libstdc++
std::basic_stringbuf Class Reference
Inheritance diagram for std::basic_stringbuf:

List of all members.

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Friends


Detailed Description

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.


Member Typedef Documentation

This is a non-standard type.

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

Definition at line 73 of file sstream.

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

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

Definition at line 64 of file sstream.

typedef traits_type::int_type std::basic_stringbuf::int_type

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

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

Definition at line 69 of file sstream.

typedef traits_type::off_type std::basic_stringbuf::off_type

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

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

Definition at line 71 of file sstream.

typedef traits_type::pos_type std::basic_stringbuf::pos_type

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

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

Definition at line 70 of file sstream.

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

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

Definition at line 65 of file sstream.


Constructor & Destructor Documentation

std::basic_stringbuf::basic_stringbuf ( ios_base::openmode  __mode = ios_base::in | ios_base::out) [inline, explicit]

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.

std::basic_stringbuf::basic_stringbuf ( const __string_type __str,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
) [inline, explicit]

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

char_type* std::basic_streambuf::eback ( ) const [inline, protected, inherited]

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 462 of file streambuf.

References std::basic_streambuf::_M_in_beg.

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

char_type* std::basic_streambuf::egptr ( ) const [inline, protected, inherited]

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 468 of file streambuf.

References std::basic_streambuf::_M_in_end.

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

char_type* std::basic_streambuf::epptr ( ) const [inline, protected, inherited]

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 515 of file streambuf.

References std::basic_streambuf::_M_out_end.

void std::basic_streambuf::gbump ( int  __n) [inline, protected, inherited]

Moving the read position.

Parameters:
nThe delta by which to move.

This just advances the read position without returning any data.

Definition at line 478 of file streambuf.

References std::basic_streambuf::_M_in_cur.

locale std::basic_streambuf::getloc ( ) const [inline, inherited]

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 224 of file streambuf.

References std::basic_streambuf::_M_buf_locale.

char_type* std::basic_streambuf::gptr ( ) const [inline, protected, inherited]

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 465 of file streambuf.

References std::basic_streambuf::_M_in_cur.

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

virtual void std::basic_streambuf::imbue ( const locale ) [inline, protected, virtual, inherited]

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.

Definition at line 556 of file streambuf.

streamsize std::basic_streambuf::in_avail ( ) [inline, inherited]

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 264 of file streambuf.

References std::basic_streambuf::egptr(), std::basic_streambuf::gptr(), and std::basic_streambuf::showmanyc().

basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf::overflow ( int_type  = traits_type::eof()) [protected, virtual]

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::max(), std::min(), std::basic_string::reserve(), std::basic_string::assign(), and std::basic_string::push_back().

basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf::pbackfail ( int_type  = traits_type::eof()) [protected, virtual]

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.

char_type* std::basic_streambuf::pbase ( ) const [inline, protected, inherited]

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 509 of file streambuf.

References std::basic_streambuf::_M_out_beg.

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

void std::basic_streambuf::pbump ( int  __n) [inline, protected, inherited]

Moving the write position.

Parameters:
nThe delta by which to move.

This just advances the write position without returning any data.

Definition at line 525 of file streambuf.

References std::basic_streambuf::_M_out_cur.

char_type* std::basic_streambuf::pptr ( ) const [inline, protected, inherited]

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 512 of file streambuf.

References std::basic_streambuf::_M_out_cur.

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

locale std::basic_streambuf::pubimbue ( const locale __loc) [inline, inherited]

Entry point for imbue().

Parameters:
locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(loc).

Definition at line 207 of file streambuf.

References std::basic_streambuf::getloc(), std::basic_streambuf::imbue(), and std::basic_streambuf::_M_buf_locale.

pos_type std::basic_streambuf::pubseekoff ( off_type  __off,
ios_base::seekdir  __way,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
) [inline, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 241 of file streambuf.

References std::basic_streambuf::seekoff().

pos_type std::basic_streambuf::pubseekpos ( pos_type  __sp,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
) [inline, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 246 of file streambuf.

References std::basic_streambuf::seekpos().

__streambuf_type* std::basic_streambuf::pubsetbuf ( char_type __s,
streamsize  __n 
) [inline, inherited]

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 237 of file streambuf.

References std::basic_streambuf::setbuf().

int std::basic_streambuf::pubsync ( ) [inline, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 251 of file streambuf.

References std::basic_streambuf::sync().

int_type std::basic_streambuf::sbumpc ( ) [inline, inherited]

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 296 of file streambuf.

