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1 | // Position types -*- C++ -*- |
2 | ||
ee60de36 | 3 | // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, |
4312e020 | 4 | // 2006, 2007, 2008 |
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5 | // Free Software Foundation, Inc. |
6 | // | |
7 | // This file is part of the GNU ISO C++ Library. This library is free | |
8 | // software; you can redistribute it and/or modify it under the | |
9 | // terms of the GNU General Public License as published by the | |
10 | // Free Software Foundation; either version 2, or (at your option) | |
11 | // any later version. | |
12 | ||
13 | // This library is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License along | |
19 | // with this library; see the file COPYING. If not, write to the Free | |
83f51799 | 20 | // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
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21 | // USA. |
22 | ||
23 | // As a special exception, you may use this file as part of a free software | |
24 | // library without restriction. Specifically, if other files instantiate | |
25 | // templates or use macros or inline functions from this file, or you compile | |
26 | // this file and link it with other files to produce an executable, this | |
27 | // file does not by itself cause the resulting executable to be covered by | |
28 | // the GNU General Public License. This exception does not however | |
29 | // invalidate any other reasons why the executable file might be covered by | |
30 | // the GNU General Public License. | |
31 | ||
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32 | /** @file postypes.h |
33 | * This is an internal header file, included by other library headers. | |
34 | * You should not attempt to use it directly. | |
35 | */ | |
36 | ||
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37 | // |
38 | // ISO C++ 14882: 27.4.1 - Types | |
39 | // ISO C++ 14882: 27.4.3 - Template class fpos | |
40 | // | |
41 | ||
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42 | #ifndef _GLIBCXX_POSTYPES_H |
43 | #define _GLIBCXX_POSTYPES_H 1 | |
44 | ||
45 | #pragma GCC system_header | |
46 | ||
47 | #include <cwchar> // For mbstate_t | |
48 | ||
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49 | #ifdef _GLIBCXX_HAVE_STDINT_H |
50 | #include <stdint.h> // For int64_t | |
51 | #endif | |
52 | ||
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53 | _GLIBCXX_BEGIN_NAMESPACE(std) |
54 | ||
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55 | // The types streamoff, streampos and wstreampos and the class |
56 | // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, | |
57 | // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbage, the | |
58 | // behaviour of these types is mostly implementation defined or | |
59 | // unspecified. The behaviour in this implementation is as noted | |
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60 | // below. |
61 | ||
0b1d67d2 PC |
62 | /** |
63 | * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. | |
64 | * | |
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65 | * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an |
66 | * implementation defined type. | |
67 | * Note: In versions of GCC up to and including GCC 3.3, streamoff | |
68 | * was typedef long. | |
0b1d67d2 | 69 | */ |
3d05b345 | 70 | #ifdef _GLIBCXX_HAVE_INT64_T |
0b1d67d2 | 71 | typedef int64_t streamoff; |
3d05b345 | 72 | #else |
0b1d67d2 | 73 | typedef long long streamoff; |
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74 | #endif |
75 | ||
ffcec5c8 | 76 | /// Integral type for I/O operation counts and buffer sizes. |
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77 | typedef ptrdiff_t streamsize; // Signed integral type |
78 | ||
ffcec5c8 JQ |
79 | /** |
80 | * @brief Class representing stream positions. | |
81 | * | |
82 | * The standard places no requirements upon the template parameter StateT. | |
83 | * In this implementation StateT must be DefaultConstructible, | |
84 | * CopyConstructible and Assignable. The standard only requires that fpos | |
85 | * should contain a member of type StateT. In this implementation it also | |
86 | * contains an offset stored as a signed integer. | |
87 | * | |
88 | * @param StateT Type passed to and returned from state(). | |
89 | */ | |
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90 | template<typename _StateT> |
91 | class fpos | |
92 | { | |
93 | private: | |
0b1d67d2 | 94 | streamoff _M_off; |
ed6814f7 | 95 | _StateT _M_state; |
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96 | |
97 | public: | |
98 | // The standard doesn't require that fpos objects can be default | |
99 | // constructed. This implementation provides a default | |
100 | // constructor that initializes the offset to 0 and default | |
101 | // constructs the state. | |
102 | fpos() | |
103 | : _M_off(0), _M_state() { } | |
104 | ||
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105 | // The standard requires that fpos objects can be constructed |
106 | // from streamoff objects using the constructor syntax, and | |
