# ostream

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    00001 // Output streams -*- C++ -*-
    00002
    00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 //
    00032 // ISO C++ 14882: 27.6.2  Output streams
    00033 //
    00034
    00035 /** @file ostream
    00036  *  This is a Standard C++ Library header.
    00037  */
    00038
    00039 #ifndef _GLIBCXX_OSTREAM
    00040 #define _GLIBCXX_OSTREAM 1
    00041
    00042 #pragma GCC system_header
    00043
    00044 #include <ios>
    00045
    00046 namespace std
    00047 {
    00048   // [27.6.2.1] Template class basic_ostream
    00049   /**
    00050    *  @brief  Controlling output.
    00051    *
    00052    *  This is the base class for all output streams.  It provides text
    00053    *  formatting of all builtin types, and communicates with any class
    00054    *  derived from basic_streambuf to do the actual output.
    00055   */
    00056   template<typename _CharT, typename _Traits>
    00057     class basic_ostream : virtual public basic_ios<_CharT, _Traits>
    00058     {
    00059     public:
    00060       // Types (inherited from basic_ios (27.4.4)):
    00061       typedef _CharT                            char_type;
    00062       typedef typename _Traits::int_type        int_type;
    00063       typedef typename _Traits::pos_type        pos_type;
    00064       typedef typename _Traits::off_type        off_type;
    00065       typedef _Traits                           traits_type;
    00066
    00067       // Non-standard Types:
    00068       typedef basic_streambuf<_CharT, _Traits>      __streambuf_type;
    00069       typedef basic_ios<_CharT, _Traits>        __ios_type;
    00070       typedef basic_ostream<_CharT, _Traits>        __ostream_type;
    00071       typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
    00072                                 __num_put_type;
    00073       typedef ctype<_CharT>                     __ctype_type;
    00074
    00075       template<typename _CharT2, typename _Traits2>
    00076         friend basic_ostream<_CharT2, _Traits2>&
    00077         operator<<(basic_ostream<_CharT2, _Traits2>&, _CharT2);
    00078
    00079       template<typename _Traits2>
    00080         friend basic_ostream<char, _Traits2>&
    00081         operator<<(basic_ostream<char, _Traits2>&, char);
    00082
    00083       template<typename _CharT2, typename _Traits2>
    00084         friend basic_ostream<_CharT2, _Traits2>&
    00085         operator<<(basic_ostream<_CharT2, _Traits2>&, const _CharT2*);
    00086
    00087       template<typename _Traits2>
    00088         friend basic_ostream<char, _Traits2>&
    00089         operator<<(basic_ostream<char, _Traits2>&, const char*);
    00090
    00091       template<typename _CharT2, typename _Traits2>
    00092         friend basic_ostream<_CharT2, _Traits2>&
    00093         operator<<(basic_ostream<_CharT2, _Traits2>&, const char*);
    00094
    00095       // [27.6.2.2] constructor/destructor
    00096       /**
    00097        *  @brief  Base constructor.
    00098        *
    00099        *  This ctor is almost never called by the user directly, rather from
    00100        *  derived classes' initialization lists, which pass a pointer to
    00101        *  their own stream buffer.
    00102       */
    00103       explicit
    00104       basic_ostream(__streambuf_type* __sb)
    00105       { this->init(__sb); }
    00106
    00107       /**
    00108        *  @brief  Base destructor.
    00109        *
    00110        *  This does very little apart from providing a virtual base dtor.
    00111       */
    00112       virtual
    00113       ~basic_ostream() { }
    00114
    00115       // [27.6.2.3] prefix/suffix
    00116       class sentry;
    00117       friend class sentry;
    00118
    00119       // [27.6.2.5] formatted output
    00120       // [27.6.2.5.3]  basic_ostream::operator<<
    00121       //@{
    00122       /**
    00123        *  @brief  Interface for manipulators.
    00124        *
    00125        *  Manuipulators such as @c std::endl and @c std::hex use these
    00126        *  functions in constructs like "std::cout << std::endl".  For more
    00127        *  information, see the iomanip header.
