1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2003-2007 Jonathan Turkanis |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) |
5 | |
6 | // See http://www.boost.org/libs/iostreams for documentation. |
7 | |
8 | #ifndef BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
9 | #define BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
10 | |
11 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
12 | # pragma once |
13 | #endif |
14 | |
15 | #include <boost/config.hpp> // DEDUCED_TYPENAME, MSVC. |
16 | #include <boost/integer_traits.hpp> |
17 | #include <boost/iostreams/categories.hpp> |
18 | #include <boost/iostreams/detail/dispatch.hpp> |
19 | #include <boost/iostreams/detail/ios.hpp> // streamsize, seekdir, openmode. |
20 | #include <boost/iostreams/detail/streambuf.hpp> |
21 | #include <boost/iostreams/detail/wrap_unwrap.hpp> |
22 | #include <boost/iostreams/operations_fwd.hpp> |
23 | #include <boost/iostreams/positioning.hpp> |
24 | #include <boost/mpl/if.hpp> |
25 | |
26 | // Must come last. |
27 | #include <boost/iostreams/detail/config/disable_warnings.hpp> |
28 | |
29 | namespace boost { namespace iostreams { |
30 | |
31 | namespace detail { |
32 | |
33 | template<typename T> |
34 | struct seek_device_impl; |
35 | |
36 | template<typename T> |
37 | struct seek_filter_impl; |
38 | |
39 | } // End namespace detail. |
40 | |
41 | template<typename T> |
42 | inline std::streampos |
43 | seek( T& t, stream_offset off, BOOST_IOS::seekdir way, |
44 | BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) |
45 | { |
46 | using namespace detail; |
47 | return seek_device_impl<T>::seek(detail::unwrap(t), off, way, which); |
48 | } |
49 | |
50 | template<typename T, typename Device> |
51 | inline std::streampos |
52 | seek( T& t, Device& dev, stream_offset off, BOOST_IOS::seekdir way, |
53 | BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) |
54 | { |
55 | using namespace detail; |
56 | return seek_filter_impl<T>::seek(detail::unwrap(t), dev, off, way, which); |
57 | } |
58 | |
59 | namespace detail { |
60 | |
61 | //------------------Definition of seek_device_impl----------------------------// |
62 | |
63 | template<typename T> |
64 | struct seek_device_impl |
65 | : mpl::if_< |
66 | is_custom<T>, |
67 | operations<T>, |
68 | seek_device_impl< |
69 | BOOST_DEDUCED_TYPENAME |
70 | dispatch< |
71 | T, iostream_tag, istream_tag, ostream_tag, |
72 | streambuf_tag, two_head, any_tag |
73 | >::type |
74 | > |
75 | >::type |
76 | { }; |
77 | |
78 | struct seek_impl_basic_ios { |
79 | template<typename T> |
80 | static std::streampos seek( T& t, stream_offset off, |
81 | BOOST_IOS::seekdir way, |
82 | BOOST_IOS::openmode which ) |
83 | { |
84 | if ( way == BOOST_IOS::beg && |
85 | ( off < integer_traits<std::streamoff>::const_min || |
86 | off > integer_traits<std::streamoff>::const_max ) ) |
87 | { |
88 | return t.rdbuf()->pubseekpos(offset_to_position(off)); |
89 | } else { |
90 | return t.rdbuf()->pubseekoff(off, way, which); |
91 | } |
92 | } |
93 | }; |
94 | |
95 | template<> |
96 | struct seek_device_impl<iostream_tag> : seek_impl_basic_ios { }; |
97 | |
98 | template<> |
99 | struct seek_device_impl<istream_tag> : seek_impl_basic_ios { }; |
100 | |
101 | template<> |
102 | struct seek_device_impl<ostream_tag> : seek_impl_basic_ios { }; |
103 | |
104 | template<> |
105 | struct seek_device_impl<streambuf_tag> { |
106 | template<typename T> |
107 | static std::streampos seek( T& t, stream_offset off, |
108 | BOOST_IOS::seekdir way, |
109 | BOOST_IOS::openmode which ) |
110 | { |
111 | if ( way == BOOST_IOS::beg && |
112 | ( off < integer_traits<std::streamoff>::const_min || |
113 | off > integer_traits<std::streamoff>::const_max ) ) |
114 | { |
115 | return t.BOOST_IOSTREAMS_PUBSEEKPOS(offset_to_position(off)); |
116 | } else { |
117 | return t.BOOST_IOSTREAMS_PUBSEEKOFF(off, way, which); |
118 | } |
119 | } |
120 | }; |
121 | |
122 | template<> |
123 | struct seek_device_impl<two_head> { |
124 | template<typename T> |
125 | static std::streampos seek( T& t, stream_offset off, |
126 | BOOST_IOS::seekdir way, |
127 | BOOST_IOS::openmode which ) |
128 | { return t.seek(off, way, which); } |
129 | }; |
130 | |
131 | template<> |
132 | struct seek_device_impl<any_tag> { |
133 | template<typename T> |
134 | static std::streampos seek( T& t, stream_offset off, |
135 | BOOST_IOS::seekdir way, |
136 | BOOST_IOS::openmode ) |
137 | { return t.seek(off, way); } |
138 | }; |
139 | |
140 | //------------------Definition of seek_filter_impl----------------------------// |
141 | |
142 | template<typename T> |
143 | struct seek_filter_impl |
144 | : mpl::if_< |
145 | is_custom<T>, |
146 | operations<T>, |
147 | seek_filter_impl< |
148 | BOOST_DEDUCED_TYPENAME |
149 | dispatch<T, two_head, any_tag>::type |
150 | > |
151 | >::type |
152 | { }; |
153 | |
154 | template<> |
155 | struct seek_filter_impl<two_head> { |
156 | template<typename T, typename Device> |
157 | static std::streampos seek( T& t, Device& d, |
158 | stream_offset off, |
159 | BOOST_IOS::seekdir way, |
160 | BOOST_IOS::openmode which ) |
161 | { return t.seek(d, off, way, which); } |
162 | }; |
163 | |
164 | template<> |
165 | struct seek_filter_impl<any_tag> { |
166 | template<typename T, typename Device> |
167 | static std::streampos seek( T& t, Device& d, |
168 | stream_offset off, |
169 | BOOST_IOS::seekdir way, |
170 | BOOST_IOS::openmode ) |
171 | { return t.seek(d, off, way); } |
172 | }; |
173 | |
174 | } // End namespace detail. |
175 | |
176 | } } // End namespaces iostreams, boost. |
177 | |
178 | #include <boost/iostreams/detail/config/enable_warnings.hpp> |
179 | |
180 | #endif // #ifndef BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
181 | |