1 // String based streams -*- C++ -*-
2
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
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 /** @file sstream
32 * This is a Standard C++ Library header.
33 */
34
35 //
36 // ISO C++ 14882: 27.7 String-based streams
37 //
38
39 #ifndef _GLIBCXX_SSTREAM
40 #define _GLIBCXX_SSTREAM 1
41
42 #pragma GCC system_header
43
44 #include <istream>
45 #include <ostream>
46
_GLIBCXX_BEGIN_NAMESPACE(std)47 _GLIBCXX_BEGIN_NAMESPACE(std)
48
49 // [27.7.1] template class basic_stringbuf
50 /**
51 * @brief The actual work of input and output (for std::string).
52 *
53 * This class associates either or both of its input and output sequences
54 * with a sequence of characters, which can be initialized from, or made
55 * available as, a @c std::basic_string. (Paraphrased from [27.7.1]/1.)
56 *
57 * For this class, open modes (of type @c ios_base::openmode) have
58 * @c in set if the input sequence can be read, and @c out set if the
59 * output sequence can be written.
60 */
61 template<typename _CharT, typename _Traits, typename _Alloc>
62 class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
63 {
64 public:
65 // Types:
66 typedef _CharT char_type;
67 typedef _Traits traits_type;
68 // _GLIBCXX_RESOLVE_LIB_DEFECTS
69 // 251. basic_stringbuf missing allocator_type
70 typedef _Alloc allocator_type;
71 typedef typename traits_type::int_type int_type;
72 typedef typename traits_type::pos_type pos_type;
73 typedef typename traits_type::off_type off_type;
74
75 typedef basic_streambuf<char_type, traits_type> __streambuf_type;
76 typedef basic_string<char_type, _Traits, _Alloc> __string_type;
77 typedef typename __string_type::size_type __size_type;
78
79 protected:
80 /**
81 * @if maint
82 * Place to stash in || out || in | out settings for current stringbuf.
83 * @endif
84 */
85 ios_base::openmode _M_mode;
86
87 // Data Members:
88 __string_type _M_string;
89
90 public:
91 // Constructors:
92 /**
93 * @brief Starts with an empty string buffer.
94 * @param mode Whether the buffer can read, or write, or both.
95 *
96 * The default constructor initializes the parent class using its
97 * own default ctor.
98 */
99 explicit
100 basic_stringbuf(ios_base::openmode __mode = ios_base::in | ios_base::out)
101 : __streambuf_type(), _M_mode(__mode), _M_string()
102 { }
103
104 /**
105 * @brief Starts with an existing string buffer.
106 * @param str A string to copy as a starting buffer.
107 * @param mode Whether the buffer can read, or write, or both.
108 *
109 * This constructor initializes the parent class using its
110 * own default ctor.
111 */
112 explicit
113 basic_stringbuf(const __string_type& __str,
114 ios_base::openmode __mode = ios_base::in | ios_base::out)
115 : __streambuf_type(), _M_mode(), _M_string(__str.data(), __str.size())
116 { _M_stringbuf_init(__mode); }
117
118 // Get and set:
119 /**
120 * @brief Copying out the string buffer.
121 * @return A copy of one of the underlying sequences.
122 *
123 * "If the buffer is only created in input mode, the underlying
124 * character sequence is equal to the input sequence; otherwise, it
125 * is equal to the output sequence." [27.7.1.2]/1
126 */
127 __string_type
128 str() const
129 {
130 __string_type __ret;
131 if (this->pptr())
132 {
133 // The current egptr() may not be the actual string end.
134 if (this->pptr() > this->egptr())
135 __ret = __string_type(this->pbase(), this->pptr());
136 else
137 __ret = __string_type(this->pbase(), this->egptr());
138 }
139 else
140 __ret = _M_string;
141 return __ret;
142 }
143
144 /**
145 * @brief Setting a new buffer.
146 * @param s The string to use as a new sequence.
147 *
148 * Deallocates any previous stored sequence, then copies @a s to
149 * use as a new one.
150 */
151 void
152 str(const __string_type& __s)
153 {
154 // Cannot use _M_string = __s, since v3 strings are COW.
155 _M_string.assign(__s.data(), __s.size());
156 _M_stringbuf_init(_M_mode);
157 }
158
159 protected:
160 // Common initialization code goes here.
161 void
162 _M_stringbuf_init(ios_base::openmode __mode)
163 {
164 _M_mode = __mode;
165 __size_type __len = 0;
166 if (_M_mode & (ios_base::ate | ios_base::app))
167 __len = _M_string.size();
168 _M_sync(const_cast<char_type*>(_M_string.data()), 0, __len);
169 }
170
171 virtual streamsize
172 showmanyc()
173 {
174 streamsize __ret = -1;
175 if (_M_mode & ios_base::in)
176 {
177 _M_update_egptr();
178 __ret = this->egptr() - this->gptr();
179 }
180 return __ret;
181 }
182
183 virtual int_type
184 underflow();
185
186 virtual int_type
187 pbackfail(int_type __c = traits_type::eof());
188
189 virtual int_type
190 overflow(int_type __c = traits_type::eof());
191
192 /**
193 * @brief Manipulates the buffer.
194 * @param s Pointer to a buffer area.
195 * @param n Size of @a s.
196 * @return @c this
197 *
198 * If no buffer has already been created, and both @a s and @a n are
199 * non-zero, then @c s is used as a buffer; see
200 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2
201 * for more.
202 */
203 virtual __streambuf_type*
204 setbuf(char_type* __s, streamsize __n)
205 {
206 if (__s && __n >= 0)
207 {
208 // This is implementation-defined behavior, and assumes
209 // that an external char_type array of length __n exists
210 // and has been pre-allocated. If this is not the case,
211 // things will quickly blow up.
212
213 // Step 1: Destroy the current internal array.
214 _M_string.clear();
215
216 // Step 2: Use the external array.
217 _M_sync(__s, __n, 0);
218 }
219 return this;
220 }
221
222 virtual pos_type
223 seekoff(off_type __off, ios_base::seekdir __way,
224 ios_base::openmode __mode = ios_base::in | ios_base::out);
225
226 virtual pos_type
227 seekpos(pos_type __sp,
228 ios_base::openmode __mode = ios_base::in | ios_base::out);
229
230 // Internal function for correctly updating the internal buffer
231 // for a particular _M_string, due to initialization or re-sizing
232 // of an existing _M_string.
233 void
234 _M_sync(char_type* __base, __size_type __i, __size_type __o);
235
236 // Internal function for correctly updating egptr() to the actual
237 // string end.
238 void
239 _M_update_egptr()
240 {
241 const bool __testin = _M_mode & ios_base::in;
242 if (this->pptr() && this->pptr() > this->egptr())
243 {
244 if (__testin)
245 this->setg(this->eback(), this->gptr(), this->pptr());
246 else
247 this->setg(this->pptr(), this->pptr(), this->pptr());
248 }
249 }
250 };
251
252
253 // [27.7.2] Template class basic_istringstream
254 /**
255 * @brief Controlling input for std::string.
256 *
257 * This class supports reading from objects of type std::basic_string,
258 * using the inherited functions from std::basic_istream. To control
259 * the associated sequence, an instance of std::basic_stringbuf is used,
260 * which this page refers to as @c sb.
261 */
262 template<typename _CharT, typename _Traits, typename _Alloc>
263 class basic_istringstream : public basic_istream<_CharT, _Traits>
264 {
265 public:
266 // Types:
267 typedef _CharT char_type;
268 typedef _Traits traits_type;
269 // _GLIBCXX_RESOLVE_LIB_DEFECTS
270 // 251. basic_stringbuf missing allocator_type
271 typedef _Alloc allocator_type;
272 typedef typename traits_type::int_type int_type;
273 typedef typename traits_type::pos_type pos_type;
274 typedef typename traits_type::off_type off_type;
275
276 // Non-standard types:
277 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
278 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
279 typedef basic_istream<char_type, traits_type> __istream_type;
280
281 private:
282 __stringbuf_type _M_stringbuf;
283
284 public:
285 // Constructors:
286 /**
287 * @brief Default constructor starts with an empty string buffer.
288 * @param mode Whether the buffer can read, or write, or both.
289 *
290 * @c ios_base::in is automatically included in @a mode.
291 *
292 * Initializes @c sb using @c mode|in, and passes @c &sb to the base
293 * class initializer. Does not allocate any buffer.
294 *
295 * @if maint
296 * That's a lie. We initialize the base class with NULL, because the
297 * string class does its own memory management.
298 * @endif
299 */
300 explicit
301 basic_istringstream(ios_base::openmode __mode = ios_base::in)
__istream_type()302 : __istream_type(), _M_stringbuf(__mode | ios_base::in)
303 { this->init(&_M_stringbuf); }
304
305 /**
306 * @brief Starts with an existing string buffer.
307 * @param str A string to copy as a starting buffer.
308 * @param mode Whether the buffer can read, or write, or both.
