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 25 _STLP_BEGIN_NAMESPACE 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. 75 basic_streambuf() 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. 123 124 virtual basic_streambuf<_CharT, _Traits>* setbuf(char_type*, streamsize); 125 126 // Alters the stream position, using an integer offset. In this 127 // class seekoff does nothing; subclasses are expected to override it. 128 virtual pos_type seekoff(off_type, ios_base::seekdir, 129 ios_base::openmode = ios_base::in | ios_base::out); 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 134 seekpos(pos_type, ios_base::openmode = ios_base::in | ios_base::out); 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. 142 basic_streambuf<_CharT, _Traits>* pubsetbuf(char_type* __s, streamsize __n) 143 { return this->setbuf(__s, __n); } 144 145 pos_type pubseekoff(off_type __offset, ios_base::seekdir __way, 146 ios_base::openmode __mod = ios_base::in | ios_base::out) 147 { return this->seekoff(__offset, __way, __mod); } 148 149 pos_type pubseekpos(pos_type __sp, 150 ios_base::openmode __mod = ios_base::in | ios_base::out) 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. 179 virtual int_type pbackfail(int_type = traits_type::eof()); 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. 190 virtual streamsize _M_xsputnc(char_type __c, streamsize __n); 191 192 // Called when there is no write position. All subclasses are expected to 193 // override this virtual member function. 194 virtual int_type overflow(int_type = traits_type::eof()); 195 196 public: // Public members for writing characters. 197 // Write a single character. 198 int_type sputc(char_type __c) { 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. 204 streamsize sputn(const char_type* __s, streamsize __n) 205 { return this->xsputn(__s, __n); } 206 207 // Extension: write __n copies of __c. 208 streamsize _M_sputnc(char_type __c, streamsize __n) 209 { return this->_M_xsputnc(__c, __n); } 210 211 private: // Helper functions. 212 int_type _M_snextc_aux(); 213 214 public: // Public members for reading characters. 215 streamsize in_avail() { 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 } 237 238 streamsize sgetn(char_type* __s, streamsize __n) 239 { return this->xsgetn(__s, __n); } 240 241 int_type sputbackc(char_type __c) { 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 } 246 247 int_type sungetc() { 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) 271 _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<char, char_traits<char> >; 272 # if !defined (_STLP_NO_WCHAR_T) 273 _STLP_EXPORT_TEMPLATE_CLASS basic_streambuf<wchar_t, char_traits<wchar_t> >; 274 # endif // _STLP_NO_WCHAR_T 275 #endif // _STLP_USE_TEMPLATE_EXPORT 276 277 _STLP_END_NAMESPACE 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: 288
