-
Notifications
You must be signed in to change notification settings - Fork 4.7k
/
meta.h
186 lines (141 loc) · 6.49 KB
/
meta.h
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
// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
#ifndef RAPIDJSON_INTERNAL_META_H_
#define RAPIDJSON_INTERNAL_META_H_
#include "../rapidjson.h"
#ifdef __GNUC__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(effc++)
#endif
#if defined(_MSC_VER) && !defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(6334)
#endif
#if RAPIDJSON_HAS_CXX11_TYPETRAITS
#include <type_traits>
#endif
//@cond RAPIDJSON_INTERNAL
RAPIDJSON_NAMESPACE_BEGIN
namespace internal {
// Helper to wrap/convert arbitrary types to void, useful for arbitrary type matching
template <typename T> struct Void { typedef void Type; };
///////////////////////////////////////////////////////////////////////////////
// BoolType, TrueType, FalseType
//
template <bool Cond> struct BoolType {
static const bool Value = Cond;
typedef BoolType Type;
};
typedef BoolType<true> TrueType;
typedef BoolType<false> FalseType;
///////////////////////////////////////////////////////////////////////////////
// SelectIf, BoolExpr, NotExpr, AndExpr, OrExpr
//
template <bool C> struct SelectIfImpl { template <typename T1, typename T2> struct Apply { typedef T1 Type; }; };
template <> struct SelectIfImpl<false> { template <typename T1, typename T2> struct Apply { typedef T2 Type; }; };
template <bool C, typename T1, typename T2> struct SelectIfCond : SelectIfImpl<C>::template Apply<T1,T2> {};
template <typename C, typename T1, typename T2> struct SelectIf : SelectIfCond<C::Value, T1, T2> {};
template <bool Cond1, bool Cond2> struct AndExprCond : FalseType {};
template <> struct AndExprCond<true, true> : TrueType {};
template <bool Cond1, bool Cond2> struct OrExprCond : TrueType {};
template <> struct OrExprCond<false, false> : FalseType {};
template <typename C> struct BoolExpr : SelectIf<C,TrueType,FalseType>::Type {};
template <typename C> struct NotExpr : SelectIf<C,FalseType,TrueType>::Type {};
template <typename C1, typename C2> struct AndExpr : AndExprCond<C1::Value, C2::Value>::Type {};
template <typename C1, typename C2> struct OrExpr : OrExprCond<C1::Value, C2::Value>::Type {};
///////////////////////////////////////////////////////////////////////////////
// AddConst, MaybeAddConst, RemoveConst
template <typename T> struct AddConst { typedef const T Type; };
template <bool Constify, typename T> struct MaybeAddConst : SelectIfCond<Constify, const T, T> {};
template <typename T> struct RemoveConst { typedef T Type; };
template <typename T> struct RemoveConst<const T> { typedef T Type; };
///////////////////////////////////////////////////////////////////////////////
// IsSame, IsConst, IsMoreConst, IsPointer
//
template <typename T, typename U> struct IsSame : FalseType {};
template <typename T> struct IsSame<T, T> : TrueType {};
template <typename T> struct IsConst : FalseType {};
template <typename T> struct IsConst<const T> : TrueType {};
template <typename CT, typename T>
struct IsMoreConst
: AndExpr<IsSame<typename RemoveConst<CT>::Type, typename RemoveConst<T>::Type>,
BoolType<IsConst<CT>::Value >= IsConst<T>::Value> >::Type {};
template <typename T> struct IsPointer : FalseType {};
template <typename T> struct IsPointer<T*> : TrueType {};
///////////////////////////////////////////////////////////////////////////////
// IsBaseOf
//
#if RAPIDJSON_HAS_CXX11_TYPETRAITS
template <typename B, typename D> struct IsBaseOf
: BoolType< ::std::is_base_of<B,D>::value> {};
#else // simplified version adopted from Boost
template<typename B, typename D> struct IsBaseOfImpl {
RAPIDJSON_STATIC_ASSERT(sizeof(B) != 0);
RAPIDJSON_STATIC_ASSERT(sizeof(D) != 0);
typedef char (&Yes)[1];
typedef char (&No) [2];
template <typename T>
static Yes Check(const D*, T);
static No Check(const B*, int);
struct Host {
operator const B*() const;
operator const D*();
};
enum { Value = (sizeof(Check(Host(), 0)) == sizeof(Yes)) };
};
template <typename B, typename D> struct IsBaseOf
: OrExpr<IsSame<B, D>, BoolExpr<IsBaseOfImpl<B, D> > >::Type {};
#endif // RAPIDJSON_HAS_CXX11_TYPETRAITS
//////////////////////////////////////////////////////////////////////////
// EnableIf / DisableIf
//
template <bool Condition, typename T = void> struct EnableIfCond { typedef T Type; };
template <typename T> struct EnableIfCond<false, T> { /* empty */ };
template <bool Condition, typename T = void> struct DisableIfCond { typedef T Type; };
template <typename T> struct DisableIfCond<true, T> { /* empty */ };
template <typename Condition, typename T = void>
struct EnableIf : EnableIfCond<Condition::Value, T> {};
template <typename Condition, typename T = void>
struct DisableIf : DisableIfCond<Condition::Value, T> {};
// SFINAE helpers
struct SfinaeTag {};
template <typename T> struct RemoveSfinaeTag;
template <typename T> struct RemoveSfinaeTag<SfinaeTag&(*)(T)> { typedef T Type; };
#define RAPIDJSON_REMOVEFPTR_(type) \
typename ::RAPIDJSON_NAMESPACE::internal::RemoveSfinaeTag \
< ::RAPIDJSON_NAMESPACE::internal::SfinaeTag&(*) type>::Type
#define RAPIDJSON_ENABLEIF(cond) \
typename ::RAPIDJSON_NAMESPACE::internal::EnableIf \
<RAPIDJSON_REMOVEFPTR_(cond)>::Type * = NULL
#define RAPIDJSON_DISABLEIF(cond) \
typename ::RAPIDJSON_NAMESPACE::internal::DisableIf \
<RAPIDJSON_REMOVEFPTR_(cond)>::Type * = NULL
#define RAPIDJSON_ENABLEIF_RETURN(cond,returntype) \
typename ::RAPIDJSON_NAMESPACE::internal::EnableIf \
<RAPIDJSON_REMOVEFPTR_(cond), \
RAPIDJSON_REMOVEFPTR_(returntype)>::Type
#define RAPIDJSON_DISABLEIF_RETURN(cond,returntype) \
typename ::RAPIDJSON_NAMESPACE::internal::DisableIf \
<RAPIDJSON_REMOVEFPTR_(cond), \
RAPIDJSON_REMOVEFPTR_(returntype)>::Type
} // namespace internal
RAPIDJSON_NAMESPACE_END
//@endcond
#if defined(_MSC_VER) && !defined(__clang__)
RAPIDJSON_DIAG_POP
#endif
#ifdef __GNUC__
RAPIDJSON_DIAG_POP
#endif
#endif // RAPIDJSON_INTERNAL_META_H_