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comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/kj/one-of.h @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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67:0e9998148a16 69:33d812a61356
1 // Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
2 // Licensed under the MIT License:
3 //
4 // Permission is hereby granted, free of charge, to any person obtaining a copy
5 // of this software and associated documentation files (the "Software"), to deal
6 // in the Software without restriction, including without limitation the rights
7 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 // copies of the Software, and to permit persons to whom the Software is
9 // furnished to do so, subject to the following conditions:
10 //
11 // The above copyright notice and this permission notice shall be included in
12 // all copies or substantial portions of the Software.
13 //
14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 // THE SOFTWARE.
21
22 #pragma once
23
24 #include "common.h"
25
26 KJ_BEGIN_HEADER
27
28 namespace kj {
29
30 namespace _ { // private
31
32 template <uint i, template<uint> class Fail, typename Key, typename... Variants>
33 struct TypeIndex_;
34 template <uint i, template<uint> class Fail, typename Key, typename First, typename... Rest>
35 struct TypeIndex_<i, Fail, Key, First, Rest...> {
36 static constexpr uint value = TypeIndex_<i + 1, Fail, Key, Rest...>::value;
37 };
38 template <uint i, template<uint> class Fail, typename Key, typename... Rest>
39 struct TypeIndex_<i, Fail, Key, Key, Rest...> { static constexpr uint value = i; };
40 template <uint i, template<uint> class Fail, typename Key>
41 struct TypeIndex_<i, Fail, Key>: public Fail<i> {};
42
43 template <uint i>
44 struct OneOfFailError_ {
45 static_assert(i == -1, "type does not match any in OneOf");
46 };
47 template <uint i>
48 struct OneOfFailZero_ {
49 static constexpr int value = 0;
50 };
51
52 template <uint i>
53 struct SuccessIfNotZero {
54 typedef int Success;
55 };
56 template <>
57 struct SuccessIfNotZero<0> {};
58
59 enum class Variants0 {};
60 enum class Variants1 { _variant0 };
61 enum class Variants2 { _variant0, _variant1 };
62 enum class Variants3 { _variant0, _variant1, _variant2 };
63 enum class Variants4 { _variant0, _variant1, _variant2, _variant3 };
64 enum class Variants5 { _variant0, _variant1, _variant2, _variant3, _variant4 };
65 enum class Variants6 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5 };
66 enum class Variants7 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6 };
67 enum class Variants8 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
68 _variant7 };
69 enum class Variants9 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
70 _variant7, _variant8 };
71 enum class Variants10 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
72 _variant7, _variant8, _variant9 };
73 enum class Variants11 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
74 _variant7, _variant8, _variant9, _variant10 };
75 enum class Variants12 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
76 _variant7, _variant8, _variant9, _variant10, _variant11 };
77 enum class Variants13 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
78 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12 };
79 enum class Variants14 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
80 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
81 _variant13 };
82 enum class Variants15 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
83 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
84 _variant13, _variant14 };
85 enum class Variants16 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
86 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
87 _variant13, _variant14, _variant15 };
88 enum class Variants17 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
89 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
90 _variant13, _variant14, _variant15, _variant16 };
91 enum class Variants18 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
92 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
93 _variant13, _variant14, _variant15, _variant16, _variant17 };
94 enum class Variants19 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
95 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
96 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18 };
97 enum class Variants20 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
98 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
99 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
100 _variant19 };
101 enum class Variants21 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
102 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
103 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
104 _variant19, _variant20 };
105 enum class Variants22 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
106 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
107 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
108 _variant19, _variant20, _variant21 };
109 enum class Variants23 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
110 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
111 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
112 _variant19, _variant20, _variant21, _variant22 };
113 enum class Variants24 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
114 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
115 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
116 _variant19, _variant20, _variant21, _variant22, _variant23 };
117 enum class Variants25 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
118 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
119 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
120 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24 };
121 enum class Variants26 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
122 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
123 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
124 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
125 _variant25 };
126 enum class Variants27 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
127 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
128 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
129 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
130 _variant25, _variant26 };
131 enum class Variants28 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
132 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
133 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
134 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
135 _variant25, _variant26, _variant27 };
136 enum class Variants29 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
