ReactOS  0.4.14-dev-98-gb0d4763
_streambuf.h
Go to the documentation of this file.
1 /*
2  * Copyright (c) 1999
3  * Silicon Graphics Computer Systems, Inc.
4  *
5  * Copyright (c) 1999
6  * Boris Fomitchev
7  *
8  * This material is provided "as is", with absolutely no warranty expressed
9  * or implied. Any use is at your own risk.
10  *
11  * Permission to use or copy this software for any purpose is hereby granted
12  * without fee, provided the above notices are retained on all copies.
13  * Permission to modify the code and to distribute modified code is granted,
14  * provided the above notices are retained, and a notice that the code was
15  * modified is included with the above copyright notice.
16  *
17  */
18 #ifndef _STLP_INTERNAL_STREAMBUF
19 #define _STLP_INTERNAL_STREAMBUF
20 
21 #ifndef _STLP_IOS_BASE_H
22 # include <stl/_ios_base.h> // Needed for ios_base bitfield members.
23 #endif // <ios_base> includes <iosfwd>.
24 
26 
27 //----------------------------------------------------------------------
28 // Class basic_streambuf<>, the base class of the streambuf hierarchy.
29 
30 // A basic_streambuf<> manages an input (get) area and an output (put)
31 // area. Each is described by three pointers: a beginning, an end, and a
32 // current position. basic_streambuf<> contains some very simple member
33 // functions that manipulate those six pointers, but almost all of the real
34 // functionality gets delegated to protected virtual member functions.
35 // All of the public member functions are inline, and most of the protected
36 // member functions are virtual.
37 
38 // Although basic_streambuf<> is not abstract, it is useful only as a base
39 // class. Its virtual member functions have default definitions such that
40 // reading from a basic_streambuf<> will always yield EOF, and writing to a
41 // basic_streambuf<> will always fail.
42 
43 // The second template parameter, _Traits, defaults to char_traits<_CharT>.
44 // The default is declared in header <iosfwd>, and it isn't declared here
45 // because C++ language rules do not allow it to be declared twice.
46 
47 template <class _CharT, class _Traits>
48 class basic_streambuf {
49  friend class basic_istream<_CharT, _Traits>;
50  friend class basic_ostream<_CharT, _Traits>;
51 
52 public: // Typedefs.
53  typedef _CharT char_type;
54  typedef typename _Traits::int_type int_type;
55  typedef typename _Traits::pos_type pos_type;
56  typedef typename _Traits::off_type off_type;
57  typedef _Traits traits_type;
58 
59 private: // Data members.
60 
61  char_type* _M_gbegin; // Beginning of get area
62  char_type* _M_gnext; // Current position within the get area
63  char_type* _M_gend; // End of get area
64 
65  char_type* _M_pbegin; // Beginning of put area
66  char_type* _M_pnext; // Current position within the put area
67  char_type* _M_pend; // End of put area
68 
69  locale _M_locale; // The streambuf's locale object
70 
71 public: // Destructor.
72  virtual ~basic_streambuf();
73 
74 protected: // The default constructor.
76 #if defined (_STLP_MSVC) && (_STLP_MSVC < 1300) && defined (_STLP_USE_STATIC_LIB)
77  //We make it inline to avoid unresolved symbol.
78  : _M_gbegin(0), _M_gnext(0), _M_gend(0),
79  _M_pbegin(0), _M_pnext(0), _M_pend(0),
80  _M_locale()
81  {}
82 #else
83  ;
84 #endif
85 
86 protected: // Protected interface to the get area.
87  char_type* eback() const { return _M_gbegin; } // Beginning
88  char_type* gptr() const { return _M_gnext; } // Current position
89  char_type* egptr() const { return _M_gend; } // End
90 
91  void gbump(int __n) { _M_gnext += __n; }
92  void setg(char_type* __gbegin, char_type* __gnext, char_type* __gend) {
93  _M_gbegin = __gbegin;
94  _M_gnext = __gnext;
95  _M_gend = __gend;
96  }
97 
98 public:
99  // An alternate public interface to the above functions
100  // which allows us to avoid using templated friends which
101  // are not supported on some compilers.
102  char_type* _M_eback() const { return eback(); }
103  char_type* _M_gptr() const { return gptr(); }
104  char_type* _M_egptr() const { return egptr(); }
105  void _M_gbump(int __n) { gbump(__n); }
106  void _M_setg(char_type* __gbegin, char_type* __gnext, char_type* __gend)
107  { this->setg(__gbegin, __gnext, __gend); }
108 
109 protected: // Protected interface to the put area
110 
111  char_type* pbase() const { return _M_pbegin; } // Beginning
112  char_type* pptr() const { return _M_pnext; } // Current position
113  char_type* epptr() const { return _M_pend; } // End
114 
115  void pbump(int __n) { _M_pnext += __n; }
116  void setp(char_type* __pbegin, char_type* __pend) {
117  _M_pbegin = __pbegin;
118  _M_pnext = __pbegin;
119  _M_pend = __pend;
120  }
121 
122 protected: // Virtual buffer management functions.
123 
125 
126  // Alters the stream position, using an integer offset. In this
127  // class seekoff does nothing; subclasses are expected to override it.
130 
131  // Alters the stream position, using a previously obtained streampos. In
132  // this class seekpos does nothing; subclasses are expected to override it.
133  virtual pos_type
135 
136  // Synchronizes (i.e. flushes) the buffer. All subclasses are expected to
137  // override this virtual member function.
138  virtual int sync();
139 
140 
141 public: // Buffer management.
143  { return this->setbuf(__s, __n); }
144 
147  { return this->seekoff(__offset, __way, __mod); }
148 
151  { return this->seekpos(__sp, __mod); }
152 
153  int pubsync() { return this->sync(); }
154 
155 protected: // Virtual get area functions, as defined in
156  // 17.5.2.4.3 and 17.5.2.4.4 of the standard.
157  // Returns a lower bound on the number of characters that we can read,
158  // with underflow, before reaching end of file. (-1 is a special value:
159  // it means that underflow will fail.) Most subclasses should probably
160  // override this virtual member function.
161  virtual streamsize showmanyc();
162 
163  // Reads up to __n characters. Return value is the number of
164  // characters read.
165  virtual streamsize xsgetn(char_type* __s, streamsize __n);
166 
167  // Called when there is no read position, i.e. when gptr() is null
168  // or when gptr() >= egptr(). Subclasses are expected to override
169  // this virtual member function.
170  virtual int_type underflow();
171 
172  // Similar to underflow(), but used for unbuffered input. Most
173  // subclasses should probably override this virtual member function.
174  virtual int_type uflow();
175 
176  // Called when there is no putback position, i.e. when gptr() is null
177  // or when gptr() == eback(). All subclasses are expected to override
178  // this virtual member function.
180 
181 protected: // Virtual put area functions, as defined in
182  // 27.5.2.4.5 of the standard.
183 
184  // Writes up to __n characters. Return value is the number of characters
185  // written.
186  virtual streamsize xsputn(const char_type* __s, streamsize __n);
187 
188  // Extension: writes up to __n copies of __c. Return value is the number
189  // of characters written.
191 
192  // Called when there is no write position. All subclasses are expected to
193  // override this virtual member function.
195 
196 public: // Public members for writing characters.
197  // Write a single character.
199  return ((_M_pnext < _M_pend) ? _Traits::to_int_type(*_M_pnext++ = __c)
200  : this->overflow(_Traits::to_int_type(__c)));
201  }
202 
203  // Write __n characters.
205  { return this->xsputn(__s, __n); }
206 
207  // Extension: write __n copies of __c.
209  { return this->_M_xsputnc(__c, __n); }
210 
211 private: // Helper functions.
213 
214 public: // Public members for reading characters.
216  return (_M_gnext < _M_gend) ? (_M_gend - _M_gnext) : this->showmanyc();
217  }
218 
219  // Advance to the next character and return it.
220  int_type snextc() {
221  return ( _M_gend - _M_gnext > 1 ?
222  _Traits::to_int_type(*++_M_gnext) :
223  this->_M_snextc_aux());
224  }
225 
226  // Return the current character and advance to the next.
227  int_type sbumpc() {
228  return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext++)
229  : this->uflow();
230  }
231 
232  // Return the current character without advancing to the next.
233  int_type sgetc() {
234  return _M_gnext < _M_gend ? _Traits::to_int_type(*_M_gnext)
235  : this->underflow();
236  }
237 
239  { return this->xsgetn(__s, __n); }
240 
242  return ((_M_gbegin < _M_gnext) && _Traits::eq(__c, *(_M_gnext - 1)))
243  ? _Traits::to_int_type(*--_M_gnext)
244  : this->pbackfail(_Traits::to_int_type(__c));
245  }
246 
248  return (_M_gbegin < _M_gnext)
249  ? _Traits::to_int_type(*--_M_gnext)
250  : this->pbackfail();
251  }
252 
253 protected: // Virtual locale functions.
254 
255  // This is a hook, called by pubimbue() just before pubimbue()
256  // sets the streambuf's locale to __loc. Note that imbue should
257  // not (and cannot, since it has no access to streambuf's private
258  // members) set the streambuf's locale itself.
259  virtual void imbue(const locale&);
260 
261 public: // Locale-related functions.
262  locale pubimbue(const locale&);
263  locale getloc() const { return _M_locale; }
264 
265 #if !defined (_STLP_NO_ANACHRONISMS)
266  void stossc() { this->sbumpc(); }
267 #endif
268 };
269 
270 #if defined (_STLP_USE_TEMPLATE_EXPORT)
272 # if !defined (_STLP_NO_WCHAR_T)
274 # endif // _STLP_NO_WCHAR_T
275 #endif // _STLP_USE_TEMPLATE_EXPORT
276 
278 
279 #if defined (_STLP_EXPOSE_STREAM_IMPLEMENTATION) && !defined (_STLP_LINK_TIME_INSTANTIATION)
280 # include <stl/_streambuf.c>
281 #endif
282 
283 #endif
284 
285 // Local Variables:
286 // mode:C++
287 // End:
_Traits::int_type int_type
Definition: _streambuf.h:54
char_type * eback() const
Definition: _streambuf.h:87
_Traits traits_type
Definition: _streambuf.h:57
void gbump(int __n)
Definition: _streambuf.h:91
virtual pos_type seekpos(pos_type, ios_base::openmode=ios_base::in|ios_base::out)
Definition: _streambuf.c:188
return __n
Definition: _algo.h:75
char_type * egptr() const
Definition: _streambuf.h:89
int_type _M_snextc_aux()
Definition: _streambuf.c:137
char_type * _M_eback() const
Definition: _streambuf.h:102
virtual int_type pbackfail(int_type=traits_type::eof())
Definition: _streambuf.c:150
virtual void imbue(const locale &)
Definition: _streambuf.c:180
basic_streambuf< _CharT, _Traits > * pubsetbuf(char_type *__s, streamsize __n)
Definition: _streambuf.h:142
_CharT char_type
Definition: _streambuf.h:53
char_type * _M_egptr() const
Definition: _streambuf.h:104
pos_type pubseekpos(pos_type __sp, ios_base::openmode __mod=ios_base::in|ios_base::out)
Definition: _streambuf.h:149
char_type * pbase() const
Definition: _streambuf.h:111
int_type sputc(char_type __c)
Definition: _streambuf.h:198
#define eq(received, expected, label, type)
Definition: locale.c:144
int seekdir
Definition: _ios_base.h:60
void setp(char_type *__pbegin, char_type *__pend)
Definition: _streambuf.h:116
virtual streamsize xsgetn(char_type *__s, streamsize __n)
Definition: _streambuf.c:54
void setg(char_type *__gbegin, char_type *__gnext, char_type *__gend)
Definition: _streambuf.h:92
char_type * pptr() const
Definition: _streambuf.h:112
#define __c
Definition: schilyio.h:209
char_type * epptr() const
Definition: _streambuf.h:113
_Traits::pos_type pos_type
Definition: _streambuf.h:55
void pbump(int __n)
Definition: _streambuf.h:115
Definition: _locale.h:75
locale _M_locale
Definition: _streambuf.h:69
char_type * _M_gend
Definition: _streambuf.h:63
char_type * _M_pnext
Definition: _streambuf.h:66
char_type * _M_gptr() const
Definition: _streambuf.h:103
int_type sbumpc()
Definition: _streambuf.h:227
virtual int_type overflow(int_type=traits_type::eof())
Definition: _streambuf.c:156
virtual pos_type seekoff(off_type, ios_base::seekdir, ios_base::openmode=ios_base::in|ios_base::out)
Definition: _streambuf.c:193
int_type snextc()
Definition: _streambuf.h:220
char_type * _M_gnext
Definition: _streambuf.h:62
void _M_gbump(int __n)
Definition: _streambuf.h:105
virtual int sync()
Definition: _streambuf.c:184
int openmode
Definition: _ios_base.h:59
static FILE * out
Definition: regtests2xml.c:44
#define _STLP_EXPORT_TEMPLATE_CLASS
Definition: features.h:987
int_type sungetc()
Definition: _streambuf.h:247
streamsize sgetn(char_type *__s, streamsize __n)
Definition: _streambuf.h:238
streamsize in_avail()
Definition: _streambuf.h:215
virtual ~basic_streambuf()
Definition: _streambuf.c:40
locale pubimbue(const locale &)
Definition: _streambuf.c:45
pos_type pubseekoff(off_type __offset, ios_base::seekdir __way, ios_base::openmode __mod=ios_base::in|ios_base::out)
Definition: _streambuf.h:145
char_type * gptr() const
Definition: _streambuf.h:88
void _M_setg(char_type *__gbegin, char_type *__gnext, char_type *__gend)
Definition: _streambuf.h:106
streamsize sputn(const char_type *__s, streamsize __n)
Definition: _streambuf.h:204
_Check_return_ _CRTIMP int __cdecl __cdecl eof(_In_ int _FileHandle)
virtual streamsize _M_xsputnc(char_type __c, streamsize __n)
Definition: _streambuf.c:112
virtual streamsize showmanyc()
Definition: _streambuf.c:175
GLuint in
Definition: glext.h:9616
virtual basic_streambuf< _CharT, _Traits > * setbuf(char_type *, streamsize)
Definition: _streambuf.c:199
#define _STLP_END_NAMESPACE
Definition: features.h:503
virtual streamsize xsputn(const char_type *__s, streamsize __n)
Definition: _streambuf.c:84
int_type sputbackc(char_type __c)
Definition: _streambuf.h:241
streamsize _M_sputnc(char_type __c, streamsize __n)
Definition: _streambuf.h:208
ptrdiff_t streamsize
Definition: char_traits.h:81
char_type * _M_pend
Definition: _streambuf.h:67
#define _STLP_BEGIN_NAMESPACE
Definition: features.h:501
virtual int_type uflow()
Definition: _streambuf.c:162
_Traits::off_type off_type
Definition: _streambuf.h:56
char_type * _M_gbegin
Definition: _streambuf.h:61
locale getloc() const
Definition: _streambuf.h:263
char_type * _M_pbegin
Definition: _streambuf.h:65
int_type sgetc()
Definition: _streambuf.h:233
virtual int_type underflow()
Definition: _streambuf.c:170