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>
get_if(T & 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
read_if(T & t,typename char_type_of<T>::type * s,std::streamsize n)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>
put_if(T & t,typename char_type_of<T>::type c)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>
write_if(T & t,const typename char_type_of<T>::type * s,std::streamsize n)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
seek_if(T & t,stream_offset off,BOOST_IOS::seekdir way,BOOST_IOS::openmode which=BOOST_IOS::in|BOOST_IOS::out)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>
getboost::iostreams::detail::read_write_if_impl88 static typename int_type_of<T>::type get(T& t)
89 { return iostreams::get(t); }
90
91 template<typename T>
92 static std::streamsize
readboost::iostreams::detail::read_write_if_impl93 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>
putboost::iostreams::detail::read_write_if_impl97 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
writeboost::iostreams::detail::read_write_if_impl103 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>
getboost::iostreams::detail::read_write_if_impl111 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
readboost::iostreams::detail::read_write_if_impl117 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>
putboost::iostreams::detail::read_write_if_impl122 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
writeboost::iostreams::detail::read_write_if_impl127 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
seekboost::iostreams::detail::seek_if_impl138 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
seekboost::iostreams::detail::seek_if_impl147 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
159