107 | // fails to give any meaningful semantics. In this | |
108 | // implementation implicit conversion is also allowed, and this | |
109 | // constructor stores the streamoff as the offset and default | |
110 | // constructs the state. | |
ffcec5c8 | 111 | /// Construct position from offset. |
0b1d67d2 | 112 | fpos(streamoff __off) |
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113 | : _M_off(__off), _M_state() { } |
114 | ||
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115 | /// Convert to streamoff. |
116 | operator streamoff() const { return _M_off; } | |
117 | ||
ffcec5c8 | 118 | /// Remember the value of @a st. |
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119 | void |
120 | state(_StateT __st) | |
121 | { _M_state = __st; } | |
122 | ||
ffcec5c8 | 123 | /// Return the last set value of @a st. |
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124 | _StateT |
125 | state() const | |
126 | { return _M_state; } | |
127 | ||
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128 | // The standard requires that this operator must be defined, but |
129 | // gives no semantics. In this implemenation it just adds it's | |
130 | // argument to the stored offset and returns *this. | |
ffcec5c8 | 131 | /// Add offset to this position. |
4c4809c1 | 132 | fpos& |
0b1d67d2 | 133 | operator+=(streamoff __off) |
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134 | { |
135 | _M_off += __off; | |
136 | return *this; | |
137 | } | |
138 | ||
139 | // The standard requires that this operator must be defined, but | |
140 | // gives no semantics. In this implemenation it just subtracts | |
141 | // it's argument from the stored offset and returns *this. | |
ffcec5c8 | 142 | /// Subtract offset from this position. |
4c4809c1 | 143 | fpos& |
0b1d67d2 | 144 | operator-=(streamoff __off) |
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145 | { |
146 | _M_off -= __off; | |
147 | return *this; | |
148 | } | |
149 | ||
150 | // The standard requires that this operator must be defined, but | |
151 | // defines it's semantics only in terms of operator-. In this | |
152 | // implementation it constructs a copy of *this, adds the | |
153 | // argument to that copy using operator+= and then returns the | |
154 | // copy. | |
ffcec5c8 | 155 | /// Add position and offset. |
4c4809c1 | 156 | fpos |
0b1d67d2 | 157 | operator+(streamoff __off) const |
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158 | { |
159 | fpos __pos(*this); | |
160 | __pos += __off; | |
161 | return __pos; | |
162 | } | |
163 | ||
164 | // The standard requires that this operator must be defined, but | |
165 | // defines it's semantics only in terms of operator+. In this | |
166 | // implementation it constructs a copy of *this, subtracts the | |
167 | // argument from that copy using operator-= and then returns the | |
168 | // copy. | |
ffcec5c8 | 169 | /// Subtract offset from position. |
4c4809c1 | 170 | fpos |
0b1d67d2 | 171 | operator-(streamoff __off) const |
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172 | { |
173 | fpos __pos(*this); | |
174 | __pos -= __off; | |
175 | return __pos; | |
176 | } | |
177 | ||
178 | // The standard requires that this operator must be defined, but | |
179 | // defines it's semantics only in terms of operator+. In this | |
180 | // implementation it returns the difference between the offset | |
181 | // stored in *this and in the argument. | |
ffcec5c8 | 182 | /// Subtract position to return offset. |
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183 | streamoff |
184 | operator-(const fpos& __other) const | |
185 | { return _M_off - __other._M_off; } | |
186 | }; | |
187 | ||
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188 | // The standard only requires that operator== must be an |
189 | // equivalence relation. In this implementation two fpos<StateT> | |
190 | // objects belong to the same equivalence class if the contained | |
191 | // offsets compare equal. | |
192 | /// Test if equivalent to another position. | |
193 | template<typename _StateT> | |
194 | inline bool | |
195 | operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) | |
196 | { return streamoff(__lhs) == streamoff(__rhs); } | |
197 | ||
198 | template<typename _StateT> | |
199 | inline bool | |
200 | operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) | |
201 | { return streamoff(__lhs) != streamoff(__rhs); } | |
202 | ||
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203 | // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos |
204 | // as implementation defined types, but clause 27.2 requires that | |
205 | // they must both be typedefs for fpos<mbstate_t> | |
ffcec5c8 | 206 | /// File position for char streams. |
4c4809c1 | 207 | typedef fpos<mbstate_t> streampos; |
ffcec5c8 | 208 | /// File position for wchar_t streams. |
4c4809c1 | 209 | typedef fpos<mbstate_t> wstreampos; |
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210 | |
211 | _GLIBCXX_END_NAMESPACE | |
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212 | |
213 | #endif |