    00128       */
    00129       inline __ostream_type&
    00130       operator<<(__ostream_type& (*__pf)(__ostream_type&));
    00131
    00132       inline __ostream_type&
    00133       operator<<(__ios_type& (*__pf)(__ios_type&));
    00134
    00135       inline __ostream_type&
    00136       operator<<(ios_base& (*__pf) (ios_base&));
    00137       //@}
    00138
    00139       // [27.6.2.5.2] arithmetic inserters
    00140       /**
    00141        *  @name Arithmetic Inserters
    00142        *
    00143        *  All the @c operator<< functions (aka <em>formatted output
    00144        *  functions</em>) have some common behavior.  Each starts by
    00145        *  constructing a temporary object of type std::basic_ostream::sentry.
    00146        *  This can have several effects, concluding with the setting of a
    00147        *  status flag; see the sentry documentation for more.
    00148        *
    00149        *  If the sentry status is good, the function tries to generate
    00150        *  whatever data is appropriate for the type of the argument.
    00151        *
    00152        *  If an exception is thrown during insertion, ios_base::badbit
    00153        *  will be turned on in the stream's error state without causing an
    00154        *  ios_base::failure to be thrown.  The original exception will then
    00155        *  be rethrown.
    00156       */
    00157       //@{
    00158       /**
    00159        *  @brief  Basic arithmetic inserters
    00160        *  @param  A variable of builtin type.
    00161        *  @return  @c *this if successful
    00162        *
    00163        *  These functions use the stream's current locale (specifically, the
    00164        *  @c num_get facet) to perform numeric formatting.
    00165       */
    00166       __ostream_type&
    00167       operator<<(long __n);
    00168
    00169       __ostream_type&
    00170       operator<<(unsigned long __n);
    00171
    00172       __ostream_type&
    00173       operator<<(bool __n);
    00174
    00175       __ostream_type&
    00176       operator<<(short __n)
    00177       {
    00178     ios_base::fmtflags __fmt = this->flags() & ios_base::basefield;
    00179     if (__fmt & ios_base::oct || __fmt & ios_base::hex)
    00180       return this->operator<<(static_cast<unsigned long>
    00181                   (static_cast<unsigned short>(__n)));
    00182     else
    00183       return this->operator<<(static_cast<long>(__n));
    00184       }
    00185
    00186       __ostream_type&
    00187       operator<<(unsigned short __n)
    00188       { return this->operator<<(static_cast<unsigned long>(__n)); }
    00189
    00190       __ostream_type&
    00191       operator<<(int __n)
    00192       {
    00193     ios_base::fmtflags __fmt = this->flags() & ios_base::basefield;
    00194     if (__fmt & ios_base::oct || __fmt & ios_base::hex)
    00195       return this->operator<<(static_cast<unsigned long>
    00196                   (static_cast<unsigned int>(__n)));
    00197     else
    00198       return this->operator<<(static_cast<long>(__n));
    00199       }
    00200
    00201       __ostream_type&
    00202       operator<<(unsigned int __n)
    00203       { return this->operator<<(static_cast<unsigned long>(__n)); }
    00204
    00205 #ifdef _GLIBCXX_USE_LONG_LONG
    00206       __ostream_type&
    00207       operator<<(long long __n);
    00208
    00209       __ostream_type&
    00210       operator<<(unsigned long long __n);
    00211 #endif
    00212
    00213       __ostream_type&
    00214       operator<<(double __f);
    00215
    00216       __ostream_type&
    00217       operator<<(float __f)
    00218       { return this->operator<<(static_cast<double>(__f)); }
    00219
    00220       __ostream_type&
    00221       operator<<(long double __f);
    00222
    00223       __ostream_type&
    00224       operator<<(const void* __p);
    00225
    00226       /**
    00227        *  @brief  Extracting from another streambuf.
