1 // Output streams -*- C++ -*-
2
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 // 2006, 2007
5 // Free Software Foundation, Inc.
6 //
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the
9 // terms of the GNU General Public License as published by the
10 // Free Software Foundation; either version 2, or (at your option)
11 // any later version.
12
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License along
19 // with this library; see the file COPYING. If not, write to the Free
20 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
21 // USA.
22
23 // As a special exception, you may use this file as part of a free software
24 // library without restriction. Specifically, if other files instantiate
25 // templates or use macros or inline functions from this file, or you compile
26 // this file and link it with other files to produce an executable, this
27 // file does not by itself cause the resulting executable to be covered by
28 // the GNU General Public License. This exception does not however
29 // invalidate any other reasons why the executable file might be covered by
30 // the GNU General Public License.
31
32 /** @file ostream
33 * This is a Standard C++ Library header.
34 */
35
36 //
37 // ISO C++ 14882: 27.6.2 Output streams
38 //
39
40 #ifndef _GLIBCXX_OSTREAM
41 #define _GLIBCXX_OSTREAM 1
42
43 #pragma GCC system_header
44
45 #include <ios>
46 #include <bits/ostream_insert.h>
47
_GLIBCXX_BEGIN_NAMESPACE(std)48 _GLIBCXX_BEGIN_NAMESPACE(std)
49
50 // [27.6.2.1] Template class basic_ostream
51 /**
52 * @brief Controlling output.
53 *
54 * This is the base class for all output streams. It provides text
55 * formatting of all builtin types, and communicates with any class
56 * derived from basic_streambuf to do the actual output.
57 */
58 template<typename _CharT, typename _Traits>
59 class basic_ostream : virtual public basic_ios<_CharT, _Traits>
60 {
61 public:
62 // Types (inherited from basic_ios (27.4.4)):
63 typedef _CharT char_type;
64 typedef typename _Traits::int_type int_type;
65 typedef typename _Traits::pos_type pos_type;
66 typedef typename _Traits::off_type off_type;
67 typedef _Traits traits_type;
68
69 // Non-standard Types:
70 typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
71 typedef basic_ios<_CharT, _Traits> __ios_type;
72 typedef basic_ostream<_CharT, _Traits> __ostream_type;
73 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
74 __num_put_type;
75 typedef ctype<_CharT> __ctype_type;
76
77 // [27.6.2.2] constructor/destructor
78 /**
79 * @brief Base constructor.
80 *
81 * This ctor is almost never called by the user directly, rather from
82 * derived classes' initialization lists, which pass a pointer to
83 * their own stream buffer.
84 */
85 explicit
86 basic_ostream(__streambuf_type* __sb)
87 { this->init(__sb); }
88
89 /**
90 * @brief Base destructor.
91 *
92 * This does very little apart from providing a virtual base dtor.
93 */
94 virtual
95 ~basic_ostream() { }
96
97 // [27.6.2.3] prefix/suffix
98 class sentry;
99 friend class sentry;
100
101 // [27.6.2.5] formatted output
102 // [27.6.2.5.3] basic_ostream::operator<<
103 //@{
104 /**
105 * @brief Interface for manipulators.
106 *
107 * Manuipulators such as @c std::endl and @c std::hex use these
108 * functions in constructs like "std::cout << std::endl". For more
109 * information, see the iomanip header.
110 */
111 __ostream_type&
112 operator<<(__ostream_type& (*__pf)(__ostream_type&))
113 {
114 // _GLIBCXX_RESOLVE_LIB_DEFECTS
115 // DR 60. What is a formatted input function?
116 // The inserters for manipulators are *not* formatted output functions.
117 return __pf(*this);
118 }
119
120 __ostream_type&
121 operator<<(__ios_type& (*__pf)(__ios_type&))
122 {
123 // _GLIBCXX_RESOLVE_LIB_DEFECTS
124 // DR 60. What is a formatted input function?
125 // The inserters for manipulators are *not* formatted output functions.
126 __pf(*this);
127 return *this;
128 }
129
130 __ostream_type&
131 operator<<(ios_base& (*__pf) (ios_base&))
132 {
133 // _GLIBCXX_RESOLVE_LIB_DEFECTS
134 // DR 60. What is a formatted input function?
135 // The inserters for manipulators are *not* formatted output functions.
136 __pf(*this);
137 return *this;
138 }
139 //@}
140
141 // [27.6.2.5.2] arithmetic inserters
142 /**
143 * @name Arithmetic Inserters
144 *
145 * All the @c operator<< functions (aka <em>formatted output
146 * functions</em>) have some common behavior. Each starts by
147 * constructing a temporary object of type std::basic_ostream::sentry.
148 * This can have several effects, concluding with the setting of a
149 * status flag; see the sentry documentation for more.
150 *
151 * If the sentry status is good, the function tries to generate
152 * whatever data is appropriate for the type of the argument.
153 *
154 * If an exception is thrown during insertion, ios_base::badbit
155 * will be turned on in the stream's error state without causing an
156 * ios_base::failure to be thrown. The original exception will then
157 * be rethrown.
158 */
159 //@{
160 /**
161 * @brief Basic arithmetic inserters
162 * @param A variable of builtin type.
163 * @return @c *this if successful
164 *
165 * These functions use the stream's current locale (specifically, the
166 * @c num_get facet) to perform numeric formatting.
167 */
168 __ostream_type&
169 operator<<(long __n)
170 { return _M_insert(__n); }
171
172 __ostream_type&
173 operator<<(unsigned long __n)
174 { return _M_insert(__n); }
175
176 __ostream_type&
177 operator<<(bool __n)
178 { return _M_insert(__n); }
179
180 __ostream_type&
181 operator<<(short __n);
182
183 __ostream_type&
184 operator<<(unsigned short __n)
185 {
186 // _GLIBCXX_RESOLVE_LIB_DEFECTS
187 // 117. basic_ostream uses nonexistent num_put member functions.
188 return _M_insert(static_cast<unsigned long>(__n));
189 }
190
191 __ostream_type&
192 operator<<(int __n);
193
194 __ostream_type&
195 operator<<(unsigned int __n)
196 {
197 // _GLIBCXX_RESOLVE_LIB_DEFECTS
198 // 117. basic_ostream uses nonexistent num_put member functions.
199 return _M_insert(static_cast<unsigned long>(__n));
200 }
201
202 #ifdef _GLIBCXX_USE_LONG_LONG
203 __ostream_type&
204 operator<<(long long __n)
205 { return _M_insert(__n); }
206
207 __ostream_type&
208 operator<<(unsigned long long __n)
209 { return _M_insert(__n); }
210 #endif
211
212 __ostream_type&
213 operator<<(double __f)
214 { return _M_insert(__f); }
215
216 __ostream_type&
217 operator<<(float __f)
218 {
219 // _GLIBCXX_RESOLVE_LIB_DEFECTS
220 // 117. basic_ostream uses nonexistent num_put member functions.
221 return _M_insert(static_cast<double>(__f));
222 }
223
224 __ostream_type&
225 operator<<(long double __f)
226 { return _M_insert(__f); }
227
228 __ostream_type&
229 operator<<(const void* __p)
230 { return _M_insert(__p); }
231
232 /**
233 * @brief Extracting from another streambuf.
234 * @param sb A pointer to a streambuf
235 *
236 * This function behaves like one of the basic arithmetic extractors,
237 * in that it also constructs a sentry object and has the same error
238 * handling behavior.
239 *
240 * If @a sb is NULL, the stream will set failbit in its error state.
241 *
242 * Characters are extracted from @a sb and inserted into @c *this
243 * until one of the following occurs:
244 *
245 * - the input stream reaches end-of-file,
246 * - insertion into the output sequence fails (in this case, the
247 * character that would have been inserted is not extracted), or
248 * - an exception occurs while getting a character from @a sb, which
249 * sets failbit in the error state
250 *
251 * If the function inserts no characters, failbit is set.
252 */
253 __ostream_type&
254 operator<<(__streambuf_type* __sb);
255 //@}
256
257 // [27.6.2.6] unformatted output functions
258 /**
259 * @name Unformatted Output Functions
260 *
261 * All the unformatted output functions have some common behavior.
262 * Each starts by constructing a temporary object of type
263 * std::basic_ostream::sentry. This has several effects, concluding
264 * with the setting of a status flag; see the sentry documentation
265 * for more.
266 *
267 * If the sentry status is good, the function tries to generate
268 * whatever data is appropriate for the type of the argument.
269 *
270 * If an exception is thrown during insertion, ios_base::badbit
271 * will be turned on in the stream's error state. If badbit is on in
272 * the stream's exceptions mask, the exception will be rethrown
273 * without completing its actions.
274 */
275 //@{
276 /**
277 * @brief Simple insertion.
278 * @param c The character to insert.
279 * @return *this
280 *
281 * Tries to insert @a c.
