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 // Contains category and mode tags for classifying filters, devices and
9 // standard stream and stream buffers types.
10 
11 #ifndef BOOST_IOSTREAMS_CATEGORIES_HPP_INCLUDED
12 #define BOOST_IOSTREAMS_CATEGORIES_HPP_INCLUDED
13 
14 #if defined(_MSC_VER)
15 # pragma once
16 #endif
17 
18 namespace boost { namespace iostreams {
19 
20 //------------------Tags for dispatch according to i/o mode-------------------//
21 
22 struct any_tag { };
23 namespace detail { struct two_sequence : virtual any_tag { }; }
24 namespace detail { struct random_access : virtual any_tag { }; }
25 namespace detail { struct one_head : virtual any_tag { }; }
26 namespace detail { struct two_head : virtual any_tag { }; }
27 struct input : virtual any_tag { };
28 struct output : virtual any_tag { };
29 struct bidirectional : virtual input, virtual output, detail::two_sequence { };
30 struct dual_use : virtual input, virtual output { }; // Pseudo-mode.
31 struct input_seekable : virtual input, virtual detail::random_access { };
32 struct output_seekable : virtual output, virtual detail::random_access { };
33 struct seekable
34     : virtual input_seekable,
35       virtual output_seekable,
36       detail::one_head
37     { };
38 struct dual_seekable
39     : virtual input_seekable,
40       virtual output_seekable,
41       detail::two_head
42     { };
43 struct bidirectional_seekable
44     : input_seekable, output_seekable,
45       bidirectional, detail::two_head
46     { };
47 
48 //------------------Tags for use as i/o categories----------------------------//
49 
50 struct device_tag : virtual any_tag { };
51 struct filter_tag : virtual any_tag { };
52 
53     //
54     // Tags for optional behavior.
55     //
56 
57 struct peekable_tag : virtual any_tag { };        // Devices.
58 struct closable_tag : virtual any_tag { };
59 struct flushable_tag : virtual any_tag { };
60 struct localizable_tag : virtual any_tag { };
61 struct optimally_buffered_tag : virtual any_tag { };
62 struct direct_tag : virtual any_tag { };          // Devices.
63 struct multichar_tag : virtual any_tag { };       // Filters.
64 
65 struct source_tag : device_tag, input { };
66 struct sink_tag : device_tag, output { };
67 struct bidirectional_device_tag : device_tag, bidirectional { };
68 struct seekable_device_tag : virtual device_tag, seekable { };
69 
70 struct input_filter_tag : filter_tag, input { };
71 struct output_filter_tag : filter_tag, output { };
72 struct bidirectional_filter_tag : filter_tag, bidirectional { };
73 struct seekable_filter_tag : filter_tag, seekable { };
74 struct dual_use_filter_tag : filter_tag, dual_use { };
75 
76 struct multichar_input_filter_tag
77     : multichar_tag,
78       input_filter_tag
79     { };
80 struct multichar_output_filter_tag
81     : multichar_tag,
82       output_filter_tag
83     { };
84 struct multichar_bidirectional_filter_tag
85     : multichar_tag,
86       bidirectional_filter_tag
87     { };
88 struct multichar_seekable_filter_tag
89     : multichar_tag,
90       seekable_filter_tag
91     { };
92 struct multichar_dual_use_filter_tag
93     : multichar_tag,
94       dual_use_filter_tag
95     { };
96 
97     //
98     // Tags for standard streams and streambufs.
99     //
100 
101 struct std_io_tag : virtual localizable_tag { };
102 struct istream_tag
103     : virtual device_tag,
104       virtual peekable_tag,
105       virtual std_io_tag
106     { };
107 struct ostream_tag
108     : virtual device_tag,
109       virtual std_io_tag
110     { };
111 struct iostream_tag
112     : istream_tag,
113       ostream_tag
114     { };
115 struct streambuf_tag
116     : device_tag,
117       peekable_tag,
118       std_io_tag
119     { };
120 struct ifstream_tag
121     : input_seekable,
122       closable_tag,
123       istream_tag
124     { };
125 struct ofstream_tag
126     : output_seekable,
127       closable_tag,
128       ostream_tag
129     { };
130 struct fstream_tag
131     : seekable,
132       closable_tag,
133       iostream_tag
134     { };
135 struct filebuf_tag
136     : seekable,
137       closable_tag,
138       streambuf_tag
139     { };
140 struct istringstream_tag
141     : input_seekable,
142       istream_tag
143     { };
144 struct ostringstream_tag
145     : output_seekable,
146       ostream_tag
147     { };
148 struct stringstream_tag
149     : dual_seekable,
150       iostream_tag
151     { };
152 struct stringbuf_tag
153     : dual_seekable,
154       streambuf_tag
155     { };
156 struct generic_istream_tag
157     : input_seekable,
158       istream_tag
159     { };
160 struct generic_ostream_tag
161     : output_seekable,
162       ostream_tag
163     { };
164 struct generic_iostream_tag
165     : seekable,
166       iostream_tag
167     { };
168 struct generic_streambuf_tag
169     : seekable,
170       streambuf_tag
171     { };
172 
173 } } // End namespaces iostreams, boost.
174 
175 #endif // #ifndef BOOST_IOSTREAMS_CATEGORIES_HPP_INCLUDED
176