| __gnu_cxx::enc_filebuf< _CharT >(3cxx) | __gnu_cxx::enc_filebuf< _CharT >(3cxx) |
NAME¶
__gnu_cxx::enc_filebuf< _CharT > -SYNOPSIS¶
Inherits std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >.Public Types¶
typedef codecvt< char_type,
Public Member Functions¶
enc_filebuf (state_type &__state)
Protected Member Functions¶
void __safe_gbump (streamsize __n)
char_type * eback () const
char_type * pbase () const
Protected Attributes¶
char_type * _M_buf
char_type _M_pback
locale pubimbue (const locale &__loc)
Detailed Description¶
template<typename _CharT>class __gnu_cxx::enc_filebuf< _CharT >¶
class enc_filebuf. Definition at line 42 of file enc_filebuf.h.Member Function Documentation¶
void std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_create_pback () [inline], [protected], [inherited]¶
Initializes pback buffers, and moves normal buffers to safety. Assumptions: _M_in_cur has already been moved back Definition at line 174 of file fstream.void std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_destroy_pback () throw () [inline], [protected], [inherited]¶
Deactivates pback buffer contents, and restores normal buffer. Assumptions: The pback buffer has only moved forward. Definition at line 191 of file fstream.void std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_set_buffer ( streamsize__off) [inline], [protected], [inherited]¶
This function sets the pointers of the internal buffer, both get and put areas. Typically: __off == egptr() - eback() upon underflow/uflow ( read mode); __off == 0 upon overflow ( write mode); __off == -1 upon open, setbuf, seekoff/pos ( uncommitted mode). NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size reflects the actual allocated memory and the last cell is reserved for the overflow char of a full put area. Definition at line 392 of file fstream.__filebuf_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::close () [inherited]¶
Closes the currently associated file. Returns:this on success, NULL on failure
If no file is currently open, this function immediately fails.
If a put buffer area exists, overflow(eof) is called to flush all the
characters. The file is then closed.
If any operations fail, this function also fails.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
void std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 478 of file streambuf.
locale std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
virtual void std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::imbue (const locale &) [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.
streamsize std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
bool std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::is_open () const throw () [inline], [inherited]¶
Returns true if the external file is open. Definition at line 224 of file fstream.__filebuf_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::open (const char *__s, ios_base::openmode__mode) [inherited]¶
Opens an external file. Parameters:s The name of the file.
mode The open mode flags.
Returns:
this on success, NULL on failure
If a file is already open, this function immediately fails. Otherwise it tries
to open the file named s using the flags given in mode.
Table 92, adapted here, gives the relation between openmode combinations and the
equivalent fopen() flags. (NB: lines app, in|out|app, in|app, binary|app,
binary|in|out|app, and binary|in|app per DR 596)
+---------------------------------------------------------+ | ios_base Flag
combination stdio equivalent | |binary in out trunc app |
+---------------------------------------------------------+ | + w | | + + a |
| + a | | + + w | | + r | | + + r+ | | + + + w+ | | + + + a+ | | + + a+ |
+---------------------------------------------------------+ | + + wb | | + + +
ab | | + + ab | | + + + wb | | + + rb | | + + + r+b | | + + + + w+b | | + + +
+ a+b | | + + + a+b |
+---------------------------------------------------------+
__filebuf_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::open (const std::string &__s, ios_base::openmode__mode) [inline], [inherited]¶
Opens an external file. Parameters:s The name of the file.
mode The open mode flags.
Returns:
this on success, NULL on failure
virtual int_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::overflow (int_type = _Traits::eof()) [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 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().
virtual int_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::pbackfail (int_type = _Traits::eof()) [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().
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
void std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 525 of file streambuf.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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
locale std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 207 of file streambuf.
pos_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::pubseekoff ( off_type__off, ios_base::seekdir__way, ios_base::openmode__mode = ios_base::in | ios_base::out) [inline], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 241 of file streambuf.
pos_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::pubseekpos ( pos_type__sp, ios_base::openmode__mode = ios_base::in | ios_base::out) [inline], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 246 of file streambuf.