309 *
310 * @c ios_base::in is automatically included in @a mode.
311 *
312 * Initializes @c sb using @a str and @c mode|in, and passes @c &sb
313 * to the base class initializer.
314 *
315 * @if maint
316 * That's a lie. We initialize the base class with NULL, because the
317 * string class does its own memory management.
318 * @endif
319 */
320 explicit
321 basic_istringstream(const __string_type& __str,
322 ios_base::openmode __mode = ios_base::in)
__istream_type()323 : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
324 { this->init(&_M_stringbuf); }
325
326 /**
327 * @brief The destructor does nothing.
328 *
329 * The buffer is deallocated by the stringbuf object, not the
330 * formatting stream.
331 */
~basic_istringstream()332 ~basic_istringstream()
333 { }
334
335 // Members:
336 /**
337 * @brief Accessing the underlying buffer.
338 * @return The current basic_stringbuf buffer.
339 *
340 * This hides both signatures of std::basic_ios::rdbuf().
341 */
342 __stringbuf_type*
rdbuf()343 rdbuf() const
344 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
345
346 /**
347 * @brief Copying out the string buffer.
348 * @return @c rdbuf()->str()
349 */
350 __string_type
str()351 str() const
352 { return _M_stringbuf.str(); }
353
354 /**
355 * @brief Setting a new buffer.
356 * @param s The string to use as a new sequence.
357 *
358 * Calls @c rdbuf()->str(s).
359 */
360 void
str(const __string_type & __s)361 str(const __string_type& __s)
362 { _M_stringbuf.str(__s); }
363 };
364
365
366 // [27.7.3] Template class basic_ostringstream
367 /**
368 * @brief Controlling output for std::string.
369 *
370 * This class supports writing to objects of type std::basic_string,
371 * using the inherited functions from std::basic_ostream. To control
372 * the associated sequence, an instance of std::basic_stringbuf is used,
373 * which this page refers to as @c sb.
374 */
375 template <typename _CharT, typename _Traits, typename _Alloc>
376 class basic_ostringstream : public basic_ostream<_CharT, _Traits>
377 {
378 public:
379 // Types:
380 typedef _CharT char_type;
381 typedef _Traits traits_type;
382 // _GLIBCXX_RESOLVE_LIB_DEFECTS
383 // 251. basic_stringbuf missing allocator_type
384 typedef _Alloc allocator_type;
385 typedef typename traits_type::int_type int_type;
386 typedef typename traits_type::pos_type pos_type;
387 typedef typename traits_type::off_type off_type;
388
389 // Non-standard types:
390 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
391 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
392 typedef basic_ostream<char_type, traits_type> __ostream_type;
393
394 private:
395 __stringbuf_type _M_stringbuf;
396
397 public:
398 // Constructors/destructor:
399 /**
400 * @brief Default constructor starts with an empty string buffer.
401 * @param mode Whether the buffer can read, or write, or both.
402 *
403 * @c ios_base::out is automatically included in @a mode.
404 *
405 * Initializes @c sb using @c mode|out, and passes @c &sb to the base
406 * class initializer. Does not allocate any buffer.
407 *
408 * @if maint
409 * That's a lie. We initialize the base class with NULL, because the
410 * string class does its own memory management.
411 * @endif
412 */
413 explicit
414 basic_ostringstream(ios_base::openmode __mode = ios_base::out)
__ostream_type()415 : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
416 { this->init(&_M_stringbuf); }
417
418 /**
419 * @brief Starts with an existing string buffer.
420 * @param str A string to copy as a starting buffer.
421 * @param mode Whether the buffer can read, or write, or both.
422 *
423 * @c ios_base::out is automatically included in @a mode.
424 *
425 * Initializes @c sb using @a str and @c mode|out, and passes @c &sb
426 * to the base class initializer.
427 *
428 * @if maint
429 * That's a lie. We initialize the base class with NULL, because the
430 * string class does its own memory management.
431 * @endif
432 */
433 explicit
434 basic_ostringstream(const __string_type& __str,
435 ios_base::openmode __mode = ios_base::out)
__ostream_type()436 : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
437 { this->init(&_M_stringbuf); }
438
439 /**
440 * @brief The destructor does nothing.
441 *
442 * The buffer is deallocated by the stringbuf object, not the
443 * formatting stream.
444 */
~basic_ostringstream()445 ~basic_ostringstream()
446 { }
447
448 // Members:
449 /**
450 * @brief Accessing the underlying buffer.
451 * @return The current basic_stringbuf buffer.
452 *
453 * This hides both signatures of std::basic_ios::rdbuf().
454 */
455 __stringbuf_type*
rdbuf()456 rdbuf() const
457 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
458
459 /**
460 * @brief Copying out the string buffer.
461 * @return @c rdbuf()->str()
462 */
463 __string_type
str()464 str() const
465 { return _M_stringbuf.str(); }
466
467 /**
468 * @brief Setting a new buffer.
469 * @param s The string to use as a new sequence.
470 *
471 * Calls @c rdbuf()->str(s).
472 */
473 void
str(const __string_type & __s)474 str(const __string_type& __s)
475 { _M_stringbuf.str(__s); }
476 };
477
478
479 // [27.7.4] Template class basic_stringstream
480 /**
481 * @brief Controlling input and output for std::string.
482 *
483 * This class supports reading from and writing to objects of type
484 * std::basic_string, using the inherited functions from
485 * std::basic_iostream. To control the associated sequence, an instance
486 * of std::basic_stringbuf is used, which this page refers to as @c sb.
487 */
488 template <typename _CharT, typename _Traits, typename _Alloc>
489 class basic_stringstream : public basic_iostream<_CharT, _Traits>
490 {
491 public:
492 // Types:
493 typedef _CharT char_type;
494 typedef _Traits traits_type;
495 // _GLIBCXX_RESOLVE_LIB_DEFECTS
496 // 251. basic_stringbuf missing allocator_type
497 typedef _Alloc allocator_type;
498 typedef typename traits_type::int_type int_type;
499 typedef typename traits_type::pos_type pos_type;
500 typedef typename traits_type::off_type off_type;
501
502 // Non-standard Types:
503 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
504 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
505 typedef basic_iostream<char_type, traits_type> __iostream_type;
506
507 private:
508 __stringbuf_type _M_stringbuf;
509
510 public:
511 // Constructors/destructors
512 /**
513 * @brief Default constructor starts with an empty string buffer.
514 * @param mode Whether the buffer can read, or write, or both.
515 *
516 * Initializes @c sb using @c mode, and passes @c &sb to the base
517 * class initializer. Does not allocate any buffer.
518 *
519 * @if maint
520 * That's a lie. We initialize the base class with NULL, because the
521 * string class does its own memory management.
522 * @endif
523 */
524 explicit
525 basic_stringstream(ios_base::openmode __m = ios_base::out | ios_base::in)
__iostream_type()526 : __iostream_type(), _M_stringbuf(__m)
527 { this->init(&_M_stringbuf); }
528
529 /**
530 * @brief Starts with an existing string buffer.
531 * @param str A string to copy as a starting buffer.
532 * @param mode Whether the buffer can read, or write, or both.
533 *
534 * Initializes @c sb using @a str and @c mode, and passes @c &sb
535 * to the base class initializer.
536 *
537 * @if maint
538 * That's a lie. We initialize the base class with NULL, because the
539 * string class does its own memory management.
540 * @endif
541 */
542 explicit
543 basic_stringstream(const __string_type& __str,
544 ios_base::openmode __m = ios_base::out | ios_base::in)
__iostream_type()545 : __iostream_type(), _M_stringbuf(__str, __m)
546 { this->init(&_M_stringbuf); }
547
548 /**
549 * @brief The destructor does nothing.
550 *
551 * The buffer is deallocated by the stringbuf object, not the
552 * formatting stream.
553 */
~basic_stringstream()554 ~basic_stringstream()
555 { }
556
557 // Members:
558 /**
559 * @brief Accessing the underlying buffer.
560 * @return The current basic_stringbuf buffer.
561 *
562 * This hides both signatures of std::basic_ios::rdbuf().
563 */
564 __stringbuf_type*
rdbuf()565 rdbuf() const
566 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
567
568 /**
569 * @brief Copying out the string buffer.
570 * @return @c rdbuf()->str()
571 */
572 __string_type
str()573 str() const
574 { return _M_stringbuf.str(); }
575
576 /**
577 * @brief Setting a new buffer.
578 * @param s The string to use as a new sequence.
579 *
580 * Calls @c rdbuf()->str(s).
581 */
582 void
str(const __string_type & __s)583 str(const __string_type& __s)
584 { _M_stringbuf.str(__s); }
585 };
586
587 _GLIBCXX_END_NAMESPACE
588
589 #ifndef _GLIBCXX_EXPORT_TEMPLATE
590 # include <bits/sstream.tcc>
591 #endif
592
593 #endif /* _GLIBCXX_SSTREAM */
594