libstdc++
std::basic_stringbuf< _CharT, _Traits, _Alloc > Class Template Reference
Inheritance diagram for std::basic_stringbuf< _CharT, _Traits, _Alloc >:

Public Types

typedef __string_type::size_type __size_type
 
typedef basic_streambuf
< char_type, traits_type > 
__streambuf_type
 
typedef basic_string
< char_type, _Traits, _Alloc > 
__string_type
 
typedef _Alloc allocator_type
 
typedef _CharT char_type
 
typedef traits_type::int_type int_type
 
typedef traits_type::off_type off_type
 
typedef traits_type::pos_type pos_type
 
typedef _Traits traits_type
 

Public Member Functions

 basic_stringbuf (ios_base::openmode __mode=ios_base::in|ios_base::out)
 
 basic_stringbuf (const __string_type &__str, ios_base::openmode __mode=ios_base::in|ios_base::out)
 
locale getloc () const
 
streamsize in_avail ()
 
locale pubimbue (const locale &__loc)
 
int_type sbumpc ()
 
int_type sgetc ()
 
streamsize sgetn (char_type *__s, streamsize __n)
 
int_type snextc ()
 
int_type sputbackc (char_type __c)
 
int_type sputc (char_type __c)
 
streamsize sputn (const char_type *__s, streamsize __n)
 
__string_type str () const
 
void str (const __string_type &__s)
 
int_type sungetc ()
 
__streambuf_typepubsetbuf (char_type *__s, streamsize __n)
 
pos_type pubseekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out)
 
pos_type pubseekpos (pos_type __sp, ios_base::openmode __mode=ios_base::in|ios_base::out)
 
int pubsync ()
 

Protected Member Functions

void __safe_gbump (streamsize __n)
 
void __safe_pbump (streamsize __n)
 
void _M_pbump (char_type *__pbeg, char_type *__pend, off_type __off)
 
void _M_stringbuf_init (ios_base::openmode __mode)
 
void _M_sync (char_type *__base, __size_type __i, __size_type __o)
 
void _M_update_egptr ()
 
void gbump (int __n)
 
virtual void imbue (const locale &)
 
virtual int_type overflow (int_type __c=traits_type::eof())
 
virtual int_type pbackfail (int_type __c=traits_type::eof())
 
void pbump (int __n)
 
virtual pos_type seekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out)
 
virtual pos_type seekpos (pos_type __sp, ios_base::openmode __mode=ios_base::in|ios_base::out)
 
virtual __streambuf_typesetbuf (char_type *__s, streamsize __n)
 
void setg (char_type *__gbeg, char_type *__gnext, char_type *__gend)
 
void setp (char_type *__pbeg, char_type *__pend)
 
virtual streamsize showmanyc ()
 
virtual int sync ()
 
virtual int_type uflow ()
 
virtual int_type underflow ()
 
virtual streamsize xsgetn (char_type *__s, streamsize __n)
 
virtual streamsize xsputn (const char_type *__s, streamsize __n)
 
char_type * eback () const
 
char_type * gptr () const
 
char_type * egptr () const
 
char_type * pbase () const
 
char_type * pptr () const
 
char_type * epptr () const
 

Protected Attributes

locale _M_buf_locale
 
char_type * _M_in_beg
 
char_type * _M_in_cur
 
char_type * _M_in_end
 
ios_base::openmode _M_mode
 
char_type * _M_out_beg
 
char_type * _M_out_cur
 
char_type * _M_out_end
 
__string_type _M_string
 

Detailed Description

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
class std::basic_stringbuf< _CharT, _Traits, _Alloc >

The actual work of input and output (for std::string).

This class associates either or both of its input and output sequences with a sequence of characters, which can be initialized from, or made available as, a std::basic_string. (Paraphrased from [27.7.1]/1.)

For this class, open modes (of type ios_base::openmode) have in set if the input sequence can be read, and out set if the output sequence can be written.

Definition at line 95 of file iosfwd.

Constructor & Destructor Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
std::basic_stringbuf< _CharT, _Traits, _Alloc >::basic_stringbuf ( ios_base::openmode  __mode = ios_base::in | ios_base::out)
inlineexplicit

Starts with an empty string buffer.

Parameters
modeWhether the buffer can read, or write, or both.

