/*
* 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>
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();
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.
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; }
# 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
class _STLP_CLASS_DECLSPEC basic_streambuf<char, char_traits<char> >
{
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.
virtual ~basic_streambuf _STLP_PSPEC2(char, char_traits<char>) ();
protected: // Constructors.
// The default constructor; defined here inline as some compilers require it
basic_streambuf _STLP_PSPEC2(char, char_traits<char>) ()
: _M_get(__REINTERPRET_CAST(FILE*,&_M_default_get)),
_M_put(__REINTERPRET_CAST(FILE*,&_M_default_put)), _M_locale()
{
// _M_lock._M_initialize();
_FILE_I_set(_M_get, 0, 0, 0);
_FILE_O_set(_M_put, 0, 0, 0);
}
// Extension: a constructor for streambufs synchronized with C stdio files.
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); }
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.
virtual basic_streambuf<char, char_traits<char> >* setbuf(char_type*, streamsize);
virtual pos_type seekoff(off_type, ios_base::seekdir,
ios_base::openmode = ios_base::in | ios_base::out);
virtual pos_type
seekpos(pos_type, ios_base::openmode = ios_base::in | ios_base::out);
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.
virtual streamsize showmanyc();
virtual streamsize xsgetn(char_type* __s, streamsize __n);
virtual int_type underflow();
virtual int_type uflow();
virtual int_type pbackfail(int_type __c = traits_type::eof());
protected: // Virtual put area functions.
virtual streamsize xsputn(const char_type* __s, streamsize __n);
virtual streamsize _M_xsputnc(char_type __c, streamsize __n);
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) {
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.
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)
: 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.
virtual void imbue(const locale&);
public: // Locale-related functions.
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
# 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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