std::strstreambuf Class Reference

Inheritance diagram for std::strstreambuf:

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List of all members.

Public Types

typedef char_traits< char > Traits
typedef basic_streambuf< char,
Traits
Base
typedef char char_type
typedef char_traits< char > traits_type
typedef traits_type::int_type int_type
typedef traits_type::pos_type pos_type
typedef traits_type::off_type off_type
typedef ctype< char_typectype_type
typedef basic_streambuf< char_type,
traits_type
streambuf_type
typedef traits_type::state_type state_type

Public Member Functions

 strstreambuf (streamsize initial_capacity=0)
 strstreambuf (void *(*alloc)(size_t), void(*__free)(void *))
 strstreambuf (char *__get, streamsize n, char *__put=0)
 strstreambuf (signed char *__get, streamsize n, signed char *__put=0)
 strstreambuf (unsigned char *__get, streamsize n, unsigned char *__put=0)
 strstreambuf (const char *__get, streamsize n)
 strstreambuf (const signed char *__get, streamsize n)
 strstreambuf (const unsigned char *__get, streamsize n)
virtual ~strstreambuf ()
void freeze (bool=true)
char * str ()
int pcount () const
locale pubimbue (const locale &__loc)
 Entry point for imbue().
locale getloc () const
 Locale access.
streambuf_typepubsetbuf (char_type *s, streamsize n)
 Entry points for derived buffer functions.
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 ()
streamsize in_avail ()
 Looking ahead into the stream.
int_type snextc ()
 Getting the next character.
int_type sbumpc ()
 Getting the next character.
int_type sgetc ()
 Getting the next character.
streamsize sgetn (char_type *s, streamsize n)
 Entry point for xsgetn.
int_type sputbackc (char_type c)
 Pushing characters back into the input stream.
int_type sungetc ()
 Moving backwards in the input stream.
int_type sputc (char_type c)
 Entry point for all single-character output functions.
streamsize sputn (const char_type *s, streamsize n)
 Entry point for all single-character output functions.

Protected Member Functions

virtual int_type overflow (int_type c=Traits::eof())
virtual int_type pbackfail (int_type c=Traits::eof())
virtual int_type underflow ()
 Fetches more data from the controlled sequence.
virtual Basesetbuf (char *__buf, streamsize n)
 Maniuplates the buffer.
virtual pos_type seekoff (off_type __off, ios_base::seekdir __dir, ios_base::openmode __mode=ios_base::in|ios_base::out)
virtual pos_type seekpos (pos_type position, ios_base::openmode __mode=ios_base::in|ios_base::out)
 Alters the stream positions.
void M_pback_create ()
void M_pback_destroy () throw ()
void M_in_cur_move (off_type n)
void M_out_cur_move (off_type n)
off_type M_out_buf_size ()
char_typeeback () const
 Access to the get area.
char_typegptr () const
char_typeegptr () const
void gbump (int n)
 Moving the read position.
void setg (char_type *__gbeg, char_type *__gnext, char_type *__gend)
 Setting the three read area pointers.
char_typepbase () const
 Access to the put area.
char_typepptr () const
char_typeepptr () const
void pbump (int n)
 Moving the write position.
void setp (char_type *__pbeg, char_type *__pend)
 Setting the three write area pointers.
virtual void imbue (const locale &)
 Changes translations.
virtual pos_type seekoff (off_type, ios_base::seekdir, ios_base::openmode=ios_base::in|ios_base::out)
 Alters the stream positions.
virtual int sync ()
 Synchronizes the buffer arrays with the controlled sequences.
virtual streamsize showmanyc ()
 Investigating the data available.
virtual streamsize xsgetn (char_type *s, streamsize n)
 Multiple character extraction.
virtual int_type uflow ()
 Fetches more data from the controlled sequence.
virtual int_type pbackfail (int_type=traits_type::eof())
 Tries to back up the input sequence.
virtual streamsize xsputn (const char_type *s, streamsize n)
 Multiple character insertion.
virtual int_type overflow (int_type=traits_type::eof())
 Consumes data from the buffer; writes to the controlled sequence.

Protected Attributes

char_typeM_buf
size_t M_buf_size
size_t M_buf_size_opt
bool M_buf_unified
char_typeM_in_beg
char_typeM_in_cur
char_typeM_in_end
char_typeM_out_beg
char_typeM_out_cur
char_typeM_out_end
ios_base::openmode M_mode
locale M_buf_locale
bool M_buf_locale_init
char_type M_pback [S_pback_size]
char_typeM_pback_cur_save
char_typeM_pback_end_save
bool M_pback_init
fpos< state_typeM_pos

Static Protected Attributes

static const size_t S_pback_size

Private Member Functions

char * M_alloc (size_t)
void M_free (char *)
void M_setup (char *__get, char *__put, streamsize n)

Private Attributes

bool M_dynamic: 1
bool M_frozen: 1
bool M_constant: 1

Friends

class basic_ios< char_type, traits_type >
class basic_istream< char_type, traits_type >
class basic_ostream< char_type, traits_type >
class istreambuf_iterator< char_type, traits_type >
class ostreambuf_iterator< char_type, traits_type >

Detailed Description

Definition at line 62 of file strstream.


Member Typedef Documentation

typedef char std::basic_streambuf< char , char_traits< char > >::char_type [inherited]

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.

Definition at line 134 of file streambuf.


Member Function Documentation

strstreambuf::int_type std::strstreambuf::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 definiton 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++/27_io/howto.html#6

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

Reimplemented from std::basic_streambuf< char, char_traits< char > >.

Definition at line 213 of file strstream.cc.

References std::basic_streambuf< char, char_traits< char > >::eback(), std::basic_streambuf< char, char_traits< char > >::egptr(), std::basic_streambuf< char, char_traits< char > >::gptr(), std::basic_streambuf< char, char_traits< char > >::pptr(), and std::basic_streambuf< char, char_traits< char > >::setg().

basic_streambuf< char, char_traits< char > > * std::strstreambuf::setbuf ( char *  ,
streamsize   
) [protected, virtual]

Maniuplates the buffer.

Each derived class provides its own appropriate behavior. See the next-to-last paragraph of http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more on this function.

Note:
Base class version does nothing, returns this.

Reimplemented from std::basic_streambuf< char, char_traits< char > >.

Definition at line 225 of file strstream.cc.

strstreambuf::pos_type std::strstreambuf::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< char, char_traits< char > >.

Definition at line 298 of file strstream.cc.

References std::ios_base::beg, and seekoff().

locale std::basic_streambuf< char , char_traits< char > >::pubimbue ( const locale __loc  )  [inline, inherited]

Entry point for imbue().

Parameters:
loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).

Definition at line 378 of file streambuf.

locale std::basic_streambuf< char , char_traits< char > >::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 395 of file streambuf.

streambuf_type* std::basic_streambuf< char , char_traits< char > >::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 408 of file streambuf.

streamsize std::basic_streambuf< char , char_traits< char > >::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 435 of file streambuf.

int_type std::basic_streambuf< char , char_traits< char > >::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 462 of file streambuf.

int_type std::basic_streambuf< char , char_traits< char > >::sbumpc (  )  [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().

int_type std::basic_streambuf< char , char_traits< char > >::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 489 of file streambuf.

streamsize std::basic_streambuf< char , char_traits< char > >::sgetn ( char_type s,
streamsize  n 
) [inline, inherited]

Entry point for xsgetn.

Parameters:
s A buffer area.
n A 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 508 of file streambuf.

int_type std::basic_streambuf< char , char_traits< char > >::sputbackc ( char_type  c  )  [inherited]

Pushing characters back into the input stream.

Parameters:
c The 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.

int_type std::basic_streambuf< char , char_traits< char > >::sungetc (  )  [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".

int_type std::basic_streambuf< char , char_traits< char > >::sputc ( char_type  c  )  [inherited]

Entry point for all single-character output functions.

Parameters:
c A 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).

streamsize std::basic_streambuf< char , char_traits< char > >::sputn ( const char_type s,
streamsize  n 
) [inline, inherited]

Entry point for all single-character output functions.

Parameters:
s A buffer read area.
n A 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 564 of file streambuf.

char_type* std::basic_streambuf< char , char_traits< char > >::eback (  )  const [inline, protected, inherited]

Access to the get area.

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

Definition at line 599 of file streambuf.

Referenced by overflow(), pbackfail(), seekoff(), str(), underflow(), and ~strstreambuf().

void std::basic_streambuf< char , char_traits< char > >::gbump ( int  n  )  [inline, protected, inherited]

Moving the read position.

Parameters:
n The delta by which to move.
This just advances the read position without returning any data.

Definition at line 615 of file streambuf.

Referenced by pbackfail().

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

Setting the three read area pointers.

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

Definition at line 626 of file streambuf.

Referenced by M_setup(), overflow(), seekoff(), strstreambuf(), and underflow().

char_type* std::basic_streambuf< char , char_traits< char > >::pbase (  )  const [inline, protected, inherited]

Access to the put area.

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

Definition at line 648 of file streambuf.

Referenced by overflow(), pcount(), and seekoff().

void std::basic_streambuf< char , char_traits< char > >::pbump ( int  n  )  [inline, protected, inherited]

Moving the write position.

Parameters:
n The delta by which to move.
This just advances the write position without returning any data.

Definition at line 664 of file streambuf.

Referenced by overflow(), and seekoff().

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

Setting the three write area pointers.

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

Definition at line 674 of file streambuf.

Referenced by M_setup(), overflow(), seekoff(), and strstreambuf().

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

Changes translations.

Parameters:
loc A 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.

Definition at line 697 of file streambuf.

virtual pos_type std::basic_streambuf< char , char_traits< char > >::seekoff ( off_type  ,
ios_base::seekdir  ,
ios_base::openmode  = ios_base::in | ios_base::out 
) [inline, protected, virtual, inherited]

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.

Definition at line 723 of file streambuf.

virtual int std::basic_streambuf< char , char_traits< char > >::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.

Definition at line 748 of file streambuf.

virtual streamsize std::basic_streambuf< char , char_traits< char > >::showmanyc (  )  [inline, protected, virtual, inherited]

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".

Definition at line 770 of file streambuf.

virtual streamsize std::basic_streambuf< char , char_traits< char > >::xsgetn ( char_type s,
streamsize  n 
) [protected, virtual, inherited]

Multiple character extraction.

Parameters:
s A buffer area.
n Maximum 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.

virtual int_type std::basic_streambuf< char , char_traits< char > >::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.

Definition at line 821 of file streambuf.

virtual int_type std::basic_streambuf< char , char_traits< char > >::pbackfail ( int_type  = traits_type::eof()  )  [inline, protected, virtual, inherited]

Tries to back up the input sequence.

Parameters:
c The 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().

Definition at line 847 of file streambuf.

virtual streamsize std::basic_streambuf< char , char_traits< char > >::xsputn ( const char_type s,
streamsize  n 
) [protected, virtual, inherited]

Multiple character insertion.

Parameters:
s A buffer area.
n Maximum 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.

virtual int_type std::basic_streambuf< char , char_traits< char > >::overflow ( int_type  = traits_type::eof()  )  [inline, protected, virtual, inherited]

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

Parameters:
c An 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 definiton 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().

Definition at line 890 of file streambuf.


The documentation for this class was generated from the following files:
Generated on Sun Jul 29 20:40:06 2007 for libstdc++-v3 Source by  doxygen 1.5.2