_streambuf<_CharT, _Traits>* pubsetbuf(char_type* __s, streamsize __n)
williamr@4:   { return this->setbuf(__s, __n); }
williamr@2: 
williamr@2:   pos_type pubseekoff(off_type __offset, ios_base::seekdir __way,
williamr@2:                       ios_base::openmode __mod = ios_base::in | ios_base::out)
williamr@4:   { return this->seekoff(__offset, __way, __mod); }
williamr@2: 
williamr@2:   pos_type pubseekpos(pos_type __sp,
williamr@2:                       ios_base::openmode __mod = ios_base::in | ios_base::out)
williamr@4:   { return this->seekpos(__sp, __mod); }
williamr@2: 
williamr@2:   int pubsync() { return this->sync(); }
williamr@2: 
williamr@2: protected:                      // Virtual get area functions, as defined in
williamr@2:                                 // 17.5.2.4.3 and 17.5.2.4.4 of the standard.
williamr@2:   // Returns a lower bound on the number of characters that we can read,
williamr@2:   // with underflow, before reaching end of file.  (-1 is a special value:
williamr@2:   // it means that underflow will fail.)  Most subclasses should probably
williamr@2:   // override this virtual member function.
williamr@4:   virtual streamsize showmanyc();
williamr@2: 
williamr@4:   // Reads up to __n characters.  Return value is the number of
williamr@2:   // characters read.
williamr@4:   virtual streamsize xsgetn(char_type* __s, streamsize __n);
williamr@2: 
williamr@2:   // Called when there is no read position, i.e. when gptr() is null
williamr@2:   // or when gptr() >= egptr().  Subclasses are expected to override
williamr@2:   // this virtual member function.
williamr@4:   virtual int_type underflow();
williamr@2: 
williamr@4:   // Similar to underflow(), but used for unbuffered input.  Most
williamr@2:   // subclasses should probably override this virtual member function.
williamr@4:   virtual int_type uflow();
williamr@2: 
williamr@2:   // Called when there is no putback position, i.e. when gptr() is null
williamr@2:   // or when gptr() == eback().  All subclasses are expected to override
williamr@2:   // this virtual member function.
williamr@4:   virtual int_type pbackfail(int_type = traits_type::eof());
williamr@2: 
williamr@2: protected:                      // Virtual put area functions, as defined in
williamr@2:                                 // 27.5.2.4.5 of the standard.
williamr@2: 
williamr@2:   // Writes up to __n characters.  Return value is the number of characters
williamr@2:   // written.
williamr@4:   virtual streamsize xsputn(const char_type* __s, streamsize __n);
williamr@2: 
williamr@2:   // Extension: writes up to __n copies of __c.  Return value is the number
williamr@2:   // of characters written.
williamr@4:   virtual streamsize _M_xsputnc(char_type __c, streamsize __n);
williamr@2: 
williamr@2:   // Called when there is no write position.  All subclasses are expected to
williamr@2:   // override this virtual member function.
williamr@4:   virtual int_type overflow(int_type = traits_type::eof());
williamr@2: 
williamr@2: public:                         // Public members for writing characters.
williamr@2:   // Write a single character.
williamr@2:   int_type sputc(char_type __c) {
williamr@2:     return ((_M_pnext < _M_pend) ? _Traits::to_int_type(*_M_pnext++ = __c)
williamr@2:       : this->overflow(_Traits::to_int_type(__c)));
williamr@2:   }
williamr@2: 
williamr@2:   // Write __n characters.
williamr@2:   streamsize sputn(const char_type* __s, streamsize __n)
williamr@4:   { return this->xsputn(__s, __n); }
williamr@2: 
williamr@2:   // Extension: write __n copies of __c.
williamr@2:   streamsize _M_sputnc(char_type __c, streamsize __n)
williamr@4:   { return this->_M_xsputnc(__c, __n); }
williamr@2: 
williamr@2: private:                        // Helper functions.
williamr@4:   int_type _M_snextc_aux();
williamr@2: 
williamr@2: public:                         // Public members for reading characters.
