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 if (__testin)
244 this->setg(this->eback(), this->gptr(), this->pptr());
245 else
246 this->setg(this->pptr(), this->pptr(), this->pptr());
247 }
248 };
249
250
251 // [27.7.2] Template class basic_istringstream
252 /**
253 * @brief Controlling input for std::string.
254 *
255 * This class supports reading from objects of type std::basic_string,
256 * using the inherited functions from std::basic_istream. To control
257 * the associated sequence, an instance of std::basic_stringbuf is used,
258 * which this page refers to as @c sb.
259 */
260 template<typename _CharT, typename _Traits, typename _Alloc>
261 class basic_istringstream : public basic_istream<_CharT, _Traits>
262 {
263 public:
264 // Types:
265 typedef _CharT char_type;
266 typedef _Traits traits_type;
267 // _GLIBCXX_RESOLVE_LIB_DEFECTS
268 // 251. basic_stringbuf missing allocator_type
269 typedef _Alloc allocator_type;
270 typedef typename traits_type::int_type int_type;
271 typedef typename traits_type::pos_type pos_type;
272 typedef typename traits_type::off_type off_type;
273
274 // Non-standard types:
275 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
276 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
277 typedef basic_istream<char_type, traits_type> __istream_type;
278
279 private:
280 __stringbuf_type _M_stringbuf;
281
282 public:
283 // Constructors:
284 /**
285 * @brief Default constructor starts with an empty string buffer.
286 * @param mode Whether the buffer can read, or write, or both.
287 *
288 * @c ios_base::in is automatically included in @a mode.
289 *
290 * Initializes @c sb using @c mode|in, and passes @c &sb to the base
291 * class initializer. Does not allocate any buffer.
292 *
293 * @if maint
294 * That's a lie. We initialize the base class with NULL, because the
295 * string class does its own memory management.
296 * @endif
297 */
298 explicit
299 basic_istringstream(ios_base::openmode __mode = ios_base::in)
__istream_type()300 : __istream_type(), _M_stringbuf(__mode | ios_base::in)
301 { this->init(&_M_stringbuf); }
302
303 /**
304 * @brief Starts with an existing string buffer.
305 * @param str A string to copy as a starting buffer.
306 * @param mode Whether the buffer can read, or write, or both.
307 *
308 * @c ios_base::in is automatically included in @a mode.
309 *
310 * Initializes @c sb using @a str and @c mode|in, and passes @c &sb
311 * to the base class initializer.
312 *
313 * @if maint
314 * That's a lie. We initialize the base class with NULL, because the
315 * string class does its own memory management.
316 * @endif
317 */
318 explicit
319 basic_istringstream(const __string_type& __str,
320 ios_base::openmode __mode = ios_base::in)
__istream_type()321 : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
322 { this->init(&_M_stringbuf); }
323
324 /**
325 * @brief The destructor does nothing.
326 *
327 * The buffer is deallocated by the stringbuf object, not the
328 * formatting stream.
329 */
~basic_istringstream()330 ~basic_istringstream()
331 { }
332
333 // Members:
334 /**
335 * @brief Accessing the underlying buffer.
336 * @return The current basic_stringbuf buffer.
337 *
338 * This hides both signatures of std::basic_ios::rdbuf().
339 */
340 __stringbuf_type*
rdbuf()341 rdbuf() const
342 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
343
344 /**
345 * @brief Copying out the string buffer.
346 * @return @c rdbuf()->str()
347 */
348 __string_type
str()349 str() const
350 { return _M_stringbuf.str(); }
351
352 /**
353 * @brief Setting a new buffer.
354 * @param s The string to use as a new sequence.
355 *
356 * Calls @c rdbuf()->str(s).
357 */
358 void
str(const __string_type & __s)359 str(const __string_type& __s)
360 { _M_stringbuf.str(__s); }
361 };
362
363
364 // [27.7.3] Template class basic_ostringstream
365 /**
366 * @brief Controlling output for std::string.
367 *
368 * This class supports writing to objects of type std::basic_string,
369 * using the inherited functions from std::basic_ostream. To control
370 * the associated sequence, an instance of std::basic_stringbuf is used,
371 * which this page refers to as @c sb.
372 */
373 template <typename _CharT, typename _Traits, typename _Alloc>
374 class basic_ostringstream : public basic_ostream<_CharT, _Traits>
375 {
376 public:
377 // Types:
378 typedef _CharT char_type;
379 typedef _Traits traits_type;
380 // _GLIBCXX_RESOLVE_LIB_DEFECTS
381 // 251. basic_stringbuf missing allocator_type
382 typedef _Alloc allocator_type;
383 typedef typename traits_type::int_type int_type;
384 typedef typename traits_type::pos_type pos_type;
385 typedef typename traits_type::off_type off_type;
386
387 // Non-standard types:
388 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
389 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
390 typedef basic_ostream<char_type, traits_type> __ostream_type;
391
392 private:
393 __stringbuf_type _M_stringbuf;
394
395 public:
396 // Constructors/destructor:
397 /**
398 * @brief Default constructor starts with an empty string buffer.
399 * @param mode Whether the buffer can read, or write, or both.
400 *
401 * @c ios_base::out is automatically included in @a mode.
402 *
403 * Initializes @c sb using @c mode|out, and passes @c &sb to the base
404 * class initializer. Does not allocate any buffer.
405 *
406 * @if maint
407 * That's a lie. We initialize the base class with NULL, because the
408 * string class does its own memory management.
409 * @endif
410 */
411 explicit
412 basic_ostringstream(ios_base::openmode __mode = ios_base::out)
__ostream_type()413 : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
414 { this->init(&_M_stringbuf); }
415
416 /**
417 * @brief Starts with an existing string buffer.
418 * @param str A string to copy as a starting buffer.
419 * @param mode Whether the buffer can read, or write, or both.
420 *
421 * @c ios_base::out is automatically included in @a mode.
422 *
423 * Initializes @c sb using @a str and @c mode|out, and passes @c &sb
424 * to the base class initializer.
425 *
426 * @if maint
427 * That's a lie. We initialize the base class with NULL, because the
428 * string class does its own memory management.
429 * @endif
430 */
431 explicit
432 basic_ostringstream(const __string_type& __str,
433 ios_base::openmode __mode = ios_base::out)
__ostream_type()434 : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
435 { this->init(&_M_stringbuf); }
436
437 /**
438 * @brief The destructor does nothing.
439 *
440 * The buffer is deallocated by the stringbuf object, not the
441 * formatting stream.
442 */
~basic_ostringstream()443 ~basic_ostringstream()
444 { }
445
446 // Members:
447 /**
448 * @brief Accessing the underlying buffer.
449 * @return The current basic_stringbuf buffer.
450 *
451 * This hides both signatures of std::basic_ios::rdbuf().
452 */
453 __stringbuf_type*
rdbuf()454 rdbuf() const
455 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
456
457 /**
458 * @brief Copying out the string buffer.
459 * @return @c rdbuf()->str()
460 */
461 __string_type
str()462 str() const
463 { return _M_stringbuf.str(); }
464
465 /**
466 * @brief Setting a new buffer.
467 * @param s The string to use as a new sequence.
468 *
469 * Calls @c rdbuf()->str(s).
470 */
471 void
str(const __string_type & __s)472 str(const __string_type& __s)
473 { _M_stringbuf.str(__s); }
474 };
475
476
477 // [27.7.4] Template class basic_stringstream
478 /**
479 * @brief Controlling input and output for std::string.
480 *
481 * This class supports reading from and writing to objects of type
482 * std::basic_string, using the inherited functions from
483 * std::basic_iostream. To control the associated sequence, an instance
484 * of std::basic_stringbuf is used, which this page refers to as @c sb.
485 */
486 template <typename _CharT, typename _Traits, typename _Alloc>
487 class basic_stringstream : public basic_iostream<_CharT, _Traits>
488 {
489 public:
490 // Types:
491 typedef _CharT char_type;
492 typedef _Traits traits_type;
493 // _GLIBCXX_RESOLVE_LIB_DEFECTS
494 // 251. basic_stringbuf missing allocator_type
495 typedef _Alloc allocator_type;
496 typedef typename traits_type::int_type int_type;
497 typedef typename traits_type::pos_type pos_type;
498 typedef typename traits_type::off_type off_type;
499
500 // Non-standard Types:
501 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
502 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
503 typedef basic_iostream<char_type, traits_type> __iostream_type;
504
505 private:
506 __stringbuf_type _M_stringbuf;
507
508 public:
509 // Constructors/destructors
510 /**
511 * @brief Default constructor starts with an empty string buffer.
512 * @param mode Whether the buffer can read, or write, or both.
513 *
514 * Initializes @c sb using @c mode, and passes @c &sb to the base
515 * class initializer. Does not allocate any buffer.
516 *
517 * @if maint
518 * That's a lie. We initialize the base class with NULL, because the
519 * string class does its own memory management.
520 * @endif
521 */
522 explicit
523 basic_stringstream(ios_base::openmode __m = ios_base::out | ios_base::in)
__iostream_type()524 : __iostream_type(), _M_stringbuf(__m)
525 { this->init(&_M_stringbuf); }
526
527 /**
528 * @brief Starts with an existing string buffer.
529 * @param str A string to copy as a starting buffer.
530 * @param mode Whether the buffer can read, or write, or both.
531 *
532 * Initializes @c sb using @a str and @c mode, and passes @c &sb
533 * to the base class initializer.
534 *
535 * @if maint
536 * That's a lie. We initialize the base class with NULL, because the
537 * string class does its own memory management.
538 * @endif
539 */
540 explicit
541 basic_stringstream(const __string_type& __str,
542 ios_base::openmode __m = ios_base::out | ios_base::in)
__iostream_type()543 : __iostream_type(), _M_stringbuf(__str, __m)
544 { this->init(&_M_stringbuf); }
545
546 /**
547 * @brief The destructor does nothing.
548 *
549 * The buffer is deallocated by the stringbuf object, not the
550 * formatting stream.
551 */
~basic_stringstream()552 ~basic_stringstream()
553 { }
554
555 // Members:
556 /**
557 * @brief Accessing the underlying buffer.
558 * @return The current basic_stringbuf buffer.
559 *
560 * This hides both signatures of std::basic_ios::rdbuf().
561 */
562 __stringbuf_type*
rdbuf()563 rdbuf() const
564 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
565
566 /**
567 * @brief Copying out the string buffer.
568 * @return @c rdbuf()->str()
569 */
570 __string_type
str()571 str() const
572 { return _M_stringbuf.str(); }
573
574 /**
575 * @brief Setting a new buffer.
576 * @param s The string to use as a new sequence.
577 *
578 * Calls @c rdbuf()->str(s).
579 */
580 void
str(const __string_type & __s)581 str(const __string_type& __s)
582 { _M_stringbuf.str(__s); }
583 };
584
585 _GLIBCXX_END_NAMESPACE
586
587 #ifndef _GLIBCXX_EXPORT_TEMPLATE
588 # include <bits/sstream.tcc>
589 #endif
590
591 #endif /* _GLIBCXX_SSTREAM */
592