The default constructor initializes the parent class using its own default ctor.

Definition at line 94 of file sstream.

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
std::basic_stringbuf< _CharT, _Traits, _Alloc >::basic_stringbuf ( const __string_type __str,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
)
inlineexplicit

Starts with an existing string buffer.

Parameters
strA string to copy as a starting buffer.
modeWhether the buffer can read, or write, or both.

This constructor initializes the parent class using its own default ctor.

Definition at line 107 of file sstream.

Member Function Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::eback ( ) const
inlineprotectedinherited

Access to the get area.

These functions are only available to other protected functions, including derived classes.

  • eback() returns the beginning pointer for the input sequence
  • gptr() returns the next pointer for the input sequence
  • egptr() returns the end pointer for the input sequence

Definition at line 461 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), std::basic_streambuf< char, char_traits< char > >::sputbackc(), and std::basic_streambuf< char, char_traits< char > >::sungetc().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::egptr ( ) const
inlineprotectedinherited

Access to the get area.

These functions are only available to other protected functions, including derived classes.

  • eback() returns the beginning pointer for the input sequence
  • gptr() returns the next pointer for the input sequence
  • egptr() returns the end pointer for the input sequence

Definition at line 467 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_streambuf< char, char_traits< char > >::in_avail(), std::basic_streambuf< char, char_traits< char > >::sbumpc(), std::basic_streambuf< char, char_traits< char > >::sgetc(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::epptr ( ) const
inlineprotectedinherited

Access to the put area.

These functions are only available to other protected functions, including derived classes.

  • pbase() returns the beginning pointer for the output sequence
  • pptr() returns the next pointer for the output sequence
  • epptr() returns the end pointer for the output sequence

Definition at line 514 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sputc().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
void std::basic_streambuf< _CharT, _Traits >::gbump ( int  __n)
inlineprotectedinherited

Moving the read position.

Parameters
nThe delta by which to move.

This just advances the read position without returning any data.

Definition at line 477 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sbumpc(), std::basic_streambuf< char, char_traits< char > >::sputbackc(), std::basic_streambuf< char, char_traits< char > >::sungetc(), and std::basic_streambuf< char, char_traits< char > >::uflow().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
locale std::basic_streambuf< _CharT, _Traits >::getloc ( ) const
inlineinherited

Locale access.

Returns
The current locale in effect.

If pubimbue(loc) has been called, then the most recent loc is returned. Otherwise the global locale in effect at the time of construction is returned.

Definition at line 223 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubimbue().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::gptr ( ) const
inlineprotectedinherited
template<typename _CharT, typename _Traits = char_traits<_CharT>>
virtual void std::basic_streambuf< _CharT, _Traits >::imbue ( const locale )
inlineprotectedvirtualinherited

Changes translations.

Parameters
locA new locale.

Translations done during I/O which depend on the current locale are changed by this call. The standard adds, Between invocations of this function a class derived from streambuf can safely cache results of calls to locale functions and to members of facets so obtained.

Note
Base class version does nothing.

Reimplemented in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 555 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubimbue().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::in_avail ( )
inlineinherited

Looking ahead into the stream.

Returns
The number of characters available.

If a read position is available, returns the number of characters available for reading before the buffer must be refilled. Otherwise returns the derived showmanyc().

Definition at line 263 of file streambuf.

template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::overflow ( int_type  = traits_type::eof())
protectedvirtual

Consumes data from the buffer; writes to the controlled sequence.

Parameters
cAn additional character to consume.
Returns
eof() to indicate failure, something else (usually c, or not_eof())

Informally, this function is called when the output buffer is full (or does not exist, as buffering need not actually be done). If a buffer exists, it is consumed, with some effect on the controlled sequence. (Typically, the buffer is written out to the sequence verbatim.) In either case, the character c is also written out, if c is not eof().

For a formal definition of this function, see a good text such as Langer & Kreft, or [27.5.2.4.5]/3-7.

A functioning output streambuf can be created by overriding only this function (no buffer area will be used).

Note
Base class version does nothing, returns eof().

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 82 of file sstream.tcc.

References std::basic_string< _CharT, _Traits, _Alloc >::assign(), std::max(), std::min(), std::ios_base::out, std::basic_string< _CharT, _Traits, _Alloc >::push_back(), and std::basic_string< _CharT, _Traits, _Alloc >::reserve().

template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::pbackfail ( int_type  = traits_type::eof())
protectedvirtual

Tries to back up the input sequence.

Parameters
cThe character to be inserted back into the sequence.
Returns
eof() on failure, some other value on success
Postcondition
The constraints of gptr(), eback(), and pptr() are the same as for underflow().
Note
Base class version does nothing, returns eof().

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 48 of file sstream.tcc.

References std::ios_base::out.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::pbase ( ) const
inlineprotectedinherited

Access to the put area.

These functions are only available to other protected functions, including derived classes.

  • pbase() returns the beginning pointer for the output sequence
  • pptr() returns the next pointer for the output sequence
  • epptr() returns the end pointer for the output sequence

Definition at line 508 of file streambuf.

Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
void std::basic_streambuf< _CharT, _Traits >::pbump ( int  __n)
inlineprotectedinherited

Moving the write position.

Parameters
nThe delta by which to move.

This just advances the write position without returning any data.

Definition at line 524 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sputc().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::pptr ( ) const
inlineprotectedinherited

Access to the put area.

These functions are only available to other protected functions, including derived classes.

  • pbase() returns the beginning pointer for the output sequence
  • pptr() returns the next pointer for the output sequence
  • epptr() returns the end pointer for the output sequence

Definition at line 511 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sputc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
locale std::basic_streambuf< _CharT, _Traits >::pubimbue ( const locale __loc)
inlineinherited

Entry point for imbue().

Parameters
locThe new locale.
Returns
The previous locale.

Calls the derived imbue(loc).

Definition at line 206 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
pos_type std::basic_streambuf< _CharT, _Traits >::pubseekoff ( off_type  __off,
ios_base::seekdir  __way,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
)
inlineinherited

Entry points for derived buffer functions.

The public versions of pubfoo dispatch to the protected derived foo member functions, passing the arguments (if any) and returning the result unchanged.

Definition at line 240 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
pos_type std::basic_streambuf< _CharT, _Traits >::pubseekpos ( pos_type  __sp,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
)
inlineinherited

Entry points for derived buffer functions.

The public versions of pubfoo dispatch to the protected derived foo member functions, passing the arguments (if any) and returning the result unchanged.

Definition at line 245 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
__streambuf_type* std::basic_streambuf< _CharT, _Traits >::pubsetbuf ( char_type __s,
streamsize  __n 
)
inlineinherited

Entry points for derived buffer functions.

The public versions of pubfoo dispatch to the protected derived foo member functions, passing the arguments (if any) and returning the result unchanged.

Definition at line 236 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int std::basic_streambuf< _CharT, _Traits >::pubsync ( )
inlineinherited

Entry points for derived buffer functions.

The public versions of pubfoo dispatch to the protected derived foo member functions, passing the arguments (if any) and returning the result unchanged.

Definition at line 250 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::sync().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::sbumpc ( )
inlineinherited

Getting the next character.

Returns
The next character, or eof.

If the input read position is available, returns that character and increments the read pointer, otherwise calls and returns uflow().

Definition at line 295 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), std::istreambuf_iterator< _CharT, _Traits >::operator++(), and std::basic_streambuf< char, char_traits< char > >::snextc().

template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff ( off_type  ,
ios_base::seekdir  ,
ios_base::openmode  = ios_base::in | ios_base::out 
)
protectedvirtual

Alters the stream positions.

Each derived class provides its own appropriate behavior.

Note
Base class version does nothing, returns a pos_type that represents an invalid stream position.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 151 of file sstream.tcc.

References std::ios_base::cur, std::ios_base::end, std::ios_base::in, and std::ios_base::out.

template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos ( pos_type  ,
ios_base::openmode  = ios_base::in | ios_base::out 
)
protectedvirtual

Alters the stream positions.

Each derived class provides its own appropriate behavior.

Note
Base class version does nothing, returns a pos_type that represents an invalid stream position.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 199 of file sstream.tcc.

References std::ios_base::in, and std::ios_base::out.

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
virtual __streambuf_type* std::basic_stringbuf< _CharT, _Traits, _Alloc >::setbuf ( char_type *  __s,
streamsize  __n 
)
inlineprotectedvirtual

Manipulates the buffer.

Parameters
sPointer to a buffer area.
nSize of s.
Returns
this

If no buffer has already been created, and both s and n are non-zero, then s is used as a buffer; see http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html for more.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 198 of file sstream.

References std::basic_string< _CharT, _Traits, _Alloc >::clear().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
void std::basic_streambuf< _CharT, _Traits >::setg ( char_type __gbeg,
char_type __gnext,
char_type __gend 
)
inlineprotectedinherited

Setting the three read area pointers.

Parameters
gbegA pointer.
gnextA pointer.
gendA pointer.
Postcondition
gbeg == eback(), gnext == gptr(), and gend == egptr()

Definition at line 488 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), and std::basic_filebuf< char_type, traits_type >::_M_set_buffer().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
void std::basic_streambuf< _CharT, _Traits >::setp ( char_type __pbeg,
char_type __pend 
)
inlineprotectedinherited

Setting the three write area pointers.

Parameters
pbegA pointer.
pendA pointer.
Postcondition
pbeg == pbase(), pbeg == pptr(), and pend == epptr()

Definition at line 534 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_set_buffer().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::sgetc ( )
inlineinherited

Getting the next character.

Returns
The next character, or eof.

If the input read position is available, returns that character, otherwise calls and returns underflow(). Does not move the read position after fetching the character.

Definition at line 317 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), std::basic_istream< _CharT, _Traits >::sentry::sentry(), and std::basic_streambuf< char, char_traits< char > >::snextc().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::sgetn ( char_type __s,
streamsize  __n 
)
inlineinherited

Entry point for xsgetn.

Parameters
sA buffer area.
nA count.

Returns xsgetn(s,n). The effect is to fill s[0] through s[n-1] with characters from the input sequence, if possible.

Definition at line 336 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
virtual streamsize std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc ( )
inlineprotectedvirtual

Investigating the data available.

Returns
An estimate of the number of characters available in the input sequence, or -1.

If it returns a positive value, then successive calls to underflow() will not return traits::eof() until at least that number of characters have been supplied. If showmanyc() returns -1, then calls to underflow() or uflow() will fail. [27.5.2.4.3]/1

Note
Base class version does nothing, returns zero.
The standard adds that the intention is not only that the calls [to underflow or uflow] will not return eof() but that they will return immediately.
The standard adds that the morphemes of showmanyc are es-how-many-see, not show-manic.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 166 of file sstream.

References std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_mode, std::basic_streambuf< _CharT, _Traits >::egptr(), std::basic_streambuf< _CharT, _Traits >::gptr(), and std::ios_base::in.

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::snextc ( )
inlineinherited

Getting the next character.

Returns
The next character, or eof.

Calls sbumpc(), and if that function returns traits::eof(), so does this function. Otherwise, sgetc().

Definition at line 277 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), and std::basic_istream< _CharT, _Traits >::sentry::sentry().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::sputbackc ( char_type  __c)
inlineinherited

Pushing characters back into the input stream.

Parameters
cThe character to push back.
Returns
The previous character, if possible.

Similar to sungetc(), but c is pushed onto the stream instead of the previous character. If successful, the next character fetched from the input stream will be c.

Definition at line 351 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::putback().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::sputc ( char_type  __c)
inlineinherited

Entry point for all single-character output functions.

Parameters
cA character to output.
Returns
c, if possible.

One of two public output functions.

If a write position is available for the output sequence (i.e., the buffer is not full), stores c in that position, increments the position, and returns traits::to_int_type(c). If a write position is not available, returns overflow(c).

Definition at line 403 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::get(), and std::ostreambuf_iterator< _CharT, _Traits >::operator=().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::sputn ( const char_type __s,
streamsize  __n 
)
inlineinherited

Entry point for all single-character output functions.

Parameters
sA buffer read area.
nA count.

One of two public output functions.

Returns xsputn(s,n). The effect is to write s[0] through s[n-1] to the output sequence, if possible.

Definition at line 429 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
__string_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::str ( ) const
inline

Copying out the string buffer.

Returns
A copy of one of the underlying sequences.

If the buffer is only created in input mode, the underlying character sequence is equal to the input sequence; otherwise, it is equal to the output sequence. [27.7.1.2]/1

Definition at line 122 of file sstream.

References std::basic_streambuf< _CharT, _Traits >::egptr(), std::basic_streambuf< _CharT, _Traits >::pbase(), and std::basic_streambuf< _CharT, _Traits >::pptr().

template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
void std::basic_stringbuf< _CharT, _Traits, _Alloc >::str ( const __string_type __s)
inline

Setting a new buffer.

Parameters
sThe string to use as a new sequence.

Deallocates any previous stored sequence, then copies s to use as a new one.

Definition at line 146 of file sstream.

References std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_mode, std::basic_string< _CharT, _Traits, _Alloc >::assign(), std::basic_string< _CharT, _Traits, _Alloc >::data(), and std::basic_string< _CharT, _Traits, _Alloc >::size().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
int_type std::basic_streambuf< _CharT, _Traits >::sungetc ( )
inlineinherited

Moving backwards in the input stream.

Returns
The previous character, if possible.

If a putback position is available, this function decrements the input pointer and returns that character. Otherwise, calls and returns pbackfail(). The effect is to unget the last character gotten.

Definition at line 376 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::unget().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
virtual int std::basic_streambuf< _CharT, _Traits >::sync ( void  )
inlineprotectedvirtualinherited

Synchronizes the buffer arrays with the controlled sequences.

Returns
-1 on failure.

Each derived class provides its own appropriate behavior, including the definition of failure.

Note
Base class version does nothing, returns zero.

Reimplemented in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 606 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubsync().

template<typename _CharT, typename _Traits = char_traits<_CharT>>
virtual int_type std::basic_streambuf< _CharT, _Traits >::uflow ( )
inlineprotectedvirtualinherited

Fetches more data from the controlled sequence.

Returns
The first character from the pending sequence.

Informally, this function does the same thing as underflow(), and in fact is required to call that function. It also returns the new character, like underflow() does. However, this function also moves the read position forward by one.

Reimplemented in __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 679 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sbumpc().

template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::underflow ( )
protectedvirtual

Fetches more data from the controlled sequence.

Returns
The first character from the pending sequence.

Informally, this function is called when the input buffer is exhausted (or does not exist, as buffering need not actually be done). If a buffer exists, it is refilled. In either case, the next available character is returned, or traits::eof() to indicate a null pending sequence.

For a formal definition of the pending sequence, see a good text such as Langer & Kreft, or [27.5.2.4.3]/7-14.

A functioning input streambuf can be created by overriding only this function (no buffer area will be used). For an example, see http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25.html

Note
Base class version does nothing, returns eof().

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 133 of file sstream.tcc.

References std::ios_base::in.

template<typename _CharT , typename _Traits >
streamsize std::basic_streambuf< _CharT, _Traits >::xsgetn ( char_type __s,
streamsize  __n 
)
protectedvirtualinherited

Multiple character extraction.

Parameters
sA buffer area.
nMaximum number of characters to assign.
Returns
The number of characters assigned.

Fills s[0] through s[n-1] with characters from the input sequence, as if by sbumpc(). Stops when either n characters have been copied, or when traits::eof() would be copied.

It is expected that derived classes provide a more efficient implementation by overriding this definition.

Reimplemented in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 47 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char, char_traits< char > >::sgetn().

template<typename _CharT , typename _Traits >
streamsize std::basic_streambuf< _CharT, _Traits >::xsputn ( const char_type __s,
streamsize  __n 
)
protectedvirtualinherited

Multiple character insertion.

Parameters
sA buffer area.
nMaximum number of characters to write.
Returns
The number of characters written.

Writes s[0] through s[n-1] to the output sequence, as if by sputc(). Stops when either n characters have been copied, or when sputc() would return traits::eof().

It is expected that derived classes provide a more efficient implementation by overriding this definition.

Reimplemented in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 81 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char, char_traits< char > >::sputn().

Member Data Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>
locale std::basic_streambuf< _CharT, _Traits >::_M_buf_locale
protectedinherited
template<typename _CharT, typename _Traits = char_traits<_CharT>, typename _Alloc = allocator<_CharT>>
ios_base::openmode std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_mode
protected

Place to stash in || out || in | out settings for current stringbuf.

Definition at line 79 of file sstream.

Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().


The documentation for this class was generated from the following files: