1// Output streams -*- C++ -*- 
2 
3// Copyright (C) 1997-2019 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 
41namespace 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#if __cplusplus >= 201703L 
249 __ostream_type& 
250 operator<<(nullptr_t) 
251 { return *this << "nullptr"; } 
252#endif 
253 
254 /** 
255 * @brief Extracting from another streambuf. 
256 * @param __sb A pointer to a streambuf 
257 * 
258 * This function behaves like one of the basic arithmetic extractors, 
259 * in that it also constructs a sentry object and has the same error 
260 * handling behavior. 
261 * 
262 * If @p __sb is NULL, the stream will set failbit in its error state. 
263 * 
264 * Characters are extracted from @p __sb and inserted into @c *this 
265 * until one of the following occurs: 
266 * 
267 * - the input stream reaches end-of-file, 
268 * - insertion into the output sequence fails (in this case, the 
269 * character that would have been inserted is not extracted), or 
270 * - an exception occurs while getting a character from @p __sb, which 
271 * sets failbit in the error state 
272 * 
273 * If the function inserts no characters, failbit is set. 
274 */ 
275 __ostream_type& 
276 operator<<(__streambuf_type* __sb); 
277 //@} 
278 
279 //@{ 
280 /** 
281 * @name Unformatted Output Functions 
282 * 
283 * All the unformatted output functions have some common behavior. 
284 * Each starts by constructing a temporary object of type 
285 * std::basic_ostream::sentry. This has several effects, concluding 
286 * with the setting of a status flag; see the sentry documentation 
287 * for more. 
288 * 
289 * If the sentry status is good, the function tries to generate 
290 * whatever data is appropriate for the type of the argument. 
291 * 
292 * If an exception is thrown during insertion, ios_base::badbit 
293 * will be turned on in the stream's error state. If badbit is on in 
294 * the stream's exceptions mask, the exception will be rethrown 
295 * without completing its actions. 
296 */ 
297 
298 /** 
299 * @brief Simple insertion. 
300 * @param __c The character to insert. 
301 * @return *this 
302 * 
303 * Tries to insert @p __c. 
304 * 
305 * @note This function is not overloaded on signed char and 
306 * unsigned char. 
307 */ 
308 __ostream_type& 
309 put(char_type __c); 
310 
311 /** 
312 * @brief Core write functionality, without sentry. 
313 * @param __s The array to insert. 
314 * @param __n Maximum number of characters to insert. 
315 */ 
316 void 
317 _M_write(const char_type* __s, streamsize __n) 
318 { 
319 const streamsize __put = this->rdbuf()->sputn(__s, __n); 
320 if (__put != __n) 
321 this->setstate(ios_base::badbit); 
322 } 
323 
324 /** 
325 * @brief Character string insertion. 
326 * @param __s The array to insert. 
327 * @param __n Maximum number of characters to insert. 
328 * @return *this 
329 * 
330 * Characters are copied from @p __s and inserted into the stream until 
331 * one of the following happens: 
332 * 
333 * - @p __n characters are inserted 
334 * - inserting into the output sequence fails (in this case, badbit 
335 * will be set in the stream's error state) 
336 * 
337 * @note This function is not overloaded on signed char and 
338 * unsigned char. 
339 */ 
340 __ostream_type& 
341 write(const char_type* __s, streamsize __n); 
342 //@} 
343 
344 /** 
345 * @brief Synchronizing the stream buffer. 
346 * @return *this 
347 * 
348 * If @c rdbuf() is a null pointer, changes nothing. 
349 * 
350 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 
351 * sets badbit. 
352 */ 
353 __ostream_type& 
354 flush(); 
355 
356 /** 
357 * @brief Getting the current write position. 
358 * @return A file position object. 
359 * 
360 * If @c fail() is not false, returns @c pos_type(-1) to indicate 
361 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 
362 */ 
363 pos_type 
364 tellp(); 
365 
366 /** 
367 * @brief Changing the current write position. 
368 * @param __pos A file position object. 
369 * @return *this 
370 * 
371 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 
372 * that function fails, sets failbit. 
373 */ 
374 __ostream_type& 
375 seekp(pos_type); 
376 
377 /** 
378 * @brief Changing the current write position. 
379 * @param __off A file offset object. 
380 * @param __dir The direction in which to seek. 
381 * @return *this 
382 * 
383 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 
384 * If that function fails, sets failbit. 
385 */ 
386 __ostream_type& 
387 seekp(off_type, ios_base::seekdir); 
388 
389 protected: 
390 basic_ostream() 
391 { this->init(0); } 
392 
393#if __cplusplus >= 201103L 
394 // Non-standard constructor that does not call init() 
395 basic_ostream(basic_iostream<_CharT, _Traits>&) { } 
396 
397 basic_ostream(const basic_ostream&) = delete; 
398 
399 basic_ostream(basic_ostream&& __rhs) 
400 : __ios_type() 
401 { __ios_type::move(__rhs); } 
402 
403 // 27.7.3.3 Assign/swap 
404 
405 basic_ostream& operator=(const basic_ostream&) = delete; 
406 
407 basic_ostream& 
408 operator=(basic_ostream&& __rhs) 
409 { 
410 swap(__rhs); 
411 return *this; 
412 } 
413 
414 void 
415 swap(basic_ostream& __rhs) 
416 { __ios_type::swap(__rhs); } 
417#endif 
418 
419 template<typename _ValueT> 
420 __ostream_type& 
421 _M_insert(_ValueT __v); 
422 }; 
423 
424 /** 
425 * @brief Performs setup work for output streams. 
426 * 
427 * Objects of this class are created before all of the standard 
428 * inserters are run. It is responsible for <em>exception-safe prefix and 
429 * suffix operations</em>. 
430 */ 
431 template <typename _CharT, typename _Traits> 
432 class basic_ostream<_CharT, _Traits>::sentry 
433 { 
434 // Data Members. 
435 bool _M_ok; 
436 basic_ostream<_CharT, _Traits>& _M_os; 
437 
438 public: 
439 /** 
440 * @brief The constructor performs preparatory work. 
441 * @param __os The output stream to guard. 
442 * 
443 * If the stream state is good (@a __os.good() is true), then if the 
444 * stream is tied to another output stream, @c is.tie()->flush() 
445 * is called to synchronize the output sequences. 
446 * 
447 * If the stream state is still good, then the sentry state becomes 
448 * true (@a okay). 
449 */ 
450 explicit 
451 sentry(basic_ostream<_CharT, _Traits>& __os); 
452 
453#pragma GCC diagnostic push 
454#pragma GCC diagnostic ignored "-Wdeprecated-declarations" 
455 /** 
456 * @brief Possibly flushes the stream. 
457 * 
458 * If @c ios_base::unitbuf is set in @c os.flags(), and 
459 * @c std::uncaught_exception() is true, the sentry destructor calls 
460 * @c flush() on the output stream. 
461 */ 
462 ~sentry() 
463 { 
464 // XXX MT 
465 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 
466 { 
467 // Can't call flush directly or else will get into recursive lock. 
468 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 
469 _M_os.setstate(ios_base::badbit); 
470 } 
471 } 
472#pragma GCC diagnostic pop 
473 
474 /** 
475 * @brief Quick status checking. 
476 * @return The sentry state. 
477 * 
478 * For ease of use, sentries may be converted to booleans. The 
479 * return value is that of the sentry state (true == okay). 
480 */ 
481#if __cplusplus >= 201103L 
482 explicit 
483#endif 
484 operator bool() const 
485 { return _M_ok; } 
486 }; 
487 
488 //@{ 
489 /** 
490 * @brief Character inserters 
491 * @param __out An output stream. 
492 * @param __c A character. 
493 * @return out 
494 * 
495 * Behaves like one of the formatted arithmetic inserters described in 
496 * std::basic_ostream. After constructing a sentry object with good 
497 * status, this function inserts a single character and any required 
498 * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then 
499 * called. 
500 * 
501 * If @p __c is of type @c char and the character type of the stream is not 
502 * @c char, the character is widened before insertion. 
503 */ 
504 template<typename _CharT, typename _Traits> 
505 inline basic_ostream<_CharT, _Traits>& 
506 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 
507 { return __ostream_insert(__out, &__c, 1); } 
508 
509 template<typename _CharT, typename _Traits> 
510 inline basic_ostream<_CharT, _Traits>& 
511 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 
512 { return (__out << __out.widen(__c)); } 
513 
514 // Specialization 
515 template <class _Traits> 
516 inline basic_ostream<char, _Traits>& 
517 operator<<(basic_ostream<char, _Traits>& __out, char __c) 
518 { return __ostream_insert(__out, &__c, 1); } 
519 
520 // Signed and unsigned 
521 template<class _Traits> 
522 inline basic_ostream<char, _Traits>& 
523 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 
524 { return (__out << static_cast<char>(__c)); } 
525 
526 template<class _Traits> 
527 inline basic_ostream<char, _Traits>& 
528 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 
529 { return (__out << static_cast<char>(__c)); } 
530 //@} 
531 
532 //@{ 
533 /** 
534 * @brief String inserters 
535 * @param __out An output stream. 
536 * @param __s A character string. 
537 * @return out 
538 * @pre @p __s must be a non-NULL pointer 
539 * 
540 * Behaves like one of the formatted arithmetic inserters described in 
541 * std::basic_ostream. After constructing a sentry object with good 
542 * status, this function inserts @c traits::length(__s) characters starting 
543 * at @p __s, widened if necessary, followed by any required padding (as 
544 * determined by [22.2.2.2.2]). @c __out.width(0) is then called. 
545 */ 
546 template<typename _CharT, typename _Traits> 
547 inline basic_ostream<_CharT, _Traits>& 
548 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 
549 { 
550 if (!__s) 
551 __out.setstate(ios_base::badbit); 
552 else 
553 __ostream_insert(__out, __s, 
554 static_cast<streamsize>(_Traits::length(__s))); 
555 return __out; 
556 } 
557 
558 template<typename _CharT, typename _Traits> 
559 basic_ostream<_CharT, _Traits> & 
560 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 
561 
562 // Partial specializations 
563 template<class _Traits> 
564 inline basic_ostream<char, _Traits>& 
565 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 
566 { 
567 if (!__s) 
568 __out.setstate(ios_base::badbit); 
569 else 
570 __ostream_insert(__out, __s, 
571 static_cast<streamsize>(_Traits::length(__s))); 
572 return __out; 
573 } 
574 
575 // Signed and unsigned 
576 template<class _Traits> 
577 inline basic_ostream<char, _Traits>& 
578 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 
579 { return (__out << reinterpret_cast<const char*>(__s)); } 
580 
581 template<class _Traits> 
582 inline basic_ostream<char, _Traits> & 
583 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 
584 { return (__out << reinterpret_cast<const char*>(__s)); } 
585 //@} 
586 
587 // Standard basic_ostream manipulators 
588 
589 /** 
590 * @brief Write a newline and flush the stream. 
591 * 
592 * This manipulator is often mistakenly used when a simple newline is 
593 * desired, leading to poor buffering performance. See 
594 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering 
595 * for more on this subject. 
596 */ 
597 template<typename _CharT, typename _Traits> 
598 inline basic_ostream<_CharT, _Traits>& 
599 endl(basic_ostream<_CharT, _Traits>& __os) 
600 { return flush(__os.put(__os.widen('\n'))); } 
601 
602 /** 
603 * @brief Write a null character into the output sequence. 
604 * 
605 * <em>Null character</em> is @c CharT() by definition. For CharT 
606 * of @c char, this correctly writes the ASCII @c NUL character 
607 * string terminator. 