282 *
283 * @note This function is not overloaded on signed char and
284 * unsigned char.
285 */
286 __ostream_type&
287 put(char_type __c);
288
289 // Core write functionality, without sentry.
290 void
291 _M_write(const char_type* __s, streamsize __n)
292 {
293 const streamsize __put = this->rdbuf()->sputn(__s, __n);
294 if (__put != __n)
295 this->setstate(ios_base::badbit);
296 }
297
298 /**
299 * @brief Character string insertion.
300 * @param s The array to insert.
301 * @param n Maximum number of characters to insert.
302 * @return *this
303 *
304 * Characters are copied from @a s and inserted into the stream until
305 * one of the following happens:
306 *
307 * - @a n characters are inserted
308 * - inserting into the output sequence fails (in this case, badbit
309 * will be set in the stream's error state)
310 *
311 * @note This function is not overloaded on signed char and
312 * unsigned char.
313 */
314 __ostream_type&
315 write(const char_type* __s, streamsize __n);
316 //@}
317
318 /**
319 * @brief Synchronizing the stream buffer.
320 * @return *this
321 *
322 * If @c rdbuf() is a null pointer, changes nothing.
323 *
324 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
325 * sets badbit.
326 */
327 __ostream_type&
328 flush();
329
330 // [27.6.2.4] seek members
331 /**
332 * @brief Getting the current write position.
333 * @return A file position object.
334 *
335 * If @c fail() is not false, returns @c pos_type(-1) to indicate
336 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
337 */
338 pos_type
339 tellp();
340
341 /**
342 * @brief Changing the current write position.
343 * @param pos A file position object.
344 * @return *this
345 *
346 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
347 * that function fails, sets failbit.
348 */
349 __ostream_type&
350 seekp(pos_type);
351
352 /**
353 * @brief Changing the current write position.
354 * @param off A file offset object.
355 * @param dir The direction in which to seek.
356 * @return *this
357 *
358 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
359 * If that function fails, sets failbit.
360 */
361 __ostream_type&
362 seekp(off_type, ios_base::seekdir);
363
364 protected:
365 explicit
366 basic_ostream() { }
367
368 template<typename _ValueT>
369 __ostream_type&
370 _M_insert(_ValueT __v);
371 };
372
373 /**
374 * @brief Performs setup work for output streams.
375 *
376 * Objects of this class are created before all of the standard
377 * inserters are run. It is responsible for "exception-safe prefix and
378 * suffix operations." Additional actions may be added by the
379 * implementation, and we list them in
380 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5
381 * under [27.6] notes.
382 */
383 template <typename _CharT, typename _Traits>
384 class basic_ostream<_CharT, _Traits>::sentry
385 {
386 // Data Members:
387 bool _M_ok;
388 basic_ostream<_CharT, _Traits>& _M_os;
389
390 public:
391 /**
392 * @brief The constructor performs preparatory work.
393 * @param os The output stream to guard.
394 *
395 * If the stream state is good (@a os.good() is true), then if the
396 * stream is tied to another output stream, @c is.tie()->flush()
397 * is called to synchronize the output sequences.
398 *
399 * If the stream state is still good, then the sentry state becomes
400 * true ("okay").
401 */
402 explicit
403 sentry(basic_ostream<_CharT, _Traits>& __os);
404
405 /**
406 * @brief Possibly flushes the stream.
407 *
408 * If @c ios_base::unitbuf is set in @c os.flags(), and
409 * @c std::uncaught_exception() is true, the sentry destructor calls
410 * @c flush() on the output stream.
411 */
~sentry()412 ~sentry()
413 {
414 // XXX MT
415 if (_M_os.flags() & ios_base::unitbuf && !uncaught_exception())
416 {
417 // Can't call flush directly or else will get into recursive lock.
418 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
419 _M_os.setstate(ios_base::badbit);
420 }
421 }
422
423 /**
424 * @brief Quick status checking.
425 * @return The sentry state.
426 *
427 * For ease of use, sentries may be converted to booleans. The
428 * return value is that of the sentry state (true == okay).
429 */
430 operator bool() const
431 { return _M_ok; }
432 };
433
434 // [27.6.2.5.4] character insertion templates
435 //@{
436 /**
437 * @brief Character inserters
438 * @param out An output stream.
439 * @param c A character.
440 * @return out
441 *
442 * Behaves like one of the formatted arithmetic inserters described in
443 * std::basic_ostream. After constructing a sentry object with good
444 * status, this function inserts a single character and any required
445 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then
446 * called.
