1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
/* Copyright 2016-2018 Joaquin M Lopez Munoz.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org/libs/poly_collection for library home page.
*/
#ifndef BOOST_POLY_COLLECTION_DETAIL_TYPE_INFO_MAP_HPP
#define BOOST_POLY_COLLECTION_DETAIL_TYPE_INFO_MAP_HPP
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/detail/workaround.hpp>
#include <functional>
#include <memory>
#include <type_traits>
#include <typeinfo>
#include <unordered_map>
#include <utility>
namespace boost{
namespace poly_collection{
namespace detail{
/* To cope with dynamic modules/libs, the standard allows for different
* std::type_info instances to describe the same type, which implies that
* std::type_info::operator== and std::type_info::hash_code are costly
* operations typically relying on the stored type name.
* type_info_ptr_hash<T> behaves roughly as a
* std::unordered_map<std::type_index,T> but maintains an internal cache of
* passed std::type_info instances so that lookup is performed (when there's a
* cache hit) without invoking std::type_info equality and hashing ops.
*/
struct type_info_ptr_hash
{
std::size_t operator()(const std::type_info* p)const noexcept
{return p->hash_code();}
};
struct type_info_ptr_equal_to
{
bool operator()(
const std::type_info* p,const std::type_info* q)const noexcept
{return *p==*q;}
};
template<typename T,typename Allocator>
class type_info_map
{
using map_type=std::unordered_map<
const std::type_info*,T,
type_info_ptr_hash,type_info_ptr_equal_to,
typename std::allocator_traits<Allocator>::template
rebind_alloc<std::pair<const std::type_info* const,T>>
>;
public:
using key_type=std::type_info;
using mapped_type=T;
using value_type=typename map_type::value_type;
using allocator_type=typename map_type::allocator_type;
using iterator=typename map_type::iterator;
using const_iterator=typename map_type::const_iterator;
type_info_map()=default;
type_info_map(const type_info_map& x):
map{x.map},
cache{make<cache_type>(std::allocator_traits<cache_allocator_type>::
select_on_container_copy_construction(x.cache.get_allocator()))}
{build_cache(x.cache);}
type_info_map(type_info_map&& x)=default;
type_info_map(const allocator_type& al):
map{make<map_type>(al)},cache{make<cache_type>(al)}{}
type_info_map(const type_info_map& x,const allocator_type& al):
map{make(x.map,al)},cache{make<cache_type>(al)}
{build_cache(x.cache);}
type_info_map(type_info_map&& x,const allocator_type& al):
map{make(std::move(x.map),al)},
cache{
al==allocator_type{x.map.get_allocator()}&&x.map.empty()?
make(std::move(x.cache),al):
make<cache_type>(al)
}
{
if(!(al==allocator_type{x.map.get_allocator()}&&x.map.empty())){
build_cache(x.cache);
}
x.map.clear();
x.cache.clear();
}
type_info_map& operator=(const type_info_map& x)
{
if(this!=&x)try{
map=x.map;
cache=make<cache_type>(map.get_allocator());
build_cache(x.cache);
}
catch(...){
map.clear();
cache.clear();
throw;
}
return *this;
}
type_info_map& operator=(type_info_map&& x)
{
if(this!=&x)try{
map=std::move(x.map);
if(map.get_allocator()==x.map.get_allocator()){
cache=std::move(x.cache);
}
else{
cache=make<cache_type>(map.get_allocator());
build_cache(x.cache);
x.cache.clear();
}
}
catch(...){
map.clear();
cache.clear();
x.map.clear();
x.cache.clear();
throw;
}
return *this;
}
allocator_type get_allocator()const noexcept{return map.get_allocator();}
iterator begin()noexcept{return map.begin();}
iterator end()noexcept{return map.end();}
const_iterator begin()const noexcept{return map.begin();}
const_iterator end()const noexcept{return map.end();}
const_iterator cbegin()const noexcept{return map.cbegin();}
const_iterator cend()const noexcept{return map.cend();}
iterator find(const key_type& key)
{
auto cit=cache.find(&key);
if(cit!=cache.end())return cit->second;
auto mit=map.find(&key);
if(mit!=map.end())cache.insert({&key,mit});
return mit;
}
const_iterator find(const key_type& key)const
{
auto cit=cache.find(&key);
if(cit!=cache.end())return cit->second;
return map.find(&key);
}
template<typename P>
std::pair<iterator,bool> insert(const key_type& key,P&& x)
{
auto c=map.bucket_count();
auto p=map.emplace(&key,std::forward<P>(x));
if(map.bucket_count()!=c)rebuild_cache();
cache.insert({&key,p.first});
return p;
}
void swap(type_info_map& x){map.swap(x.map);cache.swap(x.cache);}
private:
using cache_type=std::unordered_map<
const std::type_info*,iterator,
std::hash<const std::type_info*>,std::equal_to<const std::type_info*>,
typename std::allocator_traits<Allocator>::template
rebind_alloc<std::pair<const std::type_info* const,iterator>>
>;
using cache_allocator_type=typename cache_type::allocator_type;
#if BOOST_WORKAROUND(BOOST_LIBSTDCXX_VERSION,<40900)
/* std::unordered_map(const allocator_type&),
* std::unordered_map(const unordered_map&,const allocator_type&) and
* std::unordered_map(unordered_map&&,const allocator_type&) not available.
* We make move construction decay to copy construction.
*/
template<typename UnorderedMap>
static UnorderedMap make(const typename UnorderedMap::allocator_type& al)
{
return UnorderedMap{
10,typename UnorderedMap::hasher{},typename UnorderedMap::key_equal{},al
};
}
template<typename UnorderedMap>
static typename std::decay<UnorderedMap>::type make(
UnorderedMap&& x,
const typename std::decay<UnorderedMap>::type::allocator_type& al)
{
using RawUnorderedMap=typename std::decay<UnorderedMap>::type;
return RawUnorderedMap{
x.begin(),x.end(),0,typename RawUnorderedMap::hasher{},
typename RawUnorderedMap::key_equal{},al
};
}
#else
template<typename UnorderedMap>
static UnorderedMap make(const typename UnorderedMap::allocator_type& al)
{
return UnorderedMap{al};
}
template<typename UnorderedMap>
static typename std::decay<UnorderedMap>::type make(
UnorderedMap&& x,
const typename std::decay<UnorderedMap>::type::allocator_type& al)
{
return {std::forward<UnorderedMap>(x),al};
}
#endif
void build_cache(const cache_type& x)
{
for(const auto& p:x)cache.insert({p.first,map.find(p.first)});
}
void rebuild_cache()
{
for(auto& p:cache)p.second=map.find(p.first);
}
map_type map;
cache_type cache;
};
template<typename T,typename Allocator>
void swap(type_info_map<T,Allocator>& x,type_info_map<T,Allocator>& y)
{
x.swap(y);
}
} /* namespace poly_collection::detail */
} /* namespace poly_collection */
} /* namespace boost */
#endif
|