608 */ 
609 template<typename _CharT, typename _Traits> 
610 inline basic_ostream<_CharT, _Traits>& 
611 ends(basic_ostream<_CharT, _Traits>& __os) 
612 { return __os.put(_CharT()); } 
613 
614 /** 
615 * @brief Flushes the output stream. 
616 * 
617 * This manipulator simply calls the stream's @c flush() member function. 
618 */ 
619 template<typename _CharT, typename _Traits> 
620 inline basic_ostream<_CharT, _Traits>& 
621 flush(basic_ostream<_CharT, _Traits>& __os) 
622 { return __os.flush(); } 
623 
624#if __cplusplus >= 201103L 
625 template<typename _Ch, typename _Up> 
626 basic_ostream<_Ch, _Up>& 
627 __is_convertible_to_basic_ostream_test(basic_ostream<_Ch, _Up>*); 
628 
629 template<typename _Tp, typename = void> 
630 struct __is_convertible_to_basic_ostream_impl 
631 { 
632 using __ostream_type = void; 
633 }; 
634 
635 template<typename _Tp> 
636 using __do_is_convertible_to_basic_ostream_impl = 
637 decltype(__is_convertible_to_basic_ostream_test 
638 (declval<typename remove_reference<_Tp>::type*>())); 
639 
640 template<typename _Tp> 
641 struct __is_convertible_to_basic_ostream_impl 
642 <_Tp, 
643 __void_t<__do_is_convertible_to_basic_ostream_impl<_Tp>>> 
644 { 
645 using __ostream_type = 
646 __do_is_convertible_to_basic_ostream_impl<_Tp>; 
647 }; 
648 
649 template<typename _Tp> 
650 struct __is_convertible_to_basic_ostream 
651 : __is_convertible_to_basic_ostream_impl<_Tp> 
652 { 
653 public: 
654 using type = __not_<is_void< 
655 typename __is_convertible_to_basic_ostream_impl<_Tp>::__ostream_type>>; 
656 constexpr static bool value = type::value; 
657 }; 
658 
659 template<typename _Ostream, typename _Tp, typename = void> 
660 struct __is_insertable : false_type {}; 
661 
662 template<typename _Ostream, typename _Tp> 
663 struct __is_insertable<_Ostream, _Tp, 
664 __void_t<decltype(declval<_Ostream&>() 
665 << declval<const _Tp&>())>> 
666 : true_type {}; 
667 
668 template<typename _Ostream> 
669 using __rvalue_ostream_type = 
670 typename __is_convertible_to_basic_ostream< 
671 _Ostream>::__ostream_type; 
672 
673 /** 
674 * @brief Generic inserter for rvalue stream 
675 * @param __os An input stream. 
676 * @param __x A reference to the object being inserted. 
677 * @return os 
678 * 
679 * This is just a forwarding function to allow insertion to 
680 * rvalue streams since they won't bind to the inserter functions 
681 * that take an lvalue reference. 
682 */ 
683 template<typename _Ostream, typename _Tp> 
684 inline 
685 typename enable_if<__and_<__not_<is_lvalue_reference<_Ostream>>, 
686 __is_convertible_to_basic_ostream<_Ostream>, 
687 __is_insertable< 
688 __rvalue_ostream_type<_Ostream>, 
689 const _Tp&>>::value, 
690 __rvalue_ostream_type<_Ostream>>::type 
691 operator<<(_Ostream&& __os, const _Tp& __x) 
692 { 
693 __rvalue_ostream_type<_Ostream> __ret_os = __os; 
694 __ret_os << __x; 
695 return __ret_os; 
696 } 
697#endif // C++11 
698 
699_GLIBCXX_END_NAMESPACE_VERSION 
700} // namespace std 
701 
702#include <bits/ostream.tcc> 
703 
704#endif /* _GLIBCXX_OSTREAM */ 
705