[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 | // NOTE: I hope to replace the current implementation with a much simpler
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| 8 | // one.
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| 9 |
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| 10 | #ifndef BOOST_IOSTREAMS_NEWLINE_FILTER_HPP_INCLUDED
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| 11 | #define BOOST_IOSTREAMS_NEWLINE_FILTER_HPP_INCLUDED
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| 12 |
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| 13 | #if defined(_MSC_VER) && (_MSC_VER >= 1020)
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| 14 | # pragma once
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| 15 | #endif
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| 16 |
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| 17 | #include <cassert>
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| 18 | #include <cstdio>
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| 19 | #include <stdexcept> // logic_error.
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| 20 | #include <boost/config.hpp> // BOOST_STATIC_CONSTANT.
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| 21 | #include <boost/iostreams/categories.hpp>
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| 22 | #include <boost/iostreams/detail/char_traits.hpp>
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| 23 | #include <boost/iostreams/pipeline.hpp>
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| 24 | #include <boost/mpl/bool.hpp>
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| 25 | #include <boost/type_traits/is_convertible.hpp>
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| 26 |
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| 27 | // Must come last.
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| 28 | #include <boost/iostreams/detail/config/disable_warnings.hpp>
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| 29 |
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| 30 | #define BOOST_IOSTREAMS_ASSERT_UNREACHABLE(val) \
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| 31 | (assert("unreachable code" == 0), val) \
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| 32 | /**/
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| 33 |
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| 34 | namespace boost { namespace iostreams {
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| 35 |
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| 36 | namespace newline {
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| 37 |
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| 38 | const char CR = 0x0D;
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| 39 | const char LF = 0x0A;
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| 40 |
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| 41 | // Flags for configuring newline_filter.
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| 42 |
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| 43 | // Exactly one of the following three flags must be present.
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| 44 |
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| 45 | const int posix = 1; // Use CR as line separator.
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| 46 | const int mac = 2; // Use LF as line separator.
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| 47 | const int dos = 4; // Use CRLF as line separator.
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| 48 | const int mixed = 8; // Mixed line endings.
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| 49 | const int final_newline = 16;
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| 50 | const int platform_mask = posix | dos | mac;
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| 51 |
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| 52 | } // End namespace newline.
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| 53 |
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| 54 | namespace detail {
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| 55 |
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| 56 | class newline_base {
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| 57 | public:
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| 58 | bool is_posix() const
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| 59 | {
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| 60 | return !is_mixed() && (flags_ & newline::posix) != 0;
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| 61 | }
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| 62 | bool is_dos() const
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| 63 | {
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| 64 | return !is_mixed() && (flags_ & newline::dos) != 0;
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| 65 | }
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| 66 | bool is_mac() const
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| 67 | {
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| 68 | return !is_mixed() && (flags_ & newline::mac) != 0;
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| 69 | }
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| 70 | bool is_mixed_posix() const { return (flags_ & newline::posix) != 0; }
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| 71 | bool is_mixed_dos() const { return (flags_ & newline::dos) != 0; }
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| 72 | bool is_mixed_mac() const { return (flags_ & newline::mac) != 0; }
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| 73 | bool is_mixed() const
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| 74 | {
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| 75 | int platform =
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| 76 | (flags_ & newline::posix) != 0 ?
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| 77 | newline::posix :
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| 78 | (flags_ & newline::dos) != 0 ?
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| 79 | newline::dos :
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| 80 | (flags_ & newline::mac) != 0 ?
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| 81 | newline::mac :
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| 82 | 0;
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| 83 | return (flags_ & ~platform & newline::platform_mask) != 0;
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| 84 | }
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| 85 | bool has_final_newline() const
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| 86 | {
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| 87 | return (flags_ & newline::final_newline) != 0;
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| 88 | }
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| 89 | protected:
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| 90 | newline_base(int flags) : flags_(flags) { }
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| 91 | int flags_;
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| 92 | };
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| 93 |
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| 94 | } // End namespace detail.
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| 95 |
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| 96 | class newline_error
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| 97 | : public BOOST_IOSTREAMS_FAILURE, public detail::newline_base
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| 98 | {
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| 99 | private:
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| 100 | friend class newline_checker;
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| 101 | newline_error(int flags)
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| 102 | : BOOST_IOSTREAMS_FAILURE("bad line endings"),
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| 103 | detail::newline_base(flags)
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| 104 | { }
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| 105 | };
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| 106 |
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| 107 | class newline_filter {
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| 108 | public:
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| 109 | typedef char char_type;
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| 110 | struct category
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| 111 | : dual_use,
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| 112 | filter_tag,
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| 113 | closable_tag
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| 114 | { };
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| 115 |
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| 116 | explicit newline_filter(int target) : flags_(target)
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| 117 | {
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| 118 | if ( target != newline::posix &&
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| 119 | target != newline::dos &&
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| 120 | target != newline::mac )
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| 121 | {
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| 122 | throw std::logic_error("bad flags");
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| 123 | }
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| 124 | }
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| 125 |
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| 126 | template<typename Source>
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| 127 | int get(Source& src)
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| 128 | {
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| 129 | using iostreams::newline::CR;
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| 130 | using iostreams::newline::LF;
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| 131 |
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| 132 | if (flags_ & (has_LF | has_EOF)) {
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| 133 | if (flags_ & has_LF)
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| 134 | return newline();
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| 135 | else
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| 136 | return EOF;
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| 137 | }
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| 138 |
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| 139 | int c =
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| 140 | (flags_ & has_CR) == 0 ?
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| 141 | iostreams::get(src) :
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| 142 | CR;
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| 143 |
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| 144 | if (c == WOULD_BLOCK )
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| 145 | return WOULD_BLOCK;
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| 146 |
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| 147 | if (c == CR) {
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| 148 | flags_ |= has_CR;
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| 149 |
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| 150 | int d;
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| 151 | if ((d = iostreams::get(src)) == WOULD_BLOCK)
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| 152 | return WOULD_BLOCK;
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| 153 |
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| 154 | if (d == LF) {
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| 155 | flags_ &= ~has_CR;
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| 156 | return newline();
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| 157 | }
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| 158 |
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| 159 | if (d == EOF) {
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| 160 | flags_ |= has_EOF;
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| 161 | } else {
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| 162 | iostreams::putback(src, d);
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| 163 | }
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| 164 |
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| 165 | flags_ &= ~has_CR;
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| 166 | return newline();
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| 167 | }
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| 168 |
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| 169 | if (c == LF)
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| 170 | return newline();
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| 171 |
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| 172 | return c;
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| 173 | }
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| 174 |
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| 175 | template<typename Sink>
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| 176 | bool put(Sink& dest, char c)
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| 177 | {
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| 178 | using iostreams::newline::CR;
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| 179 | using iostreams::newline::LF;
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| 180 |
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| 181 | if ((flags_ & has_LF) != 0)
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| 182 | return c == LF ?
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| 183 | newline(dest) :
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| 184 | newline(dest) && this->put(dest, c);
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| 185 |
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| 186 | if (c == LF)
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| 187 | return newline(dest);
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| 188 |
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| 189 | if ((flags_ & has_CR) != 0)
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| 190 | return newline(dest) ?
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| 191 | this->put(dest, c) :
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| 192 | false;
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| 193 |
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| 194 | if (c == CR) {
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| 195 | flags_ |= has_CR;
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| 196 | return true;
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| 197 | }
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| 198 |
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| 199 | return iostreams::put(dest, c);
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| 200 | }
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| 201 |
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| 202 | template<typename Sink>
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| 203 | void close(Sink& dest, BOOST_IOS::openmode which)
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| 204 | {
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| 205 | typedef typename iostreams::category_of<Sink>::type category;
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| 206 | bool unfinished = (flags_ & has_CR) != 0;
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| 207 | flags_ &= newline::platform_mask;
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| 208 | if (which == BOOST_IOS::out && unfinished)
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| 209 | close(dest, is_convertible<category, output>());
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| 210 | }
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| 211 | private:
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| 212 | template<typename Sink>
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| 213 | void close(Sink& dest, mpl::true_) { newline(dest); }
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| 214 |
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| 215 | template<typename Sink>
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| 216 | void close(Sink&, mpl::false_) { }
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| 217 |
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| 218 | // Returns the appropriate element of a newline sequence.
