// Position types -*- C++ -*- // Copyright (C) 1997-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file bits/postypes.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{iosfwd} */ // // ISO C++ 14882: 27.4.1 - Types // ISO C++ 14882: 27.4.3 - Template class fpos // #ifndef _GLIBCXX_POSTYPES_H #define _GLIBCXX_POSTYPES_H 1 #pragma GCC system_header #include <cwchar> // For mbstate_t // XXX If <stdint.h> is really needed, make sure to define the macros // before including it, in order not to break <tr1/cstdint> (and <cstdint> // in C++11). Reconsider all this as soon as possible... #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \ && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)) #ifndef __STDC_LIMIT_MACROS # define _UNDEF__STDC_LIMIT_MACROS # define __STDC_LIMIT_MACROS #endif #ifndef __STDC_CONSTANT_MACROS # define _UNDEF__STDC_CONSTANT_MACROS # define __STDC_CONSTANT_MACROS #endif #include <stdint.h> // For int64_t #ifdef _UNDEF__STDC_LIMIT_MACROS # undef __STDC_LIMIT_MACROS # undef _UNDEF__STDC_LIMIT_MACROS #endif #ifdef _UNDEF__STDC_CONSTANT_MACROS # undef __STDC_CONSTANT_MACROS # undef _UNDEF__STDC_CONSTANT_MACROS #endif #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION // The types streamoff, streampos and wstreampos and the class // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the // behaviour of these types is mostly implementation defined or // unspecified. The behaviour in this implementation is as noted // below. /** * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. * * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an * implementation defined type. * Note: In versions of GCC up to and including GCC 3.3, streamoff * was typedef long. */ #ifdef _GLIBCXX_HAVE_INT64_T_LONG typedef long streamoff; #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG) typedef long long streamoff; #elif defined(_GLIBCXX_HAVE_INT64_T) typedef int64_t streamoff; #else typedef long long streamoff; #endif /// Integral type for I/O operation counts and buffer sizes. typedef ptrdiff_t streamsize; // Signed integral type /** * @brief Class representing stream positions. * * The standard places no requirements upon the template parameter StateT. * In this implementation StateT must be DefaultConstructible, * CopyConstructible and Assignable. The standard only requires that fpos * should contain a member of type StateT. In this implementation it also * contains an offset stored as a signed integer. * * @param StateT Type passed to and returned from state(). */ template<typename _StateT> class fpos { private: streamoff _M_off; _StateT _M_state; public: // The standard doesn't require that fpos objects can be default // constructed. This implementation provides a default // constructor that initializes the offset to 0 and default // constructs the state. fpos() : _M_off(0), _M_state() { } // The standard requires that fpos objects can be constructed // from streamoff objects using the constructor syntax, and // fails to give any meaningful semantics. In this // implementation implicit conversion is also allowed, and this // constructor stores the streamoff as the offset and default // constructs the state. /// Construct position from offset. fpos(streamoff __off) : _M_off(__off), _M_state() { } #if __cplusplus >= 201103L fpos(const fpos&) = default; fpos& operator=(const fpos&) = default; ~fpos() = default; #endif /// Convert to streamoff. operator streamoff() const { return _M_off; } /// Remember the value of @a st. void state(_StateT __st) { _M_state = __st; } /// Return the last set value of @a st. _StateT state() const { return _M_state; } // The standard requires that this operator must be defined, but // gives no semantics. In this implementation it just adds its // argument to the stored offset and returns *this. /// Add offset to this position. fpos& operator+=(streamoff __off) { _M_off += __off; return *this; } // The standard requires that this operator must be defined, but // gives no semantics. In this implementation it just subtracts // its argument from the stored offset and returns *this. /// Subtract offset from this position. fpos& operator-=(streamoff __off) { _M_off -= __off; return *this; } // The standard requires that this operator must be defined, but // defines its semantics only in terms of operator-. In this // implementation it constructs a copy of *this, adds the // argument to that copy using operator+= and then returns the // copy. /// Add position and offset. fpos operator+(streamoff __off) const { fpos __pos(*this); __pos += __off; return __pos; } // The standard requires that this operator must be defined, but // defines its semantics only in terms of operator+. In this // implementation it constructs a copy of *this, subtracts the // argument from that copy using operator-= and then returns the // copy. /// Subtract offset from position. fpos operator-(streamoff __off) const { fpos __pos(*this); __pos -= __off; return __pos; } // The standard requires that this operator must be defined, but // defines its semantics only in terms of operator+. In this // implementation it returns the difference between the offset // stored in *this and in the argument. /// Subtract position to return offset. streamoff operator-(const fpos& __other) const { return _M_off - __other._M_off; } }; // The standard only requires that operator== must be an // equivalence relation. In this implementation two fpos<StateT> // objects belong to the same equivalence class if the contained // offsets compare equal. /// Test if equivalent to another position. template<typename _StateT> inline bool operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) { return streamoff(__lhs) == streamoff(__rhs); } template<typename _StateT> inline bool operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) { return streamoff(__lhs) != streamoff(__rhs); } // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos // as implementation defined types, but clause 27.2 requires that // they must both be typedefs for fpos<mbstate_t> /// File position for char streams. typedef fpos<mbstate_t> streampos; /// File position for wchar_t streams. typedef fpos<mbstate_t> wstreampos; #ifdef _GLIBCXX_USE_CHAR8_T /// File position for char8_t streams. typedef fpos<mbstate_t> u8streampos; #endif #if __cplusplus >= 201103L /// File position for char16_t streams. typedef fpos<mbstate_t> u16streampos; /// File position for char32_t streams. typedef fpos<mbstate_t> u32streampos; #endif _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif