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// Position types -*- C++ -*- |
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// Copyright (C) 1997-2013 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. |
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// 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. |
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// 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. |
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// 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/>. |
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/** @file bits/postypes.h |
* This is an internal header file, included by other library headers. |
* Do not attempt to use it directly. @headername{iosfwd} |
*/ |
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// |
// ISO C++ 14882: 27.4.1 - Types |
// ISO C++ 14882: 27.4.3 - Template class fpos |
// |
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#ifndef _GLIBCXX_POSTYPES_H |
#define _GLIBCXX_POSTYPES_H 1 |
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#pragma GCC system_header |
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#include <cwchar> // For mbstate_t |
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// 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++0x). 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)) |
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#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 |
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#endif |
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namespace std _GLIBCXX_VISIBILITY(default) |
{ |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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// 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. |
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/** |
* @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 |
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/// Integral type for I/O operation counts and buffer sizes. |
typedef ptrdiff_t streamsize; // Signed integral type |
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/** |
* @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; |
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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() { } |
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// 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() { } |
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/// Convert to streamoff. |
operator streamoff() const { return _M_off; } |
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/// Remember the value of @a st. |
void |
state(_StateT __st) |
{ _M_state = __st; } |
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/// Return the last set value of @a st. |
_StateT |
state() const |
{ return _M_state; } |
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// 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; |
} |
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// 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; |
} |
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// 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; |
} |
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// 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; |
} |
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// 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; } |
}; |
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// 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); } |
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template<typename _StateT> |
inline bool |
operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) |
{ return streamoff(__lhs) != streamoff(__rhs); } |
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// 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; |
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#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 |
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_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace |
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#endif |