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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_AGGREGATE_FILTER_HPP_INCLUDED | |
9 | #define BOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED | |
10 | ||
11 | #if defined(_MSC_VER) | |
12 | # pragma once | |
13 | #endif | |
14 | ||
15 | #include <algorithm> // copy, min. | |
16 | #include <boost/assert.hpp> | |
17 | #include <iterator> // back_inserter | |
18 | #include <vector> | |
19 | #include <boost/iostreams/constants.hpp> // default_device_buffer_size | |
20 | #include <boost/iostreams/categories.hpp> | |
21 | #include <boost/iostreams/detail/char_traits.hpp> | |
22 | #include <boost/iostreams/detail/ios.hpp> // openmode, streamsize. | |
23 | #include <boost/iostreams/pipeline.hpp> | |
24 | #include <boost/iostreams/read.hpp> // check_eof | |
25 | #include <boost/iostreams/write.hpp> | |
26 | #include <boost/mpl/bool.hpp> | |
27 | #include <boost/type_traits/is_convertible.hpp> | |
28 | ||
29 | // Must come last. | |
30 | #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC. | |
31 | ||
32 | namespace boost { namespace iostreams { | |
33 | ||
34 | // | |
35 | // Template name: aggregate_filter. | |
36 | // Template parameters: | |
37 | // Ch - The character type. | |
38 | // Alloc - The allocator type. | |
39 | // Description: Utility for defining DualUseFilters which filter an | |
40 | // entire stream at once. To use, override the protected virtual | |
41 | // member do_filter. | |
42 | // Note: This filter should not be copied while it is in use. | |
43 | // | |
44 | template<typename Ch, typename Alloc = std::allocator<Ch> > | |
45 | class aggregate_filter { | |
46 | public: | |
47 | typedef Ch char_type; | |
48 | struct category | |
49 | : dual_use, | |
50 | filter_tag, | |
51 | multichar_tag, | |
52 | closable_tag | |
53 | { }; | |
54 | aggregate_filter() : ptr_(0), state_(0) { } | |
55 | virtual ~aggregate_filter() { } | |
56 | ||
57 | template<typename Source> | |
58 | std::streamsize read(Source& src, char_type* s, std::streamsize n) | |
59 | { | |
60 | using namespace std; | |
61 | BOOST_ASSERT(!(state_ & f_write)); | |
62 | state_ |= f_read; | |
63 | if (!(state_ & f_eof)) | |
64 | do_read(src); | |
65 | std::streamsize amt = | |
66 | (std::min)(n, static_cast<std::streamsize>(data_.size() - ptr_)); | |
67 | if (amt) { | |
68 | BOOST_IOSTREAMS_CHAR_TRAITS(char_type)::copy(s, &data_[ptr_], amt); | |
69 | ptr_ += amt; | |
70 | } | |
71 | return detail::check_eof(amt); | |
72 | } | |
73 | ||
74 | template<typename Sink> | |
75 | std::streamsize write(Sink&, const char_type* s, std::streamsize n) | |
76 | { | |
77 | BOOST_ASSERT(!(state_ & f_read)); | |
78 | state_ |= f_write; | |
79 | data_.insert(data_.end(), s, s + n); | |
80 | return n; | |
81 | } | |
82 | ||
83 | template<typename Sink> | |
84 | void close(Sink& sink, BOOST_IOS::openmode which) | |
85 | { | |
86 | if ((state_ & f_read) != 0 && which == BOOST_IOS::in) | |
87 | close_impl(); | |
88 | if ((state_ & f_write) != 0 && which == BOOST_IOS::out) { | |
89 | try { | |
90 | vector_type filtered; | |
91 | do_filter(data_, filtered); | |
92 | do_write( | |
93 | sink, &filtered[0], | |
94 | static_cast<std::streamsize>(filtered.size()) | |
95 | ); | |
96 | } catch (...) { | |
97 | close_impl(); | |
98 | throw; | |
99 | } | |
100 | close_impl(); | |
101 | } | |
102 | } | |
103 | ||
104 | protected: | |
105 | typedef std::vector<Ch, Alloc> vector_type; | |
106 | typedef typename vector_type::size_type size_type; | |
107 | private: | |
108 | virtual void do_filter(const vector_type& src, vector_type& dest) = 0; | |
109 | virtual void do_close() { } | |
110 | ||
111 | template<typename Source> | |
112 | void do_read(Source& src) | |
113 | { | |
114 | using std::streamsize; | |
115 | vector_type data; | |
116 | while (true) { | |
117 | const std::streamsize size = default_device_buffer_size; | |
118 | Ch buf[size]; | |
119 | std::streamsize amt; | |
120 | if ((amt = boost::iostreams::read(src, buf, size)) == -1) | |
121 | break; | |
122 | data.insert(data.end(), buf, buf + amt); | |
123 | } | |
124 | do_filter(data, data_); | |
125 | state_ |= f_eof; | |
126 | } | |
127 | ||
128 | template<typename Sink> | |
129 | void do_write(Sink& sink, const char_type* s, std::streamsize n) | |
130 | { | |
131 | typedef typename iostreams::category_of<Sink>::type category; | |
132 | typedef is_convertible<category, output> can_write; | |
133 | do_write(sink, s, n, can_write()); | |
134 | } | |
135 | ||
136 | template<typename Sink> | |
137 | void do_write(Sink& sink, const char_type* s, std::streamsize n, mpl::true_) | |
138 | { iostreams::write(sink, s, n); } | |
139 | ||
140 | template<typename Sink> | |
141 | void do_write(Sink&, const char_type*, std::streamsize, mpl::false_) { } | |
142 | ||
143 | void close_impl() | |
144 | { | |
145 | data_.clear(); | |
146 | ptr_ = 0; | |
147 | state_ = 0; | |
148 | do_close(); | |
149 | } | |
150 | ||
151 | enum flag_type { | |
152 | f_read = 1, | |
153 | f_write = f_read << 1, | |
154 | f_eof = f_write << 1 | |
155 | }; | |
156 | ||
157 | // Note: typically will not be copied while vector contains data. | |
158 | vector_type data_; | |
159 | size_type ptr_; | |
160 | int state_; | |
161 | }; | |
162 | BOOST_IOSTREAMS_PIPABLE(aggregate_filter, 1) | |
163 | ||
164 | } } // End namespaces iostreams, boost. | |
165 | ||
166 | #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC. | |
167 | ||
168 | #endif // #ifndef BOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED |