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1 : // Output streams -*- C++ -*-
2 :
3 : // Copyright (C) 1997-2017 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 0 : { 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 0 : { 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 0 : 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
561 462 : __ostream_insert(__out, __s,
562 462 : 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 : template<typename _Ch, typename _Up>
617 : basic_ostream<_Ch, _Up>&
618 : __is_convertible_to_basic_ostream_test(basic_ostream<_Ch, _Up>*);
619 :
620 : template<typename _Tp, typename = void>
621 : struct __is_convertible_to_basic_ostream_impl
622 : {
623 : using __ostream_type = void;
624 : };
625 :
626 : template<typename _Tp>
627 : using __do_is_convertible_to_basic_ostream_impl =
628 : decltype(__is_convertible_to_basic_ostream_test
629 : (declval<typename remove_reference<_Tp>::type*>()));
630 :
631 : template<typename _Tp>
632 : struct __is_convertible_to_basic_ostream_impl
633 : <_Tp,
634 : __void_t<__do_is_convertible_to_basic_ostream_impl<_Tp>>>
635 : {
636 : using __ostream_type =
637 : __do_is_convertible_to_basic_ostream_impl<_Tp>;
638 : };
639 :
640 : template<typename _Tp>
641 : struct __is_convertible_to_basic_ostream
642 : : __is_convertible_to_basic_ostream_impl<_Tp>
643 : {
644 : public:
645 : using type = __not_<is_void<
646 : typename __is_convertible_to_basic_ostream_impl<_Tp>::__ostream_type>>;
647 : constexpr static bool value = type::value;
648 : };
649 :
650 : template<typename _Ostream, typename _Tp, typename = void>
651 : struct __is_insertable : false_type {};
652 :
653 : template<typename _Ostream, typename _Tp>
654 : struct __is_insertable<_Ostream, _Tp,
655 : __void_t<decltype(declval<_Ostream&>()
656 : << declval<const _Tp&>())>>
657 : : true_type {};
658 :
659 : template<typename _Ostream>
660 : using __rvalue_ostream_type =
661 : typename __is_convertible_to_basic_ostream<
662 : _Ostream>::__ostream_type;
663 :
664 : /**
665 : * @brief Generic inserter for rvalue stream
666 : * @param __os An input stream.
667 : * @param __x A reference to the object being inserted.
668 : * @return os
669 : *
670 : * This is just a forwarding function to allow insertion to
671 : * rvalue streams since they won't bind to the inserter functions
672 : * that take an lvalue reference.
673 : */
674 : template<typename _Ostream, typename _Tp>
675 : inline
676 : typename enable_if<__and_<__not_<is_lvalue_reference<_Ostream>>,
677 : __is_convertible_to_basic_ostream<_Ostream>,
678 : __is_insertable<
679 : __rvalue_ostream_type<_Ostream>,
680 : const _Tp&>>::value,
681 : __rvalue_ostream_type<_Ostream>>::type
682 : operator<<(_Ostream&& __os, const _Tp& __x)
683 : {
684 : __rvalue_ostream_type<_Ostream> __ret_os = __os;
685 : __ret_os << __x;
686 : return __ret_os;
687 : }
688 : #endif // C++11
689 :
690 : _GLIBCXX_END_NAMESPACE_VERSION
691 : } // namespace std
692 :
693 : #include <bits/ostream.tcc>
694 :
695 : #endif /* _GLIBCXX_OSTREAM */
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