/home/ntakagi/work/STLport-5.1.5/stlport/stl/_streambuf.h Go to the documentation of this file. /* * 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:

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