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  1. // Output streams -*- C++ -*-
  2.  
  3. // Copyright (C) 1997-2015 Free Software Foundation, Inc.
  4. //
  5. // This file is part of the GNU ISO C++ Library.  This library is free
  6. // software; you can redistribute it and/or modify it under the
  7. // terms of the GNU General Public License as published by the
  8. // Free Software Foundation; either version 3, or (at your option)
  9. // any later version.
  10.  
  11. // This library is distributed in the hope that it will be useful,
  12. // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14. // GNU General Public License for more details.
  15.  
  16. // Under Section 7 of GPL version 3, you are granted additional
  17. // permissions described in the GCC Runtime Library Exception, version
  18. // 3.1, as published by the Free Software Foundation.
  19.  
  20. // You should have received a copy of the GNU General Public License and
  21. // a copy of the GCC Runtime Library Exception along with this program;
  22. // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23. // <http://www.gnu.org/licenses/>.
  24.  
  25. /** @file include/ostream
  26.  *  This is a Standard C++ Library header.
  27.  */
  28.  
  29. //
  30. // ISO C++ 14882: 27.6.2  Output streams
  31. //
  32.  
  33. #ifndef _GLIBCXX_OSTREAM
  34. #define _GLIBCXX_OSTREAM 1
  35.  
  36. #pragma GCC system_header
  37.  
  38. #include <ios>
  39. #include <bits/ostream_insert.h>
  40.  
  41. namespace std _GLIBCXX_VISIBILITY(default)
  42. {
  43. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  44.  
  45.   /**
  46.    *  @brief  Template class basic_ostream.
  47.    *  @ingroup io
  48.    *
  49.    *  @tparam _CharT  Type of character stream.
  50.    *  @tparam _Traits  Traits for character type, defaults to
  51.    *                   char_traits<_CharT>.
  52.    *
  53.    *  This is the base class for all output streams.  It provides text
  54.    *  formatting of all builtin types, and communicates with any class
  55.    *  derived from basic_streambuf to do the actual output.
  56.   */
  57.   template<typename _CharT, typename _Traits>
  58.     class basic_ostream : virtual public basic_ios<_CharT, _Traits>
  59.     {
  60.     public:
  61.       // Types (inherited from basic_ios):
  62.       typedef _CharT                                    char_type;
  63.       typedef typename _Traits::int_type                int_type;
  64.       typedef typename _Traits::pos_type                pos_type;
  65.       typedef typename _Traits::off_type                off_type;
  66.       typedef _Traits                                   traits_type;
  67.  
  68.       // Non-standard Types:
  69.       typedef basic_streambuf<_CharT, _Traits>          __streambuf_type;
  70.       typedef basic_ios<_CharT, _Traits>                __ios_type;
  71.       typedef basic_ostream<_CharT, _Traits>            __ostream_type;
  72.       typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
  73.                                                         __num_put_type;
  74.       typedef ctype<_CharT>                             __ctype_type;
  75.  
  76.       /**
  77.        *  @brief  Base constructor.
  78.        *
  79.        *  This ctor is almost never called by the user directly, rather from
  80.        *  derived classes' initialization lists, which pass a pointer to
  81.        *  their own stream buffer.
  82.       */
  83.       explicit
  84.       basic_ostream(__streambuf_type* __sb)
  85.       { this->init(__sb); }
  86.  
  87.       /**
  88.        *  @brief  Base destructor.
  89.        *
  90.        *  This does very little apart from providing a virtual base dtor.
  91.       */
  92.       virtual
  93.       ~basic_ostream() { }
  94.  
  95.       /// Safe prefix/suffix operations.
  96.       class sentry;
  97.       friend class sentry;
  98.  
  99.       //@{
  100.       /**
  101.        *  @brief  Interface for manipulators.
  102.        *
  103.        *  Manipulators such as @c std::endl and @c std::hex use these
  104.        *  functions in constructs like "std::cout << std::endl".  For more
  105.        *  information, see the iomanip header.
