[857] | 1 | // (C) Copyright Jonathan Turkanis 2003.
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| 2 | // Distributed under the Boost Software License, Version 1.0. (See accompanying
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| 3 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
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| 4 |
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| 5 | // See http://www.boost.org/libs/iostreams for documentation.
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| 6 |
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| 7 | #ifndef BOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED
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| 8 | #define BOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED
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| 9 |
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| 10 | #if defined(_MSC_VER) && (_MSC_VER >= 1020)
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| 11 | # pragma once
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| 12 | #endif
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| 13 |
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| 14 | #include <algorithm> // copy, min.
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| 15 | #include <cassert>
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| 16 | #include <iterator> // back_inserter
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| 17 | #include <vector>
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| 18 | #include <boost/iostreams/categories.hpp>
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| 19 | #include <boost/iostreams/detail/char_traits.hpp>
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| 20 | #include <boost/iostreams/detail/closer.hpp>
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| 21 | #include <boost/iostreams/detail/ios.hpp> // openmode, streamsize.
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| 22 | #include <boost/iostreams/pipeline.hpp>
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| 23 | #include <boost/mpl/bool.hpp>
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| 24 | #include <boost/type_traits/is_convertible.hpp>
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| 25 |
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| 26 | // Must come last.
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| 27 | #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
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| 28 |
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| 29 | namespace boost { namespace iostreams {
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| 30 |
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| 31 | //
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| 32 | // Template name: aggregate_filter.
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| 33 | // Template paramters:
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| 34 | // Ch - The character type.
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| 35 | // Alloc - The allocator type.
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| 36 | // Description: Utility for defining DualUseFilters which filter an
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| 37 | // entire stream at once. To use, override the protected virtual
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| 38 | // member do_filter.
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| 39 | // Note: This filter should not be copied while it is in use.
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| 40 | //
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| 41 | template<typename Ch, typename Alloc = std::allocator<Ch> >
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| 42 | class aggregate_filter {
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| 43 | public:
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| 44 | typedef Ch char_type;
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| 45 | struct category
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| 46 | : dual_use,
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| 47 | filter_tag,
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| 48 | multichar_tag,
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| 49 | closable_tag
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| 50 | { };
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| 51 | aggregate_filter() : ptr_(0), state_(0) { }
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| 52 | virtual ~aggregate_filter() { }
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| 53 |
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| 54 | template<typename Source>
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| 55 | std::streamsize read(Source& src, char_type* s, std::streamsize n)
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| 56 | {
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| 57 | using namespace std;
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| 58 | assert(!(state_ & f_write));
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| 59 | state_ |= f_read;
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| 60 | if (!(state_ & f_eof))
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| 61 | do_read(src);
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| 62 | streamsize amt =
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| 63 | (std::min)(n, static_cast<streamsize>(data_.size() - ptr_));
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| 64 | if (amt) {
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| 65 | BOOST_IOSTREAMS_CHAR_TRAITS(char_type)::copy(s, &data_[ptr_], amt);
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| 66 | ptr_ += amt;
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| 67 | }
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| 68 | return detail::check_eof(amt);
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| 69 | }
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| 70 |
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| 71 | template<typename Sink>
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| 72 | std::streamsize write(Sink&, const char_type* s, std::streamsize n)
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| 73 | {
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| 74 | assert(!(state_ & f_read));
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| 75 | state_ |= f_write;
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| 76 | data_.insert(data_.end(), s, s + n);
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| 77 | return n;
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| 78 | }
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| 79 |
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| 80 | // Give detail::closer permission to call close().
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| 81 | typedef aggregate_filter<Ch, Alloc> self;
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| 82 | friend struct detail::closer<self>;
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| 83 |
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| 84 | template<typename Sink>
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| 85 | void close(Sink& sink, BOOST_IOS::openmode which)
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| 86 | {
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| 87 | if ((state_ & f_read) && (which & BOOST_IOS::in))
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| 88 | close();
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| 89 |
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| 90 | if ((state_ & f_write) && (which & BOOST_IOS::out)) {
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| 91 | detail::closer<self> closer(*this);
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| 92 | vector_type filtered;
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| 93 | do_filter(data_, filtered);
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| 94 | do_write(
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| 95 | sink, &filtered[0],
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| 96 | static_cast<std::streamsize>(filtered.size())
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| 97 | );
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| 98 | }
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| 99 | }
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| 100 |
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| 101 | protected:
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| 102 | typedef std::vector<Ch, Alloc> vector_type;
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| 103 | typedef typename vector_type::size_type size_type;
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| 104 | private:
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| 105 | virtual void do_filter(const vector_type& src, vector_type& dest) = 0;
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| 106 | virtual void do_close() { }
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| 107 |
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| 108 | template<typename Source>
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| 109 | void do_read(Source& src)
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| 110 | {
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| 111 | using std::streamsize;
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| 112 | vector_type data;
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| 113 | while (true) {
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| 114 | const streamsize size = default_device_buffer_size;
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| 115 | Ch buf[size];
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| 116 | streamsize amt;
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| 117 | if ((amt = boost::iostreams::read(src, buf, size)) == -1)
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| 118 | break;
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| 119 | data.insert(data.end(), buf, buf + amt);
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| 120 | }
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| 121 | do_filter(data, data_);
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| 122 | state_ |= f_eof;
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| 123 | }
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| 124 |
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| 125 | template<typename Sink>
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| 126 | void do_write(Sink& sink, const char* s, std::streamsize n)
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| 127 | {
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| 128 | typedef typename iostreams::category_of<Sink>::type category;
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| 129 | typedef is_convertible<category, output> can_write;
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| 130 | do_write(sink, s, n, can_write());
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| 131 | }
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| 132 |
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| 133 | template<typename Sink>
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| 134 | void do_write(Sink& sink, const char* s, std::streamsize n, mpl::true_)
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| 135 | { iostreams::write(sink, s, n); }
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| 136 |
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| 137 | template<typename Sink>
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| 138 | void do_write(Sink&, const char*, std::streamsize, mpl::false_) { }
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| 139 |
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| 140 | void close()
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| 141 | {
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| 142 | data_.clear();
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| 143 | ptr_ = 0;
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| 144 | state_ = 0;
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| 145 | do_close();
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| 146 | }
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| 147 |
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| 148 | enum flag_type {
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| 149 | f_read = 1,
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| 150 | f_write = f_read << 1,
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| 151 | f_eof = f_write << 1
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| 152 | };
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| 153 |
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| 154 | // Note: typically will not be copied while vector contains data.
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| 155 | vector_type data_;
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| 156 | size_type ptr_;
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| 157 | int state_;
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| 158 | };
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| 159 | BOOST_IOSTREAMS_PIPABLE(aggregate_filter, 1)
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| 160 |
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| 161 | } } // End namespaces iostreams, boost.
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| 162 |
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| 163 | #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
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| 164 |
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| 165 | #endif // #ifndef BOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED
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