1 // String based streams -*- C++ -*-
3 // Copyright (C) 1997, 1998, 1999, 2002, 2003, 2004, 2005
4 // Free Software Foundation, Inc.
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)
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.
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,
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.
32 // ISO C++ 14882: 27.7 String-based streams
36 * This is a Standard C++ Library header.
39 #ifndef _GLIBCXX_SSTREAM
40 #define _GLIBCXX_SSTREAM 1
42 #pragma GCC system_header
49 // [27.7.1] template class basic_stringbuf
51 * @brief The actual work of input and output (for std::string).
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.)
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.
61 template<typename _CharT, typename _Traits, typename _Alloc>
62 class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
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;
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;
82 * Place to stash in || out || in | out settings for current stringbuf.
85 ios_base::openmode _M_mode;
88 __string_type _M_string;
93 * @brief Starts with an empty string buffer.
94 * @param mode Whether the buffer can read, or write, or both.
96 * The default constructor initializes the parent class using its
100 basic_stringbuf(ios_base::openmode __mode = ios_base::in | ios_base::out)
101 : __streambuf_type(), _M_mode(__mode), _M_string()
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.
109 * This constructor initializes the parent class using its
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); }
120 * @brief Copying out the string buffer.
121 * @return A copy of one of the underlying sequences.
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
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());
137 __ret = __string_type(this->pbase(), this->egptr());
145 * @brief Setting a new buffer.
146 * @param s The string to use as a new sequence.
148 * Deallocates any previous stored sequence, then copies @a s to
152 str(const __string_type& __s)
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);
160 // Common initialization code goes here.
162 _M_stringbuf_init(ios_base::openmode __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);
174 streamsize __ret = -1;
175 if (_M_mode & ios_base::in)
178 __ret = this->egptr() - this->gptr();
187 pbackfail(int_type __c = traits_type::eof());
190 overflow(int_type __c = traits_type::eof());
193 * @brief Manipulates the buffer.
194 * @param s Pointer to a buffer area.
195 * @param n Size of @a s.
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
203 virtual __streambuf_type*
204 setbuf(char_type* __s, streamsize __n)
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.
213 // Step 1: Destroy the current internal array.
214 _M_string.assign(__s, __n);
216 // Step 2: Use the external array.
223 seekoff(off_type __off, ios_base::seekdir __way,
224 ios_base::openmode __mode = ios_base::in | ios_base::out);
227 seekpos(pos_type __sp,
228 ios_base::openmode __mode = ios_base::in | ios_base::out);
230 // Internal function for correctly updating the internal buffer
231 // for a particular _M_string, due to initialization or
232 // re-sizing of an existing _M_string.
233 // Assumes: contents of _M_string and internal buffer match exactly.
234 // __i == _M_in_cur - _M_in_beg
235 // __o == _M_out_cur - _M_out_beg
237 _M_sync(char_type* __base, __size_type __i, __size_type __o)
239 const bool __testin = _M_mode & ios_base::in;
240 const bool __testout = _M_mode & ios_base::out;
241 char_type* __end = __base + _M_string.size();
244 this->setg(__base, __base + __i, __end);
247 // If __base comes from setbuf we cannot trust capacity()
248 // to match the size of the buffer area: in general, after
249 // Step 1 above, _M_string.capacity() >= __n.
250 if (__base == _M_string.data())
251 this->setp(__base, __base + _M_string.capacity());
253 this->setp(__base, __end);
255 // egptr() always tracks the string end. When !__testin,
256 // for the correct functioning of the streambuf inlines
257 // the other get area pointers are identical.
259 this->setg(__end, __end, __end);
263 // Internal function for correctly updating egptr() to the actual
268 const bool __testin = _M_mode & ios_base::in;
269 if (this->pptr() && this->pptr() > this->egptr())
271 this->setg(this->eback(), this->gptr(), this->pptr());
273 this->setg(this->pptr(), this->pptr(), this->pptr());
278 // [27.7.2] Template class basic_istringstream
280 * @brief Controlling input for std::string.
282 * This class supports reading from objects of type std::basic_string,
283 * using the inherited functions from std::basic_istream. To control
284 * the associated sequence, an instance of std::basic_stringbuf is used,
285 * which this page refers to as @c sb.
287 template<typename _CharT, typename _Traits, typename _Alloc>
288 class basic_istringstream : public basic_istream<_CharT, _Traits>
292 typedef _CharT char_type;
293 typedef _Traits traits_type;
294 // _GLIBCXX_RESOLVE_LIB_DEFECTS
295 // 251. basic_stringbuf missing allocator_type
296 typedef _Alloc allocator_type;
297 typedef typename traits_type::int_type int_type;
298 typedef typename traits_type::pos_type pos_type;
299 typedef typename traits_type::off_type off_type;
301 // Non-standard types:
302 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
303 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
304 typedef basic_istream<char_type, traits_type> __istream_type;
307 __stringbuf_type _M_stringbuf;
312 * @brief Default constructor starts with an empty string buffer.
313 * @param mode Whether the buffer can read, or write, or both.
315 * @c ios_base::in is automatically included in @a mode.
317 * Initializes @c sb using @c mode|in, and passes @c &sb to the base
318 * class initializer. Does not allocate any buffer.
321 * That's a lie. We initialize the base class with NULL, because the
322 * string class does its own memory management.
326 basic_istringstream(ios_base::openmode __mode = ios_base::in)
327 : __istream_type(), _M_stringbuf(__mode | ios_base::in)
328 { this->init(&_M_stringbuf); }
331 * @brief Starts with an existing string buffer.
332 * @param str A string to copy as a starting buffer.
333 * @param mode Whether the buffer can read, or write, or both.
335 * @c ios_base::in is automatically included in @a mode.
337 * Initializes @c sb using @a str and @c mode|in, and passes @c &sb
338 * to the base class initializer.
341 * That's a lie. We initialize the base class with NULL, because the
342 * string class does its own memory management.
346 basic_istringstream(const __string_type& __str,
347 ios_base::openmode __mode = ios_base::in)
348 : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
349 { this->init(&_M_stringbuf); }
352 * @brief The destructor does nothing.
354 * The buffer is deallocated by the stringbuf object, not the
357 ~basic_istringstream()
362 * @brief Accessing the underlying buffer.
363 * @return The current basic_stringbuf buffer.
365 * This hides both signatures of std::basic_ios::rdbuf().
369 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
372 * @brief Copying out the string buffer.
373 * @return @c rdbuf()->str()
377 { return _M_stringbuf.str(); }
380 * @brief Setting a new buffer.
381 * @param s The string to use as a new sequence.
383 * Calls @c rdbuf()->str(s).
386 str(const __string_type& __s)
387 { _M_stringbuf.str(__s); }
391 // [27.7.3] Template class basic_ostringstream
393 * @brief Controlling output for std::string.
395 * This class supports writing to objects of type std::basic_string,
396 * using the inherited functions from std::basic_ostream. To control
397 * the associated sequence, an instance of std::basic_stringbuf is used,
398 * which this page refers to as @c sb.
400 template <typename _CharT, typename _Traits, typename _Alloc>
401 class basic_ostringstream : public basic_ostream<_CharT, _Traits>
405 typedef _CharT char_type;
406 typedef _Traits traits_type;
407 // _GLIBCXX_RESOLVE_LIB_DEFECTS
408 // 251. basic_stringbuf missing allocator_type
409 typedef _Alloc allocator_type;
410 typedef typename traits_type::int_type int_type;
411 typedef typename traits_type::pos_type pos_type;
412 typedef typename traits_type::off_type off_type;
414 // Non-standard types:
415 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
416 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
417 typedef basic_ostream<char_type, traits_type> __ostream_type;
420 __stringbuf_type _M_stringbuf;
423 // Constructors/destructor:
425 * @brief Default constructor starts with an empty string buffer.
426 * @param mode Whether the buffer can read, or write, or both.
428 * @c ios_base::out is automatically included in @a mode.
430 * Initializes @c sb using @c mode|out, and passes @c &sb to the base
431 * class initializer. Does not allocate any buffer.
434 * That's a lie. We initialize the base class with NULL, because the
435 * string class does its own memory management.
439 basic_ostringstream(ios_base::openmode __mode = ios_base::out)
440 : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
441 { this->init(&_M_stringbuf); }
444 * @brief Starts with an existing string buffer.
445 * @param str A string to copy as a starting buffer.
446 * @param mode Whether the buffer can read, or write, or both.
448 * @c ios_base::out is automatically included in @a mode.
450 * Initializes @c sb using @a str and @c mode|out, and passes @c &sb
451 * to the base class initializer.
454 * That's a lie. We initialize the base class with NULL, because the
455 * string class does its own memory management.
459 basic_ostringstream(const __string_type& __str,
460 ios_base::openmode __mode = ios_base::out)
461 : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
462 { this->init(&_M_stringbuf); }
465 * @brief The destructor does nothing.
467 * The buffer is deallocated by the stringbuf object, not the
470 ~basic_ostringstream()
475 * @brief Accessing the underlying buffer.
476 * @return The current basic_stringbuf buffer.
478 * This hides both signatures of std::basic_ios::rdbuf().
482 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
485 * @brief Copying out the string buffer.
486 * @return @c rdbuf()->str()
490 { return _M_stringbuf.str(); }
493 * @brief Setting a new buffer.
494 * @param s The string to use as a new sequence.
496 * Calls @c rdbuf()->str(s).
499 str(const __string_type& __s)
500 { _M_stringbuf.str(__s); }
504 // [27.7.4] Template class basic_stringstream
506 * @brief Controlling input and output for std::string.
508 * This class supports reading from and writing to objects of type
509 * std::basic_string, using the inherited functions from
510 * std::basic_iostream. To control the associated sequence, an instance
511 * of std::basic_stringbuf is used, which this page refers to as @c sb.
513 template <typename _CharT, typename _Traits, typename _Alloc>
514 class basic_stringstream : public basic_iostream<_CharT, _Traits>
518 typedef _CharT char_type;
519 typedef _Traits traits_type;
520 // _GLIBCXX_RESOLVE_LIB_DEFECTS
521 // 251. basic_stringbuf missing allocator_type
522 typedef _Alloc allocator_type;
523 typedef typename traits_type::int_type int_type;
524 typedef typename traits_type::pos_type pos_type;
525 typedef typename traits_type::off_type off_type;
527 // Non-standard Types:
528 typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
529 typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
530 typedef basic_iostream<char_type, traits_type> __iostream_type;
533 __stringbuf_type _M_stringbuf;
536 // Constructors/destructors
538 * @brief Default constructor starts with an empty string buffer.
539 * @param mode Whether the buffer can read, or write, or both.
541 * Initializes @c sb using @c mode, and passes @c &sb to the base
542 * class initializer. Does not allocate any buffer.
545 * That's a lie. We initialize the base class with NULL, because the
546 * string class does its own memory management.
550 basic_stringstream(ios_base::openmode __m = ios_base::out | ios_base::in)
551 : __iostream_type(), _M_stringbuf(__m)
552 { this->init(&_M_stringbuf); }
555 * @brief Starts with an existing string buffer.
556 * @param str A string to copy as a starting buffer.
557 * @param mode Whether the buffer can read, or write, or both.
559 * Initializes @c sb using @a str and @c mode, and passes @c &sb
560 * to the base class initializer.
563 * That's a lie. We initialize the base class with NULL, because the
564 * string class does its own memory management.
568 basic_stringstream(const __string_type& __str,
569 ios_base::openmode __m = ios_base::out | ios_base::in)
570 : __iostream_type(), _M_stringbuf(__str, __m)
571 { this->init(&_M_stringbuf); }
574 * @brief The destructor does nothing.
576 * The buffer is deallocated by the stringbuf object, not the
579 ~basic_stringstream()
584 * @brief Accessing the underlying buffer.
585 * @return The current basic_stringbuf buffer.
587 * This hides both signatures of std::basic_ios::rdbuf().
591 { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
594 * @brief Copying out the string buffer.
595 * @return @c rdbuf()->str()
599 { return _M_stringbuf.str(); }
602 * @brief Setting a new buffer.
603 * @param s The string to use as a new sequence.
605 * Calls @c rdbuf()->str(s).
608 str(const __string_type& __s)
609 { _M_stringbuf.str(__s); }
613 #ifndef _GLIBCXX_EXPORT_TEMPLATE
614 # include <bits/sstream.tcc>
617 #endif /* _GLIBCXX_SSTREAM */