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1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2005-2007 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 | // Contains implementations of get, read, put, write and seek which | |
9 | // check a device's mode at runtime instead of compile time. | |
10 | ||
11 | #ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED | |
12 | #define BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED | |
13 | ||
14 | #include <boost/iostreams/categories.hpp> | |
15 | #include <boost/iostreams/detail/dispatch.hpp> | |
16 | #include <boost/iostreams/detail/error.hpp> | |
17 | #include <boost/iostreams/detail/config/unreachable_return.hpp> | |
18 | #include <boost/iostreams/get.hpp> | |
19 | #include <boost/iostreams/put.hpp> | |
20 | #include <boost/iostreams/read.hpp> | |
21 | #include <boost/iostreams/seek.hpp> | |
22 | #include <boost/iostreams/traits.hpp> | |
23 | #include <boost/iostreams/write.hpp> | |
24 | #include <boost/throw_exception.hpp> | |
25 | ||
26 | // Must come last. | |
27 | #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC. | |
28 | ||
29 | namespace boost { namespace iostreams { | |
30 | ||
31 | namespace detail { | |
32 | ||
33 | template<typename T> | |
34 | struct read_write_if_impl; | |
35 | ||
36 | template<typename T> | |
37 | struct seek_if_impl; | |
38 | ||
39 | } // End namespace detail. | |
40 | ||
41 | template<typename T> | |
42 | typename int_type_of<T>::type get_if(T& t) | |
43 | { | |
44 | typedef typename detail::dispatch<T, input, output>::type tag; | |
45 | return detail::read_write_if_impl<tag>::get(t); | |
46 | } | |
47 | ||
48 | template<typename T> | |
49 | inline std::streamsize | |
50 | read_if(T& t, typename char_type_of<T>::type* s, std::streamsize n) | |
51 | { | |
52 | typedef typename detail::dispatch<T, input, output>::type tag; | |
53 | return detail::read_write_if_impl<tag>::read(t, s, n); | |
54 | } | |
55 | ||
56 | template<typename T> | |
57 | bool put_if(T& t, typename char_type_of<T>::type c) | |
58 | { | |
59 | typedef typename detail::dispatch<T, output, input>::type tag; | |
60 | return detail::read_write_if_impl<tag>::put(t, c); | |
61 | } | |
62 | ||
63 | template<typename T> | |
64 | inline std::streamsize write_if | |
65 | (T& t, const typename char_type_of<T>::type* s, std::streamsize n) | |
66 | { | |
67 | typedef typename detail::dispatch<T, output, input>::type tag; | |
68 | return detail::read_write_if_impl<tag>::write(t, s, n); | |
69 | } | |
70 | ||
71 | template<typename T> | |
72 | inline std::streampos | |
73 | seek_if( T& t, stream_offset off, BOOST_IOS::seekdir way, | |
74 | BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) | |
75 | { | |
76 | using namespace detail; | |
77 | typedef typename dispatch<T, random_access, any_tag>::type tag; | |
78 | return seek_if_impl<tag>::seek(t, off, way, which); | |
79 | } | |
80 | ||
81 | namespace detail { | |
82 | ||
83 | //------------------Specializations of read_write_if_impl---------------------// | |
84 | ||
85 | template<> | |
86 | struct read_write_if_impl<input> { | |
87 | template<typename T> | |
88 | static typename int_type_of<T>::type get(T& t) | |
89 | { return iostreams::get(t); } | |
90 | ||
91 | template<typename T> | |
92 | static std::streamsize | |
93 | read(T& t, typename char_type_of<T>::type* s, std::streamsize n) | |
94 | { return iostreams::read(t, s, n); } | |
95 | ||
96 | template<typename T> | |
97 | static bool put(T&, typename char_type_of<T>::type) | |
98 | { boost::throw_exception(cant_write()); | |
99 | BOOST_IOSTREAMS_UNREACHABLE_RETURN(false) } | |
100 | ||
101 | template<typename T> | |
102 | static std::streamsize | |
103 | write(T&, const typename char_type_of<T>::type*, std::streamsize) | |
104 | { boost::throw_exception(cant_write()); | |
105 | BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) } | |
106 | }; | |
107 | ||
108 | template<> | |
109 | struct read_write_if_impl<output> { | |
110 | template<typename T> | |
111 | static typename int_type_of<T>::type get(T&) | |
112 | { boost::throw_exception(cant_read()); | |
113 | BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) } | |
114 | ||
115 | template<typename T> | |
116 | static std::streamsize | |
117 | read(T&, typename char_type_of<T>::type*, std::streamsize) | |
118 | { boost::throw_exception(cant_read()); | |
119 | BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) } | |
120 | ||
121 | template<typename T> | |
122 | static bool put(T& t, typename char_type_of<T>::type c) | |
123 | { return iostreams::put(t, c); } | |
124 | ||
125 | template<typename T> | |
126 | static std::streamsize | |
127 | write( T& t, const typename char_type_of<T>::type* s, | |
128 | std::streamsize n ) | |
129 | { return iostreams::write(t, s, n); } | |
130 | }; | |
131 | ||
132 | //------------------Specializations of seek_if_impl---------------------------// | |
133 | ||
134 | template<> | |
135 | struct seek_if_impl<random_access> { | |
136 | template<typename T> | |
137 | static std::streampos | |
138 | seek( T& t, stream_offset off, BOOST_IOS::seekdir way, | |
139 | BOOST_IOS::openmode which ) | |
140 | { return iostreams::seek(t, off, way, which); } | |
141 | }; | |
142 | ||
143 | template<> | |
144 | struct seek_if_impl<any_tag> { | |
145 | template<typename T> | |
146 | static std::streampos | |
147 | seek(T&, stream_offset, BOOST_IOS::seekdir, BOOST_IOS::openmode) | |
148 | { boost::throw_exception(cant_seek()); | |
149 | BOOST_IOSTREAMS_UNREACHABLE_RETURN(std::streampos()) } | |
150 | }; | |
151 | ||
152 | } // End namespace detail. | |
153 | ||
154 | } } // End namespaces iostreams, boost. | |
155 | ||
156 | #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC. | |
157 | ||
158 | #endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED |