/*

 * © Portions copyright (c) 2006-2007 Nokia Corporation.  All rights reserved.

 *

 * 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.

                                // <ios_base> includes <iosfwd>.

#endif

#ifndef _STLP_STDIO_FILE_H

#include <stl/_stdio_file.h>     // Declaration of struct FILE, and of

                                // functions to manipulate it.

#endif

_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>

#ifdef __SYMBIAN32__

class basic_streambuf 

#else

class basic_streambuf

#endif

{

  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.

  _STLP_DUMMY_IMP_DECLSPEC virtual ~basic_streambuf();

protected:                      // The default constructor.

  _STLP_DUMMY_IMP_DECLSPEC basic_streambuf();

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)

    { 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC virtual streamsize showmanyc();

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

  // characters read.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC virtual int_type underflow();

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

  // subclasses should probably override this virtual member function.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC 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.

  _STLP_DUMMY_IMP_DECLSPEC virtual void imbue(const locale&);

public:                         // Locale-related functions.

  _STLP_DUMMY_IMP_DECLSPEC locale pubimbue(const locale&);

  locale getloc() const { return _M_locale; }

# ifndef _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

};

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

// Specialization: basic_streambuf<char, char_traits<char> >

// We implement basic_streambuf<char, char_traits<char> > very differently

// than the general basic_streambuf<> template.  The main reason for this

// difference is a requirement in the C++ standard: the standard input

// and output streams cin and cout are required by default to be synchronized

// with the C library components stdin and stdout.  This means it must be

// possible to synchronize a basic_streambuf<char> with a C buffer.

//

// There are two basic ways to do that.  First, the streambuf could be

// unbuffered and delegate all buffering to stdio operations.  This

// would be correct, but slow: it would require at least one virtual

// function call for every character.  Second, the streambuf could use 

// a C stdio FILE as its buffer.  

//

// We choose the latter option.  Every streambuf has pointers to two

// FILE objects, one for the get area and one for the put area.  Ordinarily

// it just uses a FILE object as a convenient way to package the three

// get/put area pointers.  If a basic_streambuf<char> is synchronized with

// a stdio stream, though, then the pointers are to a FILE object that's

// also used by the C library.

//

// The header <stl/_stdio_file.h> encapsulates the implementation details

// of struct FILE.  It contains low-level inline functions that convert

// between whe FILE's internal representation and the three-pointer 

// representation that basic_streambuf<> needs.

_STLP_TEMPLATE_NULL 

#ifdef __SYMBIAN32__

class basic_streambuf<char, char_traits<char> >

#else

class _STLP_CLASS_DECLSPEC basic_streambuf<char, char_traits<char> >

#endif

{

  friend class basic_istream<char, char_traits<char> >;

  friend class basic_ostream<char, char_traits<char> >;

public:                         // Typedefs.

  typedef char                        char_type;

  typedef char_traits<char>::int_type int_type;

  typedef char_traits<char>::pos_type pos_type;

  typedef char_traits<char>::off_type off_type;

  typedef char_traits<char>           traits_type;

private:                        // Data members.

  FILE* _M_get;                 // Reference to the get area

  FILE* _M_put;                 // Reference to the put area

#if defined(__hpux)

  _FILEX  _M_default_get;          // Get area, unless we're syncing with stdio.

  _FILEX  _M_default_put;          // Put area, unless we're syncing with stdio.

#else

  FILE  _M_default_get;          // Get area, unless we're syncing with stdio.

  FILE  _M_default_put;          // Put area, unless we're syncing with stdio.

#endif

  locale _M_locale;

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

  _STLP_mutex _M_lock;

public:                         // Destructor.

  _STLP_DECLSPEC virtual ~basic_streambuf _STLP_PSPEC2(char, char_traits<char>) ();

public:

  // The default constructor; defined here inline as some compilers require it

  _STLP_DECLSPEC basic_streambuf _STLP_PSPEC2(char, char_traits<char>) ();

  // Extension: a constructor for streambufs synchronized with C stdio files.

  _STLP_DECLSPEC basic_streambuf _STLP_PSPEC2(char, char_traits<char>) (FILE* __get, FILE* __put);

protected:                      // Protected interface to the get area.

  char_type* eback() const { return _FILE_I_begin(_M_get); }

  char_type* gptr()  const { return _FILE_I_next(_M_get); }

  char_type* egptr() const { return _FILE_I_end(_M_get); }

  void gbump(int __n) { _FILE_I_bump(_M_get, __n); }

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

    { 

    _FILE_I_set(_M_get, __gbegin, __gnext, __gend); 

#ifdef __SYMBIAN32__

    _change_input_mode();

#endif

    }

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 _FILE_I_begin(_M_get); }

  char_type* _M_gptr()  const { return _FILE_I_next(_M_get); }

  char_type* _M_egptr() const { return _FILE_I_end(_M_get); }

  void _M_gbump(int __n) { _FILE_I_bump(_M_get, __n); }

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

    { _FILE_I_set(_M_get, __gbegin, __gnext, __gend); }

protected:                      // Protected interface to the put area

  char_type* pbase() const { return _FILE_O_begin(_M_put); }

  char_type* pptr()  const { return _FILE_O_next(_M_put); }

  char_type* epptr() const { return _FILE_O_end(_M_put); }

  void pbump(int __n) { _FILE_O_bump(_M_put, __n); }

  void setp(char_type* __pbegin, char_type* __pend)

    { _FILE_O_set(_M_put, __pbegin, __pbegin, __pend); }

protected:                      // Virtual buffer-management functions.

  _STLP_DECLSPEC virtual basic_streambuf<char, char_traits<char> >* setbuf(char_type*, streamsize);

  _STLP_DECLSPEC virtual pos_type seekoff(off_type, ios_base::seekdir,

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

  _STLP_DECLSPEC  virtual pos_type

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

  _STLP_DECLSPEC virtual int sync();

public:                         // Buffer management.

  basic_streambuf<char, char_traits<char> >* 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.

  _STLP_DECLSPEC virtual streamsize showmanyc();

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

  _STLP_DECLSPEC virtual int_type underflow();

  _STLP_DECLSPEC virtual int_type uflow();

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

protected:                      // Virtual put area functions.

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

  _STLP_DECLSPEC virtual streamsize _M_xsputnc(char_type __c, streamsize __n);

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

#ifdef __SYMBIAN32__  

  virtual int save_read_buffer () { return 0; }

  virtual void _change_input_mode() {};

#endif

public:                         // Public members for writing characters.

  // Write a single character.

  int_type sputc(char_type __c) {

    int_type __res;

	if( _FILE_O_avail(_M_put) > 0 )

	{

		_FILE_O_postincr(_M_put) = __c;

		__res = traits_type::to_int_type(__c);

	}

	else

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

    return __res;

  }

  // 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.

  _STLP_DECLSPEC int_type _M_snextc_aux();

public:                         // Public members for reading characters.

  streamsize in_avail()

    { return _FILE_I_avail(_M_get) > 0 ? _FILE_I_avail(_M_get)

#ifdef __SYMBIAN32__  

                                     + save_read_buffer()

#endif

                                     : this->showmanyc(); }

  // Advance to the next character and return it.

  int_type snextc() {

    return _FILE_I_avail(_M_get) > 1

      ? traits_type::to_int_type(_FILE_I_preincr(_M_get))

      : this->_M_snextc_aux();

  }

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

  int_type sbumpc() {

    return _FILE_I_avail(_M_get) > 0

      ? traits_type::to_int_type(_FILE_I_postincr(_M_get))

      : this->uflow();

  }

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

  int_type sgetc() {

    return _FILE_I_avail(_M_get) > 0

      ? traits_type::to_int_type(*_FILE_I_next(_M_get))

      : this->underflow();

  }

  streamsize sgetn(char_type* __s, streamsize __n)

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

  int_type sputbackc(char_type __c) {

    return _FILE_I_begin(_M_get) < _FILE_I_next(_M_get) &&

           __c == *(_FILE_I_next(_M_get) - 1)

      ? traits_type::to_int_type(_FILE_I_predecr(_M_get))

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

  }

  int_type sungetc() {

    return _FILE_I_begin(_M_get) < _FILE_I_next(_M_get)

      ? traits_type::to_int_type(_FILE_I_predecr(_M_get))

      : this->pbackfail();

  }

protected:                      // Virtual locale functions.

  _STLP_DECLSPEC virtual void imbue(const locale&);

public:                         // Locale-related functions.

  _STLP_DECLSPEC locale pubimbue(const locale&);

  locale getloc() const { return _M_locale; }

# ifndef _STLP_NO_ANACHRONISMS

public:

  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

};

_STLP_END_NAMESPACE