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Run DCE after a LoopFlatten test to reduce spurious output [nfc]
[llvm-project.git] / libcxx / include / __functional / hash.h
blob87307f7f9934493f582aba8c826119f6fb698e95
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef _LIBCPP___FUNCTIONAL_HASH_H
10 #define _LIBCPP___FUNCTIONAL_HASH_H
11
12 #include <__config>
13 #include <__functional/invoke.h>
14 #include <__functional/unary_function.h>
15 #include <__fwd/hash.h>
16 #include <__tuple/sfinae_helpers.h>
17 #include <__type_traits/is_copy_constructible.h>
18 #include <__type_traits/is_default_constructible.h>
19 #include <__type_traits/is_enum.h>
20 #include <__type_traits/is_move_constructible.h>
21 #include <__type_traits/underlying_type.h>
22 #include <__utility/forward.h>
23 #include <__utility/move.h>
24 #include <__utility/pair.h>
25 #include <__utility/swap.h>
26 #include <cstddef>
27 #include <cstdint>
28 #include <cstring>
29 #include <limits>
30
31 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
32 # pragma GCC system_header
33 #endif
34
35 _LIBCPP_BEGIN_NAMESPACE_STD
36
37 template <class _Size>
38 inline _LIBCPP_HIDE_FROM_ABI
39 _Size
40 __loadword(const void* __p)
41 {
42 _Size __r;
43 _VSTD::memcpy(&__r, __p, sizeof(__r));
44 return __r;
45 }
46
47 // We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
48 // is 64 bits. This is because cityhash64 uses 64bit x 64bit
49 // multiplication, which can be very slow on 32-bit systems.
50 template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
51 struct __murmur2_or_cityhash;
52
53 template <class _Size>
54 struct __murmur2_or_cityhash<_Size, 32>
55 {
56 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
57 _Size operator()(const void* __key, _Size __len) const {
58 // murmur2
59 const _Size __m = 0x5bd1e995;
60 const _Size __r = 24;
61 _Size __h = __len;
62 const unsigned char* __data = static_cast<const unsigned char*>(__key);
63 for (; __len >= 4; __data += 4, __len -= 4)
64 {
65 _Size __k = std::__loadword<_Size>(__data);
66 __k *= __m;
67 __k ^= __k >> __r;
68 __k *= __m;
69 __h *= __m;
70 __h ^= __k;
71 }
72 switch (__len)
73 {
74 case 3:
75 __h ^= static_cast<_Size>(__data[2] << 16);
76 _LIBCPP_FALLTHROUGH();
77 case 2:
78 __h ^= static_cast<_Size>(__data[1] << 8);
79 _LIBCPP_FALLTHROUGH();
80 case 1:
81 __h ^= __data[0];
82 __h *= __m;
83 }
84 __h ^= __h >> 13;
85 __h *= __m;
86 __h ^= __h >> 15;
87 return __h;
88 }
89 };
90
91 template <class _Size>
92 struct __murmur2_or_cityhash<_Size, 64>
93 {
94 // cityhash64
95 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
96 _Size operator()(const void* __key, _Size __len) const {
97 const char* __s = static_cast<const char*>(__key);
98 if (__len <= 32) {
99 if (__len <= 16) {
100 return __hash_len_0_to_16(__s, __len);
101 } else {
102 return __hash_len_17_to_32(__s, __len);
103 }
104 } else if (__len <= 64) {
105 return __hash_len_33_to_64(__s, __len);
106 }
107
108 // For strings over 64 bytes we hash the end first, and then as we
109 // loop we keep 56 bytes of state: v, w, x, y, and z.
110 _Size __x = std::__loadword<_Size>(__s + __len - 40);
111 _Size __y = std::__loadword<_Size>(__s + __len - 16) +
112 std::__loadword<_Size>(__s + __len - 56);
113 _Size __z = __hash_len_16(std::__loadword<_Size>(__s + __len - 48) + __len,
114 std::__loadword<_Size>(__s + __len - 24));
115 pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
116 pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
117 __x = __x * __k1 + std::__loadword<_Size>(__s);
118
119 // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
120 __len = (__len - 1) & ~static_cast<_Size>(63);
121 do {
122 __x = __rotate(__x + __y + __v.first + std::__loadword<_Size>(__s + 8), 37) * __k1;
123 __y = __rotate(__y + __v.second + std::__loadword<_Size>(__s + 48), 42) * __k1;
124 __x ^= __w.second;
125 __y += __v.first + std::__loadword<_Size>(__s + 40);
126 __z = __rotate(__z + __w.first, 33) * __k1;
127 __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
128 __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
129 __y + std::__loadword<_Size>(__s + 16));
130 _VSTD::swap(__z, __x);
131 __s += 64;
132 __len -= 64;
133 } while (__len != 0);
134 return __hash_len_16(
135 __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
136 __hash_len_16(__v.second, __w.second) + __x);
137 }
138
139 private:
140 // Some primes between 2^63 and 2^64.
141 static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
142 static const _Size __k1 = 0xb492b66fbe98f273ULL;
143 static const _Size __k2 = 0x9ae16a3b2f90404fULL;
144 static const _Size __k3 = 0xc949d7c7509e6557ULL;
145
146 _LIBCPP_HIDE_FROM_ABI
147 static _Size __rotate(_Size __val, int __shift) {
148 return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
149 }
150
151 _LIBCPP_HIDE_FROM_ABI
152 static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
153 return (__val >> __shift) | (__val << (64 - __shift));
154 }
155
156 _LIBCPP_HIDE_FROM_ABI
157 static _Size __shift_mix(_Size __val) {
158 return __val ^ (__val >> 47);
159 }
160
161 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
162 static _Size __hash_len_16(_Size __u, _Size __v) {
163 const _Size __mul = 0x9ddfea08eb382d69ULL;
164 _Size __a = (__u ^ __v) * __mul;
165 __a ^= (__a >> 47);
166 _Size __b = (__v ^ __a) * __mul;
167 __b ^= (__b >> 47);
168 __b *= __mul;
169 return __b;
170 }
171
172 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
173 static _Size __hash_len_0_to_16(const char* __s, _Size __len) {
174 if (__len > 8) {
175 const _Size __a = std::__loadword<_Size>(__s);
176 const _Size __b = std::__loadword<_Size>(__s + __len - 8);
177 return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
178 }
179 if (__len >= 4) {
180 const uint32_t __a = std::__loadword<uint32_t>(__s);
181 const uint32_t __b = std::__loadword<uint32_t>(__s + __len - 4);
182 #ifdef _LIBCPP_ABI_FIX_CITYHASH_IMPLEMENTATION
183 return __hash_len_16(__len + (static_cast<_Size>(__a) << 3), __b);
184 #else
185 return __hash_len_16(__len + (__a << 3), __b);
186 #endif
187 }
188 if (__len > 0) {
189 const unsigned char __a = static_cast<unsigned char>(__s[0]);
190 const unsigned char __b = static_cast<unsigned char>(__s[__len >> 1]);
191 const unsigned char __c = static_cast<unsigned char>(__s[__len - 1]);
192 const uint32_t __y = static_cast<uint32_t>(__a) +
193 (static_cast<uint32_t>(__b) << 8);
194 const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
195 return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
196 }
197 return __k2;
198 }
199
200 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
201 static _Size __hash_len_17_to_32(const char *__s, _Size __len) {
202 const _Size __a = std::__loadword<_Size>(__s) * __k1;
203 const _Size __b = std::__loadword<_Size>(__s + 8);
204 const _Size __c = std::__loadword<_Size>(__s + __len - 8) * __k2;
205 const _Size __d = std::__loadword<_Size>(__s + __len - 16) * __k0;
206 return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
207 __a + __rotate(__b ^ __k3, 20) - __c + __len);
208 }
209
210 // Return a 16-byte hash for 48 bytes. Quick and dirty.
211 // Callers do best to use "random-looking" values for a and b.
212 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
213 static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
214 _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
215 {
216 __a += __w;
217 __b = __rotate(__b + __a + __z, 21);
218 const _Size __c = __a;
219 __a += __x;
220 __a += __y;
221 __b += __rotate(__a, 44);
222 return pair<_Size, _Size>(__a + __z, __b + __c);
223 }
224
225 // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.
226 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
227 static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
228 const char* __s, _Size __a, _Size __b)
229 {
230 return __weak_hash_len_32_with_seeds(std::__loadword<_Size>(__s),
231 std::__loadword<_Size>(__s + 8),
232 std::__loadword<_Size>(__s + 16),
233 std::__loadword<_Size>(__s + 24),
234 __a,
235 __b);
236 }
237
238 // Return an 8-byte hash for 33 to 64 bytes.
239 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
240 static _Size __hash_len_33_to_64(const char *__s, size_t __len) {
241 _Size __z = std::__loadword<_Size>(__s + 24);
242 _Size __a = std::__loadword<_Size>(__s) +
243 (__len + std::__loadword<_Size>(__s + __len - 16)) * __k0;
244 _Size __b = __rotate(__a + __z, 52);
245 _Size __c = __rotate(__a, 37);
246 __a += std::__loadword<_Size>(__s + 8);
247 __c += __rotate(__a, 7);
248 __a += std::__loadword<_Size>(__s + 16);
249 _Size __vf = __a + __z;
250 _Size __vs = __b + __rotate(__a, 31) + __c;
251 __a = std::__loadword<_Size>(__s + 16) + std::__loadword<_Size>(__s + __len - 32);
252 __z += std::__loadword<_Size>(__s + __len - 8);
253 __b = __rotate(__a + __z, 52);
254 __c = __rotate(__a, 37);
255 __a += std::__loadword<_Size>(__s + __len - 24);
256 __c += __rotate(__a, 7);
257 __a += std::__loadword<_Size>(__s + __len - 16);
258 _Size __wf = __a + __z;
259 _Size __ws = __b + __rotate(__a, 31) + __c;
260 _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
261 return __shift_mix(__r * __k0 + __vs) * __k2;
262 }
263 };
264
265 template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
266 struct __scalar_hash;
267
268 template <class _Tp>
269 struct __scalar_hash<_Tp, 0>
270 : public __unary_function<_Tp, size_t>
271 {
272 _LIBCPP_HIDE_FROM_ABI
273 size_t operator()(_Tp __v) const _NOEXCEPT
274 {
275 union
276 {
277 _Tp __t;
278 size_t __a;
279 } __u;
280 __u.__a = 0;
281 __u.__t = __v;
282 return __u.__a;
283 }
284 };
285
286 template <class _Tp>
287 struct __scalar_hash<_Tp, 1>
288 : public __unary_function<_Tp, size_t>
289 {
290 _LIBCPP_HIDE_FROM_ABI
291 size_t operator()(_Tp __v) const _NOEXCEPT
292 {
293 union
294 {
295 _Tp __t;
296 size_t __a;
297 } __u;
298 __u.__t = __v;
299 return __u.__a;
300 }
301 };
302
303 template <class _Tp>
304 struct __scalar_hash<_Tp, 2>
305 : public __unary_function<_Tp, size_t>
306 {
307 _LIBCPP_HIDE_FROM_ABI
308 size_t operator()(_Tp __v) const _NOEXCEPT
309 {
310 union
311 {
312 _Tp __t;
313 struct
314 {
315 size_t __a;
316 size_t __b;
317 } __s;
318 } __u;
319 __u.__t = __v;
320 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
321 }
322 };
323
324 template <class _Tp>
325 struct __scalar_hash<_Tp, 3>
326 : public __unary_function<_Tp, size_t>
327 {
328 _LIBCPP_HIDE_FROM_ABI
329 size_t operator()(_Tp __v) const _NOEXCEPT
330 {
331 union
332 {
333 _Tp __t;
334 struct
335 {
336 size_t __a;
337 size_t __b;
338 size_t __c;
339 } __s;
340 } __u;
341 __u.__t = __v;
342 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
343 }
344 };
345
346 template <class _Tp>
347 struct __scalar_hash<_Tp, 4>
348 : public __unary_function<_Tp, size_t>
349 {
350 _LIBCPP_HIDE_FROM_ABI
351 size_t operator()(_Tp __v) const _NOEXCEPT
352 {
353 union
354 {
355 _Tp __t;
356 struct
357 {
358 size_t __a;
359 size_t __b;
360 size_t __c;
361 size_t __d;
362 } __s;
363 } __u;
364 __u.__t = __v;
365 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
366 }
367 };
368
369 struct _PairT {
370 size_t first;
371 size_t second;
372 };
373
374 _LIBCPP_HIDE_FROM_ABI
375 inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
376 typedef __scalar_hash<_PairT> _HashT;
377 const _PairT __p = {__lhs, __rhs};
378 return _HashT()(__p);
379 }
380
381 template<class _Tp>
382 struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
383 : public __unary_function<_Tp*, size_t>
384 {
385 _LIBCPP_HIDE_FROM_ABI
386 size_t operator()(_Tp* __v) const _NOEXCEPT
387 {
388 union
389 {
390 _Tp* __t;
391 size_t __a;
392 } __u;
393 __u.__t = __v;
394 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
395 }
396 };
397
398 template <>
399 struct _LIBCPP_TEMPLATE_VIS hash<bool>
400 : public __unary_function<bool, size_t>
401 {
402 _LIBCPP_HIDE_FROM_ABI
403 size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
404 };
405
406 template <>
407 struct _LIBCPP_TEMPLATE_VIS hash<char>
408 : public __unary_function<char, size_t>
409 {
410 _LIBCPP_HIDE_FROM_ABI
411 size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
412 };
413
414 template <>
415 struct _LIBCPP_TEMPLATE_VIS hash<signed char>
416 : public __unary_function<signed char, size_t>
417 {
418 _LIBCPP_HIDE_FROM_ABI
419 size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
420 };
421
422 template <>
423 struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
424 : public __unary_function<unsigned char, size_t>
425 {
426 _LIBCPP_HIDE_FROM_ABI
427 size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
428 };
429
430 #ifndef _LIBCPP_HAS_NO_CHAR8_T
431 template <>
432 struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
433 : public __unary_function<char8_t, size_t>
434 {
435 _LIBCPP_HIDE_FROM_ABI
436 size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
437 };
438 #endif // !_LIBCPP_HAS_NO_CHAR8_T
439
440 template <>
441 struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
442 : public __unary_function<char16_t, size_t>
443 {
444 _LIBCPP_HIDE_FROM_ABI
445 size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
446 };
447
448 template <>
449 struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
450 : public __unary_function<char32_t, size_t>
451 {
452 _LIBCPP_HIDE_FROM_ABI
453 size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
454 };
455
456 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
457 template <>
458 struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
459 : public __unary_function<wchar_t, size_t>
460 {
461 _LIBCPP_HIDE_FROM_ABI
462 size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
463 };
464 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
465
466 template <>
467 struct _LIBCPP_TEMPLATE_VIS hash<short>
468 : public __unary_function<short, size_t>
469 {
470 _LIBCPP_HIDE_FROM_ABI
471 size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
472 };
473
474 template <>
475 struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
476 : public __unary_function<unsigned short, size_t>
477 {
478 _LIBCPP_HIDE_FROM_ABI
479 size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
480 };
481
482 template <>
483 struct _LIBCPP_TEMPLATE_VIS hash<int>
484 : public __unary_function<int, size_t>
485 {
486 _LIBCPP_HIDE_FROM_ABI
487 size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
488 };
489
490 template <>
491 struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
492 : public __unary_function<unsigned int, size_t>
493 {
494 _LIBCPP_HIDE_FROM_ABI
495 size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
496 };
497
498 template <>
499 struct _LIBCPP_TEMPLATE_VIS hash<long>
500 : public __unary_function<long, size_t>
501 {
502 _LIBCPP_HIDE_FROM_ABI
503 size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
504 };
505
506 template <>
507 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
508 : public __unary_function<unsigned long, size_t>
509 {
510 _LIBCPP_HIDE_FROM_ABI
511 size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
512 };
513
514 template <>
515 struct _LIBCPP_TEMPLATE_VIS hash<long long>
516 : public __scalar_hash<long long>
517 {
518 };
519
520 template <>
521 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
522 : public __scalar_hash<unsigned long long>
523 {
524 };
525
526 #ifndef _LIBCPP_HAS_NO_INT128
527
528 template <>
529 struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
530 : public __scalar_hash<__int128_t>
531 {
532 };
533
534 template <>
535 struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
536 : public __scalar_hash<__uint128_t>
537 {
538 };
539
540 #endif
541
542 template <>
543 struct _LIBCPP_TEMPLATE_VIS hash<float>
544 : public __scalar_hash<float>
545 {
546 _LIBCPP_HIDE_FROM_ABI
547 size_t operator()(float __v) const _NOEXCEPT
548 {
549 // -0.0 and 0.0 should return same hash
550 if (__v == 0.0f)
551 return 0;
552 return __scalar_hash<float>::operator()(__v);
553 }
554 };
555
556 template <>
557 struct _LIBCPP_TEMPLATE_VIS hash<double>
558 : public __scalar_hash<double>
559 {
560 _LIBCPP_HIDE_FROM_ABI
561 size_t operator()(double __v) const _NOEXCEPT
562 {
563 // -0.0 and 0.0 should return same hash
564 if (__v == 0.0)
565 return 0;
566 return __scalar_hash<double>::operator()(__v);
567 }
568 };
569
570 template <>
571 struct _LIBCPP_TEMPLATE_VIS hash<long double>
572 : public __scalar_hash<long double>
573 {
574 _LIBCPP_HIDE_FROM_ABI
575 size_t operator()(long double __v) const _NOEXCEPT
576 {
577 // -0.0 and 0.0 should return same hash
578 if (__v == 0.0L)
579 return 0;
580 #if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
581 // Zero out padding bits
582 union
583 {
584 long double __t;
585 struct
586 {
587 size_t __a;
588 size_t __b;
589 size_t __c;
590 size_t __d;
591 } __s;
592 } __u;
593 __u.__s.__a = 0;
594 __u.__s.__b = 0;
595 __u.__s.__c = 0;
596 __u.__s.__d = 0;
597 __u.__t = __v;
598 return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
599 #elif defined(__x86_64__)
600 // Zero out padding bits
601 union
602 {
603 long double __t;
604 struct
605 {
606 size_t __a;
607 size_t __b;
608 } __s;
609 } __u;
610 __u.__s.__a = 0;
611 __u.__s.__b = 0;
612 __u.__t = __v;
613 return __u.__s.__a ^ __u.__s.__b;
614 #else
615 return __scalar_hash<long double>::operator()(__v);
616 #endif
617 }
618 };
619
620 template <class _Tp, bool = is_enum<_Tp>::value>
621 struct _LIBCPP_TEMPLATE_VIS __enum_hash
622 : public __unary_function<_Tp, size_t>
623 {
624 _LIBCPP_HIDE_FROM_ABI
625 size_t operator()(_Tp __v) const _NOEXCEPT
626 {
627 typedef typename underlying_type<_Tp>::type type;
628 return hash<type>()(static_cast<type>(__v));
629 }
630 };
631 template <class _Tp>
632 struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
633 __enum_hash() = delete;
634 __enum_hash(__enum_hash const&) = delete;
635 __enum_hash& operator=(__enum_hash const&) = delete;
636 };
637
638 template <class _Tp>
639 struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
640 {
641 };
642
643 #if _LIBCPP_STD_VER >= 17
644
645 template <>
646 struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
647 : public __unary_function<nullptr_t, size_t>
648 {
649 _LIBCPP_HIDE_FROM_ABI
650 size_t operator()(nullptr_t) const _NOEXCEPT {
651 return 662607004ull;
652 }
653 };
654 #endif
655
656 #ifndef _LIBCPP_CXX03_LANG
657 template <class _Key, class _Hash>
658 using __check_hash_requirements _LIBCPP_NODEBUG = integral_constant<bool,
659 is_copy_constructible<_Hash>::value &&
660 is_move_constructible<_Hash>::value &&
661 __invokable_r<size_t, _Hash, _Key const&>::value
662 >;
663
664 template <class _Key, class _Hash = hash<_Key> >
665 using __has_enabled_hash _LIBCPP_NODEBUG = integral_constant<bool,
666 __check_hash_requirements<_Key, _Hash>::value &&
667 is_default_constructible<_Hash>::value
668 >;
669
670 #if _LIBCPP_STD_VER >= 17
671 template <class _Type, class>
672 using __enable_hash_helper_imp _LIBCPP_NODEBUG = _Type;
673
674 template <class _Type, class ..._Keys>
675 using __enable_hash_helper _LIBCPP_NODEBUG = __enable_hash_helper_imp<_Type,
676 __enable_if_t<__all<__has_enabled_hash<_Keys>::value...>::value>
677 >;
678 #else
679 template <class _Type, class ...>
680 using __enable_hash_helper _LIBCPP_NODEBUG = _Type;
681 #endif
682
683 #endif // !_LIBCPP_CXX03_LANG
684
685 _LIBCPP_END_NAMESPACE_STD
686
687 #endif // _LIBCPP___FUNCTIONAL_HASH_H
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