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(e: 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(e: 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(e: 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(e: 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(e: 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 |
159 | |