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| 219 | int newline()
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| 220 | {
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| 221 | using iostreams::newline::CR;
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| 222 | using iostreams::newline::LF;
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| 223 |
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| 224 | switch (flags_ & newline::platform_mask) {
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| 225 | case newline::posix:
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| 226 | return LF;
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| 227 | case newline::mac:
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| 228 | return CR;
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| 229 | case newline::dos:
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| 230 | if (flags_ & has_LF) {
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| 231 | flags_ &= ~has_LF;
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| 232 | return LF;
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| 233 | } else {
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| 234 | flags_ |= has_LF;
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| 235 | return CR;
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| 236 | }
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| 237 | }
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| 238 | return BOOST_IOSTREAMS_ASSERT_UNREACHABLE(0);
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| 239 | }
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| 240 |
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| 241 | // Writes a newline sequence.
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| 242 | template<typename Sink>
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| 243 | bool newline(Sink& dest)
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| 244 | {
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| 245 | using iostreams::newline::CR;
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| 246 | using iostreams::newline::LF;
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| 247 |
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| 248 | bool success = false;
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| 249 | switch (flags_ & newline::platform_mask) {
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| 250 | case newline::posix:
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| 251 | success = boost::iostreams::put(dest, LF);
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| 252 | break;
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| 253 | case newline::mac:
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| 254 | success = boost::iostreams::put(dest, CR);
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| 255 | break;
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| 256 | case newline::dos:
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| 257 | if ((flags_ & has_LF) != 0) {
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| 258 | if ((success = boost::iostreams::put(dest, LF)))
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| 259 | flags_ &= ~has_LF;
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| 260 | } else if (boost::iostreams::put(dest, CR)) {
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| 261 | if (!(success = boost::iostreams::put(dest, LF)))
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| 262 | flags_ |= has_LF;
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| 263 | }
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| 264 | break;
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| 265 | }
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| 266 | if (success)
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| 267 | flags_ &= ~has_CR;
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| 268 | return success;
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| 269 | }
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| 270 | enum flags {
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| 271 | has_LF = 32768,
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| 272 | has_CR = has_LF << 1,
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| 273 | has_newline = has_CR << 1,
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| 274 | has_EOF = has_newline << 1
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| 275 | };
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| 276 | int flags_;
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| 277 | };
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| 278 | BOOST_IOSTREAMS_PIPABLE(newline_filter, 0)
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| 279 |
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| 280 | class newline_checker : public detail::newline_base {
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| 281 | public:
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| 282 | typedef char char_type;
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| 283 | struct category
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| 284 | : dual_use_filter_tag,
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| 285 | closable_tag
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| 286 | { };
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| 287 | explicit newline_checker(int target = newline::mixed)
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| 288 | : detail::newline_base(0), target_(target), open_(false)
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| 289 | { }
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| 290 | template<typename Source>
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| 291 | int get(Source& src)
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| 292 | {
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| 293 | using newline::CR;
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| 294 | using newline::LF;
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| 295 |
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| 296 | if (!open_) {
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| 297 | open_ = true;
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| 298 | source() = 0;
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| 299 | }
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| 300 |
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| 301 | int c;
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| 302 | if ((c = iostreams::get(src)) == WOULD_BLOCK)
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| 303 | return WOULD_BLOCK;
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| 304 |
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| 305 | // Update source flags.
