include/boost/http/detail/impl/workspace.hpp

97.1% Lines (34/35) 100.0% Functions (8/8)

Line	Hits	Source Code
1		//
2		// Copyright (c) 2019 Vinnie Falco ([email protected])
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
8		//
9
10		#ifndef BOOST_HTTP_DETAIL_IMPL_WORKSPACE_HPP
11		#define BOOST_HTTP_DETAIL_IMPL_WORKSPACE_HPP
12
13		#include <boost/config.hpp>
14
15		namespace boost {
16		namespace http {
17		namespace detail {
18
19		#if defined(BOOST_MSVC)
20		#pragma warning(push)
21		#pragma warning(disable : 4324) /* structure was padded due to __declspec(align()) */
22		#endif
23
24		struct workspace::any
25		{
26		any* next = nullptr;
27
28		BOOST_HTTP_DECL
29		virtual ~any() = 0;
30		};
31
32		template<class U>
33		struct alignas(::max_align_t)
34		workspace::any_impl : any
35		{
36		U u;
37
38		any_impl(any_impl const&) = delete;
39		any_impl(any_impl&&) = delete;
40
41		template<class... Args>
42		explicit any_impl(Args&&... args)
43		: u(std::forward<Args>(args)...)
44		{
45		}
46		};
47
48		struct workspace::undo
49		{
50		explicit
51	159	undo(workspace& ws0) noexcept
52	159	: ws_(ws0)
53	159	, head_(ws0.head_)
54		{
55	159	}
56
57	159	~undo()
58		{
59	159	if(head_)
60	✗	ws_.head_ = head_;
61	159	}
62
63		void
64	159	commit() noexcept
65		{
66	159	head_ = nullptr;
67	159	}
68
69		private:
70		workspace& ws_;
71		unsigned char* head_;
72		};
73
74		template<class T>
75		constexpr
76		std::size_t
77		workspace::
78		space_needed()
79		{
80		using U = typename std::decay<T>::type;
81
82		static_assert(
83		alignof(U) <= alignof(::max_align_t),
84		"Overaligned types not supported");
85
86		return sizeof(any_impl<U>);
87		}
88
89		template<class T, class... Args>
90		auto
91		workspace::
92		emplace(Args&&... args) ->
93		typename std::decay<T>::type&
94		{
95		static_assert(
96		alignof(T) <= alignof(::max_align_t),
97		"Overaligned types not supported");
98
99		using U = any_impl<typename
100		std::decay<T>::type>;
101
102		undo u(*this);
103		auto prev_head = head_;
104		head_ = bump_down(sizeof(U), alignof(U));
105		auto p = ::new(head_) U(
106		std::forward<Args>(args)...);
107		u.commit();
108		p->next = reinterpret_cast<
109		any*>(prev_head);
110		return p->u;
111		}
112
113		template<class T>
114		T*
115	159	workspace::
116		push_array(
117		std::size_t n,
118		T const& t)
119		{
120		struct alignas(::max_align_t)
121		U : any
122		{
123		std::size_t n_ = 0;
124
125	159	U() = default;
126	159	~U()
127		{
128	159	for(std::size_t i = n_;
129	636	i-- > 0;)
130	477	data()[i].~T();
131	318	}
132
133	159	U( std::size_t n,
134		T const& t)
135	159	: U()
136		{
137	636	while(n_ < n)
138		{
139	477	new(&data()[n_]) T(t);
140	477	++n_;
141		}
142	159	}
143
144	1113	T* data() noexcept
145		{
146		return reinterpret_cast<
147	1113	T*>(this + 1);
148		}
149		};
150
151	159	undo u(*this);
152	159	auto prev_head = head_;
153	318	head_ = bump_down(
154	159	sizeof(U) + n * sizeof(T),
155		alignof(::max_align_t));
156	159	auto p = ::new(head_) U(n, t);
157	159	u.commit();
158	159	p->next = reinterpret_cast<
159		any*>(prev_head);
160	318	return p->data();
161	159	}
162
163		#if defined(BOOST_MSVC)
164		#pragma warning(pop) /* C4324 */
165		#endif
166
167		} // detail
168		} // http
169		} // boost
170
171		#endif
172