Jeff Thompson | 86b6d64 | 2013-10-17 15:01:56 -0700 | [diff] [blame] | 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 NDNBOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED |
| 9 | #define NDNBOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED |
| 10 | |
| 11 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| 12 | # pragma once |
| 13 | #endif |
| 14 | |
| 15 | #include <algorithm> // copy, min. |
| 16 | #include <ndnboost/assert.hpp> |
| 17 | #include <iterator> // back_inserter |
| 18 | #include <vector> |
| 19 | #include <ndnboost/iostreams/constants.hpp> // default_device_buffer_size |
| 20 | #include <ndnboost/iostreams/categories.hpp> |
| 21 | #include <ndnboost/iostreams/detail/char_traits.hpp> |
| 22 | #include <ndnboost/iostreams/detail/ios.hpp> // openmode, streamsize. |
| 23 | #include <ndnboost/iostreams/pipeline.hpp> |
| 24 | #include <ndnboost/iostreams/read.hpp> // check_eof |
| 25 | #include <ndnboost/iostreams/write.hpp> |
| 26 | #include <ndnboost/mpl/bool.hpp> |
| 27 | #include <ndnboost/type_traits/is_convertible.hpp> |
| 28 | |
| 29 | // Must come last. |
| 30 | #include <ndnboost/iostreams/detail/config/disable_warnings.hpp> // MSVC. |
| 31 | |
| 32 | namespace ndnboost { 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 | NDNBOOST_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 | NDNBOOST_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 | NDNBOOST_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, NDNBOOST_IOS::openmode which) |
| 85 | { |
| 86 | if ((state_ & f_read) != 0 && which == NDNBOOST_IOS::in) |
| 87 | close_impl(); |
| 88 | if ((state_ & f_write) != 0 && which == NDNBOOST_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 = ndnboost::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 | NDNBOOST_IOSTREAMS_PIPABLE(aggregate_filter, 1) |
| 163 | |
| 164 | } } // End namespaces iostreams, boost. |
| 165 | |
| 166 | #include <ndnboost/iostreams/detail/config/enable_warnings.hpp> // MSVC. |
| 167 | |
| 168 | #endif // #ifndef NDNBOOST_IOSTREAMS_AGGREGATE_FILTER_HPP_INCLUDED |