  106.       */
  107.       __ostream_type&
  108.       operator<<(__ostream_type& (*__pf)(__ostream_type&))
  109.       {
  110.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  111.         // DR 60. What is a formatted input function?
  112.         // The inserters for manipulators are *not* formatted output functions.
  113.         return __pf(*this);
  114.       }
  115.  
  116.       __ostream_type&
  117.       operator<<(__ios_type& (*__pf)(__ios_type&))
  118.       {
  119.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  120.         // DR 60. What is a formatted input function?
  121.         // The inserters for manipulators are *not* formatted output functions.
  122.         __pf(*this);
  123.         return *this;
  124.       }
  125.  
  126.       __ostream_type&
  127.       operator<<(ios_base& (*__pf) (ios_base&))
  128.       {
  129.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  130.         // DR 60. What is a formatted input function?
  131.         // The inserters for manipulators are *not* formatted output functions.
  132.         __pf(*this);
  133.         return *this;
  134.       }
  135.       //@}
  136.  
  137.       //@{
  138.       /**
  139.        *  @name Inserters
  140.        *
  141.        *  All the @c operator<< functions (aka <em>formatted output
  142.        *  functions</em>) have some common behavior.  Each starts by
  143.        *  constructing a temporary object of type std::basic_ostream::sentry.
  144.        *  This can have several effects, concluding with the setting of a
  145.        *  status flag; see the sentry documentation for more.
  146.        *
  147.        *  If the sentry status is good, the function tries to generate
  148.        *  whatever data is appropriate for the type of the argument.
  149.        *
  150.        *  If an exception is thrown during insertion, ios_base::badbit
  151.        *  will be turned on in the stream's error state without causing an
  152.        *  ios_base::failure to be thrown.  The original exception will then
  153.        *  be rethrown.
  154.       */
  155.  
  156.       //@{
  157.       /**
  158.        *  @brief Integer arithmetic inserters
  159.        *  @param  __n A variable of builtin integral type.
  160.        *  @return  @c *this if successful
  161.        *
  162.        *  These functions use the stream's current locale (specifically, the
  163.        *  @c num_get facet) to perform numeric formatting.
  164.       */
  165.       __ostream_type&
  166.       operator<<(long __n)
  167.       { return _M_insert(__n); }
  168.  
  169.       __ostream_type&
  170.       operator<<(unsigned long __n)
  171.       { return _M_insert(__n); }
  172.  
  173.       __ostream_type&
  174.       operator<<(bool __n)
  175.       { return _M_insert(__n); }
  176.  
  177.       __ostream_type&
  178.       operator<<(short __n);
  179.  
  180.       __ostream_type&
  181.       operator<<(unsigned short __n)
  182.       {
  183.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  184.         // 117. basic_ostream uses nonexistent num_put member functions.
  185.         return _M_insert(static_cast<unsigned long>(__n));
  186.       }
  187.  
  188.       __ostream_type&
  189.       operator<<(int __n);
  190.  
  191.       __ostream_type&
  192.       operator<<(unsigned int __n)
  193.       {
  194.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  195.         // 117. basic_ostream uses nonexistent num_put member functions.
  196.         return _M_insert(static_cast<unsigned long>(__n));
  197.       }
  198.  
  199. #ifdef _GLIBCXX_USE_LONG_LONG
  200.       __ostream_type&
  201.       operator<<(long long __n)
  202.       { return _M_insert(__n); }
  203.  
  204.       __ostream_type&
  205.       operator<<(unsigned long long __n)
  206.       { return _M_insert(__n); }
  207. #endif
  208.       //@}
  209.  
  210.       //@{
  211.       /**
  212.        *  @brief  Floating point arithmetic inserters
  213.        *  @param  __f A variable of builtin floating point type.
  214.        *  @return  @c *this if successful
  215.        *
  216.        *  These functions use the stream's current locale (specifically, the
  217.        *  @c num_get facet) to perform numeric formatting.