    00228        *  @param  sb  A pointer to a streambuf
    00229        *
    00230        *  This function behaves like one of the basic arithmetic extractors,
    00231        *  in that it also constructs a sentry object and has the same error
    00232        *  handling behavior.
    00233        *
    00234        *  If @a sb is NULL, the stream will set failbit in its error state.
    00235        *
    00236        *  Characters are extracted from @a sb and inserted into @c *this
    00237        *  until one of the following occurs:
    00238        *
    00239        *  - the input stream reaches end-of-file,
    00240        *  - insertion into the output sequence fails (in this case, the
    00241        *    character that would have been inserted is not extracted), or
    00242        *  - an exception occurs while getting a character from @a sb, which
    00243        *    sets failbit in the error state
    00244        *
    00245        *  If the function inserts no characters, failbit is set.
    00246       */
    00247       __ostream_type&
    00248       operator<<(__streambuf_type* __sb);
    00249       //@}
    00250
    00251       // [27.6.2.6] unformatted output functions
    00252       /**
    00253        *  @name Unformatted Output Functions
    00254        *
    00255        *  All the unformatted output functions have some common behavior.
    00256        *  Each starts by constructing a temporary object of type
    00257        *  std::basic_ostream::sentry.  This has several effects, concluding
    00258        *  with the setting of a status flag; see the sentry documentation
    00259        *  for more.
    00260        *
    00261        *  If the sentry status is good, the function tries to generate
    00262        *  whatever data is appropriate for the type of the argument.
    00263        *
    00264        *  If an exception is thrown during insertion, ios_base::badbit
    00265        *  will be turned on in the stream's error state.  If badbit is on in
    00266        *  the stream's exceptions mask, the exception will be rethrown
    00267        *  without completing its actions.
    00268       */
    00269       //@{
    00270       /**
    00271        *  @brief  Simple insertion.
    00272        *  @param  c  The character to insert.
    00273        *  @return  *this
    00274        *
    00275        *  Tries to insert @a c.
    00276        *
    00277        *  @note  This function is not overloaded on signed char and
    00278        *         unsigned char.
    00279       */
    00280       __ostream_type&
    00281       put(char_type __c);
    00282
    00283       // Core write functionality, without sentry.
    00284       void
    00285       _M_write(const char_type* __s, streamsize __n)
    00286       {
    00287     streamsize __put = this->rdbuf()->sputn(__s, __n);
    00288     if (__put != __n)
    00289       this->setstate(ios_base::badbit);
    00290       }
    00291
    00292       /**
    00293        *  @brief  Character string insertion.
    00294        *  @param  s  The array to insert.
    00295        *  @param  n  Maximum number of characters to insert.
    00296        *  @return  *this
    00297        *
    00298        *  Characters are copied from @a s and inserted into the stream until
    00299        *  one of the following happens:
    00300        *
    00301        *  - @a n characters are inserted
    00302        *  - inserting into the output sequence fails (in this case, badbit
    00303        *    will be set in the stream's error state)
    00304        *
    00305        *  @note  This function is not overloaded on signed char and
    00306        *         unsigned char.
    00307       */
    00308       __ostream_type&
    00309       write(const char_type* __s, streamsize __n);
    00310       //@}
    00311
    00312       /**
    00313        *  @brief  Synchronizing the stream buffer.
    00314        *  @return  *this
    00315        *
    00316        *  If @c rdbuf() is a null pointer, changes nothing.
    00317        *
    00318        *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
    00319        *  sets badbit.
    00320       */
    00321       __ostream_type&
    00322       flush();
    00323
    00324       // [27.6.2.4] seek members
    00325       /**
    00326        *  @brief  Getting the current write position.
    00327        *  @return  A file position object.
    00328        *
    00329        *  If @c fail() is not false, returns @c pos_type(-1) to indicate
    00330        *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
    00331       */
    00332       pos_type
    00333       tellp();
    00334
    00335       /**
    00336        *  @brief  Changing the current write position.
    00337        *  @param  pos  A file position object.
    00338        *  @return  *this
    00339        *
    00340        *  If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos).  If
    00341        *  that function fails, sets failbit.
    00342       */
    00343       __ostream_type&
    00344       seekp(pos_type);
    00345
    00346       /**
    00347        *  @brief  Changing the current write position.
    00348        *  @param  off  A file offset object.
    00349        *  @param  dir  The direction in which to seek.
    00350        *  @return  *this
    00351        *
    00352        *  If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
    00353        *  If that function fails, sets failbit.
    00354       */
    00355        __ostream_type&
    00356       seekp(off_type, ios_base::seekdir);
    00357
    00358     protected:
    00359       explicit
    00360       basic_ostream() { }
    00361     };
    00362
    00363   /**
    00364    *  @brief  Performs setup work for output streams.
    00365    *
    00366    *  Objects of this class are created before all of the standard
    00367    *  inserters are run.  It is responsible for "exception-safe prefix and
    00368    *  suffix operations."  Additional actions may be added by the
    00369    *  implementation, and we list them in
    00370    *  http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5
    00371    *  under [27.6] notes.
    00372   */
    00373   template <typename _CharT, typename _Traits>
    00374     class basic_ostream<_CharT, _Traits>::sentry
    00375     {
    00376       // Data Members:
    00377       bool              _M_ok;
    00378       basic_ostream<_CharT,_Traits>&    _M_os;
    00379
    00380     public:
    00381       /**
    00382        *  @brief  The constructor performs preparatory work.
    00383        *  @param  os  The output stream to guard.
    00384        *
    00385        *  If the stream state is good (@a os.good() is true), then if the
    00386        *  stream is tied to another output stream, @c is.tie()->flush()
    00387        *  is called to synchronize the output sequences.
    00388        *
    00389        *  If the stream state is still good, then the sentry state becomes
    00390        *  true ("okay").
    00391       */
    00392       explicit
    00393       sentry(basic_ostream<_CharT,_Traits>& __os);
    00394
    00395       /**
    00396        *  @brief  Possibly flushes the stream.
    00397        *
    00398        *  If @c ios_base::unitbuf is set in @c os.flags(), and
    00399        *  @c std::uncaught_exception() is true, the sentry destructor calls
    00400        *  @c flush() on the output stream.
    00401       */
    00402       ~sentry()
    00403       {
    00404     // XXX MT
    00405     if (_M_os.flags() & ios_base::unitbuf && !uncaught_exception())
    00406       {
    00407         // Can't call flush directly or else will get into recursive lock.
    00408         if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
    00409           _M_os.setstate(ios_base::badbit);
    00410       }
    00411       }
    00412
    00413       /**
    00414        *  @brief  Quick status checking.
    00415        *  @return  The sentry state.
    00416        *
    00417        *  For ease of use, sentries may be converted to booleans.  The
    00418        *  return value is that of the sentry state (true == okay).
    00419       */
    00420       operator bool() const
    00421       { return _M_ok; }
    00422     };
    00423
    00424   // [27.6.2.5.4] character insertion templates
    00425   //@{
    00426   /**
    00427    *  @brief  Character inserters
    00428    *  @param  out  An output stream.
    00429    *  @param  c  A character.
    00430    *  @return  out
    00431    *
    00432    *  Behaves like one of the formatted arithmetic inserters described in
    00433    *  std::basic_ostream.  After constructing a sentry object with good
    00434    *  status, this function inserts a single character and any required
    00435    *  padding (as determined by [22.2.2.2.2]).  @c out.width(0) is then
    00436    *  called.
    00437    *
    00438    *  If @a c is of type @c char and the character type of the stream is not
    00439    *  @c char, the character is widened before insertion.
