1 // Position types -*- C++ -*- 2 3 // Copyright (C) 1997-2013 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file bits/postypes.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{iosfwd} 28 */ 29 30 // 31 // ISO C++ 14882: 27.4.1 - Types 32 // ISO C++ 14882: 27.4.3 - Template class fpos 33 // 34 35 #ifndef _GLIBCXX_POSTYPES_H 36 #define _GLIBCXX_POSTYPES_H 1 37 38 #pragma GCC system_header 39 40 #include <cwchar> // For mbstate_t 41 42 // XXX If <stdint.h> is really needed, make sure to define the macros 43 // before including it, in order not to break <tr1/cstdint> (and <cstdint> 44 // in C++0x). Reconsider all this as soon as possible... 45 #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \ 46 && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)) 47 48 #ifndef __STDC_LIMIT_MACROS 49 # define _UNDEF__STDC_LIMIT_MACROS 50 # define __STDC_LIMIT_MACROS 51 #endif 52 #ifndef __STDC_CONSTANT_MACROS 53 # define _UNDEF__STDC_CONSTANT_MACROS 54 # define __STDC_CONSTANT_MACROS 55 #endif 56 #include <stdint.h> // For int64_t 57 #ifdef _UNDEF__STDC_LIMIT_MACROS 58 # undef __STDC_LIMIT_MACROS 59 # undef _UNDEF__STDC_LIMIT_MACROS 60 #endif 61 #ifdef _UNDEF__STDC_CONSTANT_MACROS 62 # undef __STDC_CONSTANT_MACROS 63 # undef _UNDEF__STDC_CONSTANT_MACROS 64 #endif 65 66 #endif 67 68 namespace std _GLIBCXX_VISIBILITY(default) 69 { 70 _GLIBCXX_BEGIN_NAMESPACE_VERSION 71 72 // The types streamoff, streampos and wstreampos and the class 73 // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, 74 // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the 75 // behaviour of these types is mostly implementation defined or 76 // unspecified. The behaviour in this implementation is as noted 77 // below. 78 79 /** 80 * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. 81 * 82 * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an 83 * implementation defined type. 84 * Note: In versions of GCC up to and including GCC 3.3, streamoff 85 * was typedef long. 86 */ 87 #ifdef _GLIBCXX_HAVE_INT64_T_LONG 88 typedef long streamoff; 89 #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG) 90 typedef long long streamoff; 91 #elif defined(_GLIBCXX_HAVE_INT64_T) 92 typedef int64_t streamoff; 93 #else 94 typedef long long streamoff; 95 #endif 96 97 /// Integral type for I/O operation counts and buffer sizes. 98 typedef ptrdiff_t streamsize; // Signed integral type 99 100 /** 101 * @brief Class representing stream positions. 102 * 103 * The standard places no requirements upon the template parameter StateT. 104 * In this implementation StateT must be DefaultConstructible, 105 * CopyConstructible and Assignable. The standard only requires that fpos 106 * should contain a member of type StateT. In this implementation it also 107 * contains an offset stored as a signed integer. 108 * 109 * @param StateT Type passed to and returned from state(). 110 */ 111 template<typename _StateT> 112 class fpos 113 { 114 private: 115 streamoff _M_off; 116 _StateT _M_state; 117 118 public: 119 // The standard doesn't require that fpos objects can be default 120 // constructed. This implementation provides a default 121 // constructor that initializes the offset to 0 and default 122 // constructs the state. 123 fpos() 124 : _M_off(0), _M_state() { } 125 126 // The standard requires that fpos objects can be constructed 127 // from streamoff objects using the constructor syntax, and 128 // fails to give any meaningful semantics. In this 129 // implementation implicit conversion is also allowed, and this 130 // constructor stores the streamoff as the offset and default 131 // constructs the state. 132 /// Construct position from offset. 133 fpos(streamoff __off) 134 : _M_off(__off), _M_state() { } 135 136 /// Convert to streamoff. 137 operator streamoff() const { return _M_off; } 138 139 /// Remember the value of @a st. 140 void 141 state(_StateT __st) 142 { _M_state = __st; } 143 144 /// Return the last set value of @a st. 145 _StateT 146 state() const 147 { return _M_state; } 148 149 // The standard requires that this operator must be defined, but 150 // gives no semantics. In this implementation it just adds its 151 // argument to the stored offset and returns *this. 152 /// Add offset to this position. 153 fpos& 154 operator+=(streamoff __off) 155 { 156 _M_off += __off; 157 return *this; 158 } 159 160 // The standard requires that this operator must be defined, but 161 // gives no semantics. In this implementation it just subtracts 162 // its argument from the stored offset and returns *this. 163 /// Subtract offset from this position. 164 fpos& 165 operator-=(streamoff __off) 166 { 167 _M_off -= __off; 168 return *this; 169 } 170 171 // The standard requires that this operator must be defined, but 172 // defines its semantics only in terms of operator-. In this 173 // implementation it constructs a copy of *this, adds the 174 // argument to that copy using operator+= and then returns the 175 // copy. 176 /// Add position and offset. 177 fpos 178 operator+(streamoff __off) const 179 { 180 fpos __pos(*this); 181 __pos += __off; 182 return __pos; 183 } 184 185 // The standard requires that this operator must be defined, but 186 // defines its semantics only in terms of operator+. In this 187 // implementation it constructs a copy of *this, subtracts the 188 // argument from that copy using operator-= and then returns the 189 // copy. 190 /// Subtract offset from position. 191 fpos 192 operator-(streamoff __off) const 193 { 194 fpos __pos(*this); 195 __pos -= __off; 196 return __pos; 197 } 198 199 // The standard requires that this operator must be defined, but 200 // defines its semantics only in terms of operator+. In this 201 // implementation it returns the difference between the offset 202 // stored in *this and in the argument. 203 /// Subtract position to return offset. 204 streamoff 205 operator-(const fpos& __other) const 206 { return _M_off - __other._M_off; } 207 }; 208 209 // The standard only requires that operator== must be an 210 // equivalence relation. In this implementation two fpos<StateT> 211 // objects belong to the same equivalence class if the contained 212 // offsets compare equal. 213 /// Test if equivalent to another position. 214 template<typename _StateT> 215 inline bool 216 operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 217 { return streamoff(__lhs) == streamoff(__rhs); } 218 219 template<typename _StateT> 220 inline bool 221 operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 222 { return streamoff(__lhs) != streamoff(__rhs); } 223 224 // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos 225 // as implementation defined types, but clause 27.2 requires that 226 // they must both be typedefs for fpos<mbstate_t> 227 /// File position for char streams. 228 typedef fpos<mbstate_t> streampos; 229 /// File position for wchar_t streams. 230 typedef fpos<mbstate_t> wstreampos; 231 232 #if __cplusplus >= 201103L 233 /// File position for char16_t streams. 234 typedef fpos<mbstate_t> u16streampos; 235 /// File position for char32_t streams. 236 typedef fpos<mbstate_t> u32streampos; 237 #endif 238 239 _GLIBCXX_END_NAMESPACE_VERSION 240 } // namespace 241 242 #endif 243
