1// Position types -*- C++ -*-
2
3// Copyright (C) 1997-2021 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++11). 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
68namespace 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#if __cplusplus >= 201103L
137 fpos(const fpos&) = default;
138 fpos& operator=(const fpos&) = default;
139 ~fpos() = default;
140#endif
141
142 /// Convert to streamoff.
143 operator streamoff() const { return _M_off; }
144
145 /// Remember the value of @a st.
146 void
147 state(_StateT __st)
148 { _M_state = __st; }
149
150 /// Return the last set value of @a st.
151 _StateT
152 state() const
153 { return _M_state; }
154
155 // The standard requires that this operator must be defined, but
156 // gives no semantics. In this implementation it just adds its
157 // argument to the stored offset and returns *this.
158 /// Add offset to this position.
159 fpos&
160 operator+=(streamoff __off)
161 {
162 _M_off += __off;
163 return *this;
164 }
165
166 // The standard requires that this operator must be defined, but
167 // gives no semantics. In this implementation it just subtracts
168 // its argument from the stored offset and returns *this.
169 /// Subtract offset from this position.
170 fpos&
171 operator-=(streamoff __off)
172 {
173 _M_off -= __off;
174 return *this;
175 }
176
177 // The standard requires that this operator must be defined, but
178 // defines its semantics only in terms of operator-. In this
179 // implementation it constructs a copy of *this, adds the
180 // argument to that copy using operator+= and then returns the
181 // copy.
182 /// Add position and offset.
183 fpos
184 operator+(streamoff __off) const
185 {
186 fpos __pos(*this);
187 __pos += __off;
188 return __pos;
189 }
190
191 // The standard requires that this operator must be defined, but
192 // defines its semantics only in terms of operator+. In this
193 // implementation it constructs a copy of *this, subtracts the
194 // argument from that copy using operator-= and then returns the
195 // copy.
196 /// Subtract offset from position.
197 fpos
198 operator-(streamoff __off) const
199 {
200 fpos __pos(*this);
201 __pos -= __off;
202 return __pos;
203 }
204
205 // The standard requires that this operator must be defined, but
206 // defines its semantics only in terms of operator+. In this
207 // implementation it returns the difference between the offset
208 // stored in *this and in the argument.
209 /// Subtract position to return offset.
210 streamoff
211 operator-(const fpos& __other) const
212 { return _M_off - __other._M_off; }
213 };
214
215 // The standard only requires that operator== must be an
216 // equivalence relation. In this implementation two fpos<StateT>
217 // objects belong to the same equivalence class if the contained
218 // offsets compare equal.
219 /// Test if equivalent to another position.
220 template<typename _StateT>
221 inline bool
222 operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
223 { return streamoff(__lhs) == streamoff(__rhs); }
224
225 template<typename _StateT>
226 inline bool
227 operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
228 { return streamoff(__lhs) != streamoff(__rhs); }
229
230 // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos
231 // as implementation defined types, but clause 27.2 requires that
232 // they must both be typedefs for fpos<mbstate_t>
233 /// File position for char streams.
234 typedef fpos<mbstate_t> streampos;
235 /// File position for wchar_t streams.
236 typedef fpos<mbstate_t> wstreampos;
237
238#ifdef _GLIBCXX_USE_CHAR8_T
239 /// File position for char8_t streams.
240 typedef fpos<mbstate_t> u8streampos;
241#endif
242
243#if __cplusplus >= 201103L
244 /// File position for char16_t streams.
245 typedef fpos<mbstate_t> u16streampos;
246 /// File position for char32_t streams.
247 typedef fpos<mbstate_t> u32streampos;
248#endif
249
250_GLIBCXX_END_NAMESPACE_VERSION
251} // namespace
252
253#endif
254

source code of include/c++/11/bits/postypes.h