References std::basic_streambuf::gptr(), std::basic_streambuf::egptr(), std::basic_streambuf::gbump(), and std::basic_streambuf::uflow().

basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type std::basic_stringbuf::seekoff ( off_type  ,
ios_base::seekdir  ,
ios_base::openmode  = ios_base::in | ios_base::out 
) [protected, virtual]

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::end().

basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type std::basic_stringbuf::seekpos ( pos_type  ,
ios_base::openmode  = ios_base::in | ios_base::out 
) [protected, virtual]

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.

virtual __streambuf_type* std::basic_stringbuf::setbuf ( char_type __s,
streamsize  __n 
) [inline, protected, virtual]

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.

void std::basic_streambuf::setg ( char_type __gbeg,
char_type __gnext,
char_type __gend 
) [inline, protected, inherited]

Setting the three read area pointers.

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

Definition at line 489 of file streambuf.

References std::basic_streambuf::_M_in_beg, std::basic_streambuf::_M_in_cur, and std::basic_streambuf::_M_in_end.

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().

void std::basic_streambuf::setp ( char_type __pbeg,
char_type __pend 
) [inline, protected, inherited]

Setting the three write area pointers.

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

Definition at line 535 of file streambuf.

References std::basic_streambuf::_M_out_beg, std::basic_streambuf::_M_out_cur, and std::basic_streambuf::_M_out_end.

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

int_type std::basic_streambuf::sgetc ( ) [inline, inherited]

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 318 of file streambuf.

References std::basic_streambuf::gptr(), std::basic_streambuf::egptr(), and std::basic_streambuf::underflow().

streamsize std::basic_streambuf::sgetn ( char_type __s,
streamsize  __n 
) [inline, inherited]

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 337 of file streambuf.

References std::basic_streambuf::xsgetn().

virtual streamsize std::basic_stringbuf::showmanyc ( ) [inline, protected, virtual]

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

int_type std::basic_streambuf::snextc ( ) [inline, inherited]

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 278 of file streambuf.

References std::basic_streambuf::sbumpc(), and std::basic_streambuf::sgetc().

int_type std::basic_streambuf::sputbackc ( char_type  __c) [inline, inherited]

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 352 of file streambuf.

References std::basic_streambuf::eback(), std::basic_streambuf::gptr(), std::basic_streambuf::pbackfail(), and std::basic_streambuf::gbump().

int_type std::basic_streambuf::sputc ( char_type  __c) [inline, inherited]

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 404 of file streambuf.

References std::basic_streambuf::pptr(), std::basic_streambuf::epptr(), std::basic_streambuf::pbump(), and std::basic_streambuf::overflow().

streamsize std::basic_streambuf::sputn ( const char_type __s,
streamsize  __n 
) [inline, inherited]

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 430 of file streambuf.

References std::basic_streambuf::xsputn().

__string_type std::basic_stringbuf::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.

Referenced by std::basic_istringstream::str(), std::basic_ostringstream::str(), and std::basic_stringstream::str().

void std::basic_stringbuf::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.

int_type std::basic_streambuf::sungetc ( ) [inline, inherited]

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 377 of file streambuf.

References std::basic_streambuf::eback(), std::basic_streambuf::gptr(), std::basic_streambuf::gbump(), and std::basic_streambuf::pbackfail().

virtual int std::basic_streambuf::sync ( void  ) [inline, protected, virtual, inherited]

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, and __gnu_cxx::stdio_sync_filebuf.

Definition at line 607 of file streambuf.

virtual int_type std::basic_streambuf::uflow ( ) [inline, protected, virtual, inherited]

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.

Definition at line 680 of file streambuf.

References std::basic_streambuf::underflow(), std::basic_streambuf::gptr(), and std::basic_streambuf::gbump().

basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf::underflow ( ) [protected, virtual]

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.

virtual streamsize std::basic_streambuf::xsgetn ( char_type __s,
streamsize  __n 
) [protected, virtual, inherited]

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.

virtual streamsize std::basic_streambuf::xsputn ( const char_type __s,
streamsize  __n 
) [protected, virtual, inherited]

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.


Member Data Documentation

Current locale setting.

Definition at line 190 of file streambuf.

Referenced by std::basic_filebuf::basic_filebuf().

char_type* std::basic_streambuf::_M_in_beg [protected, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 182 of file streambuf.

char_type* std::basic_streambuf::_M_in_cur [protected, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 183 of file streambuf.

char_type* std::basic_streambuf::_M_in_end [protected, inherited]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 184 of file streambuf.

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 >::str(), and showmanyc().

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 185 of file streambuf.

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 186 of file streambuf.

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 187 of file streambuf.


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