137 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
138 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
139 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
140 _variant25, _variant26, _variant27, _variant28 };
141 enum class Variants30 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
142 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
143 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
144 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
145 _variant25, _variant26, _variant27, _variant28, _variant29 };
146 enum class Variants31 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
147 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
148 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
149 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
150 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30 };
151 enum class Variants32 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
152 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
153 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
154 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
155 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
156 _variant31 };
157 enum class Variants33 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
158 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
159 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
160 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
161 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
162 _variant31, _variant32 };
163 enum class Variants34 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
164 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
165 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
166 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
167 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
168 _variant31, _variant32, _variant33 };
169 enum class Variants35 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
170 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
171 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
172 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
173 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
174 _variant31, _variant32, _variant33, _variant34 };
175 enum class Variants36 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
176 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
177 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
178 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
179 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
180 _variant31, _variant32, _variant33, _variant34, _variant35 };
181 enum class Variants37 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
182 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
183 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
184 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
185 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
186 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36 };
187 enum class Variants38 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
188 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
189 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
190 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
191 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
192 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
193 _variant37 };
194 enum class Variants39 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
195 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
196 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
197 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
198 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
199 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
200 _variant37, _variant38 };
201 enum class Variants40 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
202 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
203 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
204 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
205 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
206 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
207 _variant37, _variant38, _variant39 };
208 enum class Variants41 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
209 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
210 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
211 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
212 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
213 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
214 _variant37, _variant38, _variant39, _variant40 };
215 enum class Variants42 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
216 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
217 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
218 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
219 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
220 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
221 _variant37, _variant38, _variant39, _variant40, _variant41 };
222 enum class Variants43 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
223 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
224 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
225 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
226 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
227 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
228 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42 };
229 enum class Variants44 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
230 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
231 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
232 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
233 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
234 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
235 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
236 _variant43 };
237 enum class Variants45 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
238 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
239 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
240 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
241 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
242 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
243 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
244 _variant43, _variant44 };
245 enum class Variants46 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
246 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
247 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
248 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
249 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
250 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
251 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
252 _variant43, _variant44, _variant45 };
253 enum class Variants47 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
254 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
255 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
256 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
257 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
258 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
259 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
260 _variant43, _variant44, _variant45, _variant46 };
261 enum class Variants48 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
262 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
263 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
264 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
265 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
266 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
267 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
268 _variant43, _variant44, _variant45, _variant46, _variant47 };
269 enum class Variants49 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
270 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
271 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
272 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
273 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
274 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
275 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
276 _variant43, _variant44, _variant45, _variant46, _variant47, _variant48 };
277 enum class Variants50 { _variant0, _variant1, _variant2, _variant3, _variant4, _variant5, _variant6,
278 _variant7, _variant8, _variant9, _variant10, _variant11, _variant12,
279 _variant13, _variant14, _variant15, _variant16, _variant17, _variant18,
280 _variant19, _variant20, _variant21, _variant22, _variant23, _variant24,
281 _variant25, _variant26, _variant27, _variant28, _variant29, _variant30,
282 _variant31, _variant32, _variant33, _variant34, _variant35, _variant36,
283 _variant37, _variant38, _variant39, _variant40, _variant41, _variant42,
284 _variant43, _variant44, _variant45, _variant46, _variant47, _variant48,
285 _variant49 };
286
287 template <uint i> struct Variants_;
288 template <> struct Variants_<0> { typedef Variants0 Type; };
289 template <> struct Variants_<1> { typedef Variants1 Type; };
290 template <> struct Variants_<2> { typedef Variants2 Type; };
291 template <> struct Variants_<3> { typedef Variants3 Type; };
292 template <> struct Variants_<4> { typedef Variants4 Type; };
293 template <> struct Variants_<5> { typedef Variants5 Type; };
294 template <> struct Variants_<6> { typedef Variants6 Type; };
295 template <> struct Variants_<7> { typedef Variants7 Type; };
296 template <> struct Variants_<8> { typedef Variants8 Type; };
297 template <> struct Variants_<9> { typedef Variants9 Type; };
298 template <> struct Variants_<10> { typedef Variants10 Type; };
299 template <> struct Variants_<11> { typedef Variants11 Type; };
300 template <> struct Variants_<12> { typedef Variants12 Type; };
301 template <> struct Variants_<13> { typedef Variants13 Type; };
302 template <> struct Variants_<14> { typedef Variants14 Type; };
303 template <> struct Variants_<15> { typedef Variants15 Type; };
304 template <> struct Variants_<16> { typedef Variants16 Type; };
305 template <> struct Variants_<17> { typedef Variants17 Type; };
306 template <> struct Variants_<18> { typedef Variants18 Type; };
307 template <> struct Variants_<19> { typedef Variants19 Type; };
308 template <> struct Variants_<20> { typedef Variants20 Type; };
309 template <> struct Variants_<21> { typedef Variants21 Type; };
310 template <> struct Variants_<22> { typedef Variants22 Type; };
311 template <> struct Variants_<23> { typedef Variants23 Type; };
312 template <> struct Variants_<24> { typedef Variants24 Type; };
313 template <> struct Variants_<25> { typedef Variants25 Type; };
314 template <> struct Variants_<26> { typedef Variants26 Type; };
315 template <> struct Variants_<27> { typedef Variants27 Type; };
316 template <> struct Variants_<28> { typedef Variants28 Type; };
317 template <> struct Variants_<29> { typedef Variants29 Type; };
318 template <> struct Variants_<30> { typedef Variants30 Type; };
319 template <> struct Variants_<31> { typedef Variants31 Type; };
320 template <> struct Variants_<32> { typedef Variants32 Type; };
321 template <> struct Variants_<33> { typedef Variants33 Type; };
322 template <> struct Variants_<34> { typedef Variants34 Type; };
323 template <> struct Variants_<35> { typedef Variants35 Type; };
324 template <> struct Variants_<36> { typedef Variants36 Type; };
325 template <> struct Variants_<37> { typedef Variants37 Type; };
326 template <> struct Variants_<38> { typedef Variants38 Type; };
327 template <> struct Variants_<39> { typedef Variants39 Type; };
328 template <> struct Variants_<40> { typedef Variants40 Type; };
329 template <> struct Variants_<41> { typedef Variants41 Type; };
330 template <> struct Variants_<42> { typedef Variants42 Type; };
331 template <> struct Variants_<43> { typedef Variants43 Type; };
332 template <> struct Variants_<44> { typedef Variants44 Type; };
333 template <> struct Variants_<45> { typedef Variants45 Type; };
334 template <> struct Variants_<46> { typedef Variants46 Type; };
335 template <> struct Variants_<47> { typedef Variants47 Type; };
336 template <> struct Variants_<48> { typedef Variants48 Type; };
337 template <> struct Variants_<49> { typedef Variants49 Type; };
338 template <> struct Variants_<50> { typedef Variants50 Type; };
339
340 template <uint i>
341 using Variants = typename Variants_<i>::Type;
342
343 } // namespace _ (private)
344
345 template <typename... Variants>
346 class OneOf {
347 template <typename Key>
348 static inline constexpr uint typeIndex() {
349 return _::TypeIndex_<1, _::OneOfFailError_, Key, Variants...>::value;
350 }
351 // Get the 1-based index of Key within the type list Types, or static_assert with a nice error.
352
353 template <typename Key>
354 static inline constexpr uint typeIndexOrZero() {
355 return _::TypeIndex_<1, _::OneOfFailZero_, Key, Variants...>::value;
356 }
357
358 template <uint i, typename... OtherVariants>
359 struct HasAll;
360 // Has a member type called "Success" if and only if all of `OtherVariants` are types that
361 // appear in `Variants`. Used with SFINAE to enable subset constructors.
362
363 public:
364 inline OneOf(): tag(0) {}
365
366 OneOf(const OneOf& other) { copyFrom(other); }
367 OneOf(OneOf& other) { copyFrom(other); }
368 OneOf(OneOf&& other) { moveFrom(other); }
369 // Copy/move from same OneOf type.
370
371 template <typename... OtherVariants, typename = typename HasAll<1, OtherVariants...>::Success>
372 OneOf(const OneOf<OtherVariants...>& other) { copyFromSubset(other); }
373 template <typename... OtherVariants, typename = typename HasAll<1, OtherVariants...>::Success>
374 OneOf(OneOf<OtherVariants...>& other) { copyFromSubset(other); }
375 template <typename... OtherVariants, typename = typename HasAll<1, OtherVariants...>::Success>
376 OneOf(OneOf<OtherVariants...>&& other) { moveFromSubset(other); }
377 // Copy/move from OneOf that contains a subset of the types we do.
378
379 template <typename T, typename = typename HasAll<0, Decay<T>>::Success>
380 OneOf(T&& other): tag(typeIndex<Decay<T>>()) {
381 ctor(*reinterpret_cast<Decay<T>*>(space), kj::fwd<T>(other));
382 }
383 // Copy/move from a value that matches one of the individual types in the OneOf.
384
385 ~OneOf() { destroy(); }
386
387 OneOf& operator=(const OneOf& other) { if (tag != 0) destroy(); copyFrom(other); return *this; }
388 OneOf& operator=(OneOf&& other) { if (tag != 0) destroy(); moveFrom(other); return *this; }
389
390 inline bool operator==(decltype(nullptr)) const { return tag == 0; }
391 inline bool operator!=(decltype(nullptr)) const { return tag != 0; }
392
393 template <typename T>
394 bool is() const {
395 return tag == typeIndex<T>();
396 }
397
398 template <typename T>
399 T& get() & {
400 KJ_IREQUIRE(is<T>(), "Must check OneOf::is<T>() before calling get<T>().");
401 return *reinterpret_cast<T*>(space);
402 }
403 template <typename T>
404 T&& get() && {
405 KJ_IREQUIRE(is<T>(), "Must check OneOf::is<T>() before calling get<T>().");
406 return kj::mv(*reinterpret_cast<T*>(space));
407 }
408 template <typename T>
409 const T& get() const& {
410 KJ_IREQUIRE(is<T>(), "Must check OneOf::is<T>() before calling get<T>().");
411 return *reinterpret_cast<const T*>(space);
412 }
413 template <typename T>
414 const T&& get() const&& {
415 KJ_IREQUIRE(is<T>(), "Must check OneOf::is<T>() before calling get<T>().");
416 return kj::mv(*reinterpret_cast<const T*>(space));
417 }
418
419 template <typename T, typename... Params>
420 T& init(Params&&... params) {
421 if (tag != 0) destroy();
422 ctor(*reinterpret_cast<T*>(space), kj::fwd<Params>(params)...);
423 tag = typeIndex<T>();
424 return *reinterpret_cast<T*>(space);
425 }
426
427 template <typename T>
428 Maybe<T&> tryGet() {
429 if (is<T>()) {
430 return *reinterpret_cast<T*>(space);
431 } else {
432 return nullptr;
433 }
434 }
435 template <typename T>
436 Maybe<const T&> tryGet() const {
437 if (is<T>()) {
438 return *reinterpret_cast<const T*>(space);
439 } else {
440 return nullptr;
441 }
442 }
443
444 template <uint i>
445 KJ_NORETURN(void allHandled());
446 // After a series of if/else blocks handling each variant of the OneOf, have the final else
447 // block call allHandled<n>() where n is the number of variants. This will fail to compile
448 // if new variants are added in the future.
449
450 typedef _::Variants<sizeof...(Variants)> Tag;
451
452 Tag which() const {
453 KJ_IREQUIRE(tag != 0, "Can't KJ_SWITCH_ONEOF() on uninitialized value.");
454 return static_cast<Tag>(tag - 1);
455 }
456
457 template <typename T>
458 static constexpr Tag tagFor() {
459 return static_cast<Tag>(typeIndex<T>() - 1);
460 }
461
462 OneOf* _switchSubject() & { return this; }
463 const OneOf* _switchSubject() const& { return this; }
464 _::NullableValue<OneOf> _switchSubject() && { return kj::mv(*this); }
465
466 private:
467 uint tag;
468
469 static inline constexpr size_t maxSize(size_t a) {
470 return a;
471 }
472 template <typename... Rest>
473 static inline constexpr size_t maxSize(size_t a, size_t b, Rest... rest) {
474 return maxSize(kj::max(a, b), rest...);
475 }
476 // Returns the maximum of all the parameters.
477 // TODO(someday): Generalize the above template and make it common. I tried, but C++ decided to
478 // be difficult so I cut my losses.
479
480 static constexpr auto spaceSize = maxSize(sizeof(Variants)...);
481 // TODO(msvc): This constant could just as well go directly inside space's bracket's, where it's
482 // used, but MSVC suffers a parse error on `...`.
483
484 union {
485 byte space[spaceSize];
486
487 void* forceAligned;
488 // TODO(someday): Use C++11 alignas() once we require GCC 4.8 / Clang 3.3.
489 };
490
491 template <typename... T>
492 inline void doAll(T... t) {}
493
494 template <typename T>
495 inline bool destroyVariant() {
496 if (tag == typeIndex<T>()) {
497 tag = 0;
498 dtor(*reinterpret_cast<T*>(space));
499 }
500 return false;
501 }
502 void destroy() {
503 doAll(destroyVariant<Variants>()...);
504 }
505
506 template <typename T>
507 inline bool copyVariantFrom(const OneOf& other) {
508 if (other.is<T>()) {
509 ctor(*reinterpret_cast<T*>(space), other.get<T>());
510 }
511 return false;
512 }
513 void copyFrom(const OneOf& other) {
514 // Initialize as a copy of `other`. Expects that `this` starts out uninitialized, so the tag
515 // is invalid.
516 tag = other.tag;
517 doAll(copyVariantFrom<Variants>(other)...);
518 }
519
520 template <typename T>
521 inline bool copyVariantFrom(OneOf& other) {
522 if (other.is<T>()) {
523 ctor(*reinterpret_cast<T*>(space), other.get<T>());
524 }
525 return false;
526 }
527 void copyFrom(OneOf& other) {
528 // Initialize as a copy of `other`. Expects that `this` starts out uninitialized, so the tag
529 // is invalid.
530 tag = other.tag;
531 doAll(copyVariantFrom<Variants>(other)...);
532 }
533
534 template <typename T>
535 inline bool moveVariantFrom(OneOf& other) {
536 if (other.is<T>()) {
537 ctor(*reinterpret_cast<T*>(space), kj::mv(other.get<T>()));
538 }
539 return false;
540 }
541 void moveFrom(OneOf& other) {
542 // Initialize as a copy of `other`. Expects that `this` starts out uninitialized, so the tag
543 // is invalid.
544 tag = other.tag;
545 doAll(moveVariantFrom<Variants>(other)...);
546 }
547
548 template <typename T, typename... OtherVariants>
549 inline bool copySubsetVariantFrom(const OneOf<OtherVariants...>& other) {
550 if (other.template is<T>()) {
551 tag = typeIndex<Decay<T>>();
552 ctor(*reinterpret_cast<T*>(space), other.template get<T>());
553 }
554 return false;
555 }
556 template <typename... OtherVariants>
557 void copyFromSubset(const OneOf<OtherVariants...>& other) {
558 doAll(copySubsetVariantFrom<OtherVariants>(other)...);
559 }
560
561 template <typename T, typename... OtherVariants>
562 inline bool copySubsetVariantFrom(OneOf<OtherVariants...>& other) {
563 if (other.template is<T>()) {
564 tag = typeIndex<Decay<T>>();
565 ctor(*reinterpret_cast<T*>(space), other.template get<T>());
566 }
567 return false;
568 }
569 template <typename... OtherVariants>
570 void copyFromSubset(OneOf<OtherVariants...>& other) {
571 doAll(copySubsetVariantFrom<OtherVariants>(other)...);
572 }
573
574 template <typename T, typename... OtherVariants>
575 inline bool moveSubsetVariantFrom(OneOf<OtherVariants...>& other) {
576 if (other.template is<T>()) {
577 tag = typeIndex<Decay<T>>();
578 ctor(*reinterpret_cast<T*>(space), kj::mv(other.template get<T>()));
579 }
580 return false;
581 }
582 template <typename... OtherVariants>
583 void moveFromSubset(OneOf<OtherVariants...>& other) {
584 doAll(moveSubsetVariantFrom<OtherVariants>(other)...);
585 }
586 };
587
588 template <typename... Variants>
589 template <uint i, typename First, typename... Rest>
590 struct OneOf<Variants...>::HasAll<i, First, Rest...>
591 : public HasAll<typeIndexOrZero<First>(), Rest...> {};
592 template <typename... Variants>
593 template <uint i>
594 struct OneOf<Variants...>::HasAll<i>: public _::SuccessIfNotZero<i> {};
595
596 template <typename... Variants>
597 template <uint i>
598 void OneOf<Variants...>::allHandled() {
599 // After a series of if/else blocks handling each variant of the OneOf, have the final else
600 // block call allHandled<n>() where n is the number of variants. This will fail to compile
601 // if new variants are added in the future.
602
603 static_assert(i == sizeof...(Variants), "new OneOf variants need to be handled here");
604 KJ_UNREACHABLE;
605 }
606
607 #if KJ_CPP_STD > 201402L
608 #define KJ_SWITCH_ONEOF(value) \
609 switch (auto _kj_switch_subject = (value)._switchSubject(); _kj_switch_subject->which())
610 #else
611 #define KJ_SWITCH_ONEOF(value) \
612 /* Without C++17, we can only support one switch per containing block. Deal with it. */ \
613 auto _kj_switch_subject = (value)._switchSubject(); \
614 switch (_kj_switch_subject->which())
615 #endif
616 #if !_MSC_VER || defined(__clang__)
617 #define KJ_CASE_ONEOF(name, ...) \
618 break; \
619 case ::kj::Decay<decltype(*_kj_switch_subject)>::template tagFor<__VA_ARGS__>(): \
620 for (auto& name = _kj_switch_subject->template get<__VA_ARGS__>(), *_kj_switch_done = &name; \
621 _kj_switch_done; _kj_switch_done = nullptr)
622 #else
623 // TODO(msvc): The latest MSVC which ships with VS2019 now ICEs on the implementation above. It
624 // appears we can hack around the problem by moving the `->template get<>()` syntax to an outer
625 // `if`. (This unfortunately allows wonky syntax like `KJ_CASE_ONEOF(a, B) { } else { }`.)
626 // https://developercommunity.visualstudio.com/content/problem/1143733/internal-compiler-error-on-v1670.html
627 #define KJ_CASE_ONEOF(name, ...) \
628 break; \
629 case ::kj::Decay<decltype(*_kj_switch_subject)>::template tagFor<__VA_ARGS__>(): \
630 if (auto* _kj_switch_done = &_kj_switch_subject->template get<__VA_ARGS__>()) \
631 for (auto& name = *_kj_switch_done; _kj_switch_done; _kj_switch_done = nullptr)
632 #endif
633 #define KJ_CASE_ONEOF_DEFAULT break; default:
634 // Allows switching over a OneOf.
635 //
636 // Example:
637 //
638 // kj::OneOf<int, float, const char*> variant;
639 // KJ_SWITCH_ONEOF(variant) {
640 // KJ_CASE_ONEOF(i, int) {
641 // doSomethingWithInt(i);
642 // }
643 // KJ_CASE_ONEOF(s, const char*) {
644 // doSomethingWithString(s);
645 // }
646 // KJ_CASE_ONEOF_DEFAULT {
647 // doSomethingElse();
648 // }
649 // }
650 //
651 // Notes:
652 // - If you don't handle all possible types and don't include a default branch, you'll get a
653 // compiler warning, just like a regular switch() over an enum where one of the enum values is
654 // missing.
655 // - There's no need for a `break` statement in a KJ_CASE_ONEOF; it is implied.
656 // - Under C++11 and C++14, only one KJ_SWITCH_ONEOF() can appear in a block. Wrap the switch in
657 // a pair of braces if you need a second switch in the same block. If C++17 is enabled, this is
658 // not an issue.
659 //
660 // Implementation notes:
661 // - The use of __VA_ARGS__ is to account for template types that have commas separating type
662 // parameters, since macros don't recognize <> as grouping.
663 // - _kj_switch_done is really used as a boolean flag to prevent the for() loop from actually
664 // looping, but it's defined as a pointer since that's all we can define in this context.
665
666 } // namespace kj
667
668 KJ_END_HEADER