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| 306 | if (c != EOF)
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| 307 | source() &= ~line_complete;
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| 308 | if ((source() & has_CR) != 0) {
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| 309 | if (c == LF) {
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| 310 | source() |= newline::dos;
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| 311 | source() |= line_complete;
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| 312 | } else {
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| 313 | source() |= newline::mac;
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| 314 | if (c == EOF)
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| 315 | source() |= line_complete;
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| 316 | }
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| 317 | } else if (c == LF) {
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| 318 | source() |= newline::posix;
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| 319 | source() |= line_complete;
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| 320 | }
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| 321 | source() = (source() & ~has_CR) | (c == CR ? has_CR : 0);
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| 322 |
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| 323 | // Check for errors.
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| 324 | if ( c == EOF &&
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| 325 | (target_ & newline::final_newline) != 0 &&
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| 326 | (source() & line_complete) == 0 )
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| 327 | {
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| 328 | fail();
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| 329 | }
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| 330 | if ( (target_ & newline::platform_mask) != 0 &&
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| 331 | (source() & ~target_ & newline::platform_mask) != 0 )
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| 332 | {
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| 333 | fail();
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| 334 | }
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| 335 |
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| 336 | return c;
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| 337 | }
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| 338 |
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| 339 | template<typename Sink>
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| 340 | bool put(Sink& dest, int c)
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| 341 | {
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| 342 | using iostreams::newline::CR;
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| 343 | using iostreams::newline::LF;
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| 344 |
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| 345 | if (!open_) {
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| 346 | open_ = true;
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| 347 | source() = 0;
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| 348 | }
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| 349 |
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| 350 | if (!iostreams::put(dest, c))
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| 351 | return false;
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| 352 |
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| 353 | // Update source flags.
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| 354 | source() &= ~line_complete;
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| 355 | if ((source() & has_CR) != 0) {
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| 356 | if (c == LF) {
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| 357 | source() |= newline::dos;
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| 358 | source() |= line_complete;
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| 359 | } else {
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| 360 | source() |= newline::mac;
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| 361 | }
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| 362 | } else if (c == LF) {
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| 363 | source() |= newline::posix;
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| 364 | source() |= line_complete;
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| 365 | }
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| 366 | source() = (source() & ~has_CR) | (c == CR ? has_CR : 0);
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| 367 |
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| 368 | // Check for errors.
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| 369 | if ( (target_ & newline::platform_mask) != 0 &&
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| 370 | (source() & ~target_ & newline::platform_mask) != 0 )
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| 371 | {
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| 372 | fail();
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| 373 | }
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| 374 |
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| 375 | return true;
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| 376 | }
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| 377 |
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| 378 | template<typename Sink>
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| 379 | void close(Sink&, BOOST_IOS::openmode which)
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| 380 | {
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| 381 | using iostreams::newline::final_newline;
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| 382 |
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| 383 | // Update final_newline flag.
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| 384 | if ( (source() & has_CR) != 0 ||
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| 385 | (source() & line_complete) != 0 )
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| 386 | {
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| 387 | source() |= final_newline;
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| 388 | }
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| 389 |
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| 390 | // Clear non-sticky flags.
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| 391 | source() &= ~(has_CR | line_complete);
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| 392 |
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| 393 | // Check for errors.
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| 394 | if ( (which & BOOST_IOS::out) &&
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| 395 | (target_ & final_newline) != 0 &&
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| 396 | (source() & final_newline) == 0 )
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| 397 | {
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| 398 | fail();
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| 399 | }
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| 400 | }
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| 401 | private:
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| 402 | void fail() { throw newline_error(source()); }
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| 403 | int& source() { return flags_; }
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| 404 | int source() const { return flags_; }
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| 405 |
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| 406 | enum flags {
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| 407 | has_CR = 32768,
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| 408 | line_complete = has_CR << 1
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| 409 | };
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| 410 |
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| 411 | int target_; // Represents expected input.
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| 412 | bool open_;
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| 413 | };
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| 414 | BOOST_IOSTREAMS_PIPABLE(newline_checker, 0)
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| 415 |
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| 416 | } } // End namespaces iostreams, boost.
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| 417 |
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| 418 | #include <boost/iostreams/detail/config/enable_warnings.hpp>
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| 419 |
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| 420 | #endif // #ifndef BOOST_IOSTREAMS_NEWLINE_FILTER_HPP_INCLUDED
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