  218.       */
  219.       __ostream_type&
  220.       operator<<(double __f)
  221.       { return _M_insert(__f); }
  222.  
  223.       __ostream_type&
  224.       operator<<(float __f)
  225.       {
  226.         // _GLIBCXX_RESOLVE_LIB_DEFECTS
  227.         // 117. basic_ostream uses nonexistent num_put member functions.
  228.         return _M_insert(static_cast<double>(__f));
  229.       }
  230.  
  231.       __ostream_type&
  232.       operator<<(long double __f)
  233.       { return _M_insert(__f); }
  234.       //@}
  235.  
  236.       /**
  237.        *  @brief  Pointer arithmetic inserters
  238.        *  @param  __p A variable of pointer type.
  239.        *  @return  @c *this if successful
  240.        *
  241.        *  These functions use the stream's current locale (specifically, the
  242.        *  @c num_get facet) to perform numeric formatting.
  243.       */
  244.       __ostream_type&
  245.       operator<<(const void* __p)
  246.       { return _M_insert(__p); }
  247.  
  248.       /**
  249.        *  @brief  Extracting from another streambuf.
  250.        *  @param  __sb  A pointer to a streambuf
  251.        *
  252.        *  This function behaves like one of the basic arithmetic extractors,
  253.        *  in that it also constructs a sentry object and has the same error
  254.        *  handling behavior.
  255.        *
  256.        *  If @p __sb is NULL, the stream will set failbit in its error state.
  257.        *
  258.        *  Characters are extracted from @p __sb and inserted into @c *this
  259.        *  until one of the following occurs:
  260.        *
  261.        *  - the input stream reaches end-of-file,
  262.        *  - insertion into the output sequence fails (in this case, the
  263.        *    character that would have been inserted is not extracted), or
  264.        *  - an exception occurs while getting a character from @p __sb, which
  265.        *    sets failbit in the error state
  266.        *
  267.        *  If the function inserts no characters, failbit is set.
  268.       */
  269.       __ostream_type&
  270.       operator<<(__streambuf_type* __sb);
  271.       //@}
  272.  
  273.       //@{
  274.       /**
  275.        *  @name Unformatted Output Functions
  276.        *
  277.        *  All the unformatted output functions have some common behavior.
  278.        *  Each starts by constructing a temporary object of type
  279.        *  std::basic_ostream::sentry.  This has several effects, concluding
  280.        *  with the setting of a status flag; see the sentry documentation
  281.        *  for more.
  282.        *
  283.        *  If the sentry status is good, the function tries to generate
  284.        *  whatever data is appropriate for the type of the argument.
  285.        *
  286.        *  If an exception is thrown during insertion, ios_base::badbit
  287.        *  will be turned on in the stream's error state.  If badbit is on in
  288.        *  the stream's exceptions mask, the exception will be rethrown
  289.        *  without completing its actions.
  290.       */
  291.  
  292.       /**
  293.        *  @brief  Simple insertion.
  294.        *  @param  __c  The character to insert.
  295.        *  @return  *this
  296.        *
  297.        *  Tries to insert @p __c.
  298.        *
  299.        *  @note  This function is not overloaded on signed char and
  300.        *         unsigned char.
  301.       */
  302.       __ostream_type&
  303.       put(char_type __c);
  304.  
  305.       /**
  306.        *  @brief  Core write functionality, without sentry.
  307.        *  @param  __s  The array to insert.
  308.        *  @param  __n  Maximum number of characters to insert.
  309.       */
  310.       void
  311.       _M_write(const char_type* __s, streamsize __n)
  312.       {
  313.         const streamsize __put = this->rdbuf()->sputn(__s, __n);
  314.         if (__put != __n)
  315.           this->setstate(ios_base::badbit);
  316.       }
  317.  
  318.       /**
  319.        *  @brief  Character string insertion.
  320.        *  @param  __s  The array to insert.
  321.        *  @param  __n  Maximum number of characters to insert.
  322.        *  @return  *this
  323.        *
  324.        *  Characters are copied from @p __s and inserted into the stream until
  325.        *  one of the following happens:
  326.        *
  327.        *  - @p __n characters are inserted
  328.        *  - inserting into the output sequence fails (in this case, badbit
  329.        *    will be set in the stream's error state)
  330.        *
  331.        *  @note  This function is not overloaded on signed char and
  332.        *         unsigned char.
  333.       */
  334.       __ostream_type&
  335.       write(const char_type* __s, streamsize __n);
  336.       //@}
  337.  
  338.       /**
  339.        *  @brief  Synchronizing the stream buffer.
  340.        *  @return  *this
  341.        *
  342.        *  If @c rdbuf() is a null pointer, changes nothing.
  343.        *
  344.        *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
  345.        *  sets badbit.
  346.       */
  347.       __ostream_type&
  348.       flush();
  349.  
  350.       /**
  351.        *  @brief  Getting the current write position.
  352.        *  @return  A file position object.
  353.        *
  354.        *  If @c fail() is not false, returns @c pos_type(-1) to indicate
  355.        *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
  356.       */
  357.       pos_type
  358.       tellp();
  359.  
  360.       /**
  361.        *  @brief  Changing the current write position.
  362.        *  @param  __pos  A file position object.
  363.        *  @return  *this
  364.        *
  365.        *  If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos).  If
  366.        *  that function fails, sets failbit.
  367.       */
  368.       __ostream_type&
  369.       seekp(pos_type);
  370.  
  371.       /**
  372.        *  @brief  Changing the current write position.
  373.        *  @param  __off  A file offset object.
  374.        *  @param  __dir  The direction in which to seek.
  375.        *  @return  *this
  376.        *
  377.        *  If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
  378.        *  If that function fails, sets failbit.
  379.       */
  380.        __ostream_type&
  381.       seekp(off_type, ios_base::seekdir);
  382.  
  383.     protected:
  384.       basic_ostream()
  385.       { this->init(0); }
  386.  
  387. #if __cplusplus >= 201103L
  388.       // Non-standard constructor that does not call init()
  389.       basic_ostream(basic_iostream<_CharT, _Traits>&) { }
  390.  
  391.       basic_ostream(const basic_ostream&) = delete;
  392.  
  393.       basic_ostream(basic_ostream&& __rhs)
  394.       : __ios_type()
  395.       { __ios_type::move(__rhs); }
  396.  
  397.       // 27.7.3.3 Assign/swap
  398.  
  399.       basic_ostream& operator=(const basic_ostream&) = delete;
  400.  
  401.       basic_ostream&
  402.       operator=(basic_ostream&& __rhs)
  403.       {
  404.         swap(__rhs);
  405.         return *this;
  406.       }
  407.  
  408.       void
  409.       swap(basic_ostream& __rhs)
  410.       { __ios_type::swap(__rhs); }
  411. #endif
  412.  
  413.       template<typename _ValueT>
  414.         __ostream_type&
  415.         _M_insert(_ValueT __v);
  416.     };
  417.  
  418.   /**
  419.    *  @brief  Performs setup work for output streams.
  420.    *
  421.    *  Objects of this class are created before all of the standard
  422.    *  inserters are run.  It is responsible for <em>exception-safe prefix and
  423.    *  suffix operations</em>.
  424.   */
  425.   template <typename _CharT, typename _Traits>
  426.     class basic_ostream<_CharT, _Traits>::sentry
  427.     {
  428.       // Data Members.
  429.       bool                              _M_ok;
  430.       basic_ostream<_CharT, _Traits>&   _M_os;
  431.  
  432.     public:
  433.       /**
  434.        *  @brief  The constructor performs preparatory work.
  435.        *  @param  __os  The output stream to guard.
  436.        *
  437.        *  If the stream state is good (@a __os.good() is true), then if the
  438.        *  stream is tied to another output stream, @c is.tie()->flush()
  439.        *  is called to synchronize the output sequences.
  440.        *
  441.        *  If the stream state is still good, then the sentry state becomes
  442.        *  true (@a okay).
  443.       */
  444.       explicit
  445.       sentry(basic_ostream<_CharT, _Traits>& __os);
  446.  
  447.       /**
  448.        *  @brief  Possibly flushes the stream.
  449.        *
  450.        *  If @c ios_base::unitbuf is set in @c os.flags(), and
  451.        *  @c std::uncaught_exception() is true, the sentry destructor calls
  452.        *  @c flush() on the output stream.
  453.       */
  454.       ~sentry()
  455.       {
  456.         // XXX MT
  457.         if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception())
  458.           {
  459.             // Can't call flush directly or else will get into recursive lock.
  460.             if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
  461.               _M_os.setstate(ios_base::badbit);
  462.           }
  463.       }
  464.  
  465.       /**
  466.        *  @brief  Quick status checking.
  467.        *  @return  The sentry state.
  468.        *
  469.        *  For ease of use, sentries may be converted to booleans.  The
  470.        *  return value is that of the sentry state (true == okay).
  471.       */
  472. #if __cplusplus >= 201103L
  473.       explicit
  474. #endif
  475.       operator bool() const
  476.       { return _M_ok; }
  477.     };
  478.  
  479.   //@{
  480.   /**
  481.    *  @brief  Character inserters
  482.    *  @param  __out  An output stream.
  483.    *  @param  __c  A character.
  484.    *  @return  out
  485.    *
  486.    *  Behaves like one of the formatted arithmetic inserters described in
  487.    *  std::basic_ostream.  After constructing a sentry object with good
  488.    *  status, this function inserts a single character and any required
  489.    *  padding (as determined by [22.2.2.2.2]).  @c __out.width(0) is then
  490.    *  called.
  491.    *
  492.    *  If @p __c is of type @c char and the character type of the stream is not
  493.    *  @c char, the character is widened before insertion.
  494.   */
  495.   template<typename _CharT, typename _Traits>
  496.     inline basic_ostream<_CharT, _Traits>&
  497.     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
  498.     { return __ostream_insert(__out, &__c, 1); }
  499.  
  500.   template<typename _CharT, typename _Traits>
  501.     inline basic_ostream<_CharT, _Traits>&
  502.     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
  503.     { return (__out << __out.widen(__c)); }
  504.  
  505.   // Specialization
  506.   template <class _Traits>
  507.     inline basic_ostream<char, _Traits>&
  508.     operator<<(basic_ostream<char, _Traits>& __out, char __c)
  509.     { return __ostream_insert(__out, &__c, 1); }
  510.  
  511.   // Signed and unsigned
  512.   template<class _Traits>
  513.     inline basic_ostream<char, _Traits>&
  514.     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
  515.     { return (__out << static_cast<char>(__c)); }
  516.  
  517.   template<class _Traits>
  518.     inline basic_ostream<char, _Traits>&
  519.     operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
  520.     { return (__out << static_cast<char>(__c)); }
  521.   //@}
  522.  
  523.   //@{
  524.   /**
  525.    *  @brief  String inserters
  526.    *  @param  __out  An output stream.
  527.    *  @param  __s  A character string.
  528.    *  @return  out
  529.    *  @pre  @p __s must be a non-NULL pointer
  530.    *
  531.    *  Behaves like one of the formatted arithmetic inserters described in
  532.    *  std::basic_ostream.  After constructing a sentry object with good
  533.    *  status, this function inserts @c traits::length(__s) characters starting
  534.    *  at @p __s, widened if necessary, followed by any required padding (as
  535.    *  determined by [22.2.2.2.2]).  @c __out.width(0) is then called.