447 *
448 * If @a c is of type @c char and the character type of the stream is not
449 * @c char, the character is widened before insertion.
450 */
451 template<typename _CharT, typename _Traits>
452 inline basic_ostream<_CharT, _Traits>&
453 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
454 { return __ostream_insert(__out, &__c, 1); }
455
456 template<typename _CharT, typename _Traits>
457 inline basic_ostream<_CharT, _Traits>&
458 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
459 { return (__out << __out.widen(__c)); }
460
461 // Specialization
462 template <class _Traits>
463 inline basic_ostream<char, _Traits>&
464 operator<<(basic_ostream<char, _Traits>& __out, char __c)
465 { return __ostream_insert(__out, &__c, 1); }
466
467 // Signed and unsigned
468 template<class _Traits>
469 inline basic_ostream<char, _Traits>&
470 operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
471 { return (__out << static_cast<char>(__c)); }
472
473 template<class _Traits>
474 inline basic_ostream<char, _Traits>&
475 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
476 { return (__out << static_cast<char>(__c)); }
477 //@}
478
479 //@{
480 /**
481 * @brief String inserters
482 * @param out An output stream.
483 * @param s A character string.
484 * @return out
485 * @pre @a s must be a non-NULL pointer
486 *
487 * Behaves like one of the formatted arithmetic inserters described in
488 * std::basic_ostream. After constructing a sentry object with good
489 * status, this function inserts @c traits::length(s) characters starting
490 * at @a s, widened if necessary, followed by any required padding (as
491 * determined by [22.2.2.2.2]). @c out.width(0) is then called.
492 */
493 template<typename _CharT, typename _Traits>
494 inline basic_ostream<_CharT, _Traits>&
495 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
496 {
497 if (!__s)
498 __out.setstate(ios_base::badbit);
499 else
500 __ostream_insert(__out, __s,
501 static_cast<streamsize>(_Traits::length(__s)));
502 return __out;
503 }
504
505 template<typename _CharT, typename _Traits>
506 basic_ostream<_CharT, _Traits> &
507 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
508
509 // Partial specializationss
510 template<class _Traits>
511 inline basic_ostream<char, _Traits>&
512 operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
513 {
514 if (!__s)
515 __out.setstate(ios_base::badbit);
516 else
517 __ostream_insert(__out, __s,
518 static_cast<streamsize>(_Traits::length(__s)));
519 return __out;
520 }
521
522 // Signed and unsigned
523 template<class _Traits>
524 inline basic_ostream<char, _Traits>&
525 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
526 { return (__out << reinterpret_cast<const char*>(__s)); }
527
528 template<class _Traits>
529 inline basic_ostream<char, _Traits> &
530 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
531 { return (__out << reinterpret_cast<const char*>(__s)); }
532 //@}
533
534 // [27.6.2.7] standard basic_ostream manipulators
535 /**
536 * @brief Write a newline and flush the stream.
537 *
538 * This manipulator is often mistakenly used when a simple newline is
539 * desired, leading to poor buffering performance. See
540 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more
541 * on this subject.
542 */
543 template<typename _CharT, typename _Traits>
544 inline basic_ostream<_CharT, _Traits>&
endl(basic_ostream<_CharT,_Traits> & __os)545 endl(basic_ostream<_CharT, _Traits>& __os)
546 { return flush(__os.put(__os.widen('\n'))); }
547
548 /**
549 * @brief Write a null character into the output sequence.
550 *
551 * "Null character" is @c CharT() by definition. For CharT of @c char,
552 * this correctly writes the ASCII @c NUL character string terminator.
553 */
554 template<typename _CharT, typename _Traits>
555 inline basic_ostream<_CharT, _Traits>&
ends(basic_ostream<_CharT,_Traits> & __os)556 ends(basic_ostream<_CharT, _Traits>& __os)
557 { return __os.put(_CharT()); }
558
559 /**
560 * @brief Flushes the output stream.
561 *
562 * This manipulator simply calls the stream's @c flush() member function.
563 */
564 template<typename _CharT, typename _Traits>
565 inline basic_ostream<_CharT, _Traits>&
flush(basic_ostream<_CharT,_Traits> & __os)566 flush(basic_ostream<_CharT, _Traits>& __os)
567 { return __os.flush(); }
568
569 _GLIBCXX_END_NAMESPACE
570
571 #ifndef _GLIBCXX_EXPORT_TEMPLATE
572 # include <bits/ostream.tcc>
573 #endif
574
575 #endif /* _GLIBCXX_OSTREAM */
576