| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | // | ||
| 2 | // Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com) | ||
| 3 | // | ||
| 4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | ||
| 5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | ||
| 6 | // | ||
| 7 | // Official repository: https://github.com/CPPAlliance/http_proto | ||
| 8 | // | ||
| 9 | |||
| 10 | #ifndef BOOST_HTTP_PROTO_DETAIL_WORKSPACE_HPP | ||
| 11 | #define BOOST_HTTP_PROTO_DETAIL_WORKSPACE_HPP | ||
| 12 | |||
| 13 | #include <boost/http_proto/detail/except.hpp> | ||
| 14 | #include <boost/assert.hpp> | ||
| 15 | #include <cstdlib> | ||
| 16 | #include <new> | ||
| 17 | #include <utility> | ||
| 18 | #include <stddef.h> // ::max_align_t | ||
| 19 | |||
| 20 | namespace boost { | ||
| 21 | namespace http_proto { | ||
| 22 | namespace detail { | ||
| 23 | |||
| 24 | class workspace | ||
| 25 | { | ||
| 26 | 76 | struct any | |
| 27 | { | ||
| 28 | any* next = nullptr; | ||
| 29 | |||
| 30 | BOOST_HTTP_PROTO_DECL | ||
| 31 | virtual ~any() = 0; | ||
| 32 | }; | ||
| 33 | |||
| 34 | template<class T> | ||
| 35 | struct alignas(alignof(::max_align_t)) | ||
| 36 | any_t : any | ||
| 37 | { | ||
| 38 | T t_; | ||
| 39 | |||
| 40 | any_t() = delete; | ||
| 41 | any_t(any_t&&) = default; | ||
| 42 | |||
| 43 | explicit | ||
| 44 | 28 | any_t( | |
| 45 | T&& t) | ||
| 46 | 28 | : t_(std::move(t)) | |
| 47 | { | ||
| 48 | 28 | } | |
| 49 | |||
| 50 | explicit | ||
| 51 | 6 | any_t( | |
| 52 | T const& t) | ||
| 53 | 6 | : t_(t) | |
| 54 | { | ||
| 55 | 6 | } | |
| 56 | }; | ||
| 57 | |||
| 58 | template<class T> | ||
| 59 | struct alignas(alignof(::max_align_t)) | ||
| 60 | any_n : any | ||
| 61 | { | ||
| 62 | std::size_t n_ = 0; | ||
| 63 | |||
| 64 | 21 | any_n() = default; | |
| 65 | |||
| 66 | 42 | ~any_n() | |
| 67 | { | ||
| 68 | 182 | for(std::size_t i = n_; | |
| 69 |
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182 | i-- > 0;) |
| 70 | 140 | data()[i].~T(); | |
| 71 | } | ||
| 72 | |||
| 73 | 21 | any_n( | |
| 74 | std::size_t n, | ||
| 75 | T const& t) | ||
| 76 | 21 | : any_n() | |
| 77 | { | ||
| 78 |
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91 | while(n_ < n) |
| 79 | { | ||
| 80 | 70 | new(&data()[n_]) T(t); | |
| 81 | 70 | ++n_; | |
| 82 | } | ||
| 83 | 21 | } | |
| 84 | |||
| 85 | T* | ||
| 86 | 161 | data() noexcept | |
| 87 | { | ||
| 88 | return | ||
| 89 | reinterpret_cast<T*>( | ||
| 90 | 161 | this + 1); | |
| 91 | } | ||
| 92 | }; | ||
| 93 | |||
| 94 | unsigned char* begin_ = nullptr; | ||
| 95 | unsigned char* end_ = nullptr; | ||
| 96 | unsigned char* head_ = nullptr; | ||
| 97 | |||
| 98 | public: | ||
| 99 | workspace() = default; | ||
| 100 | |||
| 101 | 15 | ~workspace() | |
| 102 | 15 | { | |
| 103 | 15 | clear(); | |
| 104 |
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15 | delete[] begin_; |
| 105 | 15 | } | |
| 106 | |||
| 107 | explicit | ||
| 108 | 15 | workspace( | |
| 109 | std::size_t n) | ||
| 110 | 15 | : begin_(new unsigned char[n]) | |
| 111 | 15 | , end_(begin_ + n) | |
| 112 | 15 | , head_(end_) | |
| 113 | { | ||
| 114 | 15 | } | |
| 115 | |||
| 116 | void* | ||
| 117 | 8 | data() noexcept | |
| 118 | { | ||
| 119 | 8 | return begin_; | |
| 120 | } | ||
| 121 | |||
| 122 | std::size_t | ||
| 123 | 35 | size() const noexcept | |
| 124 | { | ||
| 125 | 35 | return head_ - begin_; | |
| 126 | } | ||
| 127 | |||
| 128 | BOOST_HTTP_PROTO_DECL | ||
| 129 | void | ||
| 130 | clear() noexcept; | ||
| 131 | |||
| 132 | BOOST_HTTP_PROTO_DECL | ||
| 133 | void* | ||
| 134 | reserve(std::size_t n); | ||
| 135 | |||
| 136 | template<class T> | ||
| 137 | auto | ||
| 138 | 34 | push(T&& t) -> | |
| 139 | typename std::decay<T>::type& | ||
| 140 | { | ||
| 141 | |||
| 142 | using U = any_t<typename | ||
| 143 | std::decay<T>::type>; | ||
| 144 | 34 | auto p = ::new(bump_down( | |
| 145 | sizeof(U), alignof(U))) U( | ||
| 146 | 34 | std::forward<T>(t)); | |
| 147 | 34 | p->next = reinterpret_cast< | |
| 148 | 34 | any*>(head_); | |
| 149 | 34 | head_ = reinterpret_cast< | |
| 150 | unsigned char*>(p); | ||
| 151 | 34 | return p->t_; | |
| 152 | } | ||
| 153 | |||
| 154 | template<class T> | ||
| 155 | T* | ||
| 156 | 21 | push_array( | |
| 157 | std::size_t n, | ||
| 158 | T const& t) | ||
| 159 | { | ||
| 160 | using U = any_n<T>; | ||
| 161 | 21 | auto p = ::new(bump_down( | |
| 162 | 21 | sizeof(U) + n * sizeof(T), | |
| 163 | alignof(::max_align_t))) U(n, t); | ||
| 164 | 21 | p->next = reinterpret_cast< | |
| 165 | 21 | any*>(head_); | |
| 166 | 21 | head_ = reinterpret_cast< | |
| 167 | unsigned char*>(p); | ||
| 168 | 21 | return p->data(); | |
| 169 | } | ||
| 170 | |||
| 171 | private: | ||
| 172 | // https://fitzgeraldnick.com/2019/11/01/always-bump-downwards.html | ||
| 173 | void* | ||
| 174 | 38 | bump_down( | |
| 175 | std::size_t size, | ||
| 176 | std::size_t align) | ||
| 177 | { | ||
| 178 |
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38 | BOOST_ASSERT(align > 0); |
| 179 |
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38 | BOOST_ASSERT( |
| 180 | (align & (align - 1)) == 0); | ||
| 181 | |||
| 182 | 38 | auto ip0 = reinterpret_cast< | |
| 183 | 38 | std::uintptr_t>(begin_); | |
| 184 | 38 | auto ip = reinterpret_cast< | |
| 185 | 38 | std::uintptr_t>(head_); | |
| 186 |
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38 | if(size > ip - ip0) |
| 187 | ✗ | detail::throw_bad_alloc(); | |
| 188 | 38 | ip -= size; | |
| 189 | 38 | ip &= ~(align - 1); | |
| 190 |
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38 | if(ip < ip0) |
| 191 | ✗ | detail::throw_bad_alloc(); | |
| 192 | 38 | return reinterpret_cast<void*>(ip); | |
| 193 | } | ||
| 194 | }; | ||
| 195 | |||
| 196 | } // detail | ||
| 197 | } // http_proto | ||
| 198 | } // boost | ||
| 199 | |||
| 200 | #endif | ||
| 201 |