1 : // Output streams -*- C++ -*-
2 :
3 : // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
4 : // Free Software Foundation, Inc.
5 : //
6 : // This file is part of the GNU ISO C++ Library. This library is free
7 : // software; you can redistribute it and/or modify it under the
8 : // terms of the GNU General Public License as published by the
9 : // Free Software Foundation; either version 2, or (at your option)
10 : // any later version.
11 :
12 : // This library is distributed in the hope that it will be useful,
13 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : // GNU General Public License for more details.
16 :
17 : // You should have received a copy of the GNU General Public License along
18 : // with this library; see the file COPYING. If not, write to the Free
19 : // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20 : // USA.
21 :
22 : // As a special exception, you may use this file as part of a free software
23 : // library without restriction. Specifically, if other files instantiate
24 : // templates or use macros or inline functions from this file, or you compile
25 : // this file and link it with other files to produce an executable, this
26 : // file does not by itself cause the resulting executable to be covered by
27 : // the GNU General Public License. This exception does not however
28 : // invalidate any other reasons why the executable file might be covered by
29 : // the GNU General Public License.
30 :
31 : //
32 : // ISO C++ 14882: 27.6.2 Output streams
33 : //
34 :
35 : /** @file ostream
36 : * This is a Standard C++ Library header.
37 : */
38 :
39 : #ifndef _GLIBCXX_OSTREAM
40 : #define _GLIBCXX_OSTREAM 1
41 :
42 : #pragma GCC system_header
43 :
44 : #include <ios>
45 :
46 : namespace std
47 : {
48 : // [27.6.2.1] Template class basic_ostream
49 : /**
50 : * @brief Controlling output.
51 : *
52 : * This is the base class for all output streams. It provides text
53 : * formatting of all builtin types, and communicates with any class
54 : * derived from basic_streambuf to do the actual output.
55 : */
56 : template<typename _CharT, typename _Traits>
57 : class basic_ostream : virtual public basic_ios<_CharT, _Traits>
58 : {
59 : public:
60 : // Types (inherited from basic_ios (27.4.4)):
61 : typedef _CharT char_type;
62 : typedef typename _Traits::int_type int_type;
63 : typedef typename _Traits::pos_type pos_type;
64 : typedef typename _Traits::off_type off_type;
65 : typedef _Traits traits_type;
66 :
67 : // Non-standard Types:
68 : typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
69 : typedef basic_ios<_CharT, _Traits> __ios_type;
70 : typedef basic_ostream<_CharT, _Traits> __ostream_type;
71 : typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
72 : __num_put_type;
73 : typedef ctype<_CharT> __ctype_type;
74 :
75 : template<typename _CharT2, typename _Traits2>
76 : friend basic_ostream<_CharT2, _Traits2>&
77 : operator<<(basic_ostream<_CharT2, _Traits2>&, _CharT2);
78 :
79 : template<typename _Traits2>
80 : friend basic_ostream<char, _Traits2>&
81 : operator<<(basic_ostream<char, _Traits2>&, char);
82 :
83 : template<typename _CharT2, typename _Traits2>
84 : friend basic_ostream<_CharT2, _Traits2>&
85 : operator<<(basic_ostream<_CharT2, _Traits2>&, const _CharT2*);
86 :
87 : template<typename _Traits2>
88 : friend basic_ostream<char, _Traits2>&
89 : operator<<(basic_ostream<char, _Traits2>&, const char*);
90 :
91 : template<typename _CharT2, typename _Traits2>
92 : friend basic_ostream<_CharT2, _Traits2>&
93 : operator<<(basic_ostream<_CharT2, _Traits2>&, const char*);
94 :
95 : // [27.6.2.2] constructor/destructor
96 : /**
97 : * @brief Base constructor.
98 : *
99 : * This ctor is almost never called by the user directly, rather from
100 : * derived classes' initialization lists, which pass a pointer to
101 : * their own stream buffer.
102 : */
103 : explicit
104 : basic_ostream(__streambuf_type* __sb)
105 : { this->init(__sb); }
106 :
107 : /**
108 : * @brief Base destructor.
109 : *
110 : * This does very little apart from providing a virtual base dtor.
111 : */
112 : virtual
113 0 : ~basic_ostream() { }
114 :
115 : // [27.6.2.3] prefix/suffix
116 : class sentry;
117 : friend class sentry;
118 :
119 : // [27.6.2.5] formatted output
120 : // [27.6.2.5.3] basic_ostream::operator<<
121 : //@{
122 : /**
123 : * @brief Interface for manipulators.
124 : *
125 : * Manuipulators such as @c std::endl and @c std::hex use these
126 : * functions in constructs like "std::cout << std::endl". For more
127 : * information, see the iomanip header.
128 : */
129 : inline __ostream_type&
130 : operator<<(__ostream_type& (*__pf)(__ostream_type&));
131 :
132 : inline __ostream_type&
133 : operator<<(__ios_type& (*__pf)(__ios_type&));
134 :
135 : inline __ostream_type&
136 : operator<<(ios_base& (*__pf) (ios_base&));
137 : //@}
138 :
139 : // [27.6.2.5.2] arithmetic inserters
140 : /**
141 : * @name Arithmetic Inserters
142 : *
143 : * All the @c operator<< functions (aka <em>formatted output
144 : * functions</em>) have some common behavior. Each starts by
145 : * constructing a temporary object of type std::basic_ostream::sentry.
146 : * This can have several effects, concluding with the setting of a
147 : * status flag; see the sentry documentation for more.
148 : *
149 : * If the sentry status is good, the function tries to generate
150 : * whatever data is appropriate for the type of the argument.
151 : *
152 : * If an exception is thrown during insertion, ios_base::badbit
153 : * will be turned on in the stream's error state without causing an
154 : * ios_base::failure to be thrown. The original exception will then
155 : * be rethrown.
156 : */
157 : //@{
158 : /**
159 : * @brief Basic arithmetic inserters
160 : * @param A variable of builtin type.
161 : * @return @c *this if successful
162 : *
163 : * These functions use the stream's current locale (specifically, the
164 : * @c num_get facet) to perform numeric formatting.
165 : */
166 : __ostream_type&
167 : operator<<(long __n);
168 :
169 : __ostream_type&
170 : operator<<(unsigned long __n);
171 :
172 : __ostream_type&
173 : operator<<(bool __n);
174 :
175 : __ostream_type&
176 : operator<<(short __n);
177 :
178 : __ostream_type&
179 : operator<<(unsigned short __n);
180 :
181 : __ostream_type&
182 : operator<<(int __n);
183 :
184 : __ostream_type&
185 : operator<<(unsigned int __n);
186 :
187 : #ifdef _GLIBCXX_USE_LONG_LONG
188 : __ostream_type&
189 : operator<<(long long __n);
190 :
191 : __ostream_type&
192 : operator<<(unsigned long long __n);
193 : #endif
194 :
195 : __ostream_type&
196 : operator<<(double __f);
197 :
198 : __ostream_type&
199 : operator<<(float __f);
200 :
201 : __ostream_type&
202 : operator<<(long double __f);
203 :
204 : __ostream_type&
205 : operator<<(const void* __p);
206 :
207 : /**
208 : * @brief Extracting from another streambuf.
209 : * @param sb A pointer to a streambuf
210 : *
211 : * This function behaves like one of the basic arithmetic extractors,
212 : * in that it also constructs a sentry object and has the same error
213 : * handling behavior.
214 : *
215 : * If @a sb is NULL, the stream will set failbit in its error state.
216 : *
217 : * Characters are extracted from @a sb and inserted into @c *this
218 : * until one of the following occurs:
219 : *
220 : * - the input stream reaches end-of-file,
221 : * - insertion into the output sequence fails (in this case, the
222 : * character that would have been inserted is not extracted), or
223 : * - an exception occurs while getting a character from @a sb, which
224 : * sets failbit in the error state
225 : *
226 : * If the function inserts no characters, failbit is set.
227 : */
228 : __ostream_type&
229 : operator<<(__streambuf_type* __sb);
230 : //@}
231 :
232 : // [27.6.2.6] unformatted output functions
233 : /**
234 : * @name Unformatted Output Functions
235 : *
236 : * All the unformatted output functions have some common behavior.
237 : * Each starts by constructing a temporary object of type
238 : * std::basic_ostream::sentry. This has several effects, concluding
239 : * with the setting of a status flag; see the sentry documentation
240 : * for more.
241 : *
242 : * If the sentry status is good, the function tries to generate
243 : * whatever data is appropriate for the type of the argument.
244 : *
245 : * If an exception is thrown during insertion, ios_base::badbit
246 : * will be turned on in the stream's error state. If badbit is on in
247 : * the stream's exceptions mask, the exception will be rethrown
248 : * without completing its actions.
249 : */
250 : //@{
251 : /**
252 : * @brief Simple insertion.
253 : * @param c The character to insert.
254 : * @return *this
255 : *
256 : * Tries to insert @a c.
257 : *
258 : * @note This function is not overloaded on signed char and
259 : * unsigned char.
260 : */
261 : __ostream_type&
262 : put(char_type __c);
263 :
264 : // Core write functionality, without sentry.
265 : void
266 : _M_write(const char_type* __s, streamsize __n)
267 : {
268 : streamsize __put = this->rdbuf()->sputn(__s, __n);
269 : if (__put != __n)
270 : this->setstate(ios_base::badbit);
271 : }
272 :
273 : /**
274 : * @brief Character string insertion.
275 : * @param s The array to insert.
276 : * @param n Maximum number of characters to insert.
277 : * @return *this
278 : *
279 : * Characters are copied from @a s and inserted into the stream until
280 : * one of the following happens:
281 : *
282 : * - @a n characters are inserted
283 : * - inserting into the output sequence fails (in this case, badbit
284 : * will be set in the stream's error state)
285 : *
286 : * @note This function is not overloaded on signed char and
287 : * unsigned char.
288 : */
289 : __ostream_type&
290 : write(const char_type* __s, streamsize __n);
291 : //@}
292 :
293 : /**
294 : * @brief Synchronizing the stream buffer.
295 : * @return *this
296 : *
297 : * If @c rdbuf() is a null pointer, changes nothing.
298 : *
299 : * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
300 : * sets badbit.
301 : */
302 : __ostream_type&
303 : flush();
304 :
305 : // [27.6.2.4] seek members
306 : /**
307 : * @brief Getting the current write position.
308 : * @return A file position object.
309 : *
310 : * If @c fail() is not false, returns @c pos_type(-1) to indicate
311 : * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
312 : */
313 : pos_type
314 : tellp();
315 :
316 : /**
317 : * @brief Changing the current write position.
318 : * @param pos A file position object.
319 : * @return *this
320 : *
321 : * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
322 : * that function fails, sets failbit.
323 : */
324 : __ostream_type&
325 : seekp(pos_type);
326 :
327 : /**
328 : * @brief Changing the current write position.
329 : * @param off A file offset object.
330 : * @param dir The direction in which to seek.
331 : * @return *this
332 : *
333 : * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
334 : * If that function fails, sets failbit.
335 : */
336 : __ostream_type&
337 : seekp(off_type, ios_base::seekdir);
338 :
339 : protected:
340 : explicit
341 0 : basic_ostream() { }
342 : };
343 :
344 : /**
345 : * @brief Performs setup work for output streams.
346 : *
347 : * Objects of this class are created before all of the standard
348 : * inserters are run. It is responsible for "exception-safe prefix and
349 : * suffix operations." Additional actions may be added by the
350 : * implementation, and we list them in
351 : * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5
352 : * under [27.6] notes.
353 : */
354 : template <typename _CharT, typename _Traits>
355 : class basic_ostream<_CharT, _Traits>::sentry
356 : {
357 : // Data Members:
358 : bool _M_ok;
359 : basic_ostream<_CharT,_Traits>& _M_os;
360 :
361 : public:
362 : /**
363 : * @brief The constructor performs preparatory work.
364 : * @param os The output stream to guard.
365 : *
366 : * If the stream state is good (@a os.good() is true), then if the
367 : * stream is tied to another output stream, @c is.tie()->flush()
368 : * is called to synchronize the output sequences.
369 : *
370 : * If the stream state is still good, then the sentry state becomes
371 : * true ("okay").
372 : */
373 : explicit
374 : sentry(basic_ostream<_CharT,_Traits>& __os);
375 :
376 : /**
377 : * @brief Possibly flushes the stream.
378 : *
379 : * If @c ios_base::unitbuf is set in @c os.flags(), and
380 : * @c std::uncaught_exception() is true, the sentry destructor calls
381 : * @c flush() on the output stream.
382 : */
383 : ~sentry()
384 : {
385 : // XXX MT
386 : if (_M_os.flags() & ios_base::unitbuf && !uncaught_exception())
387 : {
388 : // Can't call flush directly or else will get into recursive lock.
389 : if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
390 : _M_os.setstate(ios_base::badbit);
391 : }
392 : }
393 :
394 : /**
395 : * @brief Quick status checking.
396 : * @return The sentry state.
397 : *
398 : * For ease of use, sentries may be converted to booleans. The
399 : * return value is that of the sentry state (true == okay).
400 : */
401 : operator bool() const
402 : { return _M_ok; }
403 : };
404 :
405 : // [27.6.2.5.4] character insertion templates
406 : //@{
407 : /**
408 : * @brief Character inserters
409 : * @param out An output stream.
410 : * @param c A character.
411 : * @return out
412 : *
413 : * Behaves like one of the formatted arithmetic inserters described in
414 : * std::basic_ostream. After constructing a sentry object with good
415 : * status, this function inserts a single character and any required
416 : * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then
417 : * called.
418 : *
419 : * If @a c is of type @c char and the character type of the stream is not
420 : * @c char, the character is widened before insertion.
421 : */
422 : template<typename _CharT, typename _Traits>
423 : basic_ostream<_CharT, _Traits>&
424 : operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c);
425 :
426 : template<typename _CharT, typename _Traits>
427 : basic_ostream<_CharT, _Traits>&
428 : operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
429 : { return (__out << __out.widen(__c)); }
430 :
431 : // Specialization
432 : template <class _Traits>
433 : basic_ostream<char, _Traits>&
434 : operator<<(basic_ostream<char, _Traits>& __out, char __c);
435 :
436 : // Signed and unsigned
437 : template<class _Traits>
438 : basic_ostream<char, _Traits>&
439 : operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
440 : { return (__out << static_cast<char>(__c)); }
441 :
442 : template<class _Traits>
443 : basic_ostream<char, _Traits>&
444 : operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
445 : { return (__out << static_cast<char>(__c)); }
446 : //@}
447 :
448 : //@{
449 : /**
450 : * @brief String inserters
451 : * @param out An output stream.
452 : * @param s A character string.
453 : * @return out
454 : * @pre @a s must be a non-NULL pointer
455 : *
456 : * Behaves like one of the formatted arithmetic inserters described in
457 : * std::basic_ostream. After constructing a sentry object with good
458 : * status, this function inserts @c traits::length(s) characters starting
459 : * at @a s, widened if necessary, followed by any required padding (as
460 : * determined by [22.2.2.2.2]). @c out.width(0) is then called.
461 : */
462 : template<typename _CharT, typename _Traits>
463 : basic_ostream<_CharT, _Traits>&
464 : operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s);
465 :
466 : template<typename _CharT, typename _Traits>
467 : basic_ostream<_CharT, _Traits> &
468 : operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
469 :
470 : // Partial specializationss
471 : template<class _Traits>
472 : basic_ostream<char, _Traits>&
473 : operator<<(basic_ostream<char, _Traits>& __out, const char* __s);
474 :
475 : // Signed and unsigned
476 : template<class _Traits>
477 : basic_ostream<char, _Traits>&
478 : operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
479 : { return (__out << reinterpret_cast<const char*>(__s)); }
480 :
481 : template<class _Traits>
482 : basic_ostream<char, _Traits> &
483 : operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
484 : { return (__out << reinterpret_cast<const char*>(__s)); }
485 : //@}
486 :
487 : // [27.6.2.7] standard basic_ostream manipulators
488 : /**
489 : * @brief Write a newline and flush the stream.
490 : *
491 : * This manipulator is often mistakenly used when a simple newline is
492 : * desired, leading to poor buffering performance. See
493 : * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more
494 : * on this subject.
495 : */
496 : template<typename _CharT, typename _Traits>
497 : basic_ostream<_CharT, _Traits>&
498 : endl(basic_ostream<_CharT, _Traits>& __os)
499 : { return flush(__os.put(__os.widen('\n'))); }
500 :
501 : /**
502 : * @brief Write a null character into the output sequence.
503 : *
504 : * "Null character" is @c CharT() by definition. For CharT of @c char,
505 : * this correctly writes the ASCII @c NUL character string terminator.
506 : */
507 : template<typename _CharT, typename _Traits>
508 : basic_ostream<_CharT, _Traits>&
509 : ends(basic_ostream<_CharT, _Traits>& __os)
510 : { return __os.put(_CharT()); }
511 :
512 : /**
513 : * @brief Flushes the output stream.
514 : *
515 : * This manipulator simply calls the stream's @c flush() member function.
516 : */
517 : template<typename _CharT, typename _Traits>
518 : basic_ostream<_CharT, _Traits>&
519 : flush(basic_ostream<_CharT, _Traits>& __os)
520 : { return __os.flush(); }
521 :
522 : } // namespace std
523 :
524 : #ifndef _GLIBCXX_EXPORT_TEMPLATE
525 : # include <bits/ostream.tcc>
526 : #endif
527 :
528 : #endif /* _GLIBCXX_OSTREAM */
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