williamr@2:   streamsize in_avail() {
williamr@2:     return (_M_gnext < _M_gend) ? (_M_gend - _M_gnext) : this->showmanyc();
williamr@2:   }
williamr@4: 
williamr@2:   // Advance to the next character and return it.
williamr@2:   int_type snextc() {
williamr@4:   return ( _M_gend - _M_gnext > 1 ?
williamr@2:              _Traits::to_int_type(*++_M_gnext) :
williamr@2:              this->_M_snextc_aux());
williamr@2:   }
williamr@2: 
williamr@2:   // Return the current character and advance to the next.
williamr@2:   int_type sbumpc() {
williamr@4:     return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext++)
williamr@2:       : this->uflow();
williamr@2:   }
williamr@4: 
williamr@2:   // Return the current character without advancing to the next.
williamr@2:   int_type sgetc() {
williamr@4:     return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext)
williamr@2:       : this->underflow();
williamr@2:   }
williamr@4: 
williamr@2:   streamsize sgetn(char_type* __s, streamsize __n)
williamr@2:   { return this->xsgetn(__s, __n); }
williamr@4: 
williamr@2:   int_type sputbackc(char_type __c) {
williamr@2:     return ((_M_gbegin < _M_gnext) && _Traits::eq(__c, *(_M_gnext - 1)))
williamr@2:       ? _Traits::to_int_type(*--_M_gnext)
williamr@2:       : this->pbackfail(_Traits::to_int_type(__c));
williamr@2:   }
williamr@4: 
williamr@2:   int_type sungetc() {
williamr@2:     return (_M_gbegin < _M_gnext)
williamr@2:       ? _Traits::to_int_type(*--_M_gnext)
williamr@2:       : this->pbackfail();
williamr@2:   }
williamr@2: 
williamr@2: protected:                      // Virtual locale functions.
williamr@2: 
williamr@2:   // This is a hook, called by pubimbue() just before pubimbue()
williamr@2:   // sets the streambuf's locale to __loc.  Note that imbue should
williamr@2:   // not (and cannot, since it has no access to streambuf's private
williamr@2:   // members) set the streambuf's locale itself.
williamr@4:   virtual void imbue(const locale&);
williamr@2: 
williamr@2: public:                         // Locale-related functions.
williamr@4:   locale pubimbue(const locale&);
williamr@2:   locale getloc() const { return _M_locale; }
williamr@2: 
williamr@4: #if !defined (_STLP_NO_ANACHRONISMS)
williamr@2:   void stossc() { this->sbumpc(); }
williamr@4: #endif
williamr@4: #if defined (__MVS__) || defined (__OS400__)
williamr@2: private: // Data members.
williamr@2: 
williamr@2:   char_type* _M_gbegin; // Beginning of get area
williamr@2:   char_type* _M_gnext; // Current position within the get area
williamr@2:   char_type* _M_gend; // End of get area
williamr@2: 
williamr@2:   char_type* _M_pbegin; // Beginning of put area
williamr@2:   char_type* _M_pnext; // Current position within the put area
williamr@2:   char_type* _M_pend; // End of put area
williamr@2: #endif
williamr@2: };
williamr@2: 
williamr@4: #if defined (_STLP_USE_TEMPLATE_EXPORT)
williamr@4: _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<char, char_traits<char> >;
williamr@4: #  if !defined (_STLP_NO_WCHAR_T)
williamr@4: _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<wchar_t, char_traits<wchar_t> >;
williamr@4: #  endif // _STLP_NO_WCHAR_T
williamr@4: #endif // _STLP_USE_TEMPLATE_EXPORT
williamr@2: 
williamr@4: _STLP_END_NAMESPACE
williamr@2: 
williamr@4: #if defined (_STLP_EXPOSE_STREAM_IMPLEMENTATION) && !defined (_STLP_LINK_TIME_INSTANTIATION)
williamr@4: #  include <stl/_streambuf.c>
williamr@2: #endif
williamr@2: 
williamr@2: #endif
williamr@2: 
williamr@2: // Local Variables:
williamr@2: // mode:C++
williamr@2: // End: