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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