  536.   */
  537.   template<typename _CharT, typename _Traits>
  538.     inline basic_ostream<_CharT, _Traits>&
  539.     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
  540.     {
  541.       if (!__s)
  542.         __out.setstate(ios_base::badbit);
  543.       else
  544.         __ostream_insert(__out, __s,
  545.                          static_cast<streamsize>(_Traits::length(__s)));
  546.       return __out;
  547.     }
  548.  
  549.   template<typename _CharT, typename _Traits>
  550.     basic_ostream<_CharT, _Traits> &
  551.     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
  552.  
  553.   // Partial specializations
  554.   template<class _Traits>
  555.     inline basic_ostream<char, _Traits>&
  556.     operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
  557.     {
  558.       if (!__s)
  559.         __out.setstate(ios_base::badbit);
  560.       else
  561.         __ostream_insert(__out, __s,
  562.                          static_cast<streamsize>(_Traits::length(__s)));
  563.       return __out;
  564.     }
  565.  
  566.   // Signed and unsigned
  567.   template<class _Traits>
  568.     inline basic_ostream<char, _Traits>&
  569.     operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
  570.     { return (__out << reinterpret_cast<const char*>(__s)); }
  571.  
  572.   template<class _Traits>
  573.     inline basic_ostream<char, _Traits> &
  574.     operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
  575.     { return (__out << reinterpret_cast<const char*>(__s)); }
  576.   //@}
  577.  
  578.   // Standard basic_ostream manipulators
  579.  
  580.   /**
  581.    *  @brief  Write a newline and flush the stream.
  582.    *
  583.    *  This manipulator is often mistakenly used when a simple newline is
  584.    *  desired, leading to poor buffering performance.  See
  585.    *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
  586.    *  for more on this subject.
  587.   */
  588.   template<typename _CharT, typename _Traits>
  589.     inline basic_ostream<_CharT, _Traits>&
  590.     endl(basic_ostream<_CharT, _Traits>& __os)
  591.     { return flush(__os.put(__os.widen('\n'))); }
  592.  
  593.   /**
  594.    *  @brief  Write a null character into the output sequence.
  595.    *
  596.    *  <em>Null character</em> is @c CharT() by definition.  For CharT
  597.    *  of @c char, this correctly writes the ASCII @c NUL character
  598.    *  string terminator.
  599.   */
  600.   template<typename _CharT, typename _Traits>
  601.     inline basic_ostream<_CharT, _Traits>&
  602.     ends(basic_ostream<_CharT, _Traits>& __os)
  603.     { return __os.put(_CharT()); }
  604.  
  605.   /**
  606.    *  @brief  Flushes the output stream.
  607.    *
  608.    *  This manipulator simply calls the stream's @c flush() member function.
  609.   */
  610.   template<typename _CharT, typename _Traits>
  611.     inline basic_ostream<_CharT, _Traits>&
  612.     flush(basic_ostream<_CharT, _Traits>& __os)
  613.     { return __os.flush(); }
  614.  
  615. #if __cplusplus >= 201103L
  616.   /**
  617.    *  @brief  Generic inserter for rvalue stream
  618.    *  @param  __os  An input stream.
  619.    *  @param  __x  A reference to the object being inserted.
  620.    *  @return  os
  621.    *
  622.    *  This is just a forwarding function to allow insertion to
  623.    *  rvalue streams since they won't bind to the inserter functions
  624.    *  that take an lvalue reference.
  625.   */
  626.   template<typename _CharT, typename _Traits, typename _Tp>
  627.     inline basic_ostream<_CharT, _Traits>&
  628.     operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x)
  629.     {
  630.       __os << __x;
  631.       return __os;
  632.     }
  633. #endif // C++11
  634.  
  635. _GLIBCXX_END_NAMESPACE_VERSION
  636. } // namespace std
  637.  
  638. #include <bits/ostream.tcc>
  639.  
  640. #endif  /* _GLIBCXX_OSTREAM */
  641.