libstdc++
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00001 // Position types -*- C++ -*- 00002 00003 // Copyright (C) 1997-2019 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/postypes.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{iosfwd} 00028 */ 00029 00030 // 00031 // ISO C++ 14882: 27.4.1 - Types 00032 // ISO C++ 14882: 27.4.3 - Template class fpos 00033 // 00034 00035 #ifndef _GLIBCXX_POSTYPES_H 00036 #define _GLIBCXX_POSTYPES_H 1 00037 00038 #pragma GCC system_header 00039 00040 #include <cwchar> // For mbstate_t 00041 00042 // XXX If <stdint.h> is really needed, make sure to define the macros 00043 // before including it, in order not to break <tr1/cstdint> (and <cstdint> 00044 // in C++11). Reconsider all this as soon as possible... 00045 #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \ 00046 && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)) 00047 00048 #ifndef __STDC_LIMIT_MACROS 00049 # define _UNDEF__STDC_LIMIT_MACROS 00050 # define __STDC_LIMIT_MACROS 00051 #endif 00052 #ifndef __STDC_CONSTANT_MACROS 00053 # define _UNDEF__STDC_CONSTANT_MACROS 00054 # define __STDC_CONSTANT_MACROS 00055 #endif 00056 #include <stdint.h> // For int64_t 00057 #ifdef _UNDEF__STDC_LIMIT_MACROS 00058 # undef __STDC_LIMIT_MACROS 00059 # undef _UNDEF__STDC_LIMIT_MACROS 00060 #endif 00061 #ifdef _UNDEF__STDC_CONSTANT_MACROS 00062 # undef __STDC_CONSTANT_MACROS 00063 # undef _UNDEF__STDC_CONSTANT_MACROS 00064 #endif 00065 00066 #endif 00067 00068 namespace std _GLIBCXX_VISIBILITY(default) 00069 { 00070 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00071 00072 // The types streamoff, streampos and wstreampos and the class 00073 // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, 00074 // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the 00075 // behaviour of these types is mostly implementation defined or 00076 // unspecified. The behaviour in this implementation is as noted 00077 // below. 00078 00079 /** 00080 * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. 00081 * 00082 * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an 00083 * implementation defined type. 00084 * Note: In versions of GCC up to and including GCC 3.3, streamoff 00085 * was typedef long. 00086 */ 00087 #ifdef _GLIBCXX_HAVE_INT64_T_LONG 00088 typedef long streamoff; 00089 #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG) 00090 typedef long long streamoff; 00091 #elif defined(_GLIBCXX_HAVE_INT64_T) 00092 typedef int64_t streamoff; 00093 #else 00094 typedef long long streamoff; 00095 #endif 00096 00097 /// Integral type for I/O operation counts and buffer sizes. 00098 typedef ptrdiff_t streamsize; // Signed integral type 00099 00100 /** 00101 * @brief Class representing stream positions. 00102 * 00103 * The standard places no requirements upon the template parameter StateT. 00104 * In this implementation StateT must be DefaultConstructible, 00105 * CopyConstructible and Assignable. The standard only requires that fpos 00106 * should contain a member of type StateT. In this implementation it also 00107 * contains an offset stored as a signed integer. 00108 * 00109 * @param StateT Type passed to and returned from state(). 00110 */ 00111 template<typename _StateT> 00112 class fpos 00113 { 00114 private: 00115 streamoff _M_off; 00116 _StateT _M_state; 00117 00118 public: 00119 // The standard doesn't require that fpos objects can be default 00120 // constructed. This implementation provides a default 00121 // constructor that initializes the offset to 0 and default 00122 // constructs the state. 00123 fpos() 00124 : _M_off(0), _M_state() { } 00125 00126 // The standard requires that fpos objects can be constructed 00127 // from streamoff objects using the constructor syntax, and 00128 // fails to give any meaningful semantics. In this 00129 // implementation implicit conversion is also allowed, and this 00130 // constructor stores the streamoff as the offset and default 00131 // constructs the state. 00132 /// Construct position from offset. 00133 fpos(streamoff __off) 00134 : _M_off(__off), _M_state() { } 00135 00136 #if __cplusplus >= 201103L 00137 fpos(const fpos&) = default; 00138 fpos& operator=(const fpos&) = default; 00139 ~fpos() = default; 00140 #endif 00141 00142 /// Convert to streamoff. 00143 operator streamoff() const { return _M_off; } 00144 00145 /// Remember the value of @a st. 00146 void 00147 state(_StateT __st) 00148 { _M_state = __st; } 00149 00150 /// Return the last set value of @a st. 00151 _StateT 00152 state() const 00153 { return _M_state; } 00154 00155 // The standard requires that this operator must be defined, but 00156 // gives no semantics. In this implementation it just adds its 00157 // argument to the stored offset and returns *this. 00158 /// Add offset to this position. 00159 fpos& 00160 operator+=(streamoff __off) 00161 { 00162 _M_off += __off; 00163 return *this; 00164 } 00165 00166 // The standard requires that this operator must be defined, but 00167 // gives no semantics. In this implementation it just subtracts 00168 // its argument from the stored offset and returns *this. 00169 /// Subtract offset from this position. 00170 fpos& 00171 operator-=(streamoff __off) 00172 { 00173 _M_off -= __off; 00174 return *this; 00175 } 00176 00177 // The standard requires that this operator must be defined, but 00178 // defines its semantics only in terms of operator-. In this 00179 // implementation it constructs a copy of *this, adds the 00180 // argument to that copy using operator+= and then returns the 00181 // copy. 00182 /// Add position and offset. 00183 fpos 00184 operator+(streamoff __off) const 00185 { 00186 fpos __pos(*this); 00187 __pos += __off; 00188 return __pos; 00189 } 00190 00191 // The standard requires that this operator must be defined, but 00192 // defines its semantics only in terms of operator+. In this 00193 // implementation it constructs a copy of *this, subtracts the 00194 // argument from that copy using operator-= and then returns the 00195 // copy. 00196 /// Subtract offset from position. 00197 fpos 00198 operator-(streamoff __off) const 00199 { 00200 fpos __pos(*this); 00201 __pos -= __off; 00202 return __pos; 00203 } 00204 00205 // The standard requires that this operator must be defined, but 00206 // defines its semantics only in terms of operator+. In this 00207 // implementation it returns the difference between the offset 00208 // stored in *this and in the argument. 00209 /// Subtract position to return offset. 00210 streamoff 00211 operator-(const fpos& __other) const 00212 { return _M_off - __other._M_off; } 00213 }; 00214 00215 // The standard only requires that operator== must be an 00216 // equivalence relation. In this implementation two fpos<StateT> 00217 // objects belong to the same equivalence class if the contained 00218 // offsets compare equal. 00219 /// Test if equivalent to another position. 00220 template<typename _StateT> 00221 inline bool 00222 operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 00223 { return streamoff(__lhs) == streamoff(__rhs); } 00224 00225 template<typename _StateT> 00226 inline bool 00227 operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 00228 { return streamoff(__lhs) != streamoff(__rhs); } 00229 00230 // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos 00231 // as implementation defined types, but clause 27.2 requires that 00232 // they must both be typedefs for fpos<mbstate_t> 00233 /// File position for char streams. 00234 typedef fpos<mbstate_t> streampos; 00235 /// File position for wchar_t streams. 00236 typedef fpos<mbstate_t> wstreampos; 00237 00238 #ifdef _GLIBCXX_USE_CHAR8_T 00239 /// File position for char8_t streams. 00240 typedef fpos<mbstate_t> u8streampos; 00241 #endif 00242 00243 #if __cplusplus >= 201103L 00244 /// File position for char16_t streams. 00245 typedef fpos<mbstate_t> u16streampos; 00246 /// File position for char32_t streams. 00247 typedef fpos<mbstate_t> u32streampos; 00248 #endif 00249 00250 _GLIBCXX_END_NAMESPACE_VERSION 00251 } // namespace 00252 00253 #endif