    00440   */
    00441   template<typename _CharT, typename _Traits>
    00442     basic_ostream<_CharT, _Traits>&
    00443     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c);
    00444
    00445   template<typename _CharT, typename _Traits>
    00446     basic_ostream<_CharT, _Traits>&
    00447     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
    00448     { return (__out << __out.widen(__c)); }
    00449
    00450   // Specialization
    00451   template <class _Traits>
    00452     basic_ostream<char, _Traits>&
    00453     operator<<(basic_ostream<char, _Traits>& __out, char __c);
    00454
    00455   // Signed and unsigned
    00456   template<class _Traits>
    00457     basic_ostream<char, _Traits>&
    00458     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
    00459     { return (__out << static_cast<char>(__c)); }
    00460
    00461   template<class _Traits>
    00462     basic_ostream<char, _Traits>&
    00463     operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
    00464     { return (__out << static_cast<char>(__c)); }
    00465   //@}
    00466
    00467   //@{
    00468   /**
    00469    *  @brief  String inserters
    00470    *  @param  out  An output stream.
    00471    *  @param  s  A character string.
    00472    *  @return  out
    00473    *  @pre  @a s must be a non-NULL pointer
    00474    *
    00475    *  Behaves like one of the formatted arithmetic inserters described in
    00476    *  std::basic_ostream.  After constructing a sentry object with good
    00477    *  status, this function inserts @c traits::length(s) characters starting
    00478    *  at @a s, widened if necessary, followed by any required padding (as
    00479    *  determined by [22.2.2.2.2]).  @c out.width(0) is then called.
    00480   */
    00481   template<typename _CharT, typename _Traits>
    00482     basic_ostream<_CharT, _Traits>&
    00483     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s);
    00484
    00485   template<typename _CharT, typename _Traits>
    00486     basic_ostream<_CharT, _Traits> &
    00487     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
    00488
    00489   // Partial specializationss
    00490   template<class _Traits>
    00491     basic_ostream<char, _Traits>&
    00492     operator<<(basic_ostream<char, _Traits>& __out, const char* __s);
    00493
    00494   // Signed and unsigned
    00495   template<class _Traits>
    00496     basic_ostream<char, _Traits>&
    00497     operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
    00498     { return (__out << reinterpret_cast<const char*>(__s)); }
    00499
    00500   template<class _Traits>
    00501     basic_ostream<char, _Traits> &
    00502     operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
    00503     { return (__out << reinterpret_cast<const char*>(__s)); }
    00504   //@}
    00505
    00506   // [27.6.2.7] standard basic_ostream manipulators
    00507   /**
    00508    *  @brief  Write a newline and flush the stream.
    00509    *
    00510    *  This manipulator is often mistakenly used when a simple newline is
    00511    *  desired, leading to poor buffering performance.  See
    00512    *  http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more
    00513    *  on this subject.
    00514   */
    00515   template<typename _CharT, typename _Traits>
    00516     basic_ostream<_CharT, _Traits>&
    00517     endl(basic_ostream<_CharT, _Traits>& __os)
    00518     { return flush(__os.put(__os.widen('\n'))); }
    00519
    00520   /**
    00521    *  @brief  Write a null character into the output sequence.
    00522    *
    00523    *  "Null character" is @c CharT() by definition.  For CharT of @c char,
    00524    *  this correctly writes the ASCII @c NUL character string terminator.
    00525   */
    00526   template<typename _CharT, typename _Traits>
    00527     basic_ostream<_CharT, _Traits>&
    00528     ends(basic_ostream<_CharT, _Traits>& __os)
    00529     { return __os.put(_CharT()); }
    00530
    00531   /**
    00532    *  @brief  Flushes the output stream.
    00533    *
    00534    *  This manipulator simply calls the stream's @c flush() member function.
    00535   */
    00536   template<typename _CharT, typename _Traits>
    00537     basic_ostream<_CharT, _Traits>&
    00538     flush(basic_ostream<_CharT, _Traits>& __os)
    00539     { return __os.flush(); }
    00540
    00541 } // namespace std
    00542
    00543 #ifndef _GLIBCXX_EXPORT_TEMPLATE
    00544 # include <bits/ostream.tcc>
    00545 #endif
    00546
    00547 #endif  /* _GLIBCXX_OSTREAM */