__streambuf_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.int std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::pubsync () [inline], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 251 of file streambuf.
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
virtual pos_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::seekoff (off_type, ios_base::seekdir, ios_base::openmode = ios_base::in | ios_base::out) [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.
virtual pos_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::seekpos (pos_type, ios_base::openmode = ios_base::in | ios_base::out) [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.
virtual __streambuf_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::setbuf (char_type *__s, streamsize__n) [protected], [virtual], [inherited]¶
Manipulates the buffer. Parameters:s Pointer to a buffer area.
n Size of s.
Returns:
this
If no file has been opened, and both s and n are zero, then the
stream becomes unbuffered. Otherwise, s is used as a buffer; see
http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html for more.
Reimplemented from std::basic_streambuf< _CharT, encoding_char_traits<
_CharT > >.
void std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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()
void std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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()
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
streamsize std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 337 of file streambuf.
virtual streamsize std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::showmanyc () [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.
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::sputbackc ( char_type__c) [inline], [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.
Definition at line 352 of file streambuf.
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::sputc ( char_type__c) [inline], [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).
Definition at line 404 of file streambuf.
streamsize std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 430 of file streambuf.
int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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.
virtual int std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::sync (void) [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.
virtual int_type std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::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 680 of file streambuf.
virtual int_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::underflow () [protected], [virtual], [inherited]¶
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().
virtual streamsize std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::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.
Reimplemented from std::basic_streambuf< _CharT, encoding_char_traits<
_CharT > >.
virtual streamsize std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::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.
Reimplemented from std::basic_streambuf< _CharT, encoding_char_traits<
_CharT > >.
Member Data Documentation¶
char_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_buf [protected], [inherited]¶
Pointer to the beginning of internal buffer. Definition at line 111 of file fstream.locale std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_buf_locale [protected], [inherited]¶
Current locale setting. Definition at line 190 of file streambuf.size_t std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_buf_size [protected], [inherited]¶
Actual size of internal buffer. This number is equal to the size of the put area + 1 position, reserved for the overflow char of a full area. Definition at line 118 of file fstream.char* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_ext_buf [protected], [inherited]¶
Buffer for external characters. Used for input when codecvt::always_noconv() == false. When valid, this corresponds to eback(). Definition at line 153 of file fstream.streamsize std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_ext_buf_size [protected], [inherited]¶
Size of buffer held by _M_ext_buf. Definition at line 158 of file fstream.const char* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_ext_next [protected], [inherited]¶
Pointers into the buffer held by _M_ext_buf that delimit a subsequence of bytes that have been read but not yet converted. When valid, _M_ext_next corresponds to egptr(). Definition at line 165 of file fstream.char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_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
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_in_cur [protected], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 183 of file streambuf.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_in_end [protected], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 184 of file streambuf.
ios_base::openmode std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_mode [protected], [inherited]¶
Place to stash in || out || in | out settings for current filebuf. Definition at line 96 of file fstream.char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_out_beg [protected], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 185 of file streambuf.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_out_cur [protected], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 186 of file streambuf.
char_type* std::basic_streambuf< _CharT, encoding_char_traits< _CharT > >::_M_out_end [protected], [inherited]¶
Entry point for imbue(). Parameters:loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(loc).
Definition at line 187 of file streambuf.
char_type std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_pback [protected], [inherited]¶
Necessary bits for putback buffer management. Note:pbacks of over one character are not currently
supported.
char_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_pback_cur_save [protected], [inherited]¶
Necessary bits for putback buffer management. Note:pbacks of over one character are not currently
supported.
char_type* std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_pback_end_save [protected], [inherited]¶
Necessary bits for putback buffer management. Note:pbacks of over one character are not currently
supported.
bool std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_pback_init [protected], [inherited]¶
Necessary bits for putback buffer management. Note:pbacks of over one character are not currently
supported.
bool std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >::_M_reading [protected], [inherited]¶
_M_reading == false && _M_writing == false for uncommitted mode; _M_reading == true for read mode; _M_writing == true for write mode; NB: _M_reading == true && _M_writing == true is unused. Definition at line 130